Turbine dosing system with bypass delivery

Abstract

A turbine for a turbocharger is provided that includes a turbine inlet passage configured to receive exhaust gas from an internal combustion engine, the exhaust gas received by the turbine inlet passage defining a turbine body flow; a turbine wheel chamber configured to receive a turbine body flow from the turbine inlet passage, the turbine wheel chamber configured to receive a turbine wheel, the turbine wheel supported for rotation about a turbine axis; a turbine outlet passage configured to receive a turbine body flow from the turbine wheel chamber; a dosing module configured to deliver a spray of the post-treatment fluid into a spray region of the turbine outlet passage through which the turbine body flows; and an auxiliary channel configured to receive a portion of the turbine body flow, the portion of the turbine body flow received by the auxiliary channel defining an auxiliary flow; wherein the auxiliary passage is configured to direct an auxiliary flow into a spray region of the turbine outlet passage.

Description

Background Art

[0001] Turbochargers are used in internal combustion engine systems to increase the pressure of intake air entering the engine to a pressure above atmospheric pressure. This is called "boosting." By increasing the pressure of intake air entering the engine, more oxygen is available in the engine to support the combustion of a greater amount of fuel and thereby increase the amount of power produced by the engine.

[0002] A turbocharger includes a compressor and a turbine. The compressor includes a compressor impeller configured to impart energy to an incident fluid flow, and the turbine includes a turbine impeller configured to extract energy from the incident fluid flow. The compressor impeller and the turbine impeller are attached to opposite ends of the turbocharger shaft so that the two rotate synchronously. The compressor receives intake air from the atmosphere and delivers the intake air to the intake manifold of the internal combustion engine. The turbine receives exhaust gas from the exhaust manifold of the internal combustion engine and delivers the exhaust gas to the aftertreatment system. During use, the exhaust gas leaving the internal combustion engine travels through the turbine, causing the turbine impeller to rotate. The rotation of the turbine impeller drives the compressor impeller, which is used to compress the intake air as it is delivered to the intake manifold.

[0003] The exhaust gas from an internal combustion engine contains substances that are harmful to the environment. Most countries have vehicle emission standards that limit the amount of such substances that an internal combustion engine system is allowed to emit. Therefore, modern internal combustion engine systems include an exhaust aftertreatment system designed to remove harmful substances from the exhaust gas.

[0004] Typically, the exhaust aftertreatment system will include a particulate filter and one or more catalytic reducers. The particulate filter removes heavy combustion products, such as soot, from the exhaust. The catalytic reducer removes harmful substances such as nitrogen oxides (NOx) from the exhaust. The catalytic reducer usually includes a large number of narrow passages, which are made of materials selected to support the chemical reaction of removing NOx from the exhaust. The narrow passage provides a large surface area for the occurrence of the catalytic reaction. There are several types of catalytic reducers on the market, such as two-way catalytic reducers, three-way catalytic reducers, diesel oxidation catalytic reducers (diesel oxidation catalytic reducer, DOC) and selective catalytic reducers (selectivecatalytic reducer, SCR). DOC and SCR are typically used in diesel engine systems. Specifically, for SCR, in order for the SCR reaction to work, the exhaust aftertreatment fluid must be mixed with the exhaust before the exhaust enters the catalytic reducer. The exhaust aftertreatment fluid is usually a mixture of about 30% to 35% urea (CO (NH2) 2) by volume and about 65% to 70% deionized water (H2O) by volume. Exhaust aftertreatment fluids are often referred to as Diesel Exhaust Fluid (DEF) and are commonly available under the registered trademark AdBlue.

[0005] Conventionally, DEF is mixed with the exhaust gas in a decomposition chamber. DEF is injected into the decomposition chamber using a dosing module. In the decomposition chamber, heat is exchanged from the exhaust gas to the DEF, which causes the water in the DEF to evaporate and the urea to thermally decompose into the reducing agent ammonia (NH4) required to support the SCR reaction. 3 ) and isocyanic acid (HNCO).

[0006] A typical decomposition chamber includes a relatively large cross-sectional area compared to the width of a standard exhaust pipe. Exhaust gas entering the decomposition chamber expands, resulting in a decrease in exhaust gas velocity and an increase in exhaust gas pressure. The rapid expansion of the exhaust gas results in the formation of turbulent eddies. DEF is then injected into the decomposition chamber, after which the turbulent eddies cause the DEF to mix with the exhaust gas. Heat exchange between the exhaust gas and the DEF causes the urea in the DEF to decompose into a reductant, and the mixture of the reductant and the exhaust gas is then transferred to the SCR.

[0007] If the exhaust and DEF are not mixed sufficiently, the heat exchange between the DEF and the exhaust will not be sufficient to decompose the DEF into the required reductants. In addition, poor mixing means that the reductants are not evenly distributed in the flow, and therefore some passages of the catalytic reducer will not receive enough reductants to support the SCR reaction. In order to ensure adequate mixing, the decomposition chamber typically includes a mixing plate that is configured to produce additional turbulence. However, the additional turbulence caused by the mixing plate and the fluid friction applied to the exhaust by the mixing plate will produce back pressure on the exhaust in the decomposition chamber. This back pressure is transmitted upstream and acts to increase the pumping work required by the internal combustion engine and thereby reduce the overall efficiency of the engine system.

[0008] In turbocharged engine systems, the exhaust gas leaving the turbine wheel typically has a very high velocity and has significant directional characteristics, such as high swirl around the turbine axis. Therefore, the flow conditions in the immediate vicinity of the turbine wheel outlet are typically laminar and poorly mixed. This therefore makes the turbine outlet unsuitable as a location for positioning the dosing module. In addition, the narrow geometry of the turbine outlet passage means that any aftertreatment fluid injected may impact the surfaces defining the turbine outlet. In order to support adequate mixing and reduce the risk of impact, the decomposition chamber and dosing module are typically positioned downstream of the turbine outlet passage and at a distance away from the turbine itself so that turbulence can be established. However, as the exhaust gas flows out of the turbine wheel, the exhaust gas loses energy due to pipe friction and transient heat dissipation. Therefore, when the decomposition chamber is away from the turbine, there is less heat available to cause the decomposition of the DEF.

[0009] Furthermore, when the aftertreatment fluid is injected into the exhaust, some of the aftertreatment fluid may impact one or more surfaces of the network, risking solidification and forming a blockage in the turbine outlet passage. Such a blockage can increase the back pressure of the internal combustion engine, thereby increasing pumping work and reducing the power output of the engine system.

[0010] The amount of nitrogen oxides (NOx) produced by an internal combustion engine will vary depending on the operating conditions of the engine. When more NOx is produced, a greater mass of reductant is required to support the SCR reaction to sufficiently reduce the NOx content in the exhaust gas to below an acceptable level. However, if too much DEF is introduced into the exhaust gas flow, there is an increased risk that the DEF may impact surfaces of the exhaust gas aftertreatment system and solidify. Therefore, it is known to adjust the amount of DEF delivered to the exhaust gas flow by a dosing module in proportion to the amount of nitrogen oxides contained in the flow. Typically, such exhaust gas aftertreatment systems are provided with a sensor configured to measure the nitrogen oxide content in the exhaust gas flow.

[0011] However, sensors that detect the presence of NOx will also detect the presence of other substances, particularly ammonia (NH 3) and isocyanic acid (HNCO), and cannot detect the amount of NOx separately from the other substances. Therefore, the reading from such sensors is generally proportional to the total combined amount of NOx, ammonia, and isocyanic acid in the exhaust. Therefore, in many cases, if the reductant from the decomposed DEF reaches the NOx sensor, the sensor reading will not accurately reflect the true NOx content in the exhaust gas produced by the engine. One solution to this problem is to provide a sensor that is configured to sense ammonia (NH 3 ) and isocyanate (HNCO), and the readings of these sensors are subtracted from the readings of the NOx sensor. However, this arrangement is more expensive to manufacture and more complicated to operate due to the increased number of sensors. In addition, it has been found that ammonia condensing on the sensor surface may cause damage to the sensor.

[0012] Aftertreatment fluids such as DEF are typically injected into the exhaust as a droplet spray. By spraying the aftertreatment fluid, the aftertreatment fluid can be spread throughout the exhaust. However, even if the aftertreatment fluid is sprayed, the aftertreatment fluid tends to follow the streamlines of the exhaust and therefore will not mix evenly with the exhaust until it dissipates over the length of the pipe. However, in some engine systems, the pipe may not provide enough distance for the aftertreatment fluid to be fully mixed before entering any downstream aftertreatment components (e.g., SCR). Therefore, there is a need to improve the mixing of the aftertreatment fluid in the pipe downstream of the aftertreatment fluid injection location.

[0013] When the aftertreatment fluid is injected, it is usually composed of droplets of a range of sizes. Larger droplets have a greater mass than smaller droplets and therefore carry greater momentum. Therefore, larger droplets are more likely to impact the walls of the pipe containing the exhaust. Droplets deposited on the pipe wall may cause solid deposits to form, which can cause back pressure on the engine, thereby reducing the overall power output. Therefore, it is necessary to prevent the formation of deposits in the pipe downstream of the injection point of the aftertreatment fluid. Summary of the invention

[0014] It is an object of the present invention to obviate or mitigate one or more disadvantages of the prior art, whether described herein or elsewhere.

[0015] According to a first aspect of the present invention, a turbine for a turbocharger is provided, comprising: a turbine inlet passage, the turbine inlet passage being configured to receive exhaust gas from an internal combustion engine, the exhaust gas received by the turbine inlet passage defining a turbine main flow; a turbine impeller chamber, the turbine impeller chamber being configured to receive the turbine main flow from the turbine inlet passage, the turbine impeller chamber being configured to accommodate a turbine impeller, the turbine impeller being supported to rotate about a turbine axis; a turbine outlet passage, the turbine outlet passage being configured to receive the turbine main flow from the turbine impeller chamber; a distribution module, the distribution module being configured to deliver a spray of an aftertreatment fluid to a spray region of the turbine outlet passage, the turbine main flow traveling through the spray region; and an auxiliary passage, the auxiliary passage being configured to receive a portion of the turbine main flow, the portion of the turbine main flow received by the auxiliary passage defining an auxiliary flow; wherein the auxiliary passage is configured to guide the auxiliary flow into the spray region of the turbine outlet passage.

[0016] The term "turbine bulk flow" encompasses the main flow of exhaust gas passing through the turbine. For the most part, this is the exhaust gas received by the turbine from the internal combustion engine, and this exhaust gas flows from the turbine inlet, through the turbine wheel chamber and into the turbine outlet, and then travels downstream to the exhaust aftertreatment system including one or more catalytic reducers (such as DOC or SCR reducers).

[0017] The term "auxiliary flow" covers the exhaust flow that passes through the auxiliary channel until it completely merges with the main flow of the turbine and is fluidically indistinguishable. Those skilled in the art will recognize that even when both flows flow through the turbine outlet channel, the auxiliary flow can be distinguished from the main flow of the turbine by their different flow characteristics. Flow characteristics that can be used to distinguish the auxiliary flow from the main flow of the turbine include velocity, pressure, temperature, Reynolds number, density, etc. For example, the auxiliary channel can adjust the flow direction of the auxiliary flow in the auxiliary channel. The momentum of the auxiliary flow causes the auxiliary flow to continue to flow in the same direction after entering the turbine outlet channel until enough momentum is exchanged with the main flow of the turbine, the auxiliary flow mixes with the main flow of the turbine and begins to flow in the same direction as the main flow of the turbine. At this point, the auxiliary flow and the main flow of the turbine may become difficult to distinguish from each other.

[0018] The term "spray zone" encompasses the spatial region positioned within the turbine outlet into which the aftertreatment fluid is sprayed by the dosing module. In particular, the spray zone may be a spatial region in which the velocity component of the aftertreatment fluid in the spray direction defined by the dosing module is greater than the velocity component in the direction of the turbine main flow. In other words, the spray zone encompasses the region in which the momentum and behavior of the aftertreatment fluid are more affected by the forces imparted to the aftertreatment fluid by the dosing module than by the forces imparted to the aftertreatment fluid by the turbine main flow.

[0019] The term "auxiliary passage" encompasses a passage that is separate from the turbine inlet passage, the turbine wheel chamber, and the turbine outlet passage, and that is capable of receiving exhaust gas from a first location of the turbine and delivering the exhaust gas within the turbine outlet to a second location of the turbine. The portion of the turbine from which the auxiliary passage inlet receives the exhaust gas may be substantially any portion of the turbine that receives the exhaust gas but does not form part of the auxiliary passage. For example, this may include one or more of the turbine inlet passage, the turbine wheel chamber, the turbine outlet passage, or a wastegate (i.e., bypass) passage.

[0020] The auxiliary channel "is configured to direct the auxiliary flow into the spray region" encompasses substantially any arrangement of the auxiliary channel, turbine outlet channel, and spray region, wherein the auxiliary flow is caused to pass through the spray region before it merges with the main turbine flow and becomes indistinguishable from the main turbine flow. That is, the geometry of the auxiliary channel, turbine outlet, and / or spray region is selected so that the auxiliary flow, which has traveled through the auxiliary channel, interacts fluidically with the aftertreatment fluid injected into the spray region by the dosing module when or before the auxiliary flow completely merges with and / or mixes with the main turbine flow.

[0021] Since the auxiliary flow is separated from the main flow of the turbine, the auxiliary flow can be adjusted by the auxiliary channel so that the auxiliary flow has fluid properties separated from the main flow of the turbine. For example, the geometry of the auxiliary channel can be selected to adjust the direction and speed of the auxiliary flow. Therefore, the auxiliary channel can adjust the auxiliary flow so that the momentum of the auxiliary flow carries the auxiliary flow into the spray area. Since the auxiliary flow enters the spray area, the auxiliary flow exchanges momentum with the spray of the after-treatment fluid and the main flow of the turbine. This momentum exchange can be used to provide one or more beneficial effects. In other words, in addition to the energy of the main flow of the turbine and the energy of the spray of the after-treatment fluid itself, the auxiliary flow will also introduce additional energy into the spray area, and this energy can be used to provide one or more specific beneficial effects.

[0022] Depending on how the auxiliary flow interacts with the main flow of the turbine and the after-treatment fluid in the spray area, various beneficial effects may occur. For example, the auxiliary flow can be delivered in such a way that the auxiliary flow applies high shear forces at the nozzle of the distribution module to keep the nozzle clean from the influence of the after-treatment fluid, and thereby reduce the risk of deposits forming at the nozzle. In another example, the auxiliary flow can be delivered in such a way that the momentum of the auxiliary flow is used to carry the after-treatment fluid farther into the turbine outlet channel, thereby promoting a more uniform distribution of the after-treatment fluid across the entire width of the turbine outlet channel. In yet another example, the auxiliary flow can be delivered in such a way that turbulence is generated in the turbine outlet channel to promote better heat transfer from the exhaust gas to the after-treatment fluid, so that the after-treatment fluid decomposes at a faster rate. Other possible beneficial effects will be apparent from the specification.

[0023] The distribution module can include a nozzle configured to produce the spray of the aftertreatment fluid, and the nozzle can be substantially aligned with the side wall of the turbine outlet channel or located radially outside the side wall. In some embodiments, the nozzle can be positioned substantially flush with the side wall of the turbine outlet channel. The term "substantially flush" covers the approximate or precise alignment of the distribution module with the inner surface of the turbine outlet channel that defines the periphery of the turbine outlet channel. In such embodiments, the nozzle does not protrude into the turbine outlet channel. Therefore, the nozzle does not hinder the flow through the turbine outlet channel, and thus avoids applying back pressure to the internal combustion engine.

[0024] The nozzle of the distribution module can be configured to produce a spray of the aftertreatment fluid, and can therefore be referred to as a spray generating nozzle or an atomizing nozzle. As described in the introduction, the geometry within the turbine outlet channel is very narrow. When the distribution module including the spray generating nozzle is mounted on the side wall of the turbine outlet, the sprayed aftertreatment fluid tends to impact the opposite wall of the turbine outlet. The fluid after impact may solidify, thereby causing blockage, and therefore the side wall of the turbine outlet has historically been considered to be a location that is not suitable for placing the nozzle of the distribution module. However, in this case, since the auxiliary channel delivers the auxiliary flow to the spray of the aftertreatment fluid, the auxiliary flow introduces additional energy into the aftertreatment fluid. For example, the energy can be used to increase the heat transfer to the aftertreatment fluid, and thus improve decomposition, and reduce the solidification of the aftertreatment fluid after impact. Therefore, the use of the auxiliary flow makes the nozzle of the distribution module located in a position that was previously impossible.

[0025] The dispensing module can be configured to convey the post-treatment fluid along a spray direction, and the auxiliary channel can be configured to guide the auxiliary flow into the spray area along an auxiliary flow direction that is approximately normal to the spray direction. The term "spray direction" encompasses the overall or average direction along which the post-treatment fluid is sprayed from the nozzle. For example, this can be along the longitudinal centerline of the spray area. The term "approximately normal to the spray direction" encompasses a flow with a larger velocity component in a direction orthogonal to the spray direction, but some angular misalignment can be allowed, as described below.

[0026] Since the auxiliary flow is transported in a direction generally normal to the spray direction, the auxiliary flow and the aftertreatment fluid have a higher velocity component in directions orthogonal to each other. Therefore, the auxiliary flow can apply shear force to the aftertreatment fluid in the spray area. This shear force causes the droplets in the spray to split into smaller droplets, thereby increasing the surface area that can be used for heat exchange between the two fluids, thereby promoting faster decomposition of the aftertreatment fluid. In addition, the shear force introduces turbulence into the spray area, thereby improving the mixing of the aftertreatment fluid and the exhaust gas, and again increasing the amount of heat exchange between the two fluids.

[0027] The auxiliary flow direction may be angled relative to the normal to the spray direction at an angle of up to about 30°. "Normal to the spray direction" encompasses an axis that lies in a plane orthogonal to the spray direction. In an alternative embodiment, the auxiliary flow direction may be angled relative to the normal to the spray direction at an angle of up to about 30°.

[0028] It has been found that when the auxiliary flow is inclined within one of the above ranges relative to the normal to the spray direction, the shear force exerted by the auxiliary flow on the after-treatment fluid is sufficient to cause breakup of the after-treatment fluid droplets and also introduce sufficient turbulence into the flow to provide improved mixing.

[0029] The dosing module may comprise a nozzle and the auxiliary channel may be configured to direct the auxiliary flow through the nozzle in a direction substantially normal to the spray direction. The term "through the nozzle" encompasses that the auxiliary flow is sufficiently close to the nozzle that the auxiliary flow generates shear forces on the nozzle.

[0030] During use, droplets of the after-treatment fluid may coalesce at the nozzle of the dosing module. If the temperature of the exhaust gas near the nozzle is not hot enough, the ammonia decomposed from the after-treatment fluid will solidify and may potentially form deposits that will block or restrict the flow of the after-treatment fluid from the nozzle. However, because the auxiliary gas flow is directed through the nozzle in a direction generally orthogonal to the spray direction, the auxiliary flow exerts a shear force on the nozzle that acts to blow away any droplets that have formed at the nozzle. Therefore, the nozzle remains clean and the risk of deposit formation is reduced.

[0031] The dispensing module may be configured to convey the post-treatment fluid in a spray direction, and the auxiliary channel may be configured to guide the auxiliary flow into the spray region in an auxiliary flow direction opposite to the spray direction. The term "opposite to the spray direction" encompasses flows in which a flow velocity component acting in a direction opposite to the spray direction is greater than a velocity component normal to the spray direction. The direction opposite to the spray direction may include a direction directly opposite to the spray direction or a direction inclined at an angle relative to a direction directly opposite to the spray direction.

[0032] In some cases, the after-treatment fluid delivered to the turbine outlet channel by the distribution module may impact the wall of the turbine outlet channel on the side of the channel opposite to the distribution module. The after-treatment fluid after the impact may coalesce into large droplets, which may form solid deposits on the wall of the turbine outlet channel. In this arrangement, since the auxiliary flow is delivered in the direction opposite to the spray direction, the momentum of the auxiliary flow and the momentum of the after-treatment fluid act oppositely to each other. Therefore, the auxiliary flow can prevent the after-treatment fluid from impacting the wall of the turbine outlet channel. In addition, the momentum exchange between the auxiliary flow and the after-treatment fluid causes the droplets of the after-treatment fluid to split, thereby increasing the available heat exchange area between the exhaust and the after-treatment fluid. The relatively large momentum exchange also generates a large amount of turbulence, which serves to improve the mixing of the after-treatment fluid and the exhaust in the spray area. Therefore, more heat is exchanged from the exhaust gas to the after-treatment fluid, thereby ensuring that as much of the after-treatment fluid as possible is decomposed into the required reducing agent. This helps to reduce the risk of deposits forming from aftertreatment fluid pooling on surfaces in the turbine outlet passages and also ensures that the reductant is thoroughly and evenly mixed into the bulk turbine flow.

[0033] The auxiliary flow may be oriented in an upstream direction relative to the main turbine flow, and the auxiliary flow direction may be angularly inclined at an angle between about 50° and about 90° relative to the opposite direction of the spray direction. The term "direction opposite to the spray direction" encompasses a direction that is directly opposite and flipped from the spray direction. In alternative embodiments, the auxiliary flow direction may be angularly inclined at an angle between about 55° and about 80° relative to the opposite direction of the spray direction, or inclined at an angle between about 60° and about 70°.

[0034] Since the auxiliary flow is delivered in the direction opposite to the spray direction and in the upstream direction, the auxiliary flow has a large velocity component in the direction opposite to both the after-treatment fluid and the main turbine flow. Therefore, a large amount of turbulence is generated in the spray area. The turbulence promotes the after-treatment fluid to break up into smaller droplets and better mixing. This makes the after-treatment fluid break up into the reducing agent faster and more completely.

[0035] The auxiliary flow may be oriented in a downstream direction relative to the main turbine flow, and the auxiliary flow direction may be angularly inclined at an angle between about 30° and about 90° relative to the opposite direction of the spray direction. In alternative embodiments, the auxiliary flow direction may be angularly inclined at an angle between about 40° and about 80°, or at an angle between about 45° and about 70°, or at an angle of about 55° relative to the opposite direction of the spray direction.

[0036] Since the auxiliary flow is delivered in the opposite direction to the spray direction, the auxiliary flow has a larger velocity component opposite to that of the aftertreatment fluid. This causes droplet breakup of the aftertreatment fluid, resulting in more heat exchange and faster and more complete decomposition. However, since the flow is oriented in the downstream direction relative to the main turbine flow, the amount of turbulence generated by the confluence of the main turbine flow and the auxiliary flow in the turbine outlet channel is reduced. Therefore, sufficient turbulence can be provided to promote mixing of the aftertreatment fluid and the exhaust gas in the spray area, while ensuring that the amount of turbulence does not increase to a magnitude that may cause significant resistance to flow through the turbine outlet channel and reduce the efficiency of the engine system.

[0037] The auxiliary channel may include an auxiliary channel outlet configured to deliver the auxiliary flow to the turbine outlet channel, and the turbine may also include a barrier member configured to substantially cover the auxiliary channel outlet from the perspective of the distribution module in the spray direction. In this way, the barrier member forms a barrier to prevent the post-treatment fluid from entering the auxiliary channel outlet. Therefore, the chance of the post-treatment fluid solidifying and forming solid deposits in the auxiliary channel is reduced or eliminated.

[0038] The auxiliary channel can be configured to guide the auxiliary flow into the turbine outlet channel along the auxiliary flow direction facing the center line of the turbine outlet channel; and the distribution module can be configured to convey the post-treatment fluid along the spray direction facing the center line. The auxiliary channel can be configured to convey the auxiliary flow along the auxiliary flow direction normal to the center line. In some embodiments, the auxiliary channel can be configured to convey the auxiliary flow along the auxiliary flow direction inclined relative to the center line, for example, conveying the auxiliary flow in the auxiliary flow direction inclined to about 45° in the upstream direction or the downstream direction. The distribution module can be configured to convey the post-treatment fluid along the spray direction normal to the center line. In some embodiments, the distribution module can be configured to convey the post-treatment fluid along the spray direction inclined relative to the center line, for example, conveying the post-treatment fluid in the spray direction inclined to about 45° in the upstream direction or the downstream direction.

[0039] The auxiliary channel can be configured to guide the auxiliary flow into the turbine outlet channel along the auxiliary flow direction facing downstream relative to the main flow surface of the turbine, and the auxiliary flow direction can be inclined at an angle of at least about 45° relative to the centerline of the turbine outlet channel. The "centerline" of the turbine outlet channel covers the line defined by the centroid of the turbine outlet channel along the flow direction of the exhaust gas. In the simplest form, the centerline can be a straight line coaxial with the turbine axis. However, in some embodiments, the turbine outlet channel can include complex geometries, resulting in a bent, curved, stepped or inclined centerline.

[0040] The inclination between the auxiliary flow direction and the centerline encompasses the minimum angle of the auxiliary flow direction and the centerline where the auxiliary flow is introduced into the turbine outlet channel. For example, the auxiliary channel may include an auxiliary outlet defining a centroid, and the angle of the auxiliary flow direction may be measured at the centroid of the auxiliary channel outlet relative to a line parallel to the centerline. If the centerline is not straight, the angle may be measured relative to a tangent to the centerline. The centerline position at which the tangent is taken may be the position where the normal to the centerline passes through the centroid of the auxiliary channel outlet.

[0041] During use, the velocity of the turbine body flow through the turbine outlet passage is very high. Therefore, if the after-treatment fluid is injected into the turbine outlet in the absence of the auxiliary flow, the after-treatment fluid will be carried downstream by the turbine body flow before it can spread across the entire width of the turbine outlet passage. Therefore, only a portion of the turbine body flow will carry the after-treatment fluid, and the SCR reaction will only occur in a small portion of the SCR reducer (because the reductant required to support the SCR reaction is not present).

[0042] However, when the auxiliary flow direction is inclined in the downstream direction relative to the centerline of the turbine outlet channel, the auxiliary flow contains a velocity component normal to the flow direction of the main flow of the turbine (i.e., one of the substantially orthogonal components of the velocity vector of the auxiliary flow). Due to the normal component of the velocity, when the auxiliary flow enters the turbine outlet channel, the auxiliary flow not only travels in the downstream direction, but also travels across part or all of the width of the turbine outlet channel. When the auxiliary flow travels through the spray area, the auxiliary flow will transfer part of its momentum to the after-treatment fluid to carry the after-treatment fluid across a larger proportion of the width of the turbine outlet channel. In other words, the auxiliary flow is used to "pick up" the after-treatment fluid in the spray area and carry the after-treatment fluid across a larger range of the width of the turbine outlet channel. Therefore, the after-treatment fluid is distributed more evenly across the turbine outlet channel and will not be concentrated in a local part of the main flow of the turbine.

[0043] It will be appreciated that because the auxiliary flow and the main turbine flow face in a downstream direction, the two fluid flows can merge with relatively minimal turbulence. Minimizing turbulence between the auxiliary flow and the main turbine flow can reduce back pressure on the turbine and internal combustion engine, which may otherwise adversely affect the performance of the engine.

[0044] The extent to which the auxiliary flow and aftertreatment fluid are carried across the width of the turbine outlet passage will depend on the magnitude of the normal component of the velocity of the auxiliary flow relative to the velocity of the main turbine flow. It has been found that for most operating conditions of the turbocharger, an angle of at least about 45° is required to significantly increase the penetration of the aftertreatment fluid across the main turbine flow.

[0045] The auxiliary flow direction can be inclined at an angle in the range of about 45° to about 90° relative to the centerline, or at an angle in the range of about 45° to about 60°. In general, the greater the angle between the auxiliary flow direction and the centerline, the farther the aftertreatment fluid is carried across the turbine outlet channel. If the angle is too gentle, the aftertreatment fluid may not be able to run through the entire range of the channel. However, if the angle is too steep, the aftertreatment fluid may impact the wall of the turbine outlet channel opposite to the distribution module. The aftertreatment fluid may solidify into a deposit that restricts flow through the turbine outlet channel. It has been found that by keeping the angle between the auxiliary flow direction and the centerline within the above range, a balance between these two factors can be found so that the aftertreatment fluid is more evenly distributed across the turbine outlet channel, but the impact on the wall of the turbine outlet channel is minimized.

[0046] The auxiliary channel can be configured to guide the auxiliary flow into the turbine outlet channel along the auxiliary flow direction facing upstream relative to the main flow of the turbine, and the auxiliary flow direction can be inclined at an angle of at least about 45° relative to the centerline of the turbine outlet channel. Since the auxiliary flow and the main flow of the turbine face substantially opposite directions, a relatively large amount of turbulence is formed at the point where the two fluid flows meet. This can be used to increase the turbulence in the spray area and thereby provide improved mixing of the aftertreatment fluid with the exhaust gas. Generally, when the auxiliary flow direction faces upstream relative to the main flow of the turbine, the smaller the angle between the auxiliary flow direction and the centerline, the more opposite the direction of the auxiliary flow and the direction of the main flow of the turbine are to each other. This will result in enhanced turbulence at the point where the two fluid flows meet. If the turbulence in the turbine outlet channel is too high, this may cause flow restrictions that hinder the main flow of the turbine. It has been found that a minimum angle of about 45° between the auxiliary flow direction and the centerline is necessary to keep the amount of turbulence generated below an acceptable level.

[0047] The auxiliary flow direction may be inclined relative to the centerline at an angle in the range of about 45° to about 90°. If the angle between the auxiliary flow direction and the centerline is too shallow when the auxiliary flow direction faces upstream relative to the main turbine flow, excessive turbulence may result. However, if the angle is too steep, the aftertreatment fluid may be prevented from completely penetrating the entire width of the turbine outlet passage. It has been found that when the angle between the auxiliary flow direction and the centerline is in the range of about 45° to about 60°, this may provide a good balance between these two factors.

[0048] The dosing module may define a spray direction, and the turbine outlet passage may define a centerline, and the spray direction may be oriented generally normal to the centerline. That is, the dosing module is oriented such that it injects the aftertreatment fluid in a direction generally normal to the centerline.

[0049] Since the aftertreatment fluid is directed in a direction generally normal to the centerline, the momentum of the aftertreatment fluid can carry the aftertreatment fluid across the width of the turbine outlet passage, thereby evenly distributing the aftertreatment fluid across the turbine outlet passage.

[0050] The dosing module may define a spray direction, and the spray direction may be oriented upstream relative to the turbine body flow. That is, the dosing module is oriented so that it injects aftertreatment fluid in a direction having a velocity component upstream relative to the turbine body flow.

[0051] Since the aftertreatment fluid is injected in the upstream direction, the momentum component carried by the aftertreatment fluid is opposite to the momentum of the main turbine flow. Therefore, this increases the collision amplitude between the main turbine flow and the aftertreatment fluid, causing the aftertreatment fluid to break into smaller droplets. Smaller droplets have a larger surface area for heat exchange and are therefore able to decompose the required reductant faster.

[0052] The spray direction may be tilted at an angle of up to about 90° relative to the normal to the center line. "Normal to the center line" refers to a line perpendicular to the center line, such as a line perpendicular to the center line at a point on the center line. If the center line is curved, the normal is a line perpendicular to a tangent to the center line at a point on the center line.

[0053] Generally, as the angle between the spray direction and the centerline increases in the upstream direction, the collision amplitude increases accordingly. Thus, the spray direction can be oriented up to 90° relative to the centerline so that it faces directly in the opposite direction of the main flow of the turbine. However, this reduces the extent to which the aftertreatment fluid is carried across the turbine outlet passage. It has been found that a balance between these two factors is achieved when the spray direction is inclined from about 10° to about 45° relative to the centerline.

[0054] The dosing module may define a spray direction, and the spray direction is oriented downstream relative to the turbine body flow. That is, the dosing module is oriented so that it injects the aftertreatment fluid into the turbine outlet passage in a generally downstream direction relative to the direction of the turbine body flow.

[0055] Since the spray direction is generally oriented downstream, the momentum of the aftertreatment fluid acts in the same direction as the momentum of the main turbine flow, and therefore the two fluid streams can merge with less flow disturbance. Therefore, adding the aftertreatment fluid does not add additional turbulence to the main turbine flow. This is useful, for example, for keeping the overall amplitude of turbulence in the main flow below an acceptable level so that it does not restrict flow through the turbine outlet channel. For example, the auxiliary flow can be introduced into the turbine outlet channel in a manner configured to produce a relatively large amount of turbulence (e.g., facing upstream). In this case, the main turbine flow may be turbulent enough so that thorough mixing will occur once the aftertreatment fluid is injected.

[0056] The spray direction may be tilted up to an angle of about 90° relative to the normal to the centerline. Generally, as the angle between the spray direction and the centerline increases in the downstream direction, less turbulence is generated. Therefore, the spray direction may be oriented up to 90° relative to the centerline so that it faces directly into the turbine main flow. However, this reduces the extent to which the aftertreatment fluid is carried across the turbine outlet passage. It has been found that a balance is achieved between these two factors when the spray direction is tilted up to about 45° relative to the centerline.

[0057] The auxiliary passage can be configured to allow the auxiliary flow to be delivered to the turbine outlet passage during all operating conditions of the turbine when receiving exhaust gas from the internal combustion engine. For example, the auxiliary passage can be substantially free of any structure configured to selectively restrict, reduce or prevent flow along the auxiliary passage. In one embodiment, the auxiliary passage can be substantially free of valves, and in particular, free of wastegate valves. In another embodiment, the auxiliary passage can include a valve, such as a wastegate valve, however the valve can be configured so that leakage through the valve is always allowed.

[0058] Since the auxiliary flow is allowed to be delivered to the turbine outlet passage under all operating conditions of the turbine, this ensures that there is always an auxiliary flow that can provide one or more beneficial effects.

[0059] The auxiliary channel can define a cross section perpendicular to the direction of the auxiliary flow, and the size of the narrowest part of the cross section can be set so that the mass flow rate of the auxiliary flow does not exceed about 5% of the mass flow rate of the exhaust gas delivered from the engine to the turbine inlet channel. Therefore, the flow rate of the auxiliary flow is large enough so that the auxiliary flow can affect the aftertreatment fluid and the main flow of the turbine in the turbine outlet channel, but the flow rate of the auxiliary flow is small enough so that the auxiliary flow does not reduce the overall efficiency of the turbine. Generally, the smaller the auxiliary flow, the higher the efficiency of the turbine. Preferably, the size of the cross section of the auxiliary channel is set so that the mass flow rate of the auxiliary flow does not exceed about 1% or about 2% of the mass flow rate of the exhaust gas delivered to the turbine inlet channel.

[0060] The auxiliary channel may include: an auxiliary channel inlet positioned in the turbine inlet channel; and an auxiliary channel outlet positioned in the turbine outlet channel. That is, the auxiliary channel may bypass the turbine impeller. When the auxiliary flow originates from the turbine inlet channel, the auxiliary flow pressure and temperature are generally higher than the main turbine flow in the turbine outlet channel, and thus more energy can be provided for interaction with the aftertreatment fluid.

[0061] The auxiliary passage may include a valve configured to control flow through the auxiliary passage. In this way, the auxiliary passage may be used as a wastegate passage. The valve may be configured to allow a small amount of leakage when the valve is in a closed configuration. The leakage may be large enough to support specific interactions with the turbine body flow and the aftertreatment fluid in the turbine outlet passage, such as cleaning of the nozzle, etc., while the leakage is small enough not to negatively affect the turbine performance.

[0062] The valve may be configured such that the auxiliary flow is allowed to pass through the valve during all operating conditions of the turbine. In this way, the auxiliary flow is always able to influence the aftertreatment fluid and the turbine main flow in the turbine outlet passage.

[0063] The valve may be configured such that the auxiliary flow through the valve always accounts for at least about 0.1% of the mass flow of the exhaust gas delivered from the engine to the turbine inlet passage. The greater the amount of auxiliary flow allowed, the greater the effect of the auxiliary flow on the aftertreatment fluid and the turbine main flow in the turbine outlet passage. In an alternative embodiment, the valve may be configured such that the auxiliary flow through the valve always accounts for at least about 0.2%, about 0.5%, about 1%, about 2%, or about 5% of the mass flow of the exhaust gas delivered from the engine to the turbine inlet passage.

[0064] In addition to the auxiliary passage, the turbine may also include a wastegate device, which may include: a wastegate passage, the wastegate passage fluidly connecting the turbine inlet passage and the turbine outlet passage so that exhaust gas traveling through the wastegate passage does not travel through the turbine impeller chamber; and a wastegate valve, the wastegate valve being configured to selectively allow or prevent fluid flow through the wastegate passage. The term "wastegate passage" encompasses a fluid-carrying passage that is configured to bypass the turbine impeller and the turbine impeller chamber while providing fluid flow communication between the turbine inlet passage and the turbine outlet passage. The flow through the wastegate passage may be referred to as a wastegate flow. The wastegate device may be independent of and in addition to the auxiliary passage setting. That is, the turbine may include an auxiliary passage and a wastegate passage that are separate from each other.

[0065] The wastegate passage can be configured to direct the wastegate flow into the spray region of the turbine outlet passage. By doing so, when the auxiliary flow is directed into the spray region of the turbine outlet passage, the wastegate device can affect the aftertreatment fluid and the turbine main flow in the same manner as described above. It should be understood that the wastegate device can deliver the wastegate flow in a manner corresponding to any configuration related to the auxiliary flow described herein. For example, the wastegate device can be used to support nozzle cleaning of a dosing module, increase turbulence in a turbine outlet passage, prevent aftertreatment fluid from impacting the walls of a turbine outlet passage, etc.

[0066] The wastegate passage may fluidly merge with the auxiliary passage so that the wastegate passage is in fluid communication with the turbine outlet passage via the auxiliary passage. That is, the wastegate passage is in direct fluid communication with the auxiliary passage so that during use when the wastegate valve is open, exhaust gas travels through the wastegate passage into the auxiliary passage and then continues to flow toward the turbine outlet passage.

[0067] Compared to an arrangement in which the wastegate passage and the auxiliary passage are completely separate, this arrangement can be more compact and easier to manufacture. In addition, in this arrangement, the wastegate flow merges with the auxiliary flow and becomes part of the auxiliary flow. Typically, the wastegate flow has a much larger flow than the auxiliary flow, and therefore the wastegate flow can be effectively "added" to the auxiliary flow to increase the magnitude of the benefit provided by the auxiliary flow. This is particularly beneficial in the case where the auxiliary flow does not originate from a location upstream of the turbine outlet, because in this arrangement, the wastegate flow will have a higher pressure than the auxiliary flow.

[0068] The dosing module may be configured to deliver the aftertreatment fluid to the turbine outlet passage via the auxiliary passage. That is, the nozzle of the dosing module may be positioned within the auxiliary passage so that during use the dosing module delivers the aftertreatment fluid to the auxiliary passage, the aftertreatment fluid traveling through the auxiliary passage and into the turbine outlet passage.

[0069] The auxiliary passage may include an auxiliary passage inlet configured to receive exhaust gas from the turbine outlet passage and an auxiliary passage outlet configured to deliver exhaust gas to the turbine outlet passage.

[0070] The auxiliary passage may include an outlet portion extending from the nozzle to the auxiliary passage outlet, the outlet portion may define an outlet axis, and the outlet axis may be inclined relative to the centerline of the turbine outlet passage at an angle of up to about 70°. In alternative embodiments, the outlet axis may be inclined relative to the centerline at an angle between about 20° to about 70°, an angle between about 30° to about 60°, an angle between about 40° to about 50°, or an angle of about 45°. The relative angle between the outlet axis and the centerline may be measured at the centroid of the auxiliary passage outlet.

[0071] Due to the momentum carried by the mixture of auxiliary flow and aftertreatment fluid traveling through the outlet portion of the auxiliary channel, the likelihood of aftertreatment fluid impacting the wall of the turbine outlet channel opposite the auxiliary channel outlet increases as the angle between the outlet axis and the centerline increases. Aftertreatment fluid that impacts the wall of the turbine outlet may not be hot enough to evaporate and may result in the formation of deposits. Although this can be mitigated by reducing the angle between the outlet axis and the centerline, if the angle is too small, the length of the auxiliary channel must be increased and the auxiliary channel outlet must therefore be placed at a more downstream position (and possibly outside the preferred distance from the turbine impeller outlet guide as discussed below). It has been found that when the angle between the outlet axis and the centerline is within the above range, this reduces the risk of aftertreatment fluid impacting the wall of the turbine outlet channel while keeping the auxiliary channel compact.

[0072] The auxiliary passage may include an inlet portion extending from an auxiliary passage inlet to the nozzle, the inlet portion may define an inlet axis, and wherein the inlet axis may be inclined at an angle between about 20° and about 70° relative to a centerline of the turbine outlet passage. In alternative embodiments, the inlet axis may be inclined at an angle between about 30° and about 60°, an angle between about 40° and about 50°, or an angle of about 45° relative to the centerline. The relative angle between the inlet axis and the centerline may be measured at the centroid of the auxiliary passage inlet.

[0073] As the angle of the inlet axis of the auxiliary passage increases, the momentum change required for the exhaust gas to enter the auxiliary passage increases, causing resistance to the flow. However, if the angle of the inlet axis is too small, the auxiliary passage must be made longer. It has been found that when the angle between the inlet axis and the centerline is within the above range, this reduces the amount of momentum change required for the exhaust gas to enter the auxiliary passage while keeping the overall length of the auxiliary passage compact.

[0074] The cross-sectional area of ​​the outlet portion of the auxiliary channel may increase along the outlet axis from the nozzle of the dosing module to the auxiliary channel outlet. That is, the second portion of the auxiliary channel comprises a diverging side that diverges outwardly in the direction of the auxiliary channel outlet.

[0075] The distribution module will produce a fine spray of atomized post-treatment fluid, which is ejected from the end of the distribution module in a cone shape. In some embodiments, the outlet portion of the auxiliary channel expands at an angle approximately equal to or greater than the spray cone angle of the nozzle. For example, the spray cone angle can be about 45° to about 50°, and the outlet portion can expand at an angle of about 60°. In such an embodiment, since the outlet portion of the auxiliary channel expands at a rate equal to or higher than the spray cone, this reduces the risk of the post-treatment fluid impacting the auxiliary channel wall. However, if the outlet portion expands at a too steep angle, the auxiliary flow will slow down, causing the auxiliary flow to lose the potential energy of the flow that affects the turbine outlet channel. Therefore, in an alternative embodiment, the spray cone angle can be the same as described above, and the outlet portion of the auxiliary channel expands at a more gentle angle, such as about 5° to 10°. Although the post-treatment fluid may impact the wall of the outlet portion, the speed of the auxiliary flow will remain high, so that the shear force will clean any impacted post-treatment fluid from the wall to avoid deposit formation.

[0076] The turbine outlet passage may define a diffuser portion, and the distribution module may be oriented so that the spray area is located within the diffuser portion. The term "diffuser portion" encompasses a portion of a turbine outlet passage, wherein the cross-sectional area of ​​the turbine outlet passage increases along the centerline of the turbine outlet passage. The diffuser portion may be, for example, a diffuser having a straight axis of a frustoconical wall that tapers outwardly relative to the turbine body flow. Such an axial diffuser may be axially aligned with the turbine axis. However, in alternative embodiments, substantially any expansion geometry may be used to define the diffuser portion. For example, the diffuser portion may include one or more bends.

[0077] In such an arrangement, the purpose of the diffuser section is to decelerate and increase the pressure of the turbine main flow according to the Bernoulli principle. Since the turbine outlet is connected to the atmosphere, the exhaust pressure downstream of the turbine outlet will be about atmospheric pressure. By using a diffuser, the pressure of the main flow immediately downstream of the turbine impeller can be reduced, thereby increasing the pressure difference on the turbine impeller, and allowing more energy to be extracted from the turbine main flow. Due to the expansion of the turbine main flow, turbulence will naturally occur in the diffuser section. By aligning the distribution module relative to the diffuser section so that the spray area is positioned in the diffuser section, natural turbulence can be used to provide improved mixing of the post-treatment fluid, and thus promote faster and more adequate decomposition. In addition, the expanded diameter of the diffuser section reduces the amount of the post-treatment fluid that impacts the wall, and thus reduces the risk of deposit formation. In addition, the diffuser enables the distributor to naturally tilt downstream, and thus improves the integration of the distributor with the turbine housing component.

[0078] The turbine may include a turbine wheel having an outlet guide portion, the outlet guide portion defining an outlet guide diameter, and the dosing module may be oriented so that at least a portion of the spray region is positioned within a range of about 10 times the outlet guide diameter from the turbine wheel relative to the centerline of the turbine outlet passage. The term "exit guide portion" covers a portion of the turbine wheel that serves as a turbine wheel outlet (i.e., at the far end of the turbine wheel from the perspective of the main flow of the turbine flowing therethrough). The term "exit guide diameter" covers the diameter of the outlet guide portion at the farthest end of the turbine wheel from the perspective of the main flow of the turbine. It has been found that the main flow maintains a relatively high velocity until at least about 4 or 5 times the outlet guide diameter downstream of the turbine wheel. Therefore, in an alternative embodiment, the spray region may be positioned within a range of no more than about 5, about 3, or about 2 times the outlet guide diameter from the turbine wheel relative to the centerline, so that the post-treatment fluid interacts with the main flow in the high velocity region.

[0079] As the turbine body flow leaves the turbine wheel, the temperature of the turbine body flow will be at its hottest state relative to any location downstream. Generally speaking, the hotter the turbine body flow, the more heat is available for heat exchange with the aftertreatment fluid to promote decomposition into the desired reductants. By positioning and orienting the dosing module so that the spray area is closer to the turbine wheel, more heat can be ensured to achieve faster and more complete decomposition of the aftertreatment fluid. Through experiments, it has been found that when the spray area is farther from the turbine wheel along the centerline than about 10 times the outlet inducer diameter, heat is dissipated from the turbine body flow and the decomposition rate is reduced.

[0080] The turbine may include a housing having a mounting structure to which the dosing module is mounted and which may define an aperture through which a nozzle of the dosing module passes. The housing may be substantially any solid body forming part of a structure defining a turbine inlet passage, a turbine wheel passage, a turbine outlet passage, auxiliary passages and / or any other passages that may be present as the case may be (e.g., a wastegate passage, an exhaust gas recirculation passage, etc.). In particular, the housing may be part of an assembly of various housing components defining portions of various passages of the turbine described above.

[0081] This enables the dosing module to deliver the aftertreatment fluid to the turbine outlet passage as the nozzle passes through the hole in the housing.

[0082] The aperture may be positioned no more than about 10 inducer diameters from the turbine wheel relative to a centerline of the turbine outlet passage.

[0083] According to a second aspect of the present invention, a method for operating a turbine for a turbocharger is provided, comprising: receiving exhaust gas from an internal combustion engine into a turbine inlet passage, the exhaust gas received by the turbine inlet passage defining a turbine main flow; receiving the turbine main flow from the turbine inlet passage into a turbine impeller chamber, the turbine impeller chamber being configured to accommodate a turbine impeller, the turbine impeller being supported to rotate around a turbine axis; receiving the turbine main flow from the turbine impeller chamber into a turbine outlet passage; using a dosing module to deliver a post-treatment fluid to a spray region of the turbine outlet passage, the turbine main flow traveling through the spray region; receiving a portion of the turbine main flow into an auxiliary passage, the portion of the turbine main flow received by the auxiliary passage defining an auxiliary flow; and directing the auxiliary flow into the spray region of the turbine outlet passage.

[0084] The dosing module may be configured to deliver the aftertreatment fluid in a spray direction, and the method may further include directing the auxiliary flow into the spray region in an auxiliary flow direction that is generally normal to the spray direction.

[0085] The secondary flow direction may be angled relative to the normal to the spray direction at an angle of up to about 30°.

[0086] The dosing module may include a nozzle, and the method may further include directing the secondary flow through the nozzle in a direction substantially normal to the spray direction.

[0087] The dosing module may be configured to deliver the post-treatment fluid in a spray direction, and wherein the method may further include directing the auxiliary flow into the spray region in an auxiliary flow direction opposite to the spray direction.

[0088] The method may further include orienting the auxiliary flow direction in an upstream direction relative to the turbine main flow and tilting the auxiliary flow direction relative to an opposite direction of the spray direction by an angle of up to about 45°.

[0089] The method may further include orienting the auxiliary flow direction in a downstream direction relative to the turbine main flow and tilting the auxiliary flow direction relative to an opposite direction of the spray direction by an angle of up to about 45°.

[0090] The auxiliary channel may include an auxiliary channel outlet configured to deliver the auxiliary flow to the turbine outlet channel, and the method may also include shielding the auxiliary channel outlet from the after-treatment fluid using a barrier member, wherein the barrier member is configured to substantially cover the auxiliary channel outlet from the perspective of the distribution module in the spray direction.

[0091] The auxiliary passage may be configured to direct the auxiliary flow into the turbine outlet passage in an auxiliary flow direction facing a centerline of the turbine outlet passage; and may further include directing the aftertreatment fluid in a spray direction facing the centerline.

[0092] The method may further include directing the auxiliary flow into the turbine outlet passage in an auxiliary flow direction facing downstream relative to the turbine main body flow, and the auxiliary flow direction may be inclined at an angle of at least about 45° relative to a centerline of the turbine outlet passage.

[0093] The auxiliary flow direction may be inclined at an angle in a range of about 45° to about 90° relative to the centerline.

[0094] The method may further include directing the auxiliary flow into the turbine outlet passage in an auxiliary flow direction facing upstream relative to the turbine main body flow, and the auxiliary flow direction may be inclined at an angle of at least about 45° relative to a centerline of the turbine outlet passage.

[0095] The auxiliary flow direction may be inclined at an angle in a range of about 45° to about 90° relative to the centerline.

[0096] The dosing module may define a spray direction and the turbine outlet passage may define a centre line, and the method may include orienting the spray direction substantially normal to the centre line.

[0097] The dosing module may define a spray direction, and the method may include orienting the spray direction upstream relative to the turbine body flow direction.

[0098] The spray direction may be inclined at an angle of up to about 90° relative to the normal to the centerline.

[0099] The dosing module may define a spray direction, and the method may include orienting the spray direction flow downstream relative to the turbine body.

[0100] The spray direction may be inclined at an angle of up to about 90° relative to the normal to the centerline.

[0101] The auxiliary passage may be configured to allow delivery of the auxiliary flow to the turbine outlet passage during all operating conditions of the turbine when receiving exhaust gas from the internal combustion engine.

[0102] The auxiliary passage may define a cross section perpendicular to the direction of the auxiliary flow, and the narrowest portion of the cross section may be sized such that the mass flow of the auxiliary flow does not exceed approximately 5% of the mass flow of exhaust gas delivered from the engine to the turbine inlet passage.

[0103] The auxiliary passage may include: an auxiliary passage inlet positioned in the turbine inlet passage; and an auxiliary passage outlet positioned in the turbine outlet passage.

[0104] The auxiliary passage may include a valve configured to control flow through the auxiliary passage.

[0105] The valve may be configured such that the auxiliary flow is allowed to pass through the valve during all operating conditions of the turbine.

[0106] The valve may be configured such that the auxiliary flow through the valve always accounts for at least about 1% of the mass flow of exhaust gas delivered from the engine to the turbine inlet passage.

[0107] The turbine may also include a wastegate device, which may include: a wastegate passage, which fluidly connects the turbine inlet passage and the turbine outlet passage so that exhaust gas traveling through the wastegate passage does not travel through the turbine impeller chamber; and a wastegate valve, which is configured to selectively allow or prevent fluid flow through the wastegate passage.

[0108] The wastegate passage may be configured to direct wastegate flow into the spray region of the turbine outlet passage.

[0109] The wastegate passage may fluidly merge with the auxiliary passage such that the wastegate passage is in fluid communication with the turbine outlet passage via the auxiliary passage.

[0110] The dosing module may be configured to deliver the aftertreatment fluid to the turbine outlet passage via the auxiliary passage.

[0111] The auxiliary passage may include an auxiliary passage inlet configured to receive exhaust gas from the turbine outlet passage and an auxiliary passage outlet configured to deliver exhaust gas to the turbine outlet passage.

[0112] The auxiliary passage may include an outlet portion extending from the nozzle to the auxiliary passage outlet, the outlet portion may define an outlet axis, and the outlet axis may be inclined at an angle of up to about 70° relative to a centerline of the turbine outlet passage.

[0113] The auxiliary passage may include an inlet portion extending from an auxiliary passage inlet to the nozzle, the inlet portion may define an inlet axis, and the inlet axis may be inclined at an angle between about 20° and about 70° relative to a centerline of the turbine outlet passage.

[0114] The cross-sectional area of ​​the outlet portion of the auxiliary channel may increase along the outlet axis from the nozzle of the dosing module to the auxiliary channel outlet.

[0115] The turbine outlet passage may define a diffuser portion, and the dosing module may be oriented such that the spray region is located within the diffuser portion.

[0116] The turbine may include a turbine impeller having an outlet inducer portion defining an outlet inducer diameter, and the dosing module may be oriented such that at least a portion of the spray area is positioned within approximately 10 times the outlet inducer diameter of the turbine impeller relative to a centerline of the turbine outlet passage.

[0117] The turbine may include a housing having a mounting structure to which the dosing module is mounted, and the housing may define a bore through which a nozzle of the dosing module passes.

[0118] The aperture may be located within a range of no more than about 10 inducer diameters from the turbine wheel relative to a centerline of the turbine outlet passage.

[0119] According to a third aspect of the present invention, a turbine for a turbocharger is provided, comprising: a turbine inlet passage, the turbine inlet passage being configured to receive exhaust gas from an internal combustion engine, the exhaust gas received by the turbine inlet passage defining a turbine main flow; a turbine impeller chamber, the turbine impeller chamber being configured to receive the turbine main flow from the turbine inlet passage, the turbine impeller chamber being configured to accommodate a turbine impeller, the turbine impeller being supported for rotation; a turbine outlet passage, the turbine outlet passage being configured to receive exhaust gas from the turbine impeller chamber The chamber receives the turbine main flow, the turbine outlet channel is at least partially defined by the turbine outlet channel surface, and the turbine outlet channel defines a center line; an auxiliary channel, the auxiliary channel is configured to receive a portion of the turbine main flow, the portion of the turbine main flow received by the auxiliary channel defines an auxiliary flow; and a distribution module, the distribution module is configured to deliver a spray of post-treatment fluid into the turbine outlet channel; wherein the auxiliary channel is configured to guide the auxiliary flow along the turbine outlet channel surface in an auxiliary flow layer.

[0120] The secondary flow layer encompasses the layer of fluid flowing over the turbine outlet passage surface, which exerts a shearing action on the surface. The creation of the secondary flow layer provides a number of distinct advantages.

[0121] First, the auxiliary flow layer can act as a fluid barrier that substantially inhibits the aftertreatment fluid from reaching the surface of the turbine outlet channel. In this context, it should be understood that the fluid barrier covers the fluid interaction between the auxiliary flow and the aftertreatment fluid, in which the two fluids exchange momentum in a manner that the aftertreatment fluid is deflected away from the surface of the turbine outlet channel. In particular, the auxiliary flow applies a shear force to the aftertreatment fluid, thereby preventing the aftertreatment fluid from contacting the surface of the turbine outlet channel or substantially reducing the amount of the aftertreatment fluid that can contact the surface of the turbine outlet channel. The shear force can further cause the droplets of the aftertreatment fluid to split, thereby reducing their relative mass and making the droplets more easily deflected. Therefore, the auxiliary flow layer acts as a "cushion" that inhibits the aftertreatment fluid from contacting the surface of the turbine outlet channel. Therefore, droplets of the aftertreatment fluid are less likely to solidify on the surface of the turbine outlet channel.

[0122] Second, the shearing action of the auxiliary flow layer will "disperse" any post-treatment fluid that reaches the surface of the turbine outlet passage. In other words, the auxiliary flow layer acts to thin any post-treatment fluid film formed on the turbine outlet passage. This "thinning" or "dispersion" action increases the surface area of ​​the post-treatment fluid and thereby allows more heat to be transferred to the post-treatment fluid. Since more heat is transferred to the post-treatment fluid, the post-treatment fluid evaporates more easily. This improves the decomposition of the post-treatment fluid and reduces the chance of the post-treatment fluid solidifying and forming a blockage in the turbine outlet passage.

[0123] Third, the shearing action of the auxiliary flow layer also acts to strip the aftertreatment fluid that has been deposited on the surface of the turbine outlet passage from the surface, causing the aftertreatment fluid to be re-entrained in the exhaust gas. By re-entraining the aftertreatment fluid, the decomposition of the aftertreatment fluid is improved, and the aftertreatment fluid is less likely to solidify. Finally, the shearing action simply pushes the aftertreatment fluid further downstream and towards further aftertreatment components, such as SCR catalyst devices, etc.

[0124] As a result of the above effects, the use of the auxiliary flow layer makes the turbine outlet channel a suitable location for injecting the after-treatment fluid. In particular, as described above, the risk of forming after-treatment fluid deposits in the turbine outlet channel is reduced, and the turbine outlet channel can therefore be used as a decomposition chamber for receiving and decomposing the after-treatment fluid. This means that the dosing module can be placed closer to the turbine impeller than was previously possible. The temperature of the turbine main body flow will be higher near the turbine impeller, and therefore the temperature of the turbine main body flow can be used to provide better heat transfer to the after-treatment fluid, so that the after-treatment fluid is decomposed more quickly into the reductant required to support the SCR reaction.

[0125] An "auxiliary flow" encompasses exhaust gas that has traveled through an auxiliary passage. The momentum of the auxiliary flow is primarily affected by the geometry and flow conditions within the auxiliary passage. Once the auxiliary flow leaves the auxiliary passage, it dissipates until it completely merges with the main turbine flow. An "auxiliary passage" encompasses a passage that is separate and distinct from the turbine outlet passage. In some embodiments, the auxiliary passage may be a wastegate passage that bypasses the turbine impeller and includes a wastegate valve. However, in alternative embodiments, the auxiliary passage may not bypass the turbine impeller and / or may not include a wastegate valve.

[0126] The distribution module may include a nozzle in fluid communication with the turbine outlet channel, the nozzle may be configured to produce a spray of the post-treatment fluid; and the nozzle may be positioned on a side of the turbine outlet channel opposite to the auxiliary flow layer. Optionally, during use, the auxiliary flow layer may inhibit the post-treatment fluid from reaching the portion of the turbine outlet channel surface opposite to the nozzle. That is, at least a portion of the nozzle and the auxiliary flow layer of the distribution module are arranged on opposite sides of the turbine outlet channel. Therefore, the auxiliary flow layer is able to "capture" the post-treatment fluid distributed by the nozzle and hinder or prevent the post-treatment fluid from contacting the portion of the turbine outlet channel surface roughly opposite to the nozzle. The auxiliary flow layer can also apply high shear forces to any fluid that has impacted the turbine outlet channel surface, thereby dispersing the impacted fluid and increasing heat transfer to the impacted fluid to prevent solidification of deposits. The nozzle can be aligned so that the nozzle is substantially flush with the side wall of the turbine outlet channel. The term "substantially flush" covers the distribution module being roughly aligned or precisely aligned with the inner surface of the turbine outlet channel that defines the periphery of the turbine outlet channel. In such an embodiment, the nozzle does not protrude into the turbine outlet channel. Thus, the nozzle does not create an obstruction to the flow through the turbine outlet passage and thus avoids applying back pressure to the internal combustion engine.The spray of aftertreatment fluid may be atomized.

[0127] The auxiliary channel can be configured to guide the auxiliary flow layer in a generally axial direction downstream relative to the centerline. The main flow of the turbine travels through the turbine outlet channel in a generally axial direction. When the auxiliary channel guides the auxiliary flow layer in a generally axial direction, the momentum of the auxiliary flow layer and the momentum of the main flow of the turbine act in generally the same direction. Therefore, the two momentums work together to increase the shear force in the auxiliary flow layer.

[0128] The turbine may include a shield structure protruding into the turbine outlet passage, and the shield structure may define a portion of the auxiliary passage.

[0129] The turbine impeller can impart vortex momentum to the main flow of the turbine, the vortex momentum of the main flow of the turbine can define a positive angle direction, and the auxiliary channel can be configured to deliver the auxiliary flow to the turbine outlet channel in the direction of inducing the auxiliary flow layer to swirl around the center line along the positive angle direction. Since the auxiliary channel delivers the auxiliary flow to the turbine outlet channel in the direction of inducing the vortex in the same angle direction as the main flow of the turbine, the vortex momentum of the auxiliary flow will be imparted to the vortex momentum of the main flow of the turbine, thereby increasing the amplitude of the vortex momentum of the main flow of the turbine. The rotational momentum of the combination of the turbine and the auxiliary flow increases, further increasing the speed and shear stress of the auxiliary flow layer. This increases the amount of energy available in the auxiliary flow layer for deflection and decomposition of the post-treatment fluid, and thus improves the "buffer" effect. In addition, when the auxiliary flow has vortex momentum, the auxiliary flow layer acts as a fluid agitator, which mixes the main flow of the turbine more thoroughly. This improves heat transfer to the post-treatment fluid, thereby ensuring that more post-treatment fluid is decomposed at a faster rate.

[0130] The increased velocity and shear near the surface of the turbine outlet channel make the turbine outlet channel a suitable location for injecting the aftertreatment fluid. In particular, the aftertreatment fluid injected into the turbine outlet channel will be deflected by the high velocity and high shear exhaust gas and prevented from reaching the surface of the turbine outlet channel. Therefore, the risk of aftertreatment fluid pooling and deposit formation in the turbine outlet channel is reduced, and the turbine outlet channel can therefore be used as a decomposition chamber for receiving and decomposing the aftertreatment fluid.

[0131] In order to achieve a vortex in a positive direction, the auxiliary channel can be configured to convey the auxiliary flow in a direction having a directional component that is tangential to the turbine outlet channel surface in a plane normal to the centerline. In other words, the auxiliary flow can have a directional component that is tangential to the turbine outlet channel surface in a plane normal to the centerline. Since the auxiliary flow has a directional component that is tangential to the turbine outlet channel surface, the turbine outlet channel surface will induce the auxiliary flow to vortex around the centerline.

[0132] The auxiliary passage may be configured to deliver the auxiliary flow into the turbine outlet passage in a direction between 0° and about 60° relative to a direction normal to the centerline. That is, the auxiliary passage may be configured such that in the absence of any turbine main flow, the auxiliary flow will enter the turbine outlet passage in a direction that is normal to the turbine axis (or the centerline of the turbine outlet passage) or inclined up to about 60° relative to such normal direction.

[0133] The auxiliary channel can be configured to deliver the auxiliary flow to the turbine outlet channel at a swirl angle between about 30° and about 85°. The term "swirl angle" covers the angle between the velocity vector of the flow during use and the directional component of the velocity vector parallel to the center line. In other words, the velocity vector can define the hypotenuse of a right triangle, the directional component of the velocity vector parallel to the center line can define the adjacent side of the triangle, and the directional component of the velocity vector tangent to the turbine outlet channel surface in a plane normal to the center line can define the opposite side of the triangle. The swirl angle is the angle between the hypotenuse and the adjacent side of the triangle.

[0134] The auxiliary channel may be at least partially defined by an auxiliary channel surface, wherein the auxiliary channel surface and the turbine outlet channel surface define an interface therebetween, and at the interface, the auxiliary channel surface may be substantially tangential to the turbine outlet channel surface. "Substantially tangential" should be understood as meaning that the auxiliary channel surface and the turbine outlet channel surface may be completely tangential to each other, or may have some angular misalignment as described below. When the two surfaces are tangential to each other, this ensures that the auxiliary flow is smoothly delivered to the turbine outlet channel, thereby minimizing flow recirculation or disturbances near the turbine outlet channel surface.

[0135] At the interface, the auxiliary channel surface may be inclined at an angle of up to about 15° relative to the tangent of the turbine outlet channel surface in a plane normal to the centerline. The angle of misalignment may be in a positive direction or in a negative direction relative to the tangent of the turbine outlet channel surface. It has been found that flow recirculation and disturbances are minimized when the angular misalignment between the two surfaces is within the above range. Preferably, the auxiliary channel surface is as tangent to the tangent of the turbine outlet channel surface as possible. Alternatively, the auxiliary channel surface may be inclined at an angle of up to about 2°, about 5° or about 10° relative to the tangent of the turbine outlet channel surface. When the relative angle between the tangent of the auxiliary outlet channel surface and the turbine outlet channel surface increases, it is preferred for the interface therebetween to transition from one surface to the other as smoothly as possible.

[0136] The turbine may also include a sensor device, the sensor device including a sensor channel having a sensor channel inlet and a sensor channel outlet; the sensor channel inlet may be configured to receive a portion of the turbine main flow from the turbine outlet channel to define a sensor flow, and the sensor channel outlet may be configured to deliver the sensor flow to the turbine outlet channel; and the auxiliary channel may be configured to guide the auxiliary flow into the turbine outlet channel so that the auxiliary flow layer passes downstream of the sensor channel outlet. That is, the auxiliary channel may be configured so that the auxiliary flow layer does not pass upstream of the sensor channel outlet. In some embodiments, the sensor channel may be defined by a conduit extending at least partially into the turbine outlet channel. If the auxiliary flow layer passes upstream of the sensor channel outlet, the auxiliary flow layer will impact the conduit, thereby generating unnecessary additional turbulence and dissipating energy from the auxiliary flow layer. However, when the auxiliary flow layer passes downstream of the sensor channel outlet, the auxiliary flow layer misses the conduit, and thus the flow disturbance to the auxiliary flow layer is minimized.

[0137] The turbine may be configured as a network of exhaust ducts connected to a downstream of the turbine outlet channel, the network may include a curved portion configured to receive the turbine main flow from the turbine outlet channel; and the auxiliary channel may be configured to guide the auxiliary flow into the turbine outlet channel so that the auxiliary flow layer passes through the outer top end of the curved portion. Due to the axial momentum of the turbine main flow, any aftertreatment fluid carried by the turbine main flow may impact the outer top end of the curved portion. However, since the auxiliary flow layer is guided through the outer top end of the curved portion, the auxiliary flow layer is able to form a fluid barrier on the outer top end of the curved portion, thereby inhibiting the aftertreatment fluid from contacting the outer top end and forming deposits. The term "outer top end" refers to the inner surface of the radially outermost portion of the curved portion relative to the axis of curvature of the curved portion.

[0138] The auxiliary channel may include an auxiliary channel outlet, which is configured to deliver the auxiliary flow into the turbine outlet channel so that the thickness of the auxiliary flow layer is between at least about 5% and at most about 25% of the distance defined between the turbine outlet channel surface and the centerline. Alternatively, the thickness of the auxiliary flow layer can be about 10%, 15% or 20% of the distance between the turbine outlet channel and the centerline. As the thickness of the auxiliary flow layer increases, the shear momentum that can be used to deflect the post-treatment fluid and prevent the post-treatment fluid from reaching the auxiliary channel surface is greater. It has been found that in order to provide a sufficient amount of shear momentum, the thickness of the auxiliary flow layer should be at least about 5% of the distance from the turbine outlet channel surface to the centerline. However, if the thickness of the auxiliary flow layer increases too much, the auxiliary flow layer will hinder the turbine body flow from traveling through the turbine outlet channel. It has been found that the thickness of the auxiliary flow layer should therefore not exceed about 25% of the distance from the turbine outlet channel surface to the centerline. When the cross-section of the turbine outlet passage is substantially circular, the distance defined between the turbine outlet passage surface and the centre line may be a radius of the turbine outlet passage surface relative to the centre line.

[0139] The auxiliary channel may include an auxiliary channel outlet, which is configured to deliver the auxiliary flow into the turbine outlet channel so that the width of the auxiliary flow layer can be between about 50% and about 100% of the diameter of the turbine outlet channel defined by the turbine outlet channel surface. Typically, the distribution module spreads the post-treatment fluid in a conical spray area. It should be understood that in order to form an effective fluid barrier to hinder contact between the post-treatment fluid and the turbine outlet channel surface, the auxiliary flow layer must be wide enough to capture the post-treatment fluid that has been spread by the distribution module. The diameter of the turbine outlet channel surface can be taken from a plane normal to the centerline of the centroid of the auxiliary channel outlet.

[0140] The auxiliary channel outlet may define a width and a depth, and the depth may be about 15% to about 50% of the width, and preferably may be about 25% of the width. Thus, the auxiliary channel opening is long and narrow, so that it is roughly "letterbox" shaped. When the auxiliary channel is long and narrow, this forms the auxiliary flow layer into a wide "blanket" covering a large area of ​​the turbine outlet channel surface. In addition, the narrow depth relative to the width can serve to accelerate the auxiliary flow into the turbine outlet channel. Therefore, the shear force in the auxiliary flow layer is sufficient to provide the above-mentioned effects, while the auxiliary flow layer is wide enough to capture as much post-treatment fluid as possible.

[0141] The auxiliary passage may include a wastegate valve configured to selectively allow or prevent the auxiliary flow from traveling through the auxiliary passage; the wastegate valve may include a valve opening defining a valve flow area; the auxiliary passage outlet may define an auxiliary flow area in a plane normal to the direction of the auxiliary flow; and the auxiliary flow area may be approximately 1.2 times the valve flow area. Since the auxiliary flow area is larger than the valve flow area, it prevents blockage from occurring at the auxiliary passage outlet.

[0142] The auxiliary channel may be configured to receive the portion of the turbine main flow from the turbine inlet channel. In this way, the auxiliary airflow bypasses the turbine impeller chamber. Since the auxiliary flow is taken from a position upstream of the turbine impeller, the pressure of the auxiliary flow is higher than the pressure of the turbine main flow. Therefore, more energy is available in the auxiliary flow layer to deflect and break up droplets of the post-treatment fluid, thereby improving the buffering effect.

[0143] The auxiliary channel may include a valve configured to control the flow of the auxiliary flow through the auxiliary channel. In such embodiments, the auxiliary channel is functionally equivalent to a wastegate channel. When the valve is closed, substantially all exhaust gas delivered to the turbine will travel through the turbine impeller as a turbine main flow. Under such conditions, the flow of the turbine main flow may be high enough to prevent the aftertreatment fluid from impacting the turbine outlet channel surface. This can be assisted by one or more other features of the turbine, which serve to hinder the contact between the aftertreatment fluid and the turbine outlet channel surface, such as diffusers, turbulators, etc., which can improve the mixing of the aftertreatment fluid and the turbine main flow. When the valve is opened, the energy of the turbine main flow will be reduced, and therefore the aftertreatment fluid can more easily impact the turbine outlet channel surface. However, since the auxiliary channel delivers the auxiliary flow to the turbine outlet channel in an auxiliary flow layer, the aftertreatment fluid is "buffered" by the auxiliary flow layer and is prevented from contacting the turbine outlet channel surface.

[0144] The auxiliary passage may be sized so that when the valve is open, the flow rate of the auxiliary flow through the auxiliary passage is between at least about 25% of the flow rate of the main turbine flow received by the turbine inlet passage. In order to provide an adequate wastegate effect, the auxiliary passage needs to be large enough so that the amount of exhaust gas bypassing the turbine wheel results in a significant drop in the amount of power produced by the turbine wheel. It has been found that the auxiliary passage should therefore be able to receive at least about 25% to at least about 50% of the total exhaust gas delivered to the turbine.

[0145] The auxiliary channel may include an auxiliary channel outlet configured to deliver the auxiliary flow to the turbine outlet channel, and the valve may be positioned at the auxiliary channel outlet. During use, when the valve moves between a closed position and an open position, the valve will define an opening of variable size. When the opening is smaller, the auxiliary flow will accelerate through the opening. In a conventional wastegate arrangement, the valve is typically positioned near the inlet of the wastegate channel (rather than near the outlet of the wastegate channel). Therefore, the wastegate flow traveling through the valve will expand in the wastegate channel, causing the wastegate flow to decelerate. However, in the present embodiment, by positioning the valve at the auxiliary channel outlet, it is possible to ensure that the auxiliary flow entering the turbine outlet channel has a higher velocity. This further increases the shear momentum of the auxiliary flow in the auxiliary flow layer, thereby improving the "buffering" effect.

[0146] The valve is positioned "at" the auxiliary passage outlet can at least encompass that the valve is configured to selectively block the auxiliary passage outlet itself. Additionally or alternatively, the auxiliary passage outlet can define a depth in a plane normal to the centerline, and the valve can be positioned upstream of the auxiliary passage outlet no more than about twice such depth.

[0147] In alternative embodiments, the valve may not be positioned at the auxiliary channel outlet, and may, for example, be placed upstream of the auxiliary channel outlet. For example, the valve may be positioned upstream of the turbine channel outlet by about 6, 7, 8, 10, or 15 times the depth of the turbine channel outlet.

[0148] The auxiliary passage may be configured to receive the portion of the turbine body flow from the turbine outlet passage.

[0149] The auxiliary passage may be configured such that the auxiliary flow is always allowed to pass through the auxiliary passage. That is, the auxiliary passage may be substantially free of control means, such as valves, etc., for preventing fluid flow through the auxiliary passage. Thus, the auxiliary passage may be considered to be "always open". In such an embodiment, the auxiliary flow layer is always present in the turbine passage outlet and thus provides a "buffer" effect under all operating conditions of the turbine.

[0150] The auxiliary passage can be sized so that, during use, the flow rate of the auxiliary flow can be about 0.5% to about 2% of the flow rate of the main turbine flow received by the turbine inlet passage. When the auxiliary passage is "always open", a portion of the exhaust gas will always be able to bypass the turbine impeller, and therefore the efficiency of the turbine will decrease. However, it has been found that when the auxiliary flow is small enough compared to the total exhaust gas delivered to the turbine, the efficiency drop of the turbine is minimal or negligible. In an alternative embodiment, the auxiliary passage can receive about 1%, 1.5%, 2%, 2.5%, 3%, 4% or 5% of the main turbine flow. Generally, the larger the auxiliary flow is in proportion to the main turbine flow delivered to the turbine by the engine, the more energy can be used to support the "buffer" effect of the auxiliary flow layer.

[0151] The auxiliary channel may include an auxiliary channel outlet and may define a flow area normal to the flow direction of the auxiliary flow through the auxiliary channel, and the flow area may narrow toward the auxiliary channel outlet. As the flow area narrows toward the auxiliary channel outlet, the auxiliary flow is accelerated as it travels through the auxiliary channel outlet. This may result in higher shear forces in the auxiliary flow layer, thereby inhibiting the aftertreatment fluid from reaching the turbine outlet channel surface.

[0152] The auxiliary passage may include a plurality of auxiliary passage outlets configured to deliver the auxiliary flow into the turbine outlet passage.

[0153] The auxiliary passage may include a first branch and a second branch, the first branch may define the auxiliary passage outlet, and the second branch may define a second auxiliary passage outlet, the second auxiliary passage outlet may be positioned on a side of the turbine outlet passage generally opposite the auxiliary passage outlet.

[0154] The auxiliary channel outlets may be equidistantly distributed around the center line.

[0155] The auxiliary channel may include a plenum chamber and a plurality of branches fluidly connected to the plenum chamber, the plenum chamber may be configured to receive the auxiliary flow from the auxiliary channel inlet, and the branches may be configured to deliver the auxiliary flow to the auxiliary channel outlet.

[0156] Each of the branches may be configured to deliver the secondary flow to the turbine outlet passage in a direction that may induce a swirl of the secondary flow layer about the centerline.

[0157] The auxiliary channel may include: a first auxiliary channel branch, which is configured to receive a first auxiliary flow portion and guide the first auxiliary flow portion into the turbine outlet channel as a first auxiliary flow layer; and a second auxiliary channel branch, which is configured to receive a second auxiliary flow portion and guide the second auxiliary flow portion into the turbine outlet channel as a second auxiliary flow layer.

[0158] The first auxiliary channel branch can be configured to guide the first auxiliary flow layer downstream relative to the center line in a generally axial direction into the turbine outlet channel; and the second auxiliary channel branch can be configured to guide the second auxiliary flow layer downstream relative to the center line in a generally axial direction into the turbine outlet channel.

[0159] The first auxiliary channel branch can be configured to guide the first auxiliary flow layer into the turbine outlet channel along a direction that induces a vortex in the first auxiliary flow layer along a positive angle direction around the center line; and the second auxiliary channel branch can be configured to guide the second auxiliary flow layer into the turbine outlet channel along a direction that induces a vortex in the second auxiliary flow layer along the positive angle direction around the center line.

[0160] The first auxiliary channel branch can be configured to guide the first auxiliary flow layer into the turbine outlet channel in a substantially axial direction downstream relative to the center line; and the second auxiliary channel branch can be configured to guide the second auxiliary flow layer into the turbine outlet channel in a direction that induces a vortex in the second auxiliary flow layer along the positive angle direction around the center line.

[0161] The turbine outlet passage may define a diffuser portion, and the turbine outlet passage surface may be a surface of the diffuser portion.

[0162] The turbine may include a housing assembly having a turbine housing defining the turbine inlet passage and the turbine wheel chamber and a connection adapter defining the turbine outlet passage surface and at least a portion of the turbine outlet passage.

[0163] The third aspect of the present invention may be embodied in a turbocharger.

[0164] According to a fourth aspect of the present invention, a method for operating a turbine for a turbocharger is provided, comprising: receiving exhaust gas from an internal combustion engine into a turbine inlet channel, the exhaust gas received by the turbine inlet channel defining a turbine main flow; receiving the turbine main flow from the turbine inlet channel into a turbine impeller chamber, the turbine impeller chamber being configured to accommodate a turbine impeller, the turbine impeller being supported for rotation; receiving the turbine main flow from the turbine impeller chamber into a turbine outlet channel, the turbine outlet channel being at least partially defined by a turbine outlet channel surface, the turbine outlet channel defining a centerline; receiving a portion of the turbine main flow into an auxiliary channel, the portion of the turbine main flow received by the auxiliary channel defining an auxiliary flow; delivering a spray of a post-treatment fluid into the turbine outlet channel using a dosing module; and guiding the auxiliary flow along the turbine outlet channel surface with an auxiliary flow layer.

[0165] The distribution module may include a nozzle connected to the turbine outlet channel fluid, and the nozzle may be configured to produce a spray of after-treatment fluid; and the nozzle may be positioned on a side of the turbine outlet channel opposite to the auxiliary flow layer, so that during use, the auxiliary flow layer can inhibit the after-treatment fluid from reaching the portion of the turbine outlet channel surface opposite to the nozzle.

[0166] The secondary passage may be configured to direct the secondary flow layer in a generally axial direction downstream relative to the centerline.

[0167] The turbine may include a shield structure protruding into the turbine outlet passage, and the shield structure may define a portion of the auxiliary passage.

[0168] The turbine impeller may impart a swirl momentum to the turbine main flow, the swirl momentum of the turbine main flow may define a positive angular direction, and the auxiliary channel may be configured to deliver the auxiliary flow to the turbine outlet channel in a direction that may induce a swirl of the auxiliary flow layer about the centerline along the positive angular direction.

[0169] The auxiliary passage may be configured to deliver the auxiliary flow into the turbine outlet passage in a direction between 0° and about 60° relative to a direction normal to the centerline.

[0170] The auxiliary passage may be configured to deliver the auxiliary flow to the turbine outlet passage at a swirl angle of between about 30° and about 85°.

[0171] The auxiliary passage may be at least partially defined by an auxiliary passage surface, the auxiliary passage surface and the turbine outlet passage surface may define an interface therebetween, and the auxiliary passage surface may be generally tangential to the turbine outlet passage surface at the interface.

[0172] At the interface, the secondary duct surface may be inclined at an angle of up to about 15° relative to a tangent to the turbine outlet duct surface in a plane normal to the centre line.

[0173] The turbine may also include a sensor device, which includes a sensor channel having a sensor channel inlet and a sensor channel outlet; the sensor channel inlet may be configured to receive a portion of the turbine main flow from the turbine outlet channel to define a sensor flow, and the sensor channel outlet may be configured to deliver the sensor flow to the turbine outlet channel; and the auxiliary channel may be configured to guide the auxiliary flow into the turbine outlet channel so that the auxiliary flow layer passes downstream of the sensor channel outlet.

[0174] The turbine may be configured to be connected to a network of exhaust ducts downstream of the turbine outlet channel, the network may include a curved portion configured to receive the turbine main flow from the turbine outlet channel; and the auxiliary channel may be configured to guide the auxiliary flow into the turbine outlet channel so that the auxiliary flow layer passes through the outer top end of the curved portion.

[0175] The auxiliary channel may include an auxiliary channel outlet configured to deliver the auxiliary flow into the turbine outlet channel so that the thickness of the auxiliary flow layer may be between at least about 5% and at most about 25% of the distance defined between the turbine outlet channel surface and the centerline.

[0176] The auxiliary channel may include an auxiliary channel outlet configured to deliver the auxiliary flow into the turbine outlet channel such that a width of the auxiliary flow layer may be between about 50% and about 100% of a diameter of the turbine outlet channel defined by the turbine outlet channel surface.

[0177] The secondary channel outlet may define a width and a depth, and the depth may be about 15% to about 50% of the width, and preferably may be about 25% of the width.

[0178] The auxiliary channel may include a waste gate valve configured to selectively allow or prevent the auxiliary flow from traveling through the auxiliary channel; the waste gate valve may include a valve opening that defines a valve flow area; the auxiliary channel outlet may define an auxiliary flow area in a plane normal to the direction of the auxiliary flow; the auxiliary flow area may be approximately 1.2 times the valve flow area.

[0179] The auxiliary passage may be configured to receive the portion of the turbine body flow from the turbine inlet passage.

[0180] The auxiliary passage may include a valve configured to control a flow rate of the auxiliary flow through the auxiliary passage.

[0181] The auxiliary passage may be sized such that when the valve is open, the flow rate of the auxiliary flow through the auxiliary passage may be between at least about 25% of the flow rate of the main turbine flow received by the turbine inlet passage.

[0182] The auxiliary passage may include an auxiliary passage outlet configured to deliver the auxiliary flow into the turbine outlet passage, and the valve may be positioned at the auxiliary passage outlet.

[0183] The auxiliary passage may be configured to receive the portion of the turbine body flow from the turbine outlet passage.

[0184] The auxiliary channel may be configured such that an auxiliary flow is always allowed to pass through the auxiliary channel.

[0185] The auxiliary passage may be sized such that, during use, the flow rate of the auxiliary flow may be about 0.5% to about 2% of the flow rate of the main turbine flow received by the turbine inlet passage.

[0186] The auxiliary channel may include an auxiliary channel outlet and may define a flow area normal to a flow direction of the auxiliary flow through the auxiliary channel, and the flow area may narrow toward the auxiliary channel outlet.

[0187] The auxiliary passage may include a plurality of auxiliary passage outlets configured to deliver the auxiliary flow into the turbine outlet passage.

[0188] The auxiliary passage may include a first branch and a second branch, the first branch may define the auxiliary passage outlet, and the second branch may define a second auxiliary passage outlet, the second auxiliary passage outlet may be positioned on a side of the turbine outlet passage generally opposite the auxiliary passage outlet.

[0189] The auxiliary channel outlets may be equidistantly distributed around the center line.

[0190] The auxiliary channel may include a plenum chamber and a plurality of branches fluidly connected to the plenum chamber, the plenum chamber may be configured to receive the auxiliary flow from the auxiliary channel inlet, and the branches may be configured to deliver the auxiliary flow to the auxiliary channel outlet.

[0191] Each of the branches may be configured to deliver the secondary flow to the turbine outlet passage in a direction that may induce a swirl of the secondary flow layer about the centerline.

[0192] The auxiliary channel may include: a first auxiliary channel branch, which is configured to receive a first auxiliary flow portion and guide the first auxiliary flow portion into the turbine outlet channel as a first auxiliary flow layer; and a second auxiliary channel branch, which is configured to receive a second auxiliary flow portion and guide the second auxiliary flow portion into the turbine outlet channel as a second auxiliary flow layer.

[0193] The first auxiliary channel branch can be configured to guide the first auxiliary flow layer downstream relative to the center line in a generally axial direction into the turbine outlet channel; and the second auxiliary channel branch can be configured to guide the second auxiliary flow layer downstream relative to the center line in a generally axial direction into the turbine outlet channel.

[0194] The first auxiliary channel branch can be configured to guide the first auxiliary flow layer into the turbine outlet channel along a direction that can induce a vortex in the first auxiliary flow layer around the center line along a positive angle direction; and the second auxiliary channel branch can be configured to guide the second auxiliary flow layer into the turbine outlet channel along a direction that can induce a vortex in the second auxiliary flow layer around the center line along the positive angle direction.

[0195] The first auxiliary channel branch can be configured to guide the first auxiliary flow layer into the turbine outlet channel in a substantially axial direction downstream relative to the center line; and the second auxiliary channel branch can be configured to guide the second auxiliary flow layer into the turbine outlet channel in a direction that can induce a vortex in the second auxiliary flow layer around the center line in the positive angle direction.

[0196] The turbine outlet passage may define a diffuser portion, and the turbine outlet passage surface may be a surface of the diffuser portion.

[0197] The turbine may include a housing assembly having a turbine housing defining the turbine inlet passage and the turbine wheel chamber and a connection adapter defining the turbine outlet passage surface and at least a portion of the turbine outlet passage.

[0198] According to a fifth aspect of the present invention, there is provided a post-treatment system for an internal combustion engine system, comprising: a decomposition chamber, the decomposition chamber being configured to receive a main flow from the internal combustion engine, the decomposition chamber being at least partially defined by a decomposition chamber surface, and the decomposition chamber defining a center line; an auxiliary channel, the auxiliary channel being configured to receive a portion of the main flow, the portion of the main flow received by the auxiliary channel defining an auxiliary flow; and a distribution module, the distribution module being configured to deliver a spray of the post-treatment fluid into the decomposition chamber; wherein the auxiliary channel is configured to guide the auxiliary flow along the decomposition chamber surface in an auxiliary flow layer.

[0199] Therefore, the main difference between this aspect of the present invention and the previous (fourth) aspect of the present invention for a turbine of a turbocharger is that the auxiliary flow layer is formed in the decomposition chamber instead of in the turbine outlet channel. Apart from this difference, it should be understood that the working principle and advantages of this aspect of the present invention are the same or equivalent to the previous aspects of the present invention. In particular, the decomposition chamber of this aspect can be considered to be equivalent to the turbine outlet channel of the previous aspect, the decomposition chamber surface of this aspect can be considered to be equivalent to the auxiliary channel surface of the previous aspect, the auxiliary channel of this aspect can be considered to be equivalent to the auxiliary channel of the previous aspect, and the distribution module of this aspect can be considered to be equivalent to the distribution module of the previous aspect. Since the basic operating principles are the same, it should be understood that this aspect can include any optional features of the above-mentioned previous aspects. Nevertheless, additional optional features of this aspect are presented below.

[0200] The distribution module may include a nozzle connected to the decomposition chamber fluid, and the nozzle may be configured to produce the spray of the post-treatment fluid; and the nozzle may be positioned on a side of the decomposition chamber opposite to the auxiliary flow layer, so that during use, the auxiliary flow layer may inhibit the post-treatment fluid from reaching the portion of the decomposition chamber surface opposite to the nozzle.

[0201] The secondary passage may be configured to direct the secondary flow layer in a generally axial direction downstream relative to the centerline.

[0202] The auxiliary channel may be configured to deliver the auxiliary flow to the decomposition chamber in a direction that may induce a vortex of the auxiliary flow layer about the centerline.

[0203] The auxiliary channel may be configured to deliver the auxiliary flow to the decomposition chamber in a tangential direction relative to a surface of the decomposition chamber in a plane normal to the centerline.

[0204] The internal combustion engine system may include a turbine having a turbine wheel, and the auxiliary passage may receive the auxiliary flow from an upstream position of the turbine wheel. That is, the auxiliary passage serves as a wastegate passage. The auxiliary passage may include a valve device configured to control flow through the auxiliary passage.

[0205] The turbine may impart vortex momentum to the main flow, the vortex momentum of the main flow may define a positive angle direction, and the auxiliary channel may be configured to deliver the auxiliary flow to the decomposition chamber in a direction that may induce the auxiliary flow layer to swirl around the center line along the positive angle direction.

[0206] The swirl momentum imparted by the turbine to the turbine body flow may define a first swirl angle, and the auxiliary passage may be configured to deliver the auxiliary flow to the decomposition chamber at a second swirl angle equal to or steeper than the first swirl angle.

[0207] The auxiliary channel may be configured to deliver the auxiliary flow to the decomposition chamber at a swirl angle between about 30° and about 85°.

[0208] The auxiliary channel may be at least partially defined by an auxiliary channel surface, the auxiliary channel surface and the decomposition chamber surface may define an interface therebetween, and at the interface, the auxiliary channel surface may be substantially tangent to the decomposition chamber surface.

[0209] At the interface, the auxiliary channel surface may be inclined at an angle of up to about 15° relative to a tangent line to the decomposition chamber surface in a plane normal to the centerline.

[0210] The decomposition chamber may further include a sensor device, the sensor device including a sensor channel having a sensor channel inlet and a sensor channel outlet; the sensor channel inlet may be configured to receive a portion of the main flow from the decomposition chamber to define a sensor flow, and the sensor channel outlet may be configured to deliver the sensor flow to the decomposition chamber; and the auxiliary channel may be configured to guide the auxiliary flow into the decomposition chamber so that the auxiliary flow layer may pass downstream of the sensor channel outlet.

[0211] The decomposition chamber may include a curved portion, and the auxiliary channel may be configured to guide the auxiliary flow into the decomposition chamber such that the auxiliary flow layer passes over an outer top end of the curved portion.

[0212] The auxiliary channel may include an auxiliary channel outlet, which is configured to deliver the auxiliary flow into the decomposition chamber so that the thickness of the auxiliary flow layer can be between at least about 5% and at most about 25% of the distance defined between the decomposition chamber surface and the centerline.

[0213] The auxiliary channel may include an auxiliary channel outlet configured to deliver the auxiliary flow into the decomposition chamber such that a width of the auxiliary flow layer may be between about 50% and about 100% of a diameter of the turbine outlet channel defined by the decomposition chamber surface.

[0214] The secondary channel outlet may define a width and a depth, and the depth may be about 15% to about 50% of the width, and preferably may be about 25% of the width.

[0215] The auxiliary passage may include a valve configured to control a flow rate of the auxiliary flow through the auxiliary passage.

[0216] The auxiliary channel may include an auxiliary channel outlet configured to deliver the auxiliary flow into the decomposition chamber, and the valve may be positioned at the auxiliary channel outlet.

[0217] The auxiliary channel may include an auxiliary channel outlet and may define a flow area normal to a flow direction of the auxiliary flow through the auxiliary channel, and the flow area may narrow toward the auxiliary channel outlet.

[0218] The auxiliary channel may include a plurality of auxiliary channel outlets configured to deliver the auxiliary flow into the decomposition chamber.

[0219] The auxiliary channel outlets may be equidistantly distributed around the center line.

[0220] The auxiliary channel may include a plenum chamber and a plurality of branches fluidly connected to the plenum chamber, the plenum chamber may be configured to receive the auxiliary flow from the auxiliary channel inlet, and the branches may be configured to deliver the auxiliary flow to the auxiliary channel outlet.

[0221] Each of the branches may be configured to deliver the secondary flow to the turbine outlet passage in a direction that may induce a swirl of the secondary flow layer about the centerline.

[0222] The auxiliary channel may include: a first auxiliary channel branch, which is configured to receive a first auxiliary flow portion and guide the first auxiliary flow portion into the decomposition chamber as a first auxiliary flow layer; and a second auxiliary channel branch, which is configured to receive a second auxiliary flow portion and guide the second auxiliary flow portion into the decomposition chamber as a second auxiliary flow layer.

[0223] The first auxiliary channel branch can be configured to guide the first auxiliary flow layer downstream relative to the center line in a substantially axial direction into the decomposition chamber; and the second auxiliary channel branch can be configured to guide the second auxiliary flow layer downstream relative to the center line in a substantially axial direction into the decomposition chamber.

[0224] The first auxiliary channel branch can be configured to guide the first auxiliary flow layer into the decomposition chamber along a direction that can induce a vortex in the first auxiliary flow layer around the center line along a positive angle direction; and the second auxiliary channel branch can be configured to guide the second auxiliary flow layer into the decomposition chamber along a direction that can induce a vortex in the second auxiliary flow layer around the center line along the positive angle direction.

[0225] The first auxiliary channel branch can be configured to guide the first auxiliary flow layer into the decomposition chamber in a substantially axial direction downstream relative to the center line; and the second auxiliary channel branch can be configured to guide the second auxiliary flow layer into the decomposition chamber in a direction that can induce a vortex in the second auxiliary flow layer around the center line in the positive angle direction.

[0226] According to a sixth aspect of the present invention, a turbine for a turbocharger is provided, comprising: a turbine inlet passage, the turbine inlet passage being configured to receive exhaust gas from an internal combustion engine, the exhaust gas received by the turbine inlet passage defining a turbine main flow; a turbine impeller chamber, the turbine impeller chamber being configured to receive the turbine main flow from the turbine inlet passage, the turbine impeller chamber accommodating a turbine impeller, the turbine impeller being supported for rotation; a turbine outlet passage, the turbine outlet passage being configured to receive the turbine from the turbine impeller chamber a main flow of the turbine, and the turbine outlet passage defines a center line; an auxiliary passage, the auxiliary passage is configured to receive a portion of the main flow of the turbine, the portion of the main flow of the turbine received by the auxiliary passage defines an auxiliary flow, and wherein the turbine impeller is configured to discharge the main flow of the turbine into the turbine outlet passage so that the main flow of the turbine swirls around the center line in a positive angle direction; and wherein the auxiliary passage is configured to guide the auxiliary flow into the turbine outlet passage in a negative angle direction opposite to the positive angle direction.

[0227] Since the auxiliary flow is guided in an angular direction opposite to the natural vortex motion of the main turbine flow, the auxiliary flow and the main turbine flow collide with each other, resulting in a large amount of turbulence in the turbine outlet channel. The increase in turbulence leads to improved mixing of the main turbine flow, the auxiliary flow and the aftertreatment fluid, so that a larger amount of heat is transferred to the aftertreatment fluid at a faster rate. As a result, the water component of the aftertreatment fluid evaporates more fully and faster, and the urea component is decomposed more quickly into the reductant required to support the SCR reaction. In addition, the improved mixing distributes the decomposed reductant more evenly throughout the main turbine flow downstream of the turbine, thereby ensuring that substantially all downstream SCR catalyst devices have sufficient reductant to support the required reaction.

[0228] An "auxiliary flow" encompasses exhaust gas that has traveled through an auxiliary passage. The momentum of the auxiliary flow is primarily affected by the geometry and flow conditions within the auxiliary passage. Once the auxiliary flow leaves the auxiliary passage, it dissipates until it completely merges with the main turbine flow. An "auxiliary passage" encompasses a passage that is separate and distinct from the turbine outlet passage. In some embodiments, the auxiliary passage may be a wastegate passage that bypasses the turbine impeller and includes a wastegate valve. However, in alternative embodiments, the auxiliary passage may not bypass the turbine impeller and / or may not include a wastegate valve.

[0229] The turbine may further include a distribution module configured to deliver a spray of after-treatment fluid into the turbine outlet passage. The turbine may include a distribution module mount configured to receive a distribution module.

[0230] The auxiliary flow may collide with the main turbine flow in the turbine outlet passage to produce a turbulent region, and the distribution module may include a nozzle configured to produce the spray of the after-treatment fluid, and the nozzle may be oriented to direct the after-treatment fluid into the turbulent region. Since the after-treatment fluid is directed into the turbulent region, the after-treatment fluid is directly delivered to the location in the turbine outlet passage where the maximum amount of mixing occurs. In this way, the decomposition rate of the after-treatment fluid will be accelerated.

[0231] The vortex momentum imparted to the main turbine flow by the turbine impeller may define a first vortex angle, and the auxiliary channel may be configured to deliver the auxiliary flow to the turbine outlet channel at a second vortex angle, the second vortex angle may be equal to the first vortex angle or steeper in magnitude than the first vortex angle. That is, although the vortex angle of the main turbine flow and the vortex angle of the auxiliary flow will be inclined in different directions relative to the centerline, the inclination amplitude of the second vortex angle is equal to or greater than the inclination amplitude of the second vortex angle. Since the second vortex angle is equal to or greater than the first vortex angle in amplitude, this means that the auxiliary flow has sufficient momentum to act in the negative angle direction to cause turbulence in the turbine outlet channel.

[0232] The auxiliary passage may be configured to deliver the auxiliary flow to the turbine outlet passage in a direction between 0° and about 60° relative to a direction that may be orthogonal to the centerline.

[0233] The auxiliary passage may be at least partially defined by an auxiliary passage surface, the auxiliary passage surface and the turbine outlet passage surface may define an interface therebetween, and the auxiliary passage surface may be substantially tangential to the turbine outlet passage surface at the interface. In this way, the momentum of the auxiliary flow is directly opposite to the momentum of the main turbine flow, thereby resulting in maximum turbulence.

[0234] The auxiliary channel may be configured to receive the portion of the turbine main flow from the turbine inlet channel. In this way, the auxiliary flow bypasses the turbine wheel chamber. Since the auxiliary flow is taken from a position upstream of the turbine wheel, the pressure of the auxiliary flow is higher than the pressure of the turbine main flow. Therefore, more energy is used to generate turbulence to ensure complete decomposition of the aftertreatment fluid.

[0235] The auxiliary passage may include a valve configured to control the flow rate of the auxiliary flow through the auxiliary passage. The valve may be, for example, a wastegate valve.

[0236] The auxiliary passage may be sized so that when the valve is open, the flow rate of the auxiliary flow through the auxiliary passage may be between at least about 25% and about 50% of the flow rate of the main turbine flow received by the turbine inlet passage. In order to provide an adequate wastegate effect, the auxiliary passage needs to be large enough so that the amount of exhaust gas bypassing the turbine wheel results in a significant drop in the amount of power produced by the turbine wheel. It has been found that the auxiliary passage should therefore be able to receive at least about 25% to at least about 50% of the total exhaust gas delivered to the turbine.

[0237] The auxiliary passage may be configured to receive the portion of the turbine body flow from the turbine outlet passage.

[0238] The auxiliary channel may be configured so that the auxiliary flow is always allowed to pass through the auxiliary channel. That is, the auxiliary channel may be substantially free of control devices, such as valves, etc., for preventing the flow of fluid through the auxiliary channel. Therefore, the auxiliary channel may be considered to be "always open". In such an embodiment, the auxiliary flow always collides with the main turbine flow in the turbine channel outlet to generate turbulence under all operating conditions of the turbine.

[0239] The size of the auxiliary channel can be set so that, during use, the flow rate of the auxiliary flow can be about 0.1% to about 2% of the flow rate of the main flow of the turbine received by the turbine inlet channel. When the auxiliary channel is "always open", a portion of the exhaust gas will always be able to bypass the turbine impeller, and thus the efficiency of the turbine will decrease. However, it has been found that when the auxiliary flow is small enough compared to the total exhaust gas delivered to the turbine, the efficiency drop of the turbine is at a minimum or negligible. In an alternative embodiment, the auxiliary channel can receive about 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 4% or 5% of the main flow of the turbine. Generally, the larger the auxiliary flow is in proportion to the main flow of the turbine delivered to the turbine by the engine, the more energy can be used to support improved turbulence generation and improved mixing in the turbine outlet channel.

[0240] The auxiliary passage may include an auxiliary passage outlet configured to deliver the auxiliary flow into the turbine outlet passage.

[0241] The turbine outlet passage may define a diffuser section. The diffuser section will cause the turbine body flow to expand and decelerate, thereby causing a turbulent vortex to form in the turbine outlet passage. The turbulent vortex improves mixing to support faster decomposition of the reductant and improves the distribution of the reductant throughout the turbine body flow.

[0242] The auxiliary channel outlet is defined by the surface of the diffuser portion. Since the auxiliary channel outlet is positioned in the diffuser portion, the auxiliary flow collides with the main turbine flow in the diffuser portion. Therefore, the turbulence generated by the diffuser portion and the turbulence region generated by the collision of the auxiliary flow with the main turbine flow occur at the same position within the turbine outlet channel. As a result, the amplitude of turbulent mixing is increased, further improving the decomposition rate, and uniformly distributing the reducing agent throughout the main turbine flow.

[0243] The auxiliary passage may include a plurality of auxiliary passage outlets configured to deliver the auxiliary flow into the turbine outlet passage.

[0244] The turbine may include a housing assembly having a turbine housing defining the turbine inlet passage and the turbine wheel chamber and a connection adapter defining the turbine outlet passage surface and at least a portion of the turbine outlet passage.

[0245] The sixth aspect of the present invention may be embodied in a turbocharger.

[0246] According to a seventh aspect of the present invention, a method for operating a turbine for a turbocharger is provided, comprising: receiving exhaust gas from an internal combustion engine into a turbine inlet channel, the exhaust gas received by the turbine inlet channel defining a turbine main flow; receiving the turbine main flow from the turbine inlet channel into a turbine impeller chamber, the turbine impeller chamber accommodating a turbine impeller, the turbine impeller being supported for rotation; receiving the turbine main flow from the turbine impeller chamber into a turbine outlet channel, the turbine outlet channel defining a center line; receiving a portion of the turbine main flow into an auxiliary channel, the portion of the turbine main flow received by the auxiliary channel defining an auxiliary flow; discharging the turbine main flow into the turbine outlet channel using the turbine impeller so that the turbine main flow swirls around the center line in a positive angle direction; and directing the auxiliary flow into the turbine outlet channel in a negative angle direction opposite to the positive angle direction.

[0247] The method may further include delivering a spray of after-treatment fluid into the turbine outlet passage using a dosing module.

[0248] The auxiliary flow may collide with the turbine main flow within the turbine outlet passage to produce a turbulent region, and the dosing module may include a nozzle configured to produce the spray of after-treatment fluid, the nozzle being oriented to direct the after-treatment fluid into the turbulent region.

[0249] The swirl momentum imparted to the turbine body flow by the turbine impeller may define a first swirl angle, and the auxiliary passage may be configured to deliver the auxiliary flow to the turbine outlet passage at a second swirl angle, which may be equal to the first swirl angle or steeper in magnitude than the first swirl angle.

[0250] The auxiliary passage may be configured to deliver the auxiliary flow to the turbine outlet passage in a direction between 0° and about 60° relative to a direction normal to the centerline.

[0251] The auxiliary passage may be at least partially defined by an auxiliary passage surface, the auxiliary passage surface and the turbine outlet passage surface may define an interface therebetween, and the auxiliary passage surface may be generally tangential to the turbine outlet passage surface at the interface.

[0252] The auxiliary passage may be configured to receive the portion of the turbine body flow from the turbine inlet passage.

[0253] The auxiliary passage may include a valve configured to control a flow rate of the auxiliary flow through the auxiliary passage.

[0254] The auxiliary passage may be sized such that when the valve is open, the flow rate of the auxiliary flow through the auxiliary passage may be between at least about 25% and about 50% of the flow rate of the main turbine flow received by the turbine inlet passage.

[0255] The auxiliary passage may be configured to receive the portion of the turbine body flow from the turbine outlet passage.

[0256] The auxiliary channel may be configured such that an auxiliary flow is always allowed to pass through the auxiliary channel.

[0257] The auxiliary passage may be sized such that, during use, the flow rate of the auxiliary flow may be about 0.1% to about 2% of the flow rate of the main turbine flow received by the turbine inlet passage.

[0258] The auxiliary passage may include an auxiliary passage outlet configured to deliver the auxiliary flow into the turbine outlet passage.

[0259] The turbine outlet passage may define a diffuser portion.

[0260] The secondary channel outlet may be defined by a surface of the diffuser portion.

[0261] The auxiliary passage may include a plurality of auxiliary passage outlets configured to deliver the auxiliary flow into the turbine outlet passage.

[0262] The turbine may include a housing assembly having a turbine housing defining the turbine inlet passage and the turbine wheel chamber and a connection adapter defining the turbine outlet passage surface and at least a portion of the turbine outlet passage.

[0263] According to an eighth aspect of the present invention, a turbine for a turbocharger is provided, comprising: a turbine inlet channel, the turbine inlet channel being configured to receive exhaust gas from an internal combustion engine, the exhaust gas received by the turbine inlet channel defining a turbine main flow; a turbine impeller chamber, the turbine impeller chamber being configured to receive the turbine main flow from the turbine inlet channel, the turbine impeller chamber being configured to accommodate a turbine impeller, the turbine impeller being supported for rotation; a turbine outlet channel, the turbine outlet channel being configured to receive the turbine main flow from the turbine impeller chamber, the turbine impeller chamber being configured to receive the turbine main flow The turbine outlet passage extends along a centerline and is at least partially defined by a first surface of a partition wall; a distribution module configured to deliver a spray of an aftertreatment fluid into the turbine outlet passage; and an auxiliary passage configured to receive a portion of the turbine main flow, the portion of the turbine main flow received by the auxiliary passage defining an auxiliary flow, the auxiliary passage being at least partially defined by a second surface of the partition wall; wherein the partition wall is configured to provide thermal connectivity from the auxiliary passage to the first surface via the second surface.

[0264] The term "turbine main flow" encompasses the main flow of exhaust gas through the turbine. For the most part, this is the exhaust gas received by the turbine from the internal combustion engine, and this exhaust gas flows from the turbine inlet, through the turbine wheel chamber and into the turbine outlet, and then travels downstream to the exhaust aftertreatment system including one or more catalytic reducers (such as DOC or SCR reducers).

[0265] The term "auxiliary passage" encompasses a passage separate from the turbine inlet passage, the turbine wheel chamber, and the turbine outlet passage, and the passage is capable of receiving exhaust gas from a first location of the turbine and delivering the exhaust gas to a second location. The second location may be a location within the turbine outlet. The portion of the auxiliary passage inlet of the turbine from which the exhaust gas is received may be substantially any portion of the turbine that accommodates the exhaust gas but does not form part of the auxiliary passage. For example, this may include one or more of the turbine inlet passage, the turbine wheel chamber, the turbine outlet passage, or the wastegate (i.e., bypass) passage.

[0266] The term "secondary flow" encompasses the exhaust gas flow travelling through the secondary passage. The term "dividing wall" encompasses the structure separating the secondary flow in the secondary passage from the main turbine flow in the turbine outlet passage.

[0267] As used herein, the term "centerline" encompasses a line defined by the centroid of a cross section of a turbine outlet passage along the direction of exhaust gas flow. That is, the centerline of a turbine outlet passage is an imaginary line drawn along the turbine outlet passage that is always located at the center of the geometry of the exhaust gas flowing through the turbine outlet passage. Typically, although not always, the centerline will be an extension of the turbine axis, which may deviate from the turbine axis depending on the geometry of the turbine outlet passage. The turbine axis is the axis about which the turbine wheel is configured to rotate.

[0268] As used herein, the term "distribution module" encompasses any device configured to introduce an aftertreatment fluid into a turbine outlet passage. The aftertreatment fluid may be a fluid required to support a chemical reaction in an exhaust aftertreatment process. For example, the aftertreatment fluid may be DEF for an SCR process. The aftertreatment fluid may include a reductant (i.e., a reducing agent). The term "nozzle" refers to the portion of a distribution module from which the aftertreatment fluid leaves the distribution module. That is, the aftertreatment fluid is ejected from this portion of the distribution module.

[0269] The term "thermal communication" encompasses the transfer of thermal energy from a source location to a heat sink location. For example, this may include transfer by conduction or convective heat transfer.

[0270] During use, when the aftertreatment fluid is injected into the turbine outlet channel, the aftertreatment fluid may impact the first surface. The aftertreatment fluid is usually at a lower temperature than the turbine main flow, and thus forms a heat sink that drives heat from the first surface to the aftertreatment fluid. The first surface is heated by two sources. First, the first surface is heated by the convective heat transfer of the turbine main flow traveling through the turbine outlet channel. Second, the first surface is heated by the auxiliary flow traveling through the auxiliary channel; and specifically by convective heat transfer from the auxiliary flow to the second surface and conductive heat transfer from the second surface through the material of the partition wall to the first surface. Therefore, the first surface and the second surface ensure that a larger surface area can be used to capture heat from the main flow and the auxiliary flow so that heat can be transferred to the collected aftertreatment fluid (for example, compared with the case without the auxiliary channel). As a result, the amount of heat transferred to the aftertreatment fluid after the impact increases, resulting in an increase in the temperature of the aftertreatment fluid until the aftertreatment fluid evaporates. Therefore, the formation of deposits in the turbine outlet channel is reduced or prevented.

[0271] Because the dividing wall and the first surface can mitigate the formation of solid deposits, the aftertreatment fluid can be injected closer to the turbine wheel than previously thought possible. Injecting the aftertreatment fluid closer to the turbine wheel can improve mixing and breakup of the aftertreatment fluid and thereby eliminate the need for any auxiliary mixing baffles or the like downstream.

[0272] The first surface may be disposed on a side of the partition wall opposite to the second surface. In particular, the first surface may be parallel to the second surface and face in a direction opposite to the second surface. Since the first surface and the second surface are located on opposite sides of the partition wall, a direct heat conduction path from the second surface to the first surface is provided, thereby improving heating of the first surface.

[0273] The dividing wall may define a thickness between the first surface and the second surface, the turbine comprising a turbine wheel having an outlet inducer portion, the outlet inducer portion defining an outlet inducer diameter, and the thickness of the dividing wall being about 5% of the outlet inducer diameter. Thus, the dividing wall is relatively thin compared to the flow area of ​​the turbine wheel and the turbine outlet passage. Thus, the first surface is in close proximity to the second surface, thereby improving conductive heat transfer from the second surface to the first surface.

[0274] The auxiliary channel may be configured to receive the auxiliary flow from the turbine outlet channel. The auxiliary channel receives a portion of the main turbine flow from the turbine outlet channel, increasing the amount of thermal energy that can be recovered from the main turbine flow and can be used to heat the first surface of the dividing wall. Thus, the rate of heat transfer to the dividing wall can be increased so that the temperature of the first surface is high enough to cause evaporation of any aftertreatment fluid that impacts the surface.

[0275] The auxiliary passage may be configured to receive the auxiliary flow from the turbine inlet passage. As the turbine body flow travels from the turbine inlet passage through the turbine impeller chamber to the turbine outlet passage, the energy of the turbine body flow decreases because the turbine body flow performs work on the turbine impeller to cause the turbine impeller to rotate. The reduction in energy of the turbine body flow is generally observed as a drop in temperature and pressure. Therefore, the temperature of the turbine body flow in the turbine inlet passage is higher than the temperature of the turbine body flow in the turbine outlet passage.

[0276] Since the auxiliary channel receives the auxiliary flow from the turbine inlet channel, the temperature of the auxiliary flow is higher than the temperature of the main turbine flow in the turbine outlet channel. In this way, the heat transferred to the first surface of the dividing wall is increased (at least compared to the alternative embodiment in which the auxiliary flow is received from the turbine outlet channel). In other words, since the auxiliary flow bypasses the turbine impeller, the auxiliary flow contains more energy, which can be extracted by the second surface of the dividing wall and used to heat the aftertreatment fluid collected on the first surface.

[0277] The auxiliary passage may include a valve device configured to selectively allow, prevent and / or regulate the flow of the auxiliary flow through the auxiliary passage. In this way, the auxiliary passage may act as a wastegate passage for selectively bypassing a portion of the turbine main flow around the turbine impeller.

[0278] The auxiliary passage may be configured so that flow is always permitted through the auxiliary passage. That is, the auxiliary passage may be substantially free of valves or closures that would block auxiliary flow through the auxiliary passage. However, in some embodiments, the auxiliary passage may include valves or closures, so long as the valves or closures can be controlled so that there is at least some leakage therethrough under all operating conditions of the turbine.

[0279] The turbine may include a turbine impeller having an outlet guide defining an outlet guide diameter, and the dosing module may include a nozzle configured to inject a spray of an aftertreatment fluid into the turbine outlet passage, and the nozzle of the dosing module may be spaced apart from the outlet guide of the turbine impeller by a distance of up to about 10 times the outlet guide diameter along the centerline of the turbine outlet passage. As used herein, the term "outlet guide" encompasses a portion of a turbine impeller that is configured to discharge exhaust gas into a turbine outlet passage. From a centerline perspective, the spacing between the nozzle and the outlet guide of the turbine impeller may be measured from the most downstream portion of the tip of the blades of the turbine impeller to the most upstream portion of the nozzle. Preferably, the nozzle of the distribution module is spaced apart from the outlet guide of the turbine impeller along the centerline of the turbine outlet passage by at most about 2, 3, 4 or 5 times the outlet guide diameter, and the nozzle of the distribution module is spaced apart from the outlet guide of the turbine impeller along the centerline by at least about 0.5, 1 or 2 times the outlet guide diameter.

[0280] Since the nozzle is located within a distance of at most about 10 times the diameter of the outlet inducer from the turbine impeller, the location where the after-treatment fluid is injected is relatively close to the turbine impeller. This ensures that the after-treatment fluid can be delivered to a region of the turbine main flow in the turbine outlet passage that has relatively high energy, particularly relatively high turbulent kinetic energy, and has a high temperature compared to downstream locations. Delivering the after-treatment fluid to a region of the turbine main flow with relatively high turbulent kinetic energy promotes mixing of the after-treatment fluid with the turbine main flow, and similarly, the relatively high temperature promotes decomposition of the delivered after-treatment fluid.

[0281] Furthermore, as the auxiliary flow travels through the auxiliary passage, the rate of heat transfer to the dividing wall decreases, and thus the temperature of the first surface of the dividing wall decreases along the length of the centerline. Thus, by delivering the aftertreatment fluid close to the turbine wheel, any impact of the aftertreatment fluid on the dividing wall generally occurs at the hottest region of the first surface of the dividing wall, which means that the evaporation rate of any aftertreatment fluid impacting the first surface of the dividing wall is greater than the evaporation rate at a location further downstream.

[0282] The nozzle may be positioned substantially flush with the side wall of the turbine outlet passage, or radially outward of the side wall. In some embodiments, the nozzle may be positioned substantially flush with the side wall of the turbine outlet passage. The term "substantially flush" encompasses that the distribution module is roughly aligned or precisely aligned with the inner surface of the turbine outlet passage, thereby defining the periphery of the turbine outlet passage. In such an embodiment, the nozzle does not protrude into the turbine outlet passage. Therefore, the nozzle does not impede flow through the turbine outlet passage, and thus avoids applying back pressure to the internal combustion engine.

[0283] The distribution module can be configured to deliver an atomized spray of the post-treatment fluid to the turbine outlet channel in a direction facing the first surface. In particular, the nozzle of the distribution module can be generally facing the first surface of the partition wall. The distribution module can produce a fine spray of atomized post-treatment fluid, which is ejected from the nozzle of the distribution module in a cone shape. The cone can have a top at the nozzle of the distribution module and extend generally toward the first surface of the partition wall. The partition wall can define a distal end relative to the turbine impeller, and the nozzle of the distribution module can be positioned between the turbine impeller and the distal end of the partition wall, and the nozzle is oriented to face the first surface of the partition wall.

[0284] The first surface of the dividing wall is heated by heat energy from the main flow of the turbine in the turbine outlet passage and heat energy transfer from the auxiliary flow. The atomized spray of the aftertreatment fluid is delivered in a direction facing the first surface of the dividing wall, improving the probability that any aftertreatment fluid that impinges on the inner surface of the turbine will impinge on the first surface and thereby be evaporated.

[0285] That is, the aftertreatment fluid can be delivered to the turbine outlet channel in a direction that is substantially deviated from the direction of the turbine main flow. For example, the aftertreatment fluid can be delivered in a direction substantially perpendicular to the direction of the turbine main flow in the turbine outlet channel. This not only causes the aftertreatment fluid that impacts the partition wall to impact the hotter first surface of the partition wall (the advantages of which are as described above), but also causes the delivered aftertreatment fluid to penetrate the turbine main flow, so that the aftertreatment fluid and the turbine main flow are more evenly mixed. In addition, since the aftertreatment fluid can be delivered to the turbine outlet channel in a direction substantially perpendicular to the turbine main flow, the momentum exchange between the aftertreatment fluid and the turbine main flow can be greater, which leads to improved mixing of the aftertreatment fluid with the turbine main flow.

[0286] The auxiliary channel can define an auxiliary channel outlet configured to deliver the auxiliary flow to the turbine outlet channel, and the auxiliary channel outlet can be located at least about 0.5 times the outlet guide diameter downstream of the nozzle along the center line. Since the partition wall is located downstream of the nozzle, the first surface of the partition wall can capture the aftertreatment fluid that has been sprayed into the turbine outlet channel by the nozzle. In other words, the partition wall covers the area where the aftertreatment fluid may impact. Any aftertreatment fluid that impacts the first surface of the partition wall will be heated and evaporated by the partition wall. In an alternative embodiment, the auxiliary channel outlet can be positioned at a distance of at least about 1 or 2 times the outlet guide diameter from the nozzle, and at a distance of about 5 or about 10 times the outlet guide diameter from the nozzle. The distance between the nozzle and the auxiliary channel outlet can be measured between their respective corresponding geometric centers.

[0287] The turbine may include a surface at least partially defining the turbine outlet passage, and the nozzle may be substantially aligned with or located radially outside of the surface in a radial direction relative to the centerline. That is, the nozzle is aligned with one of the surfaces defining the turbine outlet passage such that the nozzle does not protrude into the turbine outlet passage. Thus, the nozzle does not cause an obstruction to flow through the turbine outlet passage.

[0288] The surface may be a surface of a partition wall, for example a first surface.

[0289] The term "aligned" encompasses that the fluid injection portion of the nozzle is substantially flush with the surface. Those skilled in the art will appreciate that such alignment need not be absolute and that a small amount of misalignment may be tolerated, as long as the nozzle of the distribution module does not protrude into the turbine outlet passage in a manner that causes a significant obstruction to the flow. The term "radially outward" encompasses that the fluid injection portion of the nozzle is spaced apart from the surface.

[0290] The partition wall may extend circumferentially around the centerline. In particular, the partition wall may be substantially annular or frustoconical and arranged concentrically around the centerline. The partition wall may be a continuous wall formed as a single integral structure. The partition wall may be a sleeve disposed in the turbine housing.

[0291] The partition wall may be supported by a pair of elongated support columns, and the auxiliary channel may be at least partially defined between the support columns. The support columns serve to focus the energy of the auxiliary flow to a specific location, so that the auxiliary flow can be used to heat a specific portion of the partition wall.

[0292] The support posts may be positioned on a side of the turbine outlet passage opposite the dosing module, and the auxiliary passage may be defined between the support posts on a side of the turbine outlet passage opposite the dosing module. The portion of the dividing wall that aftertreatment fluid is most likely to impact is the portion opposite the dosing module. Since the posts define the auxiliary passage opposite the dosing module, this ensures that the portion of the dividing wall opposite the dosing module is hot enough to evaporate any impacting aftertreatment fluid.

[0293] The auxiliary channel may define an annular nozzle. The term "annular nozzle" encompasses a channel in the shape of an annulus having a generally decreasing cross-sectional area along the flow direction. As the auxiliary flow travels through the nozzle, the velocity of the auxiliary flow will generally increase and the pressure of the flow will generally decrease due to the reduction in the cross-sectional area of ​​the auxiliary channel. The velocity is thereby increased. The accelerated auxiliary flow may be reintroduced into the turbine outlet channel to provide a high shear layer close to the surface of the turbine outlet channel. The high shear layer may remove solid deposits formed on the surface of the turbine outlet channel and may also displace post-treatment fluid that has been deposited on the surface. Providing a high shear layer makes the turbine outlet channel a suitable location for conveying post-treatment fluid because the risk of post-treatment fluid pooling and deposit formation in the turbine outlet channel is mitigated.

[0294] The turbine outlet passage may include a diffuser portion, which is at least partially defined by the partition wall. That is, the turbine outlet passage may include a diffuser, for example defined by one or more tapered portions of a turbine housing and / or a partition wall. As used herein, the term "diffuser" encompasses an expansion passage, wherein the cross-sectional area of ​​the passage increases along the length of the passage. As the cross-sectional area of ​​the diffuser increases (i.e., as the wall defining the turbine outlet passage expands), the velocity of the turbine body flow decreases and the pressure increases. The increase in pressure can be used to improve the efficiency of the turbine. It should be understood that the cross-sectional area of ​​the diffuser portion can increase linearly or nonlinearly along its length.

[0295] The diffuser portion may be aligned with and extend symmetrically about the turbine axis. That is, the diffuser may be an axial diffuser. The diffuser may comprise a generally circular cross-section defined by the conical wall of the turbine outlet passage.

[0296] The diffuser portion may define a centerline defined by the centroid of the turbine outlet passage. The centerline may be offset from the turbine axis such that the centerline of the diffuser portion is offset from the turbine axis. The diffuser portion, despite the offset, may include a generally circular cross-section.

[0297] The dosing module may be configured to deliver the aftertreatment fluid into the diffuser portion. As explained above, as the turbine body flow travels through the diffuser portion, the velocity of the turbine body flow generally decreases and the pressure generally increases. Delivering the aftertreatment fluid into the region of the turbine body flow velocity reduction in the turbine outlet passage allows the aftertreatment fluid to penetrate the turbine body flow and mix more evenly with the turbine body flow in the turbine outlet passage.

[0298] In addition, depending on the geometry of the diffuser section and the flow conditions of the turbine main flow, the diffuser section can promote a turbulent region in the turbine main flow, deliver the aftertreatment fluid into the turbulent region of the turbine main flow, promote mixing of the aftertreatment fluid with the turbine main flow, and also reduce the impact of the aftertreatment fluid on the surface of the turbine outlet passage.

[0299] The turbine may include a support structure disposed in the auxiliary passage and configured to support the partition wall. That is, the support structure may be, for example, a column, a fin, an arm, a guide vane, a baffle, or any other suitable type of structure suitable for supporting the partition wall and separating the partition wall from the turbine housing. The support structure may extend from a surface of the turbine housing that at least partially defines the outermost surface of the auxiliary passage to the innermost surface of the auxiliary passage (e.g., a second surface of the partition wall). The support structure may be aerodynamically shaped so as to minimize disturbances to the auxiliary flow in the auxiliary passage.

[0300] The turbine may include a plurality of support structures. Where the auxiliary passage is a substantially annular passage, the plurality of support structures may be equally spaced circumferentially around the centre line.

[0301] The distribution module may include a nozzle, and the support structure may be configured to shield the nozzle from the auxiliary flow and / or the main turbine flow. That is, the support structure may be configured to deflect the auxiliary flow and / or the main turbine flow away from the nozzle. For example, the support structure may substantially surround the nozzle so as to prevent the auxiliary flow or the main turbine flow from passing through the nozzle by blocking or obstructing the nozzle from contacting the exhaust gas of the auxiliary flow and / or the turbine outlet flow.

[0302] The aftertreatment fluid is delivered to the turbine outlet passage from the nozzle of the distribution module as an atomized spray. The atomized spray of the aftertreatment fluid is generally ejected from the nozzle in a cone form, wherein the tip of the aftertreatment fluid cone is located at the nozzle. Shielding of the nozzle allows the aftertreatment fluid cone to develop, thereby promoting uniform mixing of the aftertreatment fluid with the turbine body flow in the turbine.

[0303] The nozzle may be shielded from the turbine main flow and / or auxiliary flow by a wall of the turbine housing. For example, the wall of the turbine housing may define a recessed portion, and the nozzle may be disposed in the recessed portion such that the recessed portion shields the nozzle.

[0304] The dosing module may include a nozzle positioned to be in fluid communication with the auxiliary channel so that in use the auxiliary flow may pass through the nozzle of the dosing module. It is known that when the post-treatment fluid is discharged from the dosing module, residues of the post-treatment fluid may remain at or near the nozzle and may cause solid deposits to form which block the nozzle. One benefit of the auxiliary flow passing through the nozzle is that it provides a cleaning effect because due to the relatively high temperature of the auxiliary flow, the flow may cause the post-treatment fluid that may have been deposited around the nozzle to evaporate. In addition, the auxiliary flow may be configured to remove solid deposits that have formed near the nozzle, both of which can alleviate the situation where the nozzle is blocked and cannot deliver the post-treatment fluid as an atomized spray.

[0305] Another benefit of the secondary flow passing through the nozzle is that as the aftertreatment fluid is discharged from the nozzle, the aftertreatment fluid can exchange momentum with the secondary flow before entering the turbine outlet passage. This momentum exchange can be used to provide beneficial effects, such as ensuring that the aftertreatment fluid is carried across a greater lateral extent of the turbine outlet passage.

[0306] The turbine outlet passage may include a curved portion defining a top end, and the distribution module may include a nozzle configured to deliver an aftertreatment fluid into the turbine outlet passage, the nozzle may be positioned at the top end of the curved portion, or positioned upstream of the top end of the curved portion. The term "curved portion" encompasses an axis whose centerline deviates from a straight line, causing the turbine body flow to change direction. Examples of curved portions include, but are not limited to, arcuate paths, stepped portions, and dog-leg bends. In other words, a curved portion is an area in a passage that causes the turbine body flow to change direction. Including a curved portion may be necessary due to packaging requirements of the engine compartment.

[0307] Turbulent kinetic energy will dissipate around bends in the pipe. Therefore, it is beneficial to position the nozzle so that it is not downstream of the top of the bend. This ensures that the post-treatment fluid is injected into an area with sufficient turbulent kinetic energy to allow the post-treatment fluid to be fully mixed.

[0308] The first surface may define a surface of the curved portion, and the nozzle may face the first surface. Since the distribution module faces (i.e., generally opposite) the first surface, and the first surface defines a portion of the curved portion, the aftertreatment flow that does not mix with the turbine body flow will impinge on the hot first surface rather than on the cooler downstream surface.

[0309] The auxiliary channel may include an auxiliary channel outlet, which is configured to deliver a portion of the auxiliary flow to the turbine outlet channel at a position downstream of the nozzle of the distribution module, and the partition wall may include an auxiliary orifice, which is configured to deliver a portion of the auxiliary flow to the turbine outlet channel at a position aligned with the nozzle or at a position upstream of the nozzle. The term "auxiliary orifice" covers grooves, holes, openings, etc. in the partition wall and is suitable for providing a fluid path from the auxiliary channel to the turbine outlet channel separated from the auxiliary channel outlet. The partition wall may include multiple auxiliary orifices and / or multiple auxiliary channel outlets.

[0310] The auxiliary orifice may be configured to deliver a portion of the auxiliary flow into the turbine outlet passage and into a region of the turbine main flow having relatively low turbulent kinetic energy. The region of the turbine main flow having relatively low turbulent kinetic energy may be referred to as a "recirculation zone". Delivering a portion of the auxiliary flow into the recirculation zone of the turbine main flow results in momentum exchange between the delivered auxiliary flow and the turbine main flow and increases the turbulent kinetic energy of the turbine main flow. As a result, turbulence in the turbine outlet passage is increased and a recirculation zone is avoided.

[0311] The turbine may also include a turbine housing assembly, which may include: a turbine housing, the turbine housing defining at least a portion of the turbine inlet channel, the turbine wheel chamber, and the turbine outlet channel; and a connection adapter, the connection adapter defining at least a portion of the turbine outlet channel and at least a portion of the auxiliary channel, the connection adapter may be coupled to the turbine housing at a first interface; the connection adapter may be configured to support the partition wall to extend along the centerline; and the partition wall may extend axially through the first interface along the centerline. The term "interface" encompasses a mechanical joint between two components. Such an interface may result in localized surface discontinuities between components, which present a risk of post-treatment fluid collection and deposit formation. However, in the case where the partition wall extends across the first interface, the partition wall shields the first interface from the impact of the post-treatment fluid. In other words, the partition wall forms a barrier to block the post-treatment fluid and prevent the post-treatment fluid from reaching the first interface. Therefore, the risk of collection and deposit formation at the first interface can be reduced or avoided.

[0312] The turbine housing assembly may also include a downpipe adapter configured to be connected to a downpipe, the downpipe adapter may define at least a portion of the auxiliary channel and / or the turbine outlet channel, and the downpipe adapter is coupled to the connection adapter at a second interface; and the partition wall extends axially through the second interface along the centerline. The term "downpipe adapter" covers components disposed between a connection adapter and a downstream conduit (e.g., a downpipe). As explained above with respect to the first interface, the second interface may have surface discontinuities, which risk causing post-treatment fluid collection and deposit formation. However, when the partition wall extends across the second interface, the partition wall acts as a barrier to prevent the post-treatment fluid from reaching the second interface. Therefore, post-treatment fluid collection and deposit formation at the second interface are reduced or avoided.

[0313] The auxiliary passage may be a first auxiliary passage, and the auxiliary flow may be a first auxiliary flow, and the turbine may further include a second auxiliary passage, the second auxiliary passage being configured to receive a portion of the turbine main flow from the turbine inlet passage, the portion of the turbine main flow received by the second auxiliary passage may define a second auxiliary flow, and the second auxiliary passage may be configured to deliver the second auxiliary flow to the turbine outlet passage. The term "second auxiliary passage" encompasses a passage that is separate from the first auxiliary passage, the turbine inlet passage, the turbine wheel chamber, and the turbine outlet passage, and is capable of receiving exhaust gas from the turbine inlet passage and delivering the exhaust gas to the turbine outlet passage.

[0314] Since the second auxiliary channel receives a portion of the turbine main flow from the turbine inlet channel, the energy of the second auxiliary flow is greater than the energy of the turbine main flow in the turbine outlet channel. This energy difference can be used to provide specific beneficial effects. For example, the second auxiliary flow can be delivered to the turbine outlet channel in a manner that increases the turbulent kinetic energy of the turbine main flow in the turbine outlet channel, or as another example, the second auxiliary flow can be delivered in a manner that provides a cleaning effect around the nozzle area. The second auxiliary channel can be functionally equivalent to a wastegate channel.

[0315] The second auxiliary channel may include a second auxiliary channel outlet, which may be aligned with the nozzle of the distribution module relative to the center line or positioned upstream of the nozzle of the distribution module, and the second auxiliary channel outlet may be configured to guide the second auxiliary flow along the first surface of the partition wall with a second auxiliary flow layer. Since the second auxiliary flow does not travel through the turbine impeller, the temperature of the second auxiliary flow is generally higher than the temperature of the turbine main flow in the turbine outlet channel. Therefore, guiding the second auxiliary flow along the first surface of the partition wall with the second auxiliary flow layer promotes heat transfer to the first surface, thereby further increasing the temperature of the first surface. A second auxiliary flow layer may be provided along the area where the post-treatment fluid may impact the first surface.

[0316] In addition, the second auxiliary flow layer can form a fluid barrier that substantially inhibits the post-treatment fluid from reaching the first surface. In this context, it should be understood that the fluid barrier covers the fluid interaction between the second auxiliary flow layer and the post-treatment fluid, wherein momentum is exchanged between the two fluids in a manner that causes the post-treatment fluid to be deflected away from the first surface of the partition wall. In particular, the second auxiliary flow layer applies a shear force to the post-treatment fluid, thereby preventing the post-treatment fluid from contacting the first surface of the partition wall or substantially reducing the amount of the post-treatment fluid that can contact the first surface of the partition wall. The shear force can further cause the droplets of the post-treatment fluid to split, thereby reducing their relative mass and making the droplets more easily deflected. Therefore, the second auxiliary flow layer acts as a "cushion" to inhibit the post-treatment fluid from contacting the first surface of the partition wall.

[0317] This "buffer" effect makes the turbine outlet channel a suitable location for injecting the after-treatment fluid. In particular, the after-treatment fluid injected into the turbine outlet channel will be deflected by the second auxiliary flow layer and prevented from reaching the first surface of the partition wall. Therefore, the risk of the after-treatment fluid collecting and forming deposits in the turbine outlet channel is reduced, and the turbine outlet channel can therefore be used as a decomposition chamber for receiving and decomposing the after-treatment fluid. This means that the dosing module can be placed closer to the turbine impeller than was previously possible. The temperature of the turbine main flow will be higher near the turbine impeller, and therefore the higher temperature of the turbine main flow can be used to provide improved heat transfer to the after-treatment fluid, so that the after-treatment fluid is decomposed more quickly into the reductant required to support the SCR reaction.

[0318] The nozzle of the distribution module can be positioned on a side of the turbine outlet passage opposite to the second auxiliary flow layer, so that during use, the second auxiliary flow layer inhibits the post-treatment fluid from reaching the portion of the first surface of the partition wall opposite to the nozzle. That is, the nozzle of the distribution module and at least a portion of the second auxiliary flow layer are arranged on opposite sides of the turbine outlet passage. Therefore, the second auxiliary flow layer is able to "capture" the post-treatment fluid distributed by the nozzle and hinder or prevent the post-treatment fluid from contacting the portion of the turbine outlet passage surface that is roughly opposite to the nozzle.

[0319] The second auxiliary channel can be configured to guide the second auxiliary flow into the turbine outlet channel in a direction that induces a vortex of the second auxiliary flow around the center line in the turbine outlet channel along the same angular direction as the turbine main flow in the turbine outlet channel. Since the second auxiliary channel guides the second auxiliary flow into the turbine outlet channel in a direction that induces a vortex in the same angular direction as the turbine main flow, the vortex momentum of the second auxiliary flow will be given to the vortex momentum of the turbine main flow, thereby increasing the amplitude of the vortex momentum of the turbine main flow. The rotational momentum of the turbine main flow combined with the second auxiliary flow increases, further increasing the speed and shear stress of the second auxiliary flow layer. This increases the amount of energy available for deflection and separation of the post-treatment fluid in the second auxiliary flow layer, and thus improves the "buffer" effect. In addition, when the second auxiliary flow has vortex momentum, the second auxiliary flow layer acts as a fluid agitator that mixes the turbine main flow more thoroughly. This improves heat transfer to the post-treatment fluid, thereby ensuring that more post-treatment fluid is decomposed at a faster rate.

[0320] The increased velocity and shear near the first surface of the dividing wall make the turbine outlet channel a suitable location for injecting the aftertreatment fluid. In particular, the aftertreatment fluid injected into the turbine outlet channel will be deflected by the high velocity and high shear exhaust gas and prevented from reaching the first surface of the dividing wall. Therefore, the risk of aftertreatment fluid pooling and forming deposits in the turbine outlet channel is reduced, and the turbine outlet channel can thus be used as a decomposition chamber for receiving and decomposing the aftertreatment fluid.

[0321] In order to achieve a vortex in a positive direction, the second auxiliary channel can be configured to deliver the second auxiliary flow in a direction having a directional component tangential to the surface of the turbine outlet channel in a plane normal to the centerline. In other words, the second auxiliary flow can have a directional component tangential to the surface of the turbine outlet channel in a plane normal to the centerline. Since the second auxiliary flow has a directional component tangential to the surface of the turbine outlet channel, the turbine outlet channel will induce the second auxiliary flow to vortex around the centerline.

[0322] The second auxiliary passage may include a second auxiliary passage valve device configured to selectively allow, prevent and / or regulate the flow of the second auxiliary flow through the second auxiliary passage. Thus, the second auxiliary passage may be used as a wastegate passage for selectively bypassing a portion of the turbine main flow around the turbine impeller.

[0323] Additionally or alternatively, the second auxiliary passage may be configured such that flow is always allowed through the second auxiliary passage. In particular, the second auxiliary passage may be substantially free of valves or closures. Alternatively, the second auxiliary passage may include one or more valves or closures configured to provide at least some leakage through the valves or closures under all operating conditions of the turbine.

[0324] Although only a first auxiliary passage and a second auxiliary passage are described, it should be understood that the turbine may include any number of auxiliary passages, wherein different auxiliary passages may be configured to condition the respective flows within each passage to provide different or additional beneficial effects.

[0325] The turbine may further include a controller configured to selectively activate the dosing module to deliver the aftertreatment fluid to the turbine outlet passage. In particular, the controller may be configured to activate the dosing module based on a temperature of the first surface or a time since engine ignition. In particular, the controller may be configured to activate the dosing module when the first surface has reached a predetermined temperature.

[0326] According to a ninth aspect of the present invention, there is provided a method for operating a turbine for a turbocharger, comprising: receiving exhaust gas from an internal combustion engine into a turbine inlet passage, the exhaust gas received by the turbine inlet passage defining a turbine main flow; receiving the turbine main flow from the turbine inlet passage into a turbine impeller chamber, the turbine impeller chamber being configured to accommodate a turbine impeller, the turbine impeller being supported for rotation; receiving the turbine main flow from the turbine impeller chamber into a turbine outlet passage, the turbine outlet passage extending along a centerline, and the turbine outlet passage being at least partially defined by a first surface of a partition wall; delivering an atomized spray of a post-treatment fluid into the turbine outlet passage using a distribution module including a nozzle; receiving a portion of the turbine main flow into an auxiliary passage, the portion of the turbine main flow received by the auxiliary passage defining an auxiliary flow, the auxiliary passage being at least partially defined by a second surface of the partition wall; wherein the partition wall is configured to provide thermal connectivity from the auxiliary passage to the first surface via the second surface.

[0327] The first surface may be disposed on a side of the partition wall opposite to the second surface.

[0328] The dividing wall may define a thickness between the first surface and the second surface, the turbine may include a turbine wheel having an inducer portion defining an inducer diameter, and the thickness of the dividing wall may be approximately 5% of the inducer diameter.

[0329] The auxiliary passage may be configured to receive the auxiliary flow from the turbine outlet passage.

[0330] The auxiliary passage may be configured to receive the auxiliary flow from the turbine inlet passage.

[0331] The auxiliary passage may include a valve device configured to selectively allow, prevent and / or regulate the flow of the auxiliary fluid through the auxiliary passage.

[0332] The auxiliary channel may be configured such that flow is always permitted through the auxiliary channel.

[0333] The turbine may include a turbine impeller having an outlet guide vane, the outlet guide vane defining an outlet guide vane diameter, and the dosing module may include a nozzle configured to inject the atomized spray of the aftertreatment fluid into the turbine outlet passage, and the nozzle of the dosing module may be spaced apart from the outlet guide vane of the turbine impeller along the centerline of the turbine outlet passage by a distance of up to about 10 times the outlet guide vane diameter.

[0334] The nozzle may be substantially aligned with, or located radially outward of, a sidewall of the turbine outlet passage. In some embodiments, the nozzle may be positioned substantially flush with a sidewall of the turbine outlet passage.

[0335] The dosing module may be configured to deliver the atomized spray of after-treatment fluid into the turbine outlet passage in a direction facing the first surface.

[0336] The auxiliary passage may define an auxiliary passage outlet configured to deliver the auxiliary flow into the turbine outlet passage, and the auxiliary passage outlet may be located at least about 0.5 outlet inducer diameters downstream of the nozzle along the centerline.

[0337] The turbine may include a surface at least partially defining the turbine outlet passage, and the nozzle may be substantially aligned with or located radially outward of the surface in a radial direction relative to the centerline.

[0338] The dividing wall may extend circumferentially about the centre line.

[0339] The partition wall may be supported by a pair of elongated support columns, and the auxiliary channel may be at least partially defined between the support columns.

[0340] The support struts may be positioned on a side of the turbine outlet passage opposite the distribution module, and the auxiliary passage may be defined between the support struts on a side of the turbine outlet passage opposite the distribution module.

[0341] The secondary channel may define an annular nozzle.

[0342] The turbine outlet passage may include a diffuser portion at least partially defined by the dividing wall.

[0343] The distribution module may be configured to deliver an aftertreatment fluid into the diffuser portion.

[0344] The turbine may include a support structure disposed in the auxiliary passage and configured to support the partition wall.

[0345] The distribution module may include a nozzle, and the support structure may be configured to shield the nozzle from the auxiliary flow and / or the turbine body flow.

[0346] The dosing module may comprise a nozzle positioned in fluid communication with the secondary channel such that, in use, the secondary flow may pass through the nozzle of the dosing module.

[0347] The turbine outlet passage may include a curved portion defining a top end, and the dosing module may include a nozzle configured to deliver the aftertreatment fluid into the turbine outlet passage, the nozzle may be positioned at the top end of the curved portion, or upstream of the top end of the curved portion.

[0348] The first surface may define a surface of the curved portion, and the nozzle may face the first surface.

[0349] The auxiliary channel may include an auxiliary channel outlet, which is configured to deliver a portion of the auxiliary flow to the turbine outlet channel at a position downstream of the nozzle of the distribution module, and the partition wall may include an auxiliary orifice, which is configured to deliver a portion of the auxiliary flow to the turbine outlet channel at a position aligned with the nozzle or at a position upstream of the nozzle.

[0350] The method may also include a turbine housing assembly, which may include: a turbine housing, which defines at least a portion of the turbine inlet passage, the turbine wheel chamber, and the turbine outlet passage; and a connection adapter, which defines at least a portion of the turbine outlet passage and at least a portion of the auxiliary passage, and the connection adapter can be connected to the turbine housing at a first interface; the connection adapter can be configured to support the partition wall to extend along the centerline; and the partition wall can extend axially along the centerline through the first interface.

[0351] The turbine housing assembly may also include a downtube adapter configured to be connected to the downtube, the downtube adapter may define at least a portion of the turbine outlet channel and / or the auxiliary channel, and the downtube adapter may be coupled to the connection adapter at a second interface; and the partition wall may extend axially along the centerline through the second interface.

[0352] The auxiliary channel may be a first auxiliary channel, and the auxiliary flow may be a first auxiliary flow, and the turbine may further include a second auxiliary channel, the second auxiliary channel being configured to receive a portion of the turbine main flow from the turbine inlet channel, the portion of the turbine main flow received by the second auxiliary channel may define a second auxiliary flow, and the second auxiliary channel may be configured to deliver the second auxiliary flow to the turbine outlet channel.

[0353] The second auxiliary channel may include a second auxiliary channel outlet, which may be aligned with the nozzle of the distribution module relative to the center line or positioned upstream of the nozzle, and the second auxiliary channel outlet may be configured to guide the second auxiliary flow along the first surface of the partition wall in a second auxiliary flow layer.

[0354] The second auxiliary passage may include a second auxiliary passage valve device configured to selectively allow, prevent and / or regulate the flow of a second auxiliary fluid through the second auxiliary passage.

[0355] The method may further include a controller configured to selectively activate the dosing module to deliver aftertreatment fluid into the turbine outlet passage.

[0356] The step of delivering an atomised spray of after-treatment fluid into the turbine outlet passage may be performed as a function of time from engine ignition and / or temperature of the first surface.

[0357] According to the tenth aspect of the present invention, a turbine for a turbocharger is provided, comprising: a turbine inlet channel, the turbine inlet channel being configured to receive exhaust gas from an internal combustion engine, the exhaust gas received by the turbine inlet channel defining a turbine main flow; a turbine impeller chamber, the turbine impeller chamber being configured to receive the turbine main flow from the turbine inlet channel, the turbine impeller chamber accommodating a turbine impeller, the turbine impeller being supported to rotate around a turbine axis; a turbine outlet channel, the turbine outlet channel being configured to receive the turbine main flow from the turbine impeller chamber; a distribution module, the distribution module being configured to deliver an atomized spray of an after-treatment fluid into the turbine outlet channel; an auxiliary channel, the auxiliary channel being configured to receive a portion of the turbine main flow from a position upstream of the turbine outlet channel, the portion of the turbine main flow received by the auxiliary channel defining an auxiliary flow; and an exhaust gas sensor, the exhaust gas sensor being located in the auxiliary channel; wherein the exhaust gas sensor is configured to sense one or more physical parameters of the auxiliary flow.

[0358] Since the turbine impeller extracts energy from the main flow of the turbine, the pressure of the main flow of the turbine at the upstream of the turbine outlet channel is usually higher than the pressure of the main flow of the turbine in the turbine outlet channel. In this way, the main fluid of the turbine flows out of the turbine impeller chamber and carries the aftertreatment fluid. Therefore, the aftertreatment fluid and any reducing agent (such as ammonia (NH3)) decomposed from the aftertreatment fluid will not usually pass through the upstream of the turbine outlet channel. In the present invention, since the auxiliary channel receives the auxiliary flow from the upstream position of the turbine outlet channel, the presence of the aftertreatment fluid or reducing agent in the auxiliary flow is almost completely eliminated. Therefore, the auxiliary flow will not be contaminated by the aftertreatment fluid or reducing agent, and therefore the auxiliary flow can provide an accurate representation of the real physical properties of the exhaust gas generated by the internal combustion engine. In this way, a more accurate reading of the physical parameters measured by the exhaust gas sensor can be obtained.

[0359] In the context of the present invention, a "physical parameter" of the exhaust gas encompasses essentially any quantifiable property of the exhaust gas. This may include, for example, temperature, pressure, velocity, mass, volume flow, mass flow, etc. In particular, such a "physical parameter" may include the chemical composition of the exhaust gas, and more particularly, may include the absolute concentration or relative concentration of a specific chemical component in the exhaust gas.

[0360] In the context of the present invention, a "position upstream of the turbine outlet passage" encompasses substantially any fluid position of the turbine from which fluid may flow to the turbine outlet passage (rather than out of the auxiliary passage itself).

[0361] In the context of the present invention, the exhaust gas sensor being located in the auxiliary flow channel encompasses the exhaust gas sensor having a sensing portion configured to interact with the auxiliary flow, wherein the sensing portion is exposed to the auxiliary flow in the auxiliary channel. That is, the exhaust gas sensor is positioned within the auxiliary channel such that the exhaust gas sensor is able to detect a parameter of the auxiliary flow when the auxiliary flow flows through the auxiliary channel.

[0362] The exhaust gas sensor may be configured to measure the concentration of nitrogen oxides (NOx) in the auxiliary flow. That is, the sensor may be a NOx sensor. The turbine may be used in an exhaust gas aftertreatment system including an SCR catalyst device. Since the exhaust gas sensor is configured to measure the concentration of NOx in the auxiliary flow, the amount of aftertreatment fluid required to reduce NOx to an acceptable level can be calculated, and the operation of the dosing module can be controlled accordingly. The exhaust gas sensor may be configured to sense the presence of other substances in addition to NOx in the auxiliary flow, for example, the exhaust gas sensor may sense the presence of ammonia (NH3) and isocyanic acid (HNCO).

[0363] The auxiliary passage may be sized to receive at least about 0.1% of the turbine body flow received by the turbine inlet passage.

[0364] That is, the proportion of the auxiliary passage enables at least about 0.5% of the total exhaust gas delivered from the internal combustion engine to the turbine to travel through the auxiliary passage. The remaining exhaust gas (i.e., the remaining turbine main flow) will travel through the turbine wheel chamber and enter the turbine outlet passage. Alternatively, the size of the auxiliary passage can be set to receive at least about 0.2%, 0.3%, 0.4%, 0.5%, 1%, 1.5%, 2% or 5% of the turbine main flow received by the turbine inlet passage. The relative proportion of the exhaust gas received by the auxiliary passage can be determined based on mass flow and / or volume flow. Since the auxiliary passage receives at least about 0.5% of the turbine main flow received by the turbine inlet passage, the exhaust gas sensor can obtain a sufficient amount of auxiliary flow to accurately measure one or more physical parameters of the auxiliary flow.

[0365] The size of the auxiliary channel can be set to receive at most about 10% of the turbine main flow received by the turbine inlet channel. That is, the proportion of the auxiliary channel enables at most about 10% of the total exhaust gas delivered to the turbine from the internal combustion engine to travel through the auxiliary channel. The remaining exhaust gas (that is, the remaining turbine main flow) will travel through the turbine impeller chamber and enter the turbine outlet channel. Alternatively, the size of the auxiliary channel can be set to receive at most about 1%, 1.5%, 2% or 5% of the turbine main flow received by the turbine inlet channel. The relative proportion of the exhaust gas received by the auxiliary channel can be determined based on mass flow and / or volume flow. It should be understood that since the auxiliary flow is received from a position upstream of the turbine outlet channel, the auxiliary flow will bypass at least a portion of the turbine impeller. This will reduce the amount of power generated by the turbine impeller. However, since the auxiliary channel receives at most about 10% of the turbine main flow received by the turbine inlet channel, the amount of power loss is reduced.

[0366] The auxiliary channel can be configured so that the auxiliary flow is always allowed to flow through the auxiliary channel during all operating conditions of the turbine. That is, the auxiliary channel may be substantially free of valves and / or closures configured to prevent the auxiliary flow from passing along the auxiliary channel. In other words, the auxiliary channel may include an auxiliary channel inlet connected to a position upstream of the turbine outlet channel and an auxiliary channel outlet connected to the turbine outlet channel, and the auxiliary channel may be configured so that flow from the auxiliary channel inlet to the auxiliary channel outlet is always allowed regardless of the operating conditions of the engine. Since flow is always allowed through the auxiliary channel, this ensures a constant supply of auxiliary flow to the exhaust gas sensor under all operating conditions of the engine. Therefore, the flow to the exhaust gas sensor is not interrupted, and therefore the readings generated by the exhaust gas sensor are more reliable.

[0367] The auxiliary channel may include a valve assembly configured to control the flow of the auxiliary flow through the auxiliary channel. Specifically, the auxiliary channel may be a wastegate channel having a wastegate valve. In such an embodiment, the exhaust gas sensor may be positioned within an existing wastegate device, and thus the auxiliary channel does not need to be embodied in a channel that is separate and additional to the wastegate channel. When the auxiliary channel is configured to always allow flow through the auxiliary channel, the valve assembly may be configured to allow some leakage across the valve when in its closed position. Alternatively, the valve assembly may be controlled so that the valve assembly is not completely closed.

[0368] The valve assembly may define an open configuration and a closed position, in which the auxiliary flow may be allowed to pass through the valve assembly and in which the auxiliary flow may be substantially blocked by the valve assembly, and the valve assembly may include a leakage channel configured to allow leakage from one side of the valve assembly to the other side when the valve is in the closed configuration. The leakage hole may be considered to form a part of the auxiliary channel. It should be understood that in the closed configuration, the valve assembly may substantially block the auxiliary flow by blocking a large portion of the auxiliary flow (e.g., about 90%, 95%, 98%, 98.5%, 99%, 99.5%, 99.6%, 99.7%, 99.8% or 99.9% of the auxiliary flow may be blocked by the valve assembly). The leakage channel may be positioned within the valve itself, such as within the valve member, or may be positioned within a portion of the turbine housing that houses the valve assembly.

[0369] The auxiliary passage may be configured to deliver the auxiliary flow to the turbine outlet passage. That is, the auxiliary passage may be configured to deliver the auxiliary flow to the turbine main flow at a location of the turbine outlet passage downstream of the turbine wheel chamber.

[0370] The auxiliary passage may be configured to deliver the auxiliary flow to the turbine inlet passage.

[0371] The dosing module may include a nozzle configured to generate the spray of post-treatment fluid. For example, the nozzle may be an atomizing nozzle.

[0372] The turbine outlet passage may be at least partially defined by a surface, and the turbine outlet passage may define a centerline, and the nozzle may be substantially aligned with the surface, or may be located radially outside the surface relative to the centerline. That is, the nozzle of the distribution module does not protrude into the turbine outlet passage. An inherent property of the turbine outlet passage is that it is defined by the surface of a housing component (e.g., a turbine housing, a connection adapter, a diffuser, etc.). The term "alignment" encompasses the fluid injection portion of the nozzle being substantially flush with the surface. Those skilled in the art will appreciate that such alignment need not be absolute, and a small amount of misalignment may be tolerated, as long as the nozzle of the distribution module does not protrude into the turbine outlet passage in a manner that causes a significant obstruction to the main flow of the turbine. Since the nozzle is substantially aligned with the surface, the turbine outlet passage is substantially free of obstructions that impede the flow of exhaust gas.

[0373] The turbine may include a turbine wheel having an outlet guide, the outlet guide defining an outlet guide diameter, the turbine outlet passage may define a centerline, and the nozzle may be spaced apart from the outlet guide of the turbine wheel along the centerline of the turbine outlet passage by a distance of up to about 10 times the outlet guide diameter. The term "outlet guide" encompasses a portion of the turbine wheel that serves as an outlet of the turbine wheel. In other words, from the perspective of the main flow of the turbine traveling through the turbine wheel, at the far end of the turbine wheel. From the perspective of the main flow of the turbine, the term "outlet guide diameter" encompasses the diameter of the outlet guide at the farthest portion of the turbine wheel. In alternative embodiments, the nozzle may be positioned relative to the turbine wheel along the centerline of the turbine outlet passage by no more than about 5 times, about 3 times, or about 2 times the outlet guide diameter.

[0374] As the turbine body flow leaves the turbine wheel, the temperature of the turbine body flow will be at its hottest temperature relative to any location downstream. Generally speaking, the hotter the turbine body flow, the more heat is available for heat exchange with the aftertreatment fluid to promote decomposition into the desired reductants. By positioning and orienting the dosing module so that the spray area is closer to the turbine wheel, more heat can be ensured to achieve faster and more complete decomposition of the aftertreatment fluid. It has been found experimentally that when the spray area is farther from the turbine wheel along the centerline than about 10 times the outlet inducer diameter, heat is dissipated from the turbine body flow and the decomposition rate is reduced.

[0375] The auxiliary channel may be configured to deliver the auxiliary flow to the turbine outlet channel upstream of the nozzle. That is, the auxiliary channel may include an auxiliary channel outlet configured to deliver the auxiliary flow to the turbine outlet channel, and the auxiliary channel outlet may be positioned upstream of the nozzle relative to the centerline. When the auxiliary flow rejoins the main flow of the turbine in the turbine outlet channel, the auxiliary flow will disturb the main flow of the turbine, thereby causing turbulence. It is usually beneficial to have some turbulence in the main flow of the turbine, because this can improve the mixing of the aftertreatment fluid with the exhaust gas. This in turn increases the rate of heat transfer to the aftertreatment fluid, so that the aftertreatment fluid is decomposed into the reductant required for the SCR reaction more quickly. Since the auxiliary flow is delivered to the turbine outlet channel upstream of the nozzle, turbulence can be established or promoted at a position upstream of the nozzle. Therefore, when the nozzle injects the aftertreatment fluid into the turbine outlet channel, the aftertreatment fluid will enter the turbulent area, and therefore the aftertreatment fluid will decompose faster.

[0376] The auxiliary channel can be configured to guide the auxiliary flow through the nozzle. During use, the post-treatment fluid may gather at the nozzle. If the post-treatment fluid cools, it may solidify and block the nozzle. However, when the auxiliary fluid is guided through the nozzle, the auxiliary flow will remove the gathered post-treatment fluid, thereby keeping the nozzle clean.

[0377] The auxiliary passage may be configured to receive the auxiliary flow from the turbine inlet passage. In particular, the auxiliary passage may include an auxiliary passage inlet in direct fluid communication with the turbine inlet passage. Since the auxiliary flow is received from the turbine inlet passage and conveys the aftertreatment fluid within the turbine outlet passage, the possibility of the aftertreatment fluid entering the auxiliary passage and distorting the measurement results of the exhaust gas sensor is further reduced and / or eliminated.

[0378] The turbine inlet passage may include a first volute and a second volute, and the auxiliary passage may be configured to receive the auxiliary flow from the first volute. That is, the auxiliary passage may include an auxiliary passage inlet communicating with the first volute. In particular, the auxiliary passage may be configured to receive the auxiliary flow only from the first volute, and also not from the second volute. Since the auxiliary passage receives the auxiliary flow only from the first volute, any flow disturbance caused by the auxiliary flow in the turbine inlet passage is limited to the first volute.

[0379] The tenth aspect of the present invention may be embodied in a turbocharger.

[0380] According to an eleventh aspect of the present invention, an exhaust gas aftertreatment system is provided, comprising: a turbine or a turbocharger according to the aforementioned aspect of the present invention; and a catalyst device, the catalyst device being configured to receive the turbine body flow downstream of the turbine outlet passage. In particular, the catalyst device may be a selective catalytic reduction (SCR) catalyst device.

[0381] The system may also include a controller that communicates with the exhaust gas sensor and may be configured to determine the measurement results of the one or more physical parameters of the auxiliary flow sensed by the exhaust gas sensor; the controller may also be configured to generate a control signal based on the measurement results of the one or more physical parameters, and the dosing module may communicate with the controller to receive the control signal, and the dosing module is operable to adjust the delivery rate of the aftertreatment fluid to the turbine outlet channel based on the control signal. In the context of the present invention, "communication" may include, for example, electrical communication, optical communication, wireless communication, etc. The term "adjustment" covers the fact that the dosing module is configured to adjust the delivery rate of the aftertreatment fluid. For example, this may include increasing or decreasing the delivery rate, or stopping delivery completely. Since the delivery rate of the aftertreatment fluid is adjusted based on the output of the exhaust gas sensor, excessive delivery of the aftertreatment fluid can be avoided, thereby reducing the risk of deposit formation.

[0382] According to the twelfth aspect of the present invention, a method for operating a turbine for a turbocharger is provided, which includes: receiving exhaust gas from an internal combustion engine into a turbine inlet channel, the exhaust gas received by the turbine inlet channel defining a turbine main flow; receiving the turbine main flow from the turbine inlet channel into a turbine impeller chamber, the turbine impeller chamber accommodating a turbine impeller, the turbine impeller being supported to rotate around a turbine axis; receiving the turbine main flow from the turbine impeller chamber into a turbine outlet channel; receiving a portion of the turbine main flow into an auxiliary channel, the portion of the turbine main flow received by the auxiliary channel defining an auxiliary flow; delivering an atomized spray of an after-treatment fluid into the turbine outlet channel using a dosing module; and sensing one or more physical parameters of the auxiliary flow using an exhaust gas sensor connected to the auxiliary flow fluid.

[0383] The exhaust gas sensor may be configured to measure a concentration of nitrogen oxides (NOx) in the secondary flow.

[0384] The auxiliary passage may be sized to receive at least about 0.1% of the turbine body flow received by the turbine inlet passage.

[0385] The auxiliary passage may be sized to receive at most about 10% of the turbine body flow received by the turbine inlet passage.

[0386] The auxiliary passage may be configured such that the auxiliary flow is always allowed to flow through the auxiliary passage during all operating conditions of the turbine.

[0387] The auxiliary passage may include a valve assembly configured to control a flow rate of the auxiliary stream through the auxiliary passage.

[0388] The valve assembly may define an open configuration and a closed position, wherein in the open configuration, the auxiliary flow is allowed to pass through the valve assembly, and in the closed position, the auxiliary flow is substantially blocked by the valve assembly, and the valve assembly may include a leakage channel, which is configured to allow leakage from one side of the valve assembly to the other side when the valve is in the closed configuration.

[0389] The auxiliary passage may be configured to deliver the auxiliary flow to the turbine outlet passage.

[0390] The auxiliary passage may be configured to deliver the auxiliary flow to the turbine inlet passage.

[0391] The dosing module may include a nozzle configured to generate the spray of after-treatment fluid.

[0392] The turbine outlet passage may be at least partially defined by a surface, with the turbine outlet passage defining a centerline, and the nozzle may be substantially aligned with the surface or may be located radially outward of the surface relative to the centerline.

[0393] The turbine may include a turbine wheel having an outlet inducer, the outlet inducer defining an outlet inducer diameter, the turbine outlet passage may define a centerline, and the nozzle may be spaced apart from the outlet inducer of the turbine wheel along the centerline of the turbine outlet passage by a distance of up to about 10 times the outlet inducer diameter.

[0394] The auxiliary passage may be configured to deliver the auxiliary flow into the turbine outlet passage upstream of the nozzle.

[0395] The secondary passage may be configured to direct the secondary flow through the nozzle.

[0396] The auxiliary passage may be configured to receive the auxiliary flow from the turbine inlet passage.

[0397] The turbine inlet passage may include a first volute and a second volute, and the auxiliary passage may be configured to receive the auxiliary flow from the first volute.

[0398] The method may also include: using a controller to determine the measurement results of the one or more physical parameters of the auxiliary flow sensed by the exhaust gas sensor; and using the controller to generate a control signal based on the measurement results of the one or more physical parameters of the auxiliary flow; using the dosing module to adjust the delivery rate of the aftertreatment fluid to the turbine outlet channel based on the control signal.

[0399] According to the thirteenth aspect of the present invention, an exhaust aftertreatment system is provided, which includes a turbine, the turbine being configured to receive an exhaust flow from an internal combustion engine, the turbine comprising: a turbine inlet channel, the turbine inlet channel being configured to receive exhaust from the internal combustion engine, the exhaust received by the turbine inlet channel defining a main flow; a turbine impeller chamber, the turbine impeller chamber being configured to receive the main flow from the turbine inlet channel, the turbine impeller chamber being configured to accommodate a turbine impeller, the turbine impeller being supported to rotate around a turbine axis; a turbine outlet channel, the turbine outlet channel being configured to receive the main flow from the turbine inlet channel The turbine wheel chamber receives the main flow; and a distribution module, which is configured to deliver a spray of after-treatment fluid to the turbine outlet channel; an exhaust channel, which is configured to receive the main flow from the turbine outlet channel; and an auxiliary channel, which is configured to receive a portion of the main flow, and the portion of the main flow received by the auxiliary channel defines an auxiliary flow; wherein the exhaust channel includes a predicted after-treatment fluid concentration area, and wherein the auxiliary channel is configured to deliver the auxiliary flow to the exhaust channel to the predicted after-treatment fluid concentration area.

[0400] In the present context, the term "aftertreatment fluid" encompasses the fluid injected into the turbine outlet passage by the dosing module and any products generated by the fluid (e.g., products resulting from heating). The aftertreatment fluid is commonly referred to as diesel exhaust fluid (DEF) and comprises a mixture of urea and water. During use, urea decomposes into the products ammonia and isocyanic acid, but in addition to this, other products may also be formed. In the present context, such reducing agents are also included within the meaning of aftertreatment fluid.

[0401] The after-treatment fluid concentration area covers the spatial area of ​​the after-treatment fluid in the exhaust passage that presents a high concentration relative to the exhaust gas. In this context, the high concentration of the after-treatment fluid covers the following spatial area, wherein the concentration of the after-treatment fluid in the spatial area is higher than the expected concentration of the after-treatment fluid in the exhaust passage when the after-treatment fluid is evenly distributed. The concentration of the after-treatment fluid can be quantified as the volume fraction (expressed in parts per million), mole fraction or any other suitable measure of the main flow in the exhaust passage. Such after-treatment fluid concentration areas are not expected to have, because the after-treatment fluid is not fully mixed with the exhaust gas to support the conversion of NOx contained in the exhaust gas by the catalyst device located further downstream. For example, in the after-treatment fluid concentration area, the urea content of the after-treatment fluid may not have been decomposed. Even if the urea has been decomposed, due to the presence of the after-treatment fluid concentration area, the urea will not be evenly distributed over the entire width of the exhaust passage. This may cause the reductant supply received by some parts of the downstream catalyst device to be insufficient to support the conversion of NOx.

[0402] The predicted aftertreatment fluid concentration area encompasses a theoretical spatial region of the exhaust passage where the aftertreatment fluid concentration area is expected to exist without auxiliary flow being delivered to the exhaust passage. That is, the predicted aftertreatment fluid concentration area does not define the aftertreatment fluid concentration area itself, but rather defines the location of the possible aftertreatment fluid concentration area when no auxiliary flow is delivered to the exhaust passage. The predicted aftertreatment fluid concentration area can be calculated, for example, using computational fluid dynamics, and / or determined by real-world testing in an engine test cell.

[0403] During use, as the auxiliary flow is delivered to the exhaust passage and enters the predicted aftertreatment fluid concentration area, the auxiliary flow exchanges momentum with the aftertreatment fluid in the predicted aftertreatment fluid concentration area, resulting in a more uniform distribution of the aftertreatment fluid across the width of the exhaust passage. As a result, the decomposition of urea is increased and the resulting reductant is evenly dispersed across the width of the exhaust passage. This ensures that all parts of the downstream catalyst device receive a sufficient amount of reductant to support the conversion of NOx.

[0404] The exhaust passage may define a centerline and may include a non-linear portion that causes a change in the momentum of the main flow, the turbine may include a turbine impeller having an outlet guide defining an outlet guide diameter; and the auxiliary passage may be configured to deliver the auxiliary flow to the predicted aftertreatment fluid concentration area at a position within about 5 times the outlet guide diameter of the non-linear portion along the centerline. In this context, "non-linearity" covers any feature of the exhaust passage that is different from a straight pipe section and that induces a measurable change in the momentum of the main flow. This includes, but is not limited to, changes in pipe width, tapered and stepped pipe sections, bends, the presence of turbulators or blunt bodies in the main flow of the turbine, etc. Because such non-linear portions cause changes in the momentum of the main flow, it has been found that such non-linear portions increase the chance of forming a concentrated area of ​​aftertreatment fluid. For example, such non-linear portions may result in stagnant or recirculation areas where aftertreatment fluid can be collected. When the auxiliary flow is introduced into the exhaust channel within about 5 times the diameter of the outlet guide of the non-straight portion, the auxiliary flow can exchange momentum with the after-treatment fluid at a location where the after-treatment fluid concentration area may appear. In an alternative embodiment, the auxiliary channel can be configured to deliver the auxiliary flow to the predicted after-treatment fluid concentration area at a location within about 3 times, about 2 times, or about 1 times the diameter of the outlet guide along the center line from the bend. In other alternative embodiments, the auxiliary channel can be configured to deliver the auxiliary flow to the predicted after-treatment fluid concentration area at the non-straight portion. Generally, the closer the auxiliary flow is delivered to the non-straight portion, the greater the possibility that the auxiliary flow disperses the after-treatment fluid. The auxiliary flow can be delivered upstream or downstream of the non-straight portion.

[0405] The non-linear portion may include a bend. Since the bend changes the momentum direction of the main flow, it has been found that the aftertreatment fluid concentration area is likely to appear at the bend of the exhaust passage. In particular, the aftertreatment fluid concentration area may appear slightly downstream of the bend.

[0406] The exhaust passage may include a curved portion having an inner curved surface and an outer curved surface, the inner curved surface defining an inner curved radius, the outer curved surface defining an outer curved radius, the outer curved radius may be greater than the inner curved radius, a portion of the predicted after-treatment fluid concentration area may cover at least a portion of the outer curved surface; and the auxiliary channel may be configured to deliver the auxiliary flow to the portion of the predicted after-treatment fluid concentration area covering the outer curved surface. In the present context, the term "covering" encompasses the spatial area of ​​the predicted after-treatment fluid concentration area distributed on a portion of the exhaust passage wall defining the outer curved surface. Typically, due to the momentum of the after-treatment fluid upstream of the bend, the predicted after-treatment fluid concentration area will be formed along at least a portion of the outer surface of the bend, because the after-treatment fluid does not change direction until it is acted upon by the outer surface. Therefore, the outer surface of the bend of the exhaust passage is a suitable location for delivering the auxiliary flow.

[0407] The auxiliary passage may include an auxiliary passage outlet configured to deliver the auxiliary flow to the exhaust passage, and the auxiliary passage outlet may be defined by an opening formed in the outer curved surface.

[0408] The outer curved surface may define a proximal end and a distal end relative to the direction of the main flow, and the auxiliary channel outlet may be positioned at the distal end of the outer curved surface. Due to the momentum of the post-treatment fluid upstream of the bend, the predicted post-treatment fluid concentration area is more likely to form on and cover the outer surface at the distal end of the bend (rather than the proximal end of the bend). Therefore, the distal end of the outer curved surface is a suitable location for introducing the auxiliary flow.

[0409] The bend may define a centerline having an inlet vector and an outlet vector, and the outlet vector may be inclined at an angle of at least about 30° relative to the inlet vector. That is, the bend may be a bend having an amplitude of at least about 30°. In alternative embodiments, the outlet vector may be inclined at an angle of at least about 45°, about 60°, about 75°, or about 90° relative to the inlet vector. Generally, the greater the change in direction around the bend, the more likely it is that a post-treatment fluid concentration zone will be formed. Therefore, it is beneficial to introduce an auxiliary flow at a bend having a greater degree of curvature.

[0410] The exhaust channel may define a centerline; and the auxiliary channel may be configured to deliver the auxiliary flow to the exhaust channel along an auxiliary flow direction, and the auxiliary flow direction may be inclined at least about 15° relative to the centerline. The auxiliary flow direction covers the direction vector of the auxiliary flow at the outlet of the auxiliary channel. In alternative embodiments, the auxiliary flow direction may be inclined at an angle of at least about 30°, about 45°, about 60°, about 75°, or about 90° relative to the centerline. Generally, the steeper the relative angle between the auxiliary flow direction and the centerline, the greater the turbulence generated by the momentum exchange between the auxiliary flow and the main flow. The increase in turbulence in the main flow will serve to disperse the post-treatment fluid, and thus will mitigate the formation or continuation of the post-treatment fluid concentration zone.

[0411] The auxiliary flow direction can face upstream relative to the direction of the main flow. The auxiliary flow direction can be tilted upstream at an angle of at least about 15 °, about 30 °, about 45 °, about 60 ° or about 75 °. When the auxiliary flow faces upstream, the amplitude difference between the momentum of the main flow and the momentum of the auxiliary flow will increase, thereby causing turbulence to form an increase and improving the dispersion of the post-treatment fluid.

[0412] The auxiliary flow direction can face downstream relative to the direction of the main flow. The auxiliary flow direction can be tilted downstream at an angle of at least about 15 °, about 30 °, about 45 °, about 60 ° or about 75 °. When the auxiliary flow faces downstream, the amplitude difference between the momentum of the main flow and the momentum of the auxiliary flow can reduce. Therefore, the angle of introduction can be changed, thereby producing enough turbulence to improve the dispersion of the post-treatment fluid, but the turbulence should not be too large, because the turbulence can cause the obstruction to the main flow.

[0413] The predicted geometry of the post-treatment fluid concentration region may be determined using a computational model.

[0414] The predicted aftertreatment fluid concentration area may include a spatial region in which the concentration of the aftertreatment fluid in the spatial region is at least about 50% higher than the expected concentration of the aftertreatment fluid in the exhaust passage when the aftertreatment fluid is uniformly distributed. In other words, the aftertreatment fluid concentration area includes a spatial region in which the concentration of the aftertreatment fluid in the spatial region is at least about 50% higher than the average concentration of the aftertreatment fluid in the entire exhaust passage. In alternative embodiments, the aftertreatment fluid concentration area may include a spatial region in which the concentration of the aftertreatment fluid in the spatial region is at least about 100%, about 150%, or about 200% higher than the average concentration of the aftertreatment fluid in the entire exhaust passage.

[0415] The predicted post-treatment fluid concentration area may include a spatial region in which the concentration of the post-treatment fluid in the spatial region is at least about 2.25% of the volume of the main flow. It has been found that if the post-treatment fluid is completely evenly distributed throughout the main flow, the relative concentration of the post-treatment fluid is about 1.5% of the volume of the main flow. Therefore, in the context of the present invention, the high concentration area may cover a spatial region in which the concentration of the post-treatment fluid is at least 2.25% of the volume of the main flow. In an alternative embodiment, the predicted post-treatment fluid concentration area may include a spatial region in which the concentration of the post-treatment fluid is at least about 3%, about 3.5%, about 4% or about 5% of the volume of the main flow.

[0416] The auxiliary passage may receive the auxiliary flow from a location upstream of the turbine outlet passage. For example, the auxiliary passage may receive the auxiliary flow from the turbine inlet passage, the auxiliary flow from leakage on the blades of the turbine impeller in the turbine wheel chamber, or the auxiliary flow from leakage around the nozzle guide vanes in a variable geometry mechanism.

[0417] The auxiliary passage may include a valve configured to allow, prevent or regulate the flow of the auxiliary flow. The valve may be a wastegate valve, and the auxiliary passage may be a wastegate passage. The size of the auxiliary passage may be configured to allow the auxiliary passage to receive a sufficient amount of the auxiliary flow to provide a wastegate effect for the turbine. For example, the size of the auxiliary passage may be configured to allow the flow of the auxiliary flow to be at least about 20%, or about 50%, of the flow of the main flow delivered by the internal combustion engine to the turbine inlet passage.

[0418] The auxiliary passage may be configured such that the auxiliary flow is always allowed to travel through the auxiliary passage. In such an embodiment, the auxiliary passage may be sized such that the flow rate of the auxiliary flow is small compared to the main flow, so that the auxiliary flow does not adversely affect the power generated by the turbine. For example, the auxiliary passage may be sized such that the flow rate of the auxiliary flow is at most about 1%, about 2%, about 5%, or about 10% of the flow rate of the main flow delivered by the internal combustion engine to the turbine inlet passage.

[0419] According to a fourteenth aspect of the present invention, an exhaust aftertreatment system is provided, which includes a turbine, wherein the turbine is configured to receive an exhaust flow from an internal combustion engine, and the turbine includes: a turbine inlet channel, wherein the turbine inlet channel is configured to receive exhaust gas from an internal combustion engine, and the exhaust gas received by the turbine inlet channel defines a main flow; a turbine impeller chamber, wherein the turbine impeller chamber is configured to receive the main flow from the turbine inlet channel, wherein the turbine impeller chamber accommodates a turbine impeller, wherein the turbine impeller is supported to rotate around a turbine axis, and wherein the turbine has an outlet guide vane defining an outlet guide vane diameter; and a turbine outlet channel, wherein the turbine outlet channel Configured to receive the main flow from the turbine wheel chamber; and a distribution module, the distribution module is configured to deliver a spray of after-treatment fluid to the turbine outlet channel; an exhaust channel, the exhaust channel is configured to receive the main flow from the turbine outlet channel, the exhaust channel defines a center line and includes a non-linear portion; and an auxiliary channel, the auxiliary channel is configured to receive a portion of the main flow, the portion of the main flow received by the auxiliary channel defines an auxiliary flow; wherein the auxiliary channel is configured to deliver the auxiliary flow to the exhaust channel at a position along the center line within about 5 times the outlet guide diameter of the non-linear portion.

[0420] The non-linear portion may include a curved portion.

[0421] The curved portion may include an inner curved surface and an outer curved surface, the inner curved surface defining an inner curved radius, the outer curved surface defining an outer curved radius, the outer curved radius may be greater than the inner curved radius, the auxiliary channel may include an auxiliary channel outlet configured to deliver the auxiliary flow to the exhaust channel; and the auxiliary channel outlet may be defined by an opening formed in the outer curved surface.

[0422] The outer curved surface may define a proximal end and a distal end relative to the direction of the bulk flow, and the auxiliary channel outlet may be positioned at the distal end of the outer curved surface.

[0423] The bend may define a centerline having an entry vector and an exit vector, and the exit vector may be inclined at an angle of at least about 30° relative to the entry vector.

[0424] The auxiliary passage may be configured to deliver the auxiliary flow to the exhaust passage along an auxiliary flow direction, and the auxiliary flow direction may be inclined at least about 15° relative to the centerline.

[0425] The auxiliary flow direction may face upstream relative to the direction of the main flow.

[0426] The auxiliary flow direction may face downstream relative to the direction of the main flow.

[0427] According to the fifteenth aspect of the present invention, an exhaust aftertreatment system is provided, which includes a turbine, wherein the turbine is configured to receive an exhaust flow from an internal combustion engine, and the turbine includes: a turbine inlet channel, wherein the turbine inlet channel is configured to receive exhaust gas from an internal combustion engine, and the exhaust gas received by the turbine inlet channel defines a main flow; a turbine impeller chamber, wherein the turbine impeller chamber is configured to receive the main flow from the turbine inlet channel, and the turbine impeller chamber is configured to accommodate a turbine impeller, and the turbine impeller is supported to rotate around a turbine axis; a turbine outlet channel, wherein the turbine outlet channel is configured to be discharged from the turbine impeller chamber. chamber to receive the main flow; and a distribution module, the distribution module is configured to deliver a spray of after-treatment fluid to the turbine outlet channel; an exhaust channel, the exhaust channel is configured to receive the main flow from the turbine outlet channel; and an auxiliary channel, the auxiliary channel is configured to receive a portion of the main flow, the portion of the main flow received by the auxiliary channel defining an auxiliary flow; wherein the inner surface of the exhaust channel includes a predicted after-treatment fluid impact risk area, and wherein the auxiliary channel is configured to guide the auxiliary flow with an auxiliary flow layer along the portion of the inner surface that defines the predicted after-treatment fluid impact risk area.

[0428] In the present context, the term "aftertreatment fluid" encompasses the fluid injected into the turbine outlet passage by the dosing module and any products produced by the fluid (e.g., products produced as a result of heating). The aftertreatment fluid is commonly referred to as diesel exhaust fluid (DEF) and comprises a mixture of urea and water. During use, urea decomposes into the products ammonia and isocyanic acid. Such reducing agents are also encompassed within the meaning of aftertreatment fluid.

[0429] The "after-treatment fluid impact risk zone" covers areas in the inner surface of the exhaust channel where the risk of after-treatment fluid impact is high. That is, the after-treatment fluid impact risk zone includes areas where the momentum of the after-treatment fluid inside the exhaust channel will cause the after-treatment fluid to collide with the exhaust channel wall. In these areas, the wall will be covered to a certain extent by the after-treatment fluid layer after the impact. The after-treatment fluid impact high risk area can be defined as any theoretical or observed area on the inner surface of the exhaust channel where the after-treatment fluid concentration is higher than the average concentration of the after-treatment fluid on the inner surface of the exhaust channel as a whole. Additionally or alternatively, the existence of the after-treatment fluid impact risk zone can be determined based on the theoretical or observed wall film thickness of the after-treatment fluid on the inner surface of the exhaust conduit. The existence of such after-treatment fluid impact risk areas can be determined by using computational fluid dynamics and / or by real-world modeling in an engine test unit. Such after-treatment fluid impact risk areas are undesirable because the after-treatment fluid that impacts the exhaust channel wall may solidify and cause blockage.

[0430] The predicted aftertreatment fluid impact risk area covers a theoretical area of ​​the inner surface of the exhaust passage, where the aftertreatment fluid impact risk area is expected to exist when no auxiliary flow is delivered to the exhaust passage. That is, the predicted aftertreatment fluid impact risk area does not define the aftertreatment fluid impact risk area itself, but rather defines the location of the possible aftertreatment fluid impact risk area when no auxiliary flow is delivered to the exhaust passage. For example, computational fluid dynamics can be used to calculate the predicted aftertreatment impact risk area.

[0431] The "auxiliary flow layer" covers a fast-moving and high-shear exhaust layer passing over the inner surface of the exhaust channel. The auxiliary flow layer helps to reduce the amount of after-treatment fluid that impacts the inner surface of the exhaust channel in a number of ways. First, the auxiliary flow layer forms a fluid barrier that significantly inhibits the after-treatment fluid from reaching the predicted after-treatment fluid impact risk zone of the inner surface. Secondly, the auxiliary flow layer applies a shear force to the after-treatment fluid, which is used to "disperse" any after-treatment fluid after impact, so that it forms a wider and thinner layer on the inner surface of the exhaust channel. This increases the heat transfer to the after-treatment fluid after impact, causing it to evaporate faster and prevent it from forming solid deposits. Finally, the high shear force applied by the auxiliary flow layer to the after-treatment fluid after impact is used to re-entrain the after-treatment fluid that has been collected on the inner surface. As a result of the combination of these properties, during use, the auxiliary flow layer reduces the risk of after-treatment fluid impact at the after-treatment fluid impact risk zone. In this way, deposit formation in the exhaust channel can be reduced or completely avoided.

[0432] The exhaust passage may define a centerline and may include a non-linear portion that causes a change in momentum of the bulk flow, and the non-linear portion may be at least partially defined by a portion of the interior surface that includes the after-treatment fluid impingement risk zone.

[0433] The non-linear portion may include a curved portion of the exhaust passage.

[0434] The curved portion may include an inner curved surface and an outer curved surface, the inner curved surface defining an inner curved radius, the outer curved surface defining an outer curved radius, the outer curved radius may be greater than the inner curved radius, and the outer curved surface may include a portion of the inner surface defining the predicted post-treatment fluid impact risk zone.

[0435] The auxiliary passage may include an auxiliary passage outlet configured to deliver the auxiliary flow to the exhaust passage, and the auxiliary passage outlet may be defined by an opening formed in the outer curved surface.

[0436] The outer curved surface may define a proximal end and a distal end relative to the direction of the main flow, and the auxiliary channel outlet may be positioned at the distal end of the outer curved surface. Due to the momentum of the post-treatment fluid upstream of the bend, the predicted post-treatment fluid concentration area is more likely to form on and cover the outer surface at the distal end of the bend (rather than the proximal end of the bend). Therefore, the distal end of the outer curved surface is a suitable location for introducing the auxiliary flow.

[0437] The bend may define a centerline having an inlet vector and an outlet vector, and the outlet vector may be inclined at an angle of at least about 30° relative to the inlet vector. That is, the bend may be a bend having an amplitude of at least about 30°. In alternative embodiments, the outlet vector may be inclined at an angle of at least about 45°, about 60°, about 75°, or about 90° relative to the inlet vector. Generally, the greater the change in direction around the bend, the more likely it is that a post-treatment fluid concentration zone will be formed. Therefore, it is beneficial to introduce an auxiliary flow at a bend having a greater degree of curvature.

[0438] Computational models may be used to determine the geometry of the predicted post-treatment fluid concentration zone.

[0439] The predicted aftertreatment fluid impact risk zone may include a region of the inner surface of the exhaust passage where an impact rate of aftertreatment fluid by mass may be more than about 50% higher than an average impact rate of aftertreatment fluid by mass of the surface of the exhaust passage as a whole.

[0440] The auxiliary passage may receive the auxiliary flow from a location upstream of the turbine outlet passage. For example, the auxiliary passage may receive the auxiliary flow from the turbine inlet passage, the auxiliary flow from leakage on the blades of the turbine impeller in the turbine wheel chamber, or the auxiliary flow from leakage around the nozzle guide vanes in a variable geometry mechanism.

[0441] The auxiliary passage may include a valve configured to allow, prevent or regulate the flow of the auxiliary flow. The valve may be a wastegate valve, and the auxiliary passage may be a wastegate passage. The size of the auxiliary passage may be configured to allow the auxiliary passage to receive a sufficient amount of the auxiliary flow to provide a wastegate effect for the turbine. For example, the size of the auxiliary passage may be configured to allow the flow of the auxiliary flow to be at least about 20%, or about 50%, of the flow of the main flow delivered by the internal combustion engine to the turbine inlet passage.

[0442] The auxiliary passage may be configured such that the auxiliary flow is always allowed to travel through the auxiliary passage. In such an embodiment, the auxiliary passage may be sized such that the flow rate of the auxiliary flow is small compared to the main flow, so that the auxiliary flow does not adversely affect the power generated by the turbine. For example, the auxiliary passage may be sized such that the flow rate of the auxiliary flow is at most about 1%, about 2%, about 5%, or about 10% of the flow rate of the main flow delivered by the internal combustion engine to the turbine inlet passage.

[0443] According to the sixteenth aspect of the present invention, an exhaust aftertreatment system is provided, which includes a turbine, the turbine being configured to receive an exhaust flow from an internal combustion engine, the turbine comprising: a turbine inlet channel, the turbine inlet channel being configured to receive exhaust gas from an internal combustion engine, the exhaust gas received by the turbine inlet channel defining a main flow; a turbine impeller chamber, the turbine impeller chamber being configured to receive the main flow from the turbine inlet channel, the turbine impeller chamber being configured to accommodate a turbine impeller, the turbine impeller being supported to rotate around a turbine axis; a turbine outlet channel, the turbine outlet channel being configured The invention provides a method of receiving the main flow from the turbine wheel chamber; and a distribution module, which is configured to deliver a spray of the after-treatment fluid to the turbine outlet channel; an exhaust channel, which is configured to receive the main flow from the turbine outlet channel, and the exhaust channel includes a non-straight portion defined by the inner surface of the exhaust channel; and an auxiliary channel, which is configured to receive a portion of the main flow, and the portion of the main flow received by the auxiliary channel defines an auxiliary flow; wherein the auxiliary channel is configured to guide the auxiliary flow along the inner surface of the non-straight portion with an auxiliary flow layer.

[0444] The auxiliary passage may receive the auxiliary flow from a location upstream of the turbine outlet passage. For example, the auxiliary passage may receive the auxiliary flow from the turbine inlet passage, the auxiliary flow from leakage on the blades of the turbine impeller in the turbine wheel chamber, or the auxiliary flow from leakage around the nozzle guide vanes in a variable geometry mechanism.

[0445] The non-linear portion may include a curved portion of the exhaust passage.

[0446] The curved portion may include an inner curved surface and an outer curved surface, the inner curved surface defining an inner curved radius, the outer curved surface defining an outer curved radius, the outer curved radius may be greater than the inner curved radius, the outer curved surface may include the inner surface; and the auxiliary channel may be configured to guide the auxiliary flow layer along the outer curved surface.

[0447] The auxiliary passage may include an auxiliary passage outlet configured to deliver the auxiliary flow to the exhaust passage; and the auxiliary passage outlet may be defined by an opening formed in the outer curved surface.

[0448] The outer curved surface may define a proximal end and a distal end relative to the direction of the bulk flow, and the auxiliary channel outlet may be positioned at the distal end of the outer curved surface.

[0449] The bend may define a centerline having an entry vector and an exit vector, and the exit vector may be inclined at an angle of at least about 30° relative to the entry vector.

[0450] According to the seventeenth aspect of the present invention, an exhaust aftertreatment system is provided, which includes: a turbine, the turbine being configured to receive an exhaust flow from an internal combustion engine, the turbine including: a turbine inlet channel, the turbine inlet channel being configured to receive exhaust from an internal combustion engine, the exhaust received by the turbine inlet channel defining a main flow; a turbine impeller chamber, the turbine impeller chamber being configured to receive the main flow from the turbine inlet channel, the turbine impeller chamber being configured to accommodate a turbine impeller, the turbine impeller being supported to rotate around a turbine axis; a turbine outlet channel, the turbine outlet channel being configured to receive the main flow from the turbine impeller chamber; and a distribution module, the distribution module A block is configured to deliver a spray of an aftertreatment fluid into the turbine outlet channel; an exhaust channel, the exhaust channel is configured to receive the main flow from the turbine outlet channel; and an auxiliary channel, the auxiliary channel is configured to receive a portion of the main flow, the portion of the main flow received by the auxiliary channel defining the auxiliary flow; wherein the exhaust channel is at least partially defined by a first surface of a partition wall, and the auxiliary channel is at least partially defined by a second surface of the partition wall, the partition wall is configured to provide thermal connectivity from the auxiliary channel to the first surface via the second surface; and wherein at least a portion of the first surface of the partition wall includes an aftertreatment fluid impact risk area.

[0451] During use, when the aftertreatment fluid is injected into the turbine outlet channel, the aftertreatment fluid may impact the first surface. The aftertreatment fluid is usually at a lower temperature than the main flow of the turbine, and thus forms a heat sink that drives heat from the first surface to the aftertreatment fluid. The first surface is heated by two sources. First, the first surface is heated by the convective heat transfer of the main flow traveling through the exhaust channel. Second, the first surface is heated by the auxiliary flow traveling through the auxiliary channel; and in particular by convective heat transfer from the auxiliary flow to the second surface and conductive heat transfer from the second surface through the material of the partition wall to the first surface. Therefore, the first surface and the second surface ensure that a larger surface area can be used to capture heat from the main flow and the auxiliary flow so that heat can be transferred to the aftertreatment fluid (for example, compared with the case without the auxiliary channel). As a result, the amount of heat transferred to the aftertreatment fluid after the impact increases, resulting in an increase in the temperature of the aftertreatment fluid until the aftertreatment fluid evaporates. Therefore, the formation of deposits in the exhaust channel is reduced or prevented.

[0452] The first surface may be disposed on a side of the partition wall opposite to the second surface. In particular, the first surface may be parallel to the second surface and face in a direction opposite to the second surface. Since the first surface and the second surface are located on opposite sides of the partition wall, a direct heat conduction path from the second surface to the first surface is provided, thereby improving heating of the first surface.

[0453] The partition wall may define a thickness between the first surface and the second surface, the turbine comprising a turbine wheel having an outlet guide portion, the outlet guide portion defining an outlet guide diameter, and the thickness of the partition wall may be about 1% to about 10% of the outlet guide diameter. Thus, the partition wall is relatively thin compared to the geometry of the turbine and the exhaust passage. Since the partition wall is thin, heat conduction through the partition wall is better. In some embodiments, the thickness of the partition wall may be up to about 40% of the outlet guide diameter.

[0454] The exhaust passage may include a non-linear portion defined at least in part by a portion of the first surface including the after-treatment fluid impingement risk zone.

[0455] The non-linear portion may include a curved portion.

[0456] The curved portion may include an inner curved surface and an outer curved surface, the inner curved surface defining an inner curved radius, the outer curved surface defining an outer curved radius, the outer curved radius may be greater than the inner curved radius, and the outer curved surface may include a portion of the first surface defining the post-treatment fluid impact risk zone.

[0457] The auxiliary passage may include an auxiliary passage outlet configured to deliver the auxiliary flow to the exhaust passage; and the auxiliary passage outlet may be defined by an opening formed in the outer curved surface.

[0458] The outer curved surface may define a proximal end and a distal end relative to the direction of the bulk flow, and the auxiliary channel outlet may be positioned at the distal end of the outer curved surface.

[0459] The geometry of the post-treatment fluid impact risk zone may be determined using a computational model. Alternatively, the post-treatment fluid impact risk zone may be determined by physical inspection, such as by observing evidence of post-treatment fluid impact (eg, surface pitting, etc.).

[0460] The predicted aftertreatment fluid impact risk zone may include a region of the inner surface of the exhaust passage where an impact rate of aftertreatment fluid by mass may be more than about 50% higher than an average impact rate of aftertreatment fluid by mass of the surface of the exhaust passage as a whole.

[0461] The auxiliary passage may receive the auxiliary flow from a location upstream of the turbine outlet passage. For example, the auxiliary passage may receive the auxiliary flow from the turbine inlet passage, the auxiliary flow from leakage on the blades of the turbine impeller in the turbine wheel chamber, or the auxiliary flow from leakage around the nozzle guide vanes in a variable geometry mechanism.

[0462] The auxiliary passage may include a valve configured to allow, prevent or regulate the flow of the auxiliary flow. The valve may be a wastegate valve, and the auxiliary passage may be a wastegate passage. The size of the auxiliary passage may be configured to allow the auxiliary passage to receive a sufficient amount of the auxiliary flow to provide a wastegate effect for the turbine. For example, the size of the auxiliary passage may be configured to allow the flow of the auxiliary flow to be at least about 20%, or about 50%, of the flow of the main flow delivered by the internal combustion engine to the turbine inlet passage.

[0463] The auxiliary passage may be configured such that the auxiliary flow is always allowed to travel through the auxiliary passage. In such an embodiment, the auxiliary passage may be sized such that the flow rate of the auxiliary flow is small compared to the main flow, so that the auxiliary flow does not adversely affect the power generated by the turbine. For example, the auxiliary passage may be sized such that the flow rate of the auxiliary flow is at most about 1%, about 2%, about 5%, or about 10% of the flow rate of the main flow delivered by the internal combustion engine to the turbine inlet passage.

[0464] According to the eighteenth aspect of the present invention, there is provided an exhaust aftertreatment system, which includes a turbine, the turbine being configured to receive an exhaust flow from an internal combustion engine, the turbine comprising: a turbine inlet passage, the turbine inlet passage being configured to receive exhaust gas from an internal combustion engine, the exhaust gas received by the turbine inlet passage defining a main flow; a turbine impeller chamber, the turbine impeller chamber being configured to receive the main flow from the turbine inlet passage, the turbine impeller chamber being configured to accommodate a turbine impeller, the turbine impeller being supported to rotate around a turbine axis; a turbine outlet passage, the turbine outlet passage being configured to receive the main flow from the turbine impeller chamber; and a distribution A module, the distribution module is configured to deliver a spray of aftertreatment fluid to the turbine outlet channel; an exhaust channel, the exhaust channel is configured to receive the main flow from the turbine outlet channel, the exhaust channel defines a bend; and an auxiliary channel, the auxiliary channel is configured to receive a portion of the main flow, the portion of the main flow received by the auxiliary channel defines an auxiliary flow; wherein the bend of the exhaust channel is at least partially defined by a first surface of a partition wall, and the auxiliary channel is at least partially defined by a second surface of the partition wall, and the partition wall is configured to provide thermal connectivity from the auxiliary channel to the first surface via the second surface.

[0465] The first surface may be disposed on a side of the partition wall opposite to the second surface.

[0466] The dividing wall may define a thickness between the first surface and the second surface, the turbine may include a turbine wheel having an outlet inducer portion defining an outlet inducer diameter, and the thickness of the dividing wall may be about 1% to about 10% of the outlet inducer diameter.

[0467] The curved portion may include an inner curved surface defining an inner curved radius and an outer curved surface defining an outer curved radius, the outer curved radius may be greater than the inner curved radius, and the outer curved surface may include the first surface of the partition wall.

[0468] The auxiliary passage may include an auxiliary passage outlet configured to deliver the auxiliary flow to the exhaust passage; and the auxiliary passage outlet may be defined by an opening formed in the outer curved surface.

[0469] The outer curved surface may define a proximal end and a distal end relative to the direction of the bulk flow, and the auxiliary channel outlet may be positioned at the distal end of the outer curved surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0470] A detailed description of various embodiments of the present invention will now be provided with reference to the accompanying drawings, in which:

[0471] Figure 1 is a schematic diagram of an internal combustion engine system of the prior art;

[0472] Figure 2 is a schematic side cross-sectional view of an embodiment of a turbine according to the present invention;

[0473] Figure 2A A computational fluid dynamics model of aftertreatment fluid particle positions in a turbine according to the present invention is shown;

[0474] Figure 2B A computational fluid dynamics model of aftertreatment fluid concentration in a turbine according to the present invention is shown;

[0475] Figure 3 yes Figure 2 An enlarged side cross-sectional view of a portion of a turbine;

[0476] Figure 4 is a schematic side cross-sectional view of another embodiment of a turbine according to the present invention;

[0477] Figure 5is a schematic side cross-sectional view of another embodiment of a turbine according to the present invention;

[0478] Figure 6 is a schematic side cross-sectional view of another embodiment of a turbine according to the present invention;

[0479] Figure 7 is a schematic side cross-sectional view of another embodiment of a turbine according to the present invention;

[0480] Fig. 7A is a schematic side cross-sectional view of another embodiment of a turbine according to the present invention, which includes a barrier member;

[0481] Figure 8 is a schematic side cross-sectional view of a portion of a turbine according to another embodiment of the present invention;

[0482] Fig. 9 is a schematic side cross-sectional view of another embodiment of a turbine according to the present invention;

[0483] Fig. 9A is a schematic side cross-sectional view of another embodiment of a turbine according to the present invention;

[0484] Fig.10 is a schematic side cross-sectional view of another embodiment of a turbine according to the present invention;

[0485] Fig.11 is a schematic side cross-sectional view of another embodiment of a turbine according to the present invention;

[0486] Fig.12 is a schematic side cross-sectional view of another embodiment of a turbine according to the present invention;

[0487] Fig.13 shows a side cross-sectional view of a turbine according to an embodiment of the present invention;

[0488] Fig.14 Shows Fig.13 an end view of a turbine in section;

[0489] Fig.15 Shown through Fig.14 The line AA intercepts Fig.13 A side cross-sectional view of a wastegate device of a turbine;

[0490] Fig.16 Shows Fig.13 an opposite side cross-sectional view of a turbine;

[0491] Fig.17 Shows Fig.13 Illustration of wall shear within the flow volume of a turbine;

[0492] Fig.18 A variant of the turbine according to the invention is shown, which comprises a bifurcated auxiliary channel;

[0493] Fig.19 shows a side cross-sectional view of a turbine according to another embodiment of the present invention;

[0494] Fig. 20 Shown through Fig.19 The line BB intercepts Fig.19 an end view of a turbine in section;

[0495] Fig.21 shows a schematic side cross-sectional view of a turbine according to another embodiment of the present invention;

[0496] Fig. 22 shows a schematic side cross-sectional view of a turbine according to another embodiment of the present invention;

[0497] Fig.23 Shown through Fig. 22 The line CC intercepts Fig. 22 A schematic end view in section of a turbine of;

[0498] Fig.24 is a schematic side cross-sectional view of a turbine according to another embodiment of the present invention;

[0499] Fig.25 yes Fig.24 A schematic end view in section of a turbine of;

[0500] Fig.26 is a schematic side cross-sectional view of a turbine according to another embodiment of the present invention;

[0501] Fig. 27 yes Fig.26 A schematic end view in section of a turbine of;

[0502] Fig.28 is a schematic side cross-sectional view of a turbine according to another embodiment of the present invention;

[0503] Fig.29 yes Fig.28 A schematic end view in section of a turbine of FIG.

[0504] Fig.30 is a schematic perspective view of a post-processing system according to another embodiment of the present invention;

[0505] Fig.31 yes Fig.30 A schematic side cross-sectional view of an aftertreatment system of FIG.

[0506] Fig.32It passes through Fig.31 A schematic end cross-sectional view taken along line DD;

[0507] Fig.33 shows a side cross-sectional view of a turbine according to another embodiment of the present invention;

[0508] Fig.34 Shows Fig.33 an end view of a turbine in section;

[0509] Fig.35 The turbine is shown in Fig.33 another side sectional view in a plane orthogonal to the views shown;

[0510] Fig.36 is a schematic side cross-sectional view of another embodiment of a turbine according to the present invention;

[0511] Figure 37 is based on Fig.36 a schematic end view of a turbine of;

[0512] Fig.38A is a schematic side cross-sectional view of another embodiment of a turbine according to the present invention;

[0513] Fig.38B is based on Fig.38A A schematic side cross-sectional view of a variation of a turbine;

[0514] Fig.39 is a schematic side cross-sectional view of another embodiment of a turbine according to the present invention;

[0515] Fig.40 is a schematic side cross-sectional view of another embodiment of a turbine according to the present invention;

[0516] Fig.41A is a schematic side cross-sectional view of another embodiment of a turbine according to the present invention;

[0517] Fig.41B shows the results of a CFD simulation of a turbine according to another embodiment, showing the variation of exhaust gas turbulence kinetic energy downstream of the turbine impeller; and

[0518] FIG42 is a schematic side cross-sectional view of another embodiment of a turbine according to the present invention;

[0519] Fig.43A shows a schematic end cross-sectional view of another embodiment of a turbine according to the invention;

[0520] Fig.44A yes Fig.43A A side cross-sectional view of an embodiment of the invention taken through line AA;

[0521] Fig.44B yes Fig.43A A partial side cross-sectional view of an embodiment of the invention taken through line BB;

[0522] Fig.45 shows a side cross-sectional view of another embodiment of a turbine according to the present invention;

[0523] Fig.46 Shown according to Fig.45 An end view of a turbine;

[0524] Fig.47 shows a schematic side cross-sectional view of a turbine according to another embodiment of the present invention;

[0525] Fig.48 is a schematic side cross-sectional view of another embodiment of a turbine according to the present invention;

[0526] Fig.49 is a schematic side cross-sectional view of another embodiment of a turbomachine according to the present invention, which includes a wastegate device;

[0527] Fig.50 is a schematic side cross-sectional view of another embodiment of a turbine according to the present invention, which includes a double volute inlet passage;

[0528] Fig.51 is a schematic diagram of an internal combustion engine system according to the present invention;

[0529] Fig.52 A perspective view showing a computational fluid dynamics model of an exhaust aftertreatment system according to the present invention;

[0530] Figure 53 to Figure 58 Shows Fig.52 Relative concentrations of aftertreatment fluids in various cross sections of the exhaust aftertreatment system;

[0531] Fig.59 A perspective view of a computational fluid dynamics model of an exhaust aftertreatment system is shown, illustrating the likelihood of exhaust aftertreatment fluid impinging on surfaces of the exhaust aftertreatment system;

[0532] Fig.60 Shows Fig.59 Another perspective on the computational fluid dynamics model of

[0533] Fig.61 is a plan cross-sectional view of a turbine according to one or more aspects of the present invention;

[0534] Fig.62 yes Fig.61 A top sectional view of a turbine;

[0535] Fig.63 It is captured through the distribution module. Fig.61 an end view of a turbine in section;

[0536] Fig.64 is intercepted through the sensing channel Fig.61 A side cross-sectional view of a turbine;

[0537] Fig.65 is a side cross-sectional view of a turbine according to one or more aspects of the present invention;

[0538] Fig.66 It is intercepted through the distribution module and the sensing channel. Fig.65 an end view in section of a turbine of; and

[0539] Fig.67 It is intercepted through the distribution module Fig.65 A side cutaway view of a turbine. DETAILED DESCRIPTION

[0540] Figure 1 A schematic diagram of a turbocharged diesel engine system 1002 according to the prior art is shown. The system 1002 includes a diesel internal combustion engine 1004, a turbocharger 1006, and an exhaust aftertreatment system 1008. The turbocharger 1006 includes a compressor 1010 and a turbine 1012, which are mounted to a common turbocharger shaft 1014 so that the two rotate synchronously. The compressor 1010 receives intake air from a low-pressure intake duct 1016 connected to the atmosphere. The low-pressure intake duct 1016 may include a particulate filter for cleaning the intake air. The compressor 1010 uses the power provided by the turbocharger shaft 1014 to compress the intake air, and supplies the compressed intake air to the engine 1004 through a high-pressure intake duct 1018 and an intake manifold 1020. Although not shown, the high-pressure intake duct 1018 may include an intercooler configured to cool the intake air before the intake air reaches the engine 1004. Inside the engine 1004, an internal combustion process occurs and useful work is produced. As a result of the internal combustion process, the engine 1004 produces exhaust gas. The engine 1004 is fluidly connected to an exhaust manifold 1022, which is configured to receive exhaust gas from the engine 1004. The exhaust manifold 1022 is connected to the turbine 1012 via a high-pressure exhaust conduit 1024. The turbine 1012 extracts energy from the exhaust gas to drive the turbocharger shaft 1014, and thereby provides power for the compressor 1010. The exhaust gas leaving the turbine 1012 is supplied to the exhaust aftertreatment system 1008 through a downpipe 1026. The downpipe 1026 is relatively long in length, for example at least 2 meters long, such as Figure 1Indicated by the dotted line in .

[0541] The exhaust aftertreatment system 1008 includes a decomposition chamber 1028 having a diameter greater than the diameter of the downcomer 1026. The decomposition chamber 1028 includes a mixing element 1030 disposed therein. The mixing element 1030 generally includes a plurality of baffles configured to deflect the flow through the decomposition chamber 1028 to induce turbulence within the decomposition chamber 1028. The exhaust aftertreatment system 1008 includes a dosing module 1032 configured to inject an exhaust aftertreatment fluid (and specifically a diesel exhaust fluid (DEF)) into the decomposition chamber 1028 located downstream of the mixing element 1030, in an area where the exhaust gas is most turbulent. The heat exchange between the DEF in the decomposition chamber 1028 and the exhaust gas causes the urea contained in the DEF to decompose into a reducing agent ammonia (NH 3 ) and isocyanate (HNCO). Then, the mixture of the reducing agent and the exhaust gas is delivered to the selective catalytic reducer 1034 (selective catalytic reducer, SCR) and the diesel oxidation catalyst device 1036 (diesel oxidation catalyst, DOC). Finally, the exhaust gas is delivered to the outlet pipe 1038 and further delivered to the muffler (not shown) and then discharged to the atmosphere.

[0542] Figure 2A schematic cross-sectional view of a turbine 1100 according to an embodiment of the present invention is shown. The turbine 1100 includes a turbine housing 1102 and a turbine impeller 1104, which is supported by a turbocharger shaft 1106 and is configured to rotate around a turbine axis 1108. The turbine housing 1102 defines a turbine inlet passage 1110, a turbine impeller chamber 1112, and a turbine outlet passage 1114. The turbine inlet passage 1110 is configured to receive exhaust gas from an internal combustion engine (not shown). The exhaust gas received from the internal combustion engine through the turbine inlet passage 1110 defines a turbine bulk flow 1118. The turbine inlet passage 1110 is in the shape of a volute, configured to cause the turbine bulk flow to swirl around the turbine axis 110. The turbine impeller chamber 1112 is configured to receive the turbine bulk flow 1118 from the turbine inlet passage 1110. As the turbine body flow 1118 travels through the turbine wheel chamber 1112, the turbine body flow 1118 impacts the blades (not shown) of the turbine wheel 1104, thereby rotating the turbine wheel 1104 and driving the turbocharger shaft 1106. The turbine wheel 1104 redirects the turbine body flow 1118 so that it flows in an axial direction relative to the turbine axis 1108, and delivers the turbine body flow 1118 to the turbine outlet passage 1114. Therefore, the turbine 1100 is a so-called "radial" turbine. However, in alternative embodiments, the turbine 1100 can be an "axial" turbine, in which the exhaust gas flows from the turbine inlet passage 1110 to the turbine outlet passage 1114 in a generally axial direction.

[0543] The turbine outlet passage 1114 includes a generally tapered sidewall 1116 that defines a diffuser portion 1120 that is configured to expand the exhaust gas in the turbine outlet 114. The sidewall 1116 tapers outward at an angle of about 7°, but in alternative embodiments, any suitable tapering angle may be used. For example, the tapering angle may be up to about 10°, or about 15°, or about 20°. The diffuser portion 1120 is symmetrically centered on the turbine axis 1108 so that the turbine axis 1108 defines a centerline 1109 of the turbine outlet passage 1114. However, in alternative embodiments, the diffuser portion 1120 may have any suitable shape. In such an embodiment, the centerline 1109 may be defined by the centroid of the turbine outlet passage 1114 relative to the direction of the turbine body flow 1118. Thus, the centerline 1109 may bend or otherwise deviate from the turbine axis 1108 depending on the shape of the turbine outlet passage 1114. In still other embodiments, the turbine outlet passage 1114 may include a constant diameter portion located immediately downstream of the turbine wheel 1104 and upstream of the diffuser portion 1120. In other embodiments, the turbine outlet passage 1114 may include a diffuser portion 1120 formed of a plurality of conical stepped sections separated by constant diameter portions.

[0544] The turbine 1100 also includes a dosing module 1122, which is configured to deliver an exhaust aftertreatment fluid to the turbine outlet passage. The aftertreatment fluid is particularly diesel exhaust fluid (DEF), and is typically sold under the trademark AdBlue. The dosing module 1122 includes a nozzle 1124 that is connected to the turbine outlet passage 1114 with a fluid flow. The nozzle 1124 is particularly an atomizing nozzle that is configured to produce a substantially atomized spray of the aftertreatment fluid in the turbine outlet passage 1114. The nozzle 1124 produces a generally conical spray pattern, but in alternative embodiments, substantially any suitable spray pattern (e.g., fan-shaped, etc.) may be used. The spray pattern has a spray angle A1 of about 45° to about 55°, but in alternative embodiments, substantially any suitable spray angle A1, such as 30°, may be used.

[0545] refer to Figure 3, the nozzle 1124 is received in an aperture 1126 defined by a mounting structure 1130 of the turbine housing 1102. The mounting structure 1130 has a so-called "dog house" design that includes a notch-like recess formed in a sidewall 1116 of the turbine outlet passage 1114. The mounting structure 1130 is shaped so that the nozzle 1124 delivers the aftertreatment fluid in a spray direction 1132 that faces generally upstream relative to the turbine body flow 1118. In this embodiment, the spray direction 1132 is inclined at an angle A2 of about 20° relative to a normal 1134 to the centerline 1109 in an upstream direction relative to the turbine body flow 1118.

[0546] The aftertreatment fluid is sprayed into the spray region 1128 of the turbine outlet passage 1114. The spray region 1128 covers a spatial region in which the atomized spray of the aftertreatment fluid has a greater velocity component in the spray direction 1132 than in the direction of the turbine main flow 1118. Almost all of the velocity of the atomized spray of the aftertreatment fluid leaving the nozzle 1124 is along the spray direction 1132, or is inclined relative to the spray direction 1132 up to half of the spray angle A1. However, as the atomized spray of the aftertreatment fluid passes laterally through the turbine outlet passage 1114 (i.e., in a direction normal to the turbine main flow 1118), the interaction between the aftertreatment fluid and the turbine main flow 1118 changes the direction of the atomized spray of the aftertreatment fluid until the aftertreatment fluid flows completely in the direction of the turbine main flow 1118 (i.e., until the aftertreatment fluid is "carried away" by the momentum of the turbine main flow 1118). The spray region 1128 corresponds to a portion of the turbine outlet passage 1114 in which the individual droplets of the aftertreatment fluid carry more momentum from the dosing module 1122 than from the turbine bulk flow 1118. Thus, the geometry of the spray region 1128 is a property of the delivery intensity of the dosing module 1128 relative to the momentum of the turbine bulk flow 1118. For simplicity, the spray region 1128 is Figure 2 However, it should be understood that due to the interaction between the turbine body flow 1118 and the aftertreatment fluid explained above, the spray region 1128 may not actually have a complete conical shape.

[0547] Figure 2A A side view of a computational fluid dynamics model of an alternative embodiment of a turbine 1100 is shown. In particular, Figure 2AParticles 1115 of after-treatment fluid are shown having been sprayed from a dosing module 1122 (not shown) into a turbine outlet passage 1114. Although the dosing module 1122 is not shown, a mounting structure 1130 for mounting the dosing module 1122 to the turbine housing can be seen. It is apparent that the spray of after-treatment fluid particles 1115 is ejected from the mounting structure 1130 for the dosing module 1122 in a generally conical spray pattern that defines a spray region 1128. Figure 2B Shown through Figure 2A A cross-sectional view of a computational fluid dynamics model of a turbine. In particular, Figure 2B The relative concentration of after-treatment fluid (ie, DEF) is shown traveling through the turbine outlet passage 1114. Again, it can be seen that the after-treatment fluid is sprayed from the mounting structure 1130 in a conical after-treatment fluid spray area 1128.

[0548] Return to reference Figure 2 , the dosing module 1122 is positioned and oriented so that the spray area 1128 is close to the outlet of the turbine impeller 1104. Generally, due to transient dissipation, the temperature of the turbine body flow 1118 will be hotter near the turbine impeller 1104 than at any position downstream. Since thermal energy is required to cause decomposition of the aftertreatment fluid, it is preferred for the spray area to be as close to the turbine impeller 1104 as possible. In particular, it is preferred for the dosing module 1122 to be positioned and oriented so that at least a portion of the spray area 1128 is within about 10 times the outlet guide diameter D of the turbine impeller 1104 along the centerline 1109; the outlet guide diameter D is the diameter of the outlet guide portion of the turbine impeller 1104. It has been found that the turbine body flow 1118 maintains a relatively high velocity until it is at least about 4 or 5 times the outlet guide diameter from the turbine impeller 1104. Thus, in alternative embodiments, the dosing module 1122 may be positioned and oriented such that at least a portion of the spray region 1128 is within approximately 2, 3, or 5 times the guide diameter D of the turbine wheel 1104 along the centerline 1109 to take advantage of the higher velocity of the turbine body flow 1118 in such regions. Depending on the orientation of the dosing module 1122, in some embodiments, this may be achieved by positioning the apertures 1126 within the same distance along the centerline 1109 as described above. It is preferred that the aftertreatment fluid does not enter the turbine wheel chamber 1112 because the aftertreatment fluid may impact the turbine wheel 1104, which may result in the formation of deposits. Thus, it is preferred that the spray region 1128 be positioned completely downstream of the turbine wheel chamber 1112 (i.e., such that the spray region 1128 does not overlap the turbine wheel chamber 1112).

[0549] The turbine 1100 also includes an auxiliary passage 1136 having an auxiliary passage inlet 1138 and an auxiliary passage outlet 1140. The auxiliary passage 1136 is defined by an elongated conduit of the turbine housing 1102 extending between the auxiliary passage inlet 1138 and the auxiliary passage outlet 1140. However, in other embodiments, the auxiliary passage may be at least partially formed by a component (e.g., an external conduit, etc.) separate from the turbine housing 1102. The sidewall (and in particular the volute) of the turbine housing 1102 that defines the turbine inlet passage 1110 includes an opening that defines the auxiliary passage inlet 1132. As shown in FIG. Figure 3 As shown, the mounting structure 1130 of the turbine outlet passage 1114 includes an opening in the sidewall 1141 extending generally normal to the nozzle 1124 , which defines the auxiliary passage outlet 1140 .

[0550] During use, the auxiliary passage 1136 receives a portion of the turbine main flow 1118 from the turbine inlet passage 1110 through the auxiliary passage inlet 1138. The portion of the turbine main flow 1118 received by the auxiliary passage 1136 defines an auxiliary flow 1142. The duct-shaped structure of the auxiliary passage 1136 regulates the auxiliary flow 1142 so that the auxiliary flow 1142 flows in a substantially uniform direction. The auxiliary flow 1142 is then delivered by the auxiliary passage outlet to the turbine outlet passage 1114. The direction of the auxiliary flow 1142 when the auxiliary flow 1142 leaves the auxiliary passage outlet 1140 defines an auxiliary flow direction 1144. Figure 2 As shown, the structure of the auxiliary passage 1136 is selected so that the auxiliary flow direction 1144 is substantially normal to the spray direction 1132. Therefore, when the auxiliary flow 1142 enters the turbine outlet passage 1114, the momentum of the auxiliary flow 1142 carries the auxiliary flow 1142 into the spray region 1128.

[0551] As the auxiliary stream 1142 enters the spray region 1128, the auxiliary stream 1142 collides with the atomized droplets of the aftertreatment fluid. This provides many benefits. First, the collision splits the aftertreatment fluid into smaller droplets. This increases the surface area available for heat exchange between the aftertreatment fluid and the exhaust gas in the turbine outlet. Therefore, the decomposition rate of the aftertreatment fluid is improved. In addition, the collision also scatters the aftertreatment fluid droplets, causing the aftertreatment fluid droplets to spread throughout the turbine outlet channel. As a result, the aftertreatment fluid and the subsequent reductant are more evenly distributed throughout the turbine body flow.

[0552] In addition, because the spray direction 1132 faces upstream, it has a momentum component opposite to the turbine main flow 1118. This increases the collision amplitude between the turbine main flow and the aftertreatment fluid. Generally, the greater the angle of the spray direction 1132 toward the turbine main flow 1118, the greater the collision amplitude. However, it has been found that if the angle between the spray direction 1132 and the turbine main flow 1118 is greater than about 45°, the aftertreatment fluid will not be carried across the entire range of the turbine outlet channel. Therefore, the angle A2 between the spray direction 1132 and the normal 1134 to the centerline 1109 should preferably be kept below this value.

[0553] During use, the aftertreatment fluid may coalesce around the nozzle 1124. If the aftertreatment fluid cools, it may solidify into deposits that may clog the nozzle 1124 and prevent successful operation of the aftertreatment system. Figure 2 and Figure 3 As shown, in order to solve this problem, the auxiliary channel outlet 1140 is positioned within the mounting structure 1130 and is close enough to the nozzle 1124 so that it generates a shear force on the nozzle 1124. This shear force can prevent droplets of the post-treatment fluid from agglomerating near the nozzle 1124 and thus keep the nozzle 1124 clean during operation. In order to promote the cleaning of the nozzle 1124 of the dosing module 1122, preferably, the auxiliary channel outlet 1140 is positioned as close to the nozzle 1124 as possible along the spray axis 1132. In particular, if it is desired to promote the cleaning of the nozzle 1124, the auxiliary channel outlet 1140 can be positioned so that it is substantially flush with the nozzle 1124, thereby increasing the shear force applied across the nozzle 1124. However, referring to Figure 3In the illustrated embodiment, the auxiliary channel outlet 1140 is offset (i.e., spaced apart) a short distance from the nozzle 1124 along the spray direction 1132. In particular, the auxiliary channel outlet 1140 can be spaced apart from the nozzle 1124 along the spray axis 1132 by about 25% of the diameter of the turbine outlet channel (at the same axial position along the centerline 1109 as the auxiliary channel outlet 1140). This allows the aftertreatment fluid to disperse outward and collide with a larger amount of auxiliary flow. If the auxiliary channel outlet is spaced apart from the nozzle 1124 in this way, the auxiliary flow 1142 will interact with the fully developed droplets and serve to carry these droplets into the turbine outlet channel 1114. However, it should be noted that the velocity of the turbine body flow 1118 increases as it moves away from the sidewall 1118. Therefore, if the auxiliary passage outlet 1140 is spaced too far from the nozzle 1124, the velocity of the turbine main flow 1118 will be too great relative to the auxiliary flow 1142 and will weaken the effect of the auxiliary flow 1142 on the aftertreatment fluid and may prevent the auxiliary flow 1142 from reaching the nozzle 1124. Therefore, it is preferred that the maximum spacing from the auxiliary passage outlet 1140 to the nozzle 1124 along the spray axis 1132 does not exceed about 25% of the diameter of the turbine outlet passage 1114.

[0554] Although the auxiliary flow direction 1144 is normal to the spray direction 1132, it should be understood that in alternative embodiments, the auxiliary flow direction can be slightly tilted relative to the normal of the spray direction, for example, by about 20° or about 30°. Angles within this range tend to provide sufficient lateral collisions with the post-treatment fluid, thereby promoting spray splitting and scattering. It has been found that if the auxiliary flow direction 1144 deviates from the normal inclination or angle in the direction toward the distribution module 1122, this will promote increased disturbances to the post-treatment fluid, thereby promoting the formation of smaller droplets. However, tilting or angled the auxiliary flow direction 1144 toward the distribution module 1122 will increase the risk of the post-treatment fluid impacting the sidewall 1116 and solidifying on the sidewall 1116. On the other hand, if the auxiliary flow deviates from the normal inclination in the direction toward the centerline of the turbine, the auxiliary flow 1142 will promote the post-treatment fluid to further penetrate into the turbine outlet channel 1114. However, this will not cause the droplets of the post-treatment fluid to split so much, and therefore the mixing of the post-treatment fluid is not very good.

[0555] The dosing module 1122 and mounting structure 1130 may be oriented at substantially any circumferential position relative to the centerline 1109 of the turbine outlet passage 1114. That is, the dosing module and mounting structure 1130 may be positioned at any angular position relative to the centerline 1109 in a plane normal to the centerline. The precise circumferential position of the dosing module 1122 may be selected based on a variety of factors, including packaging requirements and the desired orientation of the dosing module relative to other components of the turbine 1100 (e.g., the auxiliary passage 1136).

[0556] Figure 4 An alternative embodiment of the present invention is shown, in which the auxiliary channel outlet 1140 directly faces the distribution module 1122, and the auxiliary channel 1136 is configured to convey the auxiliary flow 1142 along the auxiliary flow direction 1144 that is completely opposite to the spray direction 1132. During use, the auxiliary flow 1142 enters the spray area 1128, and then the auxiliary flow 1142 collides with the post-treatment fluid. Since the auxiliary flow direction 1144 is directly opposite to the spray direction 1132, the momentum difference between the auxiliary flow 1142 and the post-treatment fluid is at its maximum, and therefore the collision amplitude between the fluid particles constituting the auxiliary flow and the post-treatment fluid is at its maximum. The collision causes the droplets of the post-treatment fluid to split and scatter more effectively, thereby increasing the amount of heat transferred to the post-treatment fluid to promote decomposition, and improving the mixing of the post-treatment fluid with the turbine main flow 1118. In addition, since the auxiliary flow 1142 directly faces the spray direction, the auxiliary flow 1142 prevents the post-treatment fluid from impacting the side wall 1116 of the turbine outlet channel opposite to the distribution module 1122. In this way, the formation of deposits on the side walls 1116 of the turbine outlet passage 1114 is avoided.

[0557] Despite Figure 4 In the embodiment shown, the auxiliary flow direction 1144 is directly opposite to the spray direction 1132, but it should be understood that in alternative embodiments, the auxiliary flow direction 1144 can be inclined relative to the spray direction 1132. Figure 5An alternative embodiment is shown in which the auxiliary flow direction 1144 is oriented at an angle A3 of about 40° in the upstream direction relative to the main turbine flow. When the inclination A3 of the auxiliary flow direction 1144 relative to the spray direction 1132 is about 50°, the momentum component of the auxiliary flow 1142 opposite to the spray direction 1132 is large enough to cause the spray splitting as described above. In addition, because the auxiliary flow direction 1144 faces upstream relative to the main turbine flow 1118, the auxiliary flow 1142 generates turbulence with the main turbine flow 1118, which provides improved mixing of the aftertreatment fluid with the exhaust gas in the spray area 1128. This promotes improved decomposition of the aftertreatment fluid and more uniform distribution of the reductant in the main turbine flow 1118. In order to provide increased turbulence, it has been found that the angle A4 between the auxiliary flow direction 1144 and the centerline 1109 should be in the range of about 45° to about 90°, and preferably in the range of about 45° to about 60°. However, if the turbulence generated is too great, it will restrict flow through the turbine outlet passage 1114 and exert back pressure on the turbine 1100, resulting in reduced power output from the engine.

[0558] Figure 6 An alternative embodiment is shown in which the auxiliary flow 1142 is oriented at an angle A3 of about 45° in the downstream direction relative to the main turbine flow 1118. However, in alternative embodiments, the angle A3 can be between about 0° and about 90°, between about 0° and about 45°, between about 30° and about 90°, between about 40° and about 80°, between about 45° and about 70°, about 45° or about 55°. In the case where the inclination A3 of the auxiliary flow direction 1144 relative to the spray direction 1132 is within the above range, the momentum component of the auxiliary flow 1142 opposite to the spray direction 1132 is large enough to cause the spray to split. Since the auxiliary flow 1142 faces downstream relative to the main turbine flow 1118, the amount of turbulence in the turbine outlet channel 1114 is reduced, and thus high back pressure on the turbine 1100 is avoided. However, this is at the expense of reduced mixing of the post-processing fluid with the main turbine flow 1118.

[0559] Preferably, in such an embodiment, the auxiliary channel outlet 1140 should be positioned slightly upstream of the nozzle 1124 of the dispensing module 1122 relative to the centerline 1109, such as Figure 6 This helps ensure that the product of the combined momentum of the auxiliary flow 1142 and the main turbine flow 1118 directs the auxiliary flow 1142 into the spray region 1128 .

[0560] Figure 7Another alternative embodiment of the present invention is shown in which the nozzle 1124 of the dosing module 1122 is mounted flush with the tapered sidewall 1116 of the turbine outlet passage 1114. Thus, the spray direction 1132 is oriented in a downstream direction relative to the turbine main flow 1118 and is inclined at an angle A2 relative to the normal 1134 to the centerline 1109, which is equal to the tapered angle of the sidewall 1116. In this embodiment, the auxiliary passage 1136 is configured to deliver an auxiliary flow 1142 to the turbine outlet passage 1114 in an auxiliary flow direction 1144 that is inclined at an angle A4 of about 60° relative to the centerline 1109 of the turbine outlet passage 1114. Because the auxiliary flow direction 1144 is inclined or angled toward the centerline 1109, when the auxiliary flow 1142 enters the spray region, the momentum of the auxiliary flow 1142 will carry the aftertreatment fluid across a larger lateral range of the turbine outlet passage 1114 (i.e., a larger range of the normal 1134 along the centerline 1109). Therefore, the aftertreatment fluid 1142 is more evenly distributed across the entire width of the turbine outlet passage 1114. In addition, because the spray direction 1132 faces downstream relative to the main turbine flow 1118, the momentum of the auxiliary flow 1142 and the momentum of the aftertreatment fluid are generally facing the same direction. Therefore, it is easier for the auxiliary flow 1142 to transfer momentum to the aftertreatment fluid so as to carry the aftertreatment fluid across the turbine outlet passage 1114.

[0561] Although the angle A4 in the present embodiment is about 60°, it should be understood that in alternative embodiments, the angle A4 can be substantially any suitable angle, wherein the auxiliary flow 1142 can transfer momentum to the aftertreatment fluid so as to carry the aftertreatment fluid across the lateral extent of the turbine outlet passage 1114. It has been found that when the angle A4 is less than about 45°, the momentum of the auxiliary flow 1142 in the direction of the normal 1134 of the centerline 1109 is insufficient to increase the extent of the aftertreatment fluid flowing laterally across the turbine outlet passage. Therefore, the angle A4 should be greater than this value. However, if the angle A4 is too steep, the aftertreatment fluid may be carried across the turbine outlet passage 1114 too far, so that the aftertreatment fluid will impact the sidewall 1116 opposite to the dosing module, and there is a risk of forming deposits. Therefore, the angle A4 should be in the range of about 45° to about 60°. In order to obtain the best momentum assistance, the angle A4 should be about 67.5° minus the angle A2.

[0562] In addition, although the nozzle 1124 of the distribution module 1122 is oriented to be flush with the side wall 1116, it should be understood that in alternative embodiments, the distribution module 1122 can be oriented so that the distribution module 1122 is tilted relative to the side wall 1116. For example, the distribution module 1122 can be oriented so that the angle A2 between the spray direction 1132 and the normal 1134 of the centerline 1109 reaches about 90°. The more inclined the spray direction 1132 is relative to the normal 1134 of the centerline 1109, the more aligned the aftertreatment fluid is with the turbine main flow 1118, and thus the turbulence generated between the aftertreatment fluid and the turbine main flow 1118 is less, and thus the back pressure on the turbine is avoided. However, in the case of a larger angle, the aftertreatment fluid may not mix well and may not be evenly distributed across the width of the turbine outlet channel. If the angle A2 is less than about 45°, a balance can be achieved between these two factors.

[0563] Fig. 7A Another alternative embodiment is shown, in which the auxiliary channel 1136 includes a valve device 1147, which is configured to allow, prevent or regulate flow through the auxiliary channel 1136. The valve device 1147 can be essentially any valve device (e.g., flap type, lift type, rotating cylinder type, etc.). The auxiliary channel 1136 receives the auxiliary flow 1142 from the turbine inlet channel 1110 through the auxiliary channel inlet 1138, and delivers the auxiliary flow 1142 to the turbine outlet channel 1114 through the auxiliary channel outlet 1140. Therefore, the auxiliary channel 1136 is used as a wastegate channel, and the valve device 1147 is used as a wastegate valve. The auxiliary channel outlet 1140 is positioned relative to the dosing module 1122, so that the auxiliary channel outlet 1140 is generally opposite to the spray direction 1132. However, in contrast to Figure 4 An embodiment of Fig. 7A The turbine 1100 also includes a barrier member 1166 that extends substantially normal to the spray direction 1132 and is disposed between the auxiliary channel outlet 1140 and the dosing module 1122 .

[0564] The size of the barrier member 1166 is set so that the barrier member 1166 substantially covers the auxiliary channel outlet 1140 along the spray direction 1132 from the perspective of the dosing module 1122. In particular, the range of the barrier member 1166 is generally normal to the spray direction 1132, and the axial range along the centerline 1109 is longer than the corresponding range of the auxiliary channel outlet 1140, and the circumferential range defined by the barrier member 1166 relative to the centerline 1109 is longer than the corresponding circumferential range of the auxiliary channel outlet 1140. Therefore, the barrier member 1166 prevents the aftertreatment fluid delivered to the turbine outlet channel 1114 by the dosing module 1122 from entering the auxiliary channel 1136 via the auxiliary channel outlet. This reduces or prevents the aftertreatment fluid from impacting the surface of the auxiliary channel 1136, and thus reduces the chance of the aftertreatment fluid solidifying in the auxiliary channel 1136 and causing blockage. Preferably, the barrier member 1166 is made of a corrosion-resistant material, such as stainless steel. The barrier member 1166 is preferably made of sheet metal provided as an insert within the turbine housing. Alternatively, the barrier member 1166 may be an integral part (eg, an integrally cast part) of the housing or a connection adapter or the like.

[0565] The barrier member 1166 is spaced apart from the sidewall 1116 of the turbine housing 1102 to define a passage 1168 within the turbine outlet passage 1114. The passage 1168 is open at opposite proximal and distal ends relative to the turbine impeller 1104. The proximal end receives a portion of the turbine main body flow from the turbine outlet passage 1114. The auxiliary channel outlet 1140 is disposed between the proximal and distal ends of the passage 1168 so that the auxiliary channel outlet 1140 is covered by the barrier member 1166, as discussed above. The passage 1168 receives the auxiliary flow 1142 from the auxiliary channel outlet 1140. The momentum of the turbine main body flow 1118 in the passage 1168 interacts with the auxiliary flow 1142 and deflects the auxiliary flow 1142 so that the auxiliary flow 1142 flows away from the turbine impeller 1104 in a generally axial direction along the centerline 1109. The mixture of the turbine main flow 1118 and the auxiliary flow then exits the passage 1168 via the distal end, whereupon it enters the spray region 1128. In some embodiments, the barrier member 1166 may be sized so that the proximal end of the passage 1168 is positioned upstream of the most upstream extent of the spray region 1128. As such, this eliminates the possibility that the aftertreatment fluid will enter the proximal end of the passage 1168. However, even if the proximal end of the passage 1168 is located downstream of the most upstream portion of the spray region 1128, the fact that the barrier member 1166 covers the auxiliary passage outlet 1140 provides a sufficient amount of shielding to mitigate the formation of solid deposits in the auxiliary passage 1136.

[0566] Figure 8Another embodiment of the present invention is shown in which the dosing module 1122 is oriented so that the spray direction 1132 faces approximately normal to the centerline 1109. Since the spray direction 1132 is normal to the centerline 1109, the aftertreatment fluid is injected into the turbine outlet passage 1114 with maximum momentum in a lateral direction relative to the turbine main flow 1118. Therefore, the aftertreatment fluid is carried across a greater lateral extent of the turbine outlet passage 1114. In addition, since the auxiliary passage outlet 1140 is positioned on the mounting structure (e.g. Figure 2 and Figure 3 In the embodiment of the invention, the auxiliary flow 1142 can exert a shear force on the nozzle 1124 to keep the nozzle clean. In addition, the auxiliary channel 1136 is oriented so that the auxiliary channel 1136 is inclined at an angle A4 of about 20° relative to the centerline 1109 and the normal 1146 to the spray direction. Therefore, the auxiliary flow can also increase the momentum of the aftertreatment fluid in the lateral direction across the turbine outlet channel 1114, thereby ensuring that the aftertreatment fluid is distributed across the entire width of the channel 1114.

[0567] In all of the above-described embodiments, the auxiliary passage 1136 is substantially free of flow restrictors or valves that would obstruct or selectively prevent flow from the auxiliary passage inlet 1138 to the auxiliary passage outlet 1140. Thus, the auxiliary passage acts as a full-load bypass that can operate under all operating conditions of the turbine 1100 to deliver the auxiliary flow 1142 to the spray region 1128, and thereby can always provide the above-described beneficial effects of delivering the auxiliary flow to the spray region 1128. The cross-sectional area of ​​the auxiliary passage 1136 can be selected so that the auxiliary flow 1142 accounts for a relatively small proportion of the turbine main flow 1118. For example, the mass flow rate of the auxiliary flow 1142 can be about 0.1%, 0.2%, 0.5%, 1%, 2%, or 5% of the mass flow rate of the exhaust gas entering the turbine inlet 110 (i.e., the mass flow rate of the exhaust gas leaving the engine). Thus, the auxiliary passage 1136 acts as a constant or "full-duty" bypass. The auxiliary channel 1136 may define a constant cross-sectional area along its entire length, or the cross-sectional area of ​​the auxiliary channel 1136 may vary along the length of the auxiliary channel. In the case where the cross-sectional area of ​​the auxiliary channel 1136 varies, the flow rate of the auxiliary flow can be controlled by appropriately setting the size of the narrowest portion of the auxiliary channel 1136.

[0568] refer to Fig. 9In other embodiments, the auxiliary passage 1136 may connect the turbine inlet passage 1110 to the turbine outlet passage 1114, and the auxiliary passage 1136 may include a valve 1147 configured to selectively allow, prevent, or regulate flow from the turbine inlet passage 1110 to the turbine outlet passage 1114 through the auxiliary passage 1136. In such an embodiment, the auxiliary passage 1136 is functionally equivalent to a wastegate passage, and the valve 1147 is functionally equivalent to a wastegate valve. Therefore, the size of the auxiliary passage 1136 may be selected so that the maximum allowable flow through the auxiliary passage 1136 is large enough to provide sufficient wastegate function. For example, the size of the auxiliary passage 1136 may be set so that the mass flow rate of the auxiliary flow can reach about 25% or about 50% of the mass flow rate of the exhaust gas entering the turbine inlet 110.

[0569] The valve 1147 may be configured such that the valve 1147 substantially blocks flow through the auxiliary passage 1136. However, if this is the case, when the valve 1147 is fully closed, no auxiliary flow travels through the auxiliary passage 1136, and thus the auxiliary flow cannot affect the aftertreatment fluid or the turbine body flow in the turbine outlet passage. Therefore, the valve 1147 may be designed such that the valve 1147 cannot completely block flow through the auxiliary passage. For example, the valve 1147 may be configured such that the valve 1147 cannot be completely closed, or the valve 1147 may be controlled so that the valve 1147 is not completely closed during use. Additionally or alternatively, the valve 1147 may include one or more leakage channels that are configured to allow a small amount of auxiliary flow to travel through the valve 1147 even when the valve 1147 is in the most restricted configuration of the valve. The amount of leakage allowed may be about 0.1%, 0.2%, 0.5%, 1%, 2%, or 5% of the mass flow of the exhaust gas entering the turbine inlet 110. In such an embodiment, the auxiliary flow is always allowed to flow through the auxiliary passage 1136 so that the auxiliary flow can affect the aftertreatment fluid and the turbine body flow during all operating conditions of the engine, while the turbine is also able to bypass a larger amount of flow through the wastegate passage to provide adequate wastegate function.

[0570] exist Fig. 9 In the embodiment of the invention, the auxiliary passage 1136 is configured to introduce the auxiliary flow 1142 into the turbine outlet passage 1114 through the nozzle 1124 of the dosing module 1122, thereby keeping the nozzle 1124 clean. In particular, the auxiliary passage 1136 is configured so that the auxiliary flow direction 1144 at the auxiliary passage outlet 1140 is angled approximately orthogonally to the spray direction 1132 of the aftertreatment fluid. In this regard, Fig. 9 The embodiments provided above are similar to the Figure 2The embodiments have the same advantages and can therefore have corresponding structures.

[0571] Fig. 9A Shows Fig. 9 A variation of an embodiment in which the auxiliary channel 1136 is configured to introduce an auxiliary flow 1142 into the turbine outlet channel 1114 in an auxiliary flow direction 1144 that is substantially normal to the turbine axis 1108. The auxiliary channel outlet 1140 is positioned upstream of the dosing module 1122 relative to the turbine axis 1108. The dosing module 1122 is mounted in a mounting structure 1130 of the previous type described above. The auxiliary channel outlet 1140 and the dosing module 1122 are positioned on the same side of the turbine axis 1108 as each other, so that both the auxiliary flow direction 1144 and the spray direction 1132 are oriented in the same direction substantially transverse to the turbine axis 1108. However, the nozzle 1124 of the dosing module 1122 is oriented in a slightly upstream direction relative to the turbine axis 1108. In particular, the angle of the spray direction 1132 relative to the turbine axis 1108 , the spray angle A1 of the nozzle 1124 , and the spacing of the nozzle 1124 from the auxiliary passage outlet 1140 are selected so that the auxiliary flow 1142 will enter a portion of the spray area 1128 .

[0572] During use, when the wastegate valve 1147 is open, the auxiliary flow 1142 will be delivered to the turbine outlet passage 1114 through the auxiliary passage 1136. Since the auxiliary flow direction 1144 is generally orthogonal to the turbine axis 1108, the auxiliary flow will impact and be reflected by the portion of the sidewall 1116 on the opposite side of the auxiliary passage outlet 1140 relative to the turbine axis 1108. The impact of the auxiliary flow 1142 on the sidewall 1116 will generate a relatively large amount of turbulence, which improves the mixing of the aftertreatment fluid with the auxiliary flow 1142 and the main turbine flow 1118. As a result, the aftertreatment fluid will break up faster and will be more evenly distributed throughout the turbine outlet passage.

[0573] Furthermore, because the dosing module 1122 is positioned on the same side of the turbine outlet passage 1114 as the auxiliary passage outlet 1140 relative to the turbine axis 1108, the likelihood of any aftertreatment fluid entering...

Claims

1. A turbine for a turbocharger, comprising: a turbine inlet passage configured to receive exhaust gas from an internal combustion engine, the exhaust gas received by the turbine inlet passage defining a turbine body flow; a turbine wheel chamber configured to receive the turbine body flow from the turbine inlet passage, the turbine wheel chamber configured to house a turbine wheel supported for rotation about a turbine axis; a turbine outlet passage configured to receive the turbine body flow from the turbine wheel chamber; a distribution module configured to deliver a spray of aftertreatment fluid into a spray region of the turbine outlet passage through which the turbine body flow travels; and an auxiliary passage configured to receive a portion of the turbine main body flow, the portion of the turbine main body flow received by the auxiliary passage defining an auxiliary flow; Wherein, the auxiliary passage is configured to guide the auxiliary flow into the spray region of the turbine outlet passage.

2. The turbine according to claim 1, wherein: The dosing module includes a nozzle configured to generate the spray of aftertreatment fluid, and wherein the nozzle is substantially aligned with or located radially outward of a sidewall of the turbine outlet passage.

3. The turbine according to claim 1 or 2, wherein: The dosing module is configured to deliver the aftertreatment fluid in a spray direction, and the auxiliary channel is configured to direct the auxiliary flow into the spray region in an auxiliary flow direction that is generally normal to the spray direction.

4. The turbine according to claim 3, wherein: The secondary flow direction is angled relative to the normal to the spray direction at an angle of up to about 30°.

5. The turbine according to any one of claims 1 to 4, wherein: The dosing module comprises a nozzle, and the auxiliary channel is configured to direct the auxiliary flow through the nozzle in a direction substantially normal to the spraying direction.

6. The turbine according to claim 1, wherein: The dosing module is configured to deliver the post-treatment fluid in a spray direction, and the auxiliary channel is configured to guide the auxiliary flow into the spray region in an auxiliary flow direction opposite to the spray direction.

7. The turbine according to claim 6, wherein: The auxiliary flow is oriented in an upstream direction relative to the main turbine flow, and wherein the auxiliary flow direction is angularly inclined at an angle between about 50° and about 90° relative to an opposite direction of the spray direction.

8. The turbine according to claim 6, wherein: The auxiliary flow is directed in a downstream direction relative to the main turbine flow, and wherein the auxiliary flow direction is angularly inclined at an angle between about 30° and about 90° relative to an opposite direction of the spray direction.

9. A turbine according to any one of claims 6 to 8, wherein: The auxiliary channel comprises an auxiliary channel outlet configured to deliver the auxiliary flow to the turbine outlet channel, and wherein the turbine further comprises a barrier member configured to substantially cover the auxiliary channel outlet from the perspective of the dosing module in the spraying direction.

10. The turbine of claim 1, wherein: The auxiliary passage is configured to direct the auxiliary flow into the turbine outlet passage in an auxiliary flow direction facing a centerline of the turbine outlet passage; and The distribution module is configured to deliver the after-treatment fluid in a spray direction facing the centerline.

11. The turbine according to claim 1, wherein: The auxiliary passage is configured to direct the auxiliary flow into the turbine outlet passage in an auxiliary flow direction facing downstream relative to the turbine main body flow, and The auxiliary flow direction is inclined at an angle of at least about 45° relative to a centerline of the turbine outlet passage.

12. The turbine according to claim 11, wherein: The auxiliary flow direction is inclined at an angle in a range of about 45° to about 90° relative to the center line, or at an angle in a range of about 45° to about 60°.

13. The turbine according to claim 1, wherein: The auxiliary passage is configured to direct the auxiliary flow into the turbine outlet passage in an auxiliary flow direction facing upstream relative to the turbine main body flow, and The auxiliary flow direction is inclined at an angle of at least about 45° relative to a centerline of the turbine outlet passage.

14. The turbine according to claim 13, wherein: The auxiliary flow direction is inclined at an angle in the range of about 45° to about 90° relative to the centerline.

15. The turbine according to claim 1, wherein: The dosing module defines a spray direction, and the turbine outlet passage defines a centerline, and wherein the spray direction is oriented generally normal to the centerline.

16. The turbine according to claim 1, wherein: The distribution module defines a spray direction, and wherein the spray direction is oriented upstream relative to the turbine body flow direction.

17. The turbine according to claim 16, wherein: The spray direction is inclined at an angle of about 90° relative to the normal to the center line.

18. The turbine of claim 1, wherein: The dosing module defines a spray direction, and wherein the spray direction is oriented downstream relative to the turbine body flow direction.

19. The turbine according to claim 18, wherein: The spray direction is inclined at an angle of about 90° relative to the normal to the center line.

20. A turbine according to any one of claims 1 to 19, wherein: The auxiliary passage is configured to allow delivery of the auxiliary flow to the turbine outlet passage during all operating conditions of the turbine when receiving exhaust gas from the internal combustion engine.

21. The turbine according to claim 20, wherein: The auxiliary passage defines a cross section perpendicular to the direction of the auxiliary flow, and wherein the narrowest portion of the cross section is sized such that the mass flow of the auxiliary flow does not exceed approximately 5% of the mass flow of exhaust gas delivered from the engine to the turbine inlet passage.

22. A turbine according to any one of claims 1 to 21, wherein: The auxiliary channel comprises: an auxiliary passage inlet positioned in the turbine inlet passage; and An auxiliary passage outlet is positioned in the turbine outlet passage.

23. The turbine according to claim 22, wherein: The auxiliary passage includes a valve configured to control flow through the auxiliary passage.

24. The turbine according to claim 23, wherein: The valve is configured such that the auxiliary flow is allowed to pass through the valve during all operating conditions of the turbine.

25. The turbine according to claim 24, wherein: The valve is configured such that the auxiliary flow through the valve always accounts for at least about 0.1% of the mass flow of exhaust gas delivered from the engine to the turbine inlet passage.

26. A turbine according to any one of claims 1 to 25, wherein: In addition to the auxiliary passage, the turbine also includes a wastegate device, which includes: a wastegate passage fluidly connecting the turbine inlet passage and the turbine outlet passage such that exhaust gas traveling through the wastegate passage does not travel through the turbine wheel chamber; and A wastegate valve is configured to selectively allow or prevent fluid flow through the wastegate passage.

27. A turbine according to claim 26, wherein: The wastegate passage is configured to direct wastegate flow into the spray region of the turbine outlet passage.

28. The turbine of claim 26, wherein: The wastegate passage fluidly merges with the auxiliary passage such that the wastegate passage is in fluid communication with the turbine outlet passage via the auxiliary passage.

29. A turbine according to claim 28, wherein: The dosing module is configured to deliver aftertreatment fluid to the turbine outlet passage via the auxiliary passage.

30. A turbine according to any one of claims 1 to 21 or 26 to 29, wherein: The auxiliary passage includes an auxiliary passage inlet configured to receive exhaust gas from the turbine outlet passage and an auxiliary passage outlet configured to deliver exhaust gas to the turbine outlet passage.

31. A turbine according to claim 30, wherein: The auxiliary passage includes an outlet portion extending from the nozzle to the auxiliary passage outlet, the outlet portion defining an outlet axis, and wherein the outlet axis is inclined at an angle of up to about 70° relative to a centerline of the turbine outlet passage.

32. A turbine according to claim 30 or 31, wherein: The auxiliary passage includes an inlet portion extending from an auxiliary passage inlet to the nozzle, the inlet portion defining an inlet axis, and wherein the inlet axis is inclined at an angle between about 20° and about 70° relative to a centerline of the turbine outlet passage.

33. A turbine according to any one of claims 30 to 32, wherein: The cross-sectional area of ​​the outlet portion of the auxiliary channel increases along the outlet axis from the nozzle of the dosing module to the auxiliary channel outlet.

34. A turbine according to any one of claims 1 to 33, wherein: The turbine outlet passage defines a diffuser portion, and wherein the dosing module is oriented such that the spray region is located within the diffuser portion.

35. A turbine according to any one of claims 1 to 34, wherein: The turbine includes a turbine impeller having an outlet inducer portion, the outlet inducer portion defining an outlet inducer diameter, and wherein the dosing module is oriented such that at least a portion of the spray area is positioned within approximately 10 times the outlet inducer diameter of the turbine impeller relative to a centerline of the turbine outlet passage.

36. A turbine according to any one of claims 1 to 35, wherein: The turbine includes a housing having a mounting structure to which the dosing module is mounted and the housing defines a bore through which a nozzle of the dosing module passes.

37. A turbine according to claim 36, wherein: The aperture is positioned relative to a centerline of the turbine outlet passage within a range of no more than about 10 inducer diameters from the turbine wheel.

38. A method of operating a turbine for a turbocharger, comprising: receiving exhaust gas from an internal combustion engine into a turbine inlet passage, the exhaust gas received by the turbine inlet passage defining a turbine bulk flow; receiving the turbine body flow from the turbine inlet passage into a turbine wheel chamber configured to house a turbine wheel supported for rotation about a turbine axis; receiving the turbine body flow from the turbine wheel chamber into a turbine outlet passage; delivering an aftertreatment fluid using a dosing module into a spray region of the turbine outlet passage through which the turbine body flow travels; receiving a portion of the main turbine flow into an auxiliary passage, the portion of the main turbine flow received by the auxiliary passage defining an auxiliary flow; as well as The secondary flow is directed into the spray region of the turbine outlet passage.

39. The method of claim 38, wherein: The dosing module is configured to deliver the aftertreatment fluid in a spray direction, and wherein the method further comprises directing the auxiliary flow into the spray region in an auxiliary flow direction that is substantially normal to the spray direction.

40. The method of claim 39, wherein: The secondary flow direction is angled relative to the normal to the spray direction at an angle of up to about 30°.

41. The method according to any one of claims 38 to 40, wherein: The dosing module comprises a nozzle, and the method further comprises directing the secondary flow through the nozzle in a direction substantially normal to the spray direction.

42. The method of claim 38, wherein: The dosing module is configured to deliver the post-treatment fluid in a spray direction, and wherein the method further comprises directing the auxiliary flow into the spray region in an auxiliary flow direction opposite to the spray direction.

43. The method of claim 42, wherein: The method further includes orienting the auxiliary flow direction in an upstream direction relative to the main turbine flow and tilting the auxiliary flow direction relative to an opposite direction of the spray direction by an angle of up to about 45°.

44. The method of claim 42, wherein: The method further includes orienting the auxiliary flow direction in a downstream direction relative to the main turbine flow and tilting the auxiliary flow direction relative to an opposite direction of the spray direction by an angle of up to about 45°.

45. A turbine according to any one of claims 42 to 45, wherein: The auxiliary channel includes an auxiliary channel outlet configured to deliver the auxiliary flow to the turbine outlet channel, and wherein the method further includes shielding the auxiliary channel outlet from the after-treatment fluid using a barrier member, the barrier member being configured to substantially cover the auxiliary channel outlet from the perspective of the distribution module in the spray direction.

46. ​​A turbine according to any one of claims 38 to 45, wherein: The auxiliary passage is configured to direct the auxiliary flow into the turbine outlet passage in an auxiliary flow direction facing a centerline of the turbine outlet passage; and further comprising directing the aftertreatment fluid in a spray direction facing the centerline.

47. The method of claim 38, wherein: The method further includes directing the auxiliary flow into the turbine outlet passage in an auxiliary flow direction facing downstream relative to the turbine main flow direction, and The auxiliary flow direction is inclined at an angle of at least about 45° relative to a centerline of the turbine outlet passage.

48. The method of claim 47, wherein: The auxiliary flow direction is inclined at an angle in the range of about 45° to about 90° relative to the centerline.

49. The method of claim 38, wherein: The method further includes directing the auxiliary flow into the turbine outlet passage in an auxiliary flow direction facing upstream relative to the turbine main flow, and The auxiliary flow direction is inclined at an angle of at least about 45° relative to a centerline of the turbine outlet passage.

50. The method of claim 49, wherein: The auxiliary flow direction is inclined at an angle in the range of about 45° to about 90° relative to the centerline.

51. The method of claim 38, wherein: The dosing module defines a spray direction and the turbine outlet passage defines a centerline, and wherein the method includes orienting the spray direction substantially normal to the centerline.

52. The method of claim 38, wherein: The dosing module defines a spray direction, and wherein the method includes orienting the spray direction upstream relative to the turbine body flow direction.

53. The method of claim 52, wherein: The spray direction is inclined at an angle of about 90° relative to the normal to the center line.

54. The method of claim 38, wherein: The dosing module defines a spray direction, and wherein the method includes orienting the spray direction flow-wise downstream relative to the turbine body.

55. The method of claim 54, wherein: The spray direction is inclined at an angle of about 90° relative to the normal to the center line.

56. A method according to any one of claims 38 to 55, wherein: The auxiliary passage is configured to allow delivery of the auxiliary flow to the turbine outlet passage during all operating conditions of the turbine when receiving exhaust gas from the internal combustion engine.

57. The method of claim 56, wherein: The auxiliary passage defines a cross section perpendicular to the direction of the auxiliary flow, and wherein the narrowest portion of the cross section is sized such that the mass flow of the auxiliary flow does not exceed approximately 5% of the mass flow of exhaust gas delivered from the engine to the turbine inlet passage.

58. The method of any one of claims 38 to 56, wherein: The auxiliary channel comprises: an auxiliary passage inlet positioned in the turbine inlet passage; and An auxiliary passage outlet is positioned in the turbine outlet passage.

59. The method of claim 58, wherein: The auxiliary passage includes a valve configured to control flow through the auxiliary passage.

60. The method of claim 59, wherein: The valve is configured such that the auxiliary flow is allowed to pass through the valve during all operating conditions of the turbine.

61. The method of claim 60, wherein: The valve is configured such that the auxiliary flow through the valve always accounts for at least about 0.1% of the mass flow of exhaust gas delivered from the engine to the turbine inlet passage.

62. The method of any one of claims 38 to 61, wherein: The turbine also includes a wastegate device, the wastegate device comprising: a wastegate passage fluidly connecting the turbine inlet passage and the turbine outlet passage such that exhaust gas traveling through the wastegate passage does not travel through the turbine wheel chamber; and A wastegate valve is configured to selectively allow or prevent fluid flow through the wastegate passage.

63. The method of claim 62, wherein: The wastegate passage is configured to direct wastegate flow into the spray region of the turbine outlet passage.

64. The method of claim 62, wherein: The wastegate passage fluidly merges with the auxiliary passage such that the wastegate passage is in fluid communication with the turbine outlet passage via the auxiliary passage.

65. The method of claim 60, wherein: The dosing module is configured to deliver the aftertreatment fluid to the turbine outlet passage via the auxiliary passage.

66. The method of claim 64 or 65, wherein: The auxiliary passage includes an auxiliary passage inlet configured to receive exhaust gas from the turbine outlet passage and an auxiliary passage outlet configured to deliver exhaust gas to the turbine outlet passage.

67. The method of claim 66, wherein: The auxiliary passage includes an outlet portion extending from the nozzle to the auxiliary passage outlet, the outlet portion defining an outlet axis, and wherein the outlet axis is inclined at an angle of up to about 70° relative to a centerline of the turbine outlet passage.

68. The method of claim 66 or 70, wherein: The auxiliary passage includes an inlet portion extending from an auxiliary passage inlet to the nozzle, the inlet portion defining an inlet axis, and wherein the inlet axis is inclined at an angle between about 20° and about 70° relative to a centerline of the turbine outlet passage.

69. The method according to any one of claims 66 to 68, wherein: The cross-sectional area of ​​the outlet portion of the auxiliary channel increases along the outlet axis from the nozzle of the dosing module to the auxiliary channel outlet.

70. The method of any one of claims 38 to 69, wherein: The turbine outlet passage defines a diffuser portion, and wherein the dosing module is oriented such that the spray region is located within the diffuser portion.

71. The method of any one of claims 38 to 70, wherein: The turbine includes a turbine impeller having an outlet inducer portion, the outlet inducer portion defining an outlet inducer diameter, and wherein the dosing module is oriented such that at least a portion of the spray area is positioned within approximately 10 times the outlet inducer diameter of the turbine impeller relative to a centerline of the turbine outlet passage.

72. The method of any one of claims 38 to 71, wherein: The turbine includes a housing having a mounting structure to which the dosing module is mounted and the housing defines a bore through which a nozzle of the dosing module passes.

73. The method of claim 72, wherein: The aperture is positioned relative to a centerline of the turbine outlet passage within a range of no more than about 10 inducer diameters from the turbine wheel.

74. A turbine for a turbocharger, comprising: a turbine inlet passage configured to receive exhaust gas from an internal combustion engine, the exhaust gas received by the turbine inlet passage defining a turbine body flow; a turbine wheel chamber configured to receive the turbine body flow from the turbine inlet passage, the turbine wheel chamber configured to house a turbine wheel supported for rotation; a turbine outlet passage configured to receive the turbine body flow from the turbine wheel chamber, the turbine outlet passage being at least partially defined by a turbine outlet passage surface, and the turbine outlet passage defining a centerline; an auxiliary passage configured to receive a portion of the turbine main body flow, the portion of the turbine main body flow received by the auxiliary passage defining an auxiliary flow; and a distribution module configured to deliver a spray of aftertreatment fluid into the turbine outlet passage; Wherein, the auxiliary passage is configured to guide the auxiliary flow along the turbine outlet passage surface in an auxiliary flow layer.

75. A turbine according to claim 74, wherein: The dosing module includes a nozzle in fluid communication with the turbine outlet passage, the nozzle being configured to produce a spray of aftertreatment fluid; and Wherein, the nozzle is positioned on a side of the turbine outlet passage opposite to the auxiliary flow layer.

76. A turbine according to any one of claims 74 or 75, wherein: The secondary passage is configured to direct the secondary flow layer in a generally axial direction downstream relative to the centerline.

77. A turbine according to any one of claims 74 to 76, wherein The turbine includes a shield structure protruding into the turbine outlet passage, the shield structure defining a portion of the auxiliary passage.

78. A turbine according to any one of claims 74, 75 or 77, wherein: The turbine wheel imparts a swirl momentum to the turbine body flow, the swirl momentum of the turbine body flow defining a positive angular direction, and wherein the auxiliary passage is configured to deliver the auxiliary flow to the turbine outlet passage in a direction that induces a swirl of the auxiliary flow layer about the centerline along the positive angular direction.

79. A turbine according to any one of claims 74 to 78, wherein The auxiliary passage is configured to deliver the auxiliary flow into the turbine outlet passage in a direction between 0° and about 60° relative to a direction normal to the centerline.

80. The turbine of claim 79, wherein: The auxiliary passage is configured to deliver the auxiliary flow to the turbine outlet passage at a swirl angle between about 30° and about 85°.

81. A turbine according to any one of claims 78 to 80, wherein The auxiliary passage is at least partially defined by an auxiliary passage surface, wherein the auxiliary passage surface and the turbine outlet passage surface define an interface therebetween, and Wherein, at the interface, the auxiliary channel surface is substantially tangent to the turbine outlet channel surface.

82. A turbine according to claim 81, wherein At the interface, the secondary duct surface is inclined at an angle of up to about 15° relative to a tangent to the turbine outlet duct surface in a plane normal to the centerline.

83. A turbine according to any one of claims 78 to 82, wherein: The turbomachine further includes a sensor arrangement including a sensor passage having a sensor passage inlet and a sensor passage outlet; wherein the sensor passage inlet is configured to receive a portion of the turbine body flow from the turbine outlet passage to define a sensor flow, and the sensor passage outlet is configured to deliver the sensor flow to the turbine outlet passage; and The auxiliary passage is configured to guide the auxiliary flow into the turbine outlet passage so that the auxiliary flow layer passes downstream of the sensor passage outlet.

84. A turbine according to any one of claims 78 to 83, wherein the turbine being configured to be connected to a network of exhaust conduits downstream of the turbine outlet passage, the network including a curved portion configured to receive the turbine body flow from the turbine outlet passage; and The auxiliary passage is configured to guide the auxiliary flow into the turbine outlet passage so that the auxiliary flow layer passes through the outer tip of the curved portion.

85. A turbine according to any one of claims 74 to 84, wherein The auxiliary channel includes an auxiliary channel outlet configured to deliver the auxiliary flow into the turbine outlet channel such that the thickness of the auxiliary flow layer is between at least about 5% and at most about 25% of a distance defined between the turbine outlet channel surface and the centerline.

86. A turbine according to any one of claims 74 to 85, wherein The auxiliary channel includes an auxiliary channel outlet configured to deliver the auxiliary flow into the turbine outlet channel such that a width of the auxiliary flow layer is between about 50% and about 100% of a diameter of the turbine outlet channel defined by the turbine outlet channel surface.

87. A turbine according to any one of claims 85 or 86, wherein The secondary channel outlet defines a width and a depth, and wherein the depth is about 15% to about 50% of the width, and preferably about 25% of the width.

88. A turbine according to any one of claims 86 or 87, wherein: The auxiliary passage includes a wastegate valve configured to selectively allow or prevent the auxiliary flow from traveling through the auxiliary passage; The wastegate valve includes a valve opening defining a valve flow area; The auxiliary passage outlet defines an auxiliary flow area in a plane normal to the direction of the auxiliary flow; and The auxiliary flow area is approximately 1.2 times the valve flow area.

89. A turbine according to any one of claims 74 to 88, wherein The auxiliary passage is configured to receive the portion of the turbine body flow from the turbine inlet passage.

90. A turbine according to any one of claims 74 to 89, wherein: The auxiliary passage includes a valve configured to control a flow rate of an auxiliary stream through the auxiliary passage.

91. A turbine according to claim 90, wherein: The auxiliary passage is sized such that when the valve is open, a flow rate of the auxiliary flow through the auxiliary passage is between at least about 25% of a flow rate of the main turbine flow received by the turbine inlet passage.

92. A turbine according to claim 90 or 91, wherein: The auxiliary passage includes an auxiliary passage outlet configured to deliver the auxiliary flow into the turbine outlet passage, and wherein the valve is positioned at the auxiliary passage outlet.

93. A turbine according to any one of claims 74 to 87, wherein: The auxiliary passage is configured to receive the portion of the turbine body flow from the turbine outlet passage.

94. A turbine according to claim 89 or 93, wherein: The auxiliary channel is configured such that an auxiliary flow is always allowed to pass through the auxiliary channel.

95. A turbine according to claim 94, wherein: The auxiliary passage is sized such that, during use, the flow rate of the auxiliary flow is about 0.5% to about 2% of the flow rate of the main turbine flow received by the turbine inlet passage.

96. A turbine according to any one of claims 74 to 95, wherein: The auxiliary channel includes an auxiliary channel outlet and defines a flow area normal to a flow direction of an auxiliary flow through the auxiliary channel, and wherein the flow area narrows toward the auxiliary channel outlet.

97. A turbine according to any one of claims 74 to 96, wherein: The auxiliary passage includes a plurality of auxiliary passage outlets configured to deliver the auxiliary flow into the turbine outlet passage.

98. A turbine according to claim 97, wherein: The auxiliary passage includes a first branch defining the auxiliary passage outlet and a second branch defining a second auxiliary passage outlet, wherein the second auxiliary passage outlet is positioned on a side of the turbine outlet passage generally opposite the auxiliary passage outlet.

99. The turbine according to claim 97, wherein: The auxiliary channel outlets are equidistantly distributed around the center line.

100. A turbine according to any one of claims 74 to 99, wherein: The auxiliary channel includes a plenum and a plurality of branches fluidly connected to the plenum, wherein the plenum is configured to receive the auxiliary flow from an inlet of the auxiliary channel, and the branches are configured to deliver the auxiliary flow to an outlet of the auxiliary channel.

101. The turbine according to claim 100, wherein: Each of the branches is configured to deliver the secondary flow to the turbine exit passage in a direction that induces a swirl in the secondary flow layer about the centerline.

102. A turbine according to any one of claims 74 to 101, wherein: The auxiliary channel comprises: a first auxiliary channel branch configured to receive a first auxiliary flow portion and direct the first auxiliary flow portion into the turbine outlet channel as a first auxiliary flow layer; and A second auxiliary channel branch is configured to receive a second auxiliary flow portion and direct the second auxiliary flow portion into the turbine outlet channel in a second auxiliary flow layer.

103. The turbine according to claim 101, wherein: The first auxiliary passage branch is configured to direct the first auxiliary flow layer downstream relative to the centerline in a generally axial direction into the turbine exit passage; and The second auxiliary channel branch is configured to guide the second auxiliary flow layer downstream in a substantially axial direction relative to the centerline into the turbine outlet channel.

104. The turbine according to claim 102, wherein: the first auxiliary passage branch being configured to direct the first auxiliary flow layer into the turbine exit passage in a direction inducing a vortex of the first auxiliary flow layer about the centerline in a positive angular direction; and Wherein, the second auxiliary channel branch is configured to guide the second auxiliary flow layer into the turbine outlet channel in a direction that induces a vortex of the second auxiliary flow layer about the centerline in the positive angle direction.

105. The turbine according to claim 102, wherein: The first auxiliary passage branch is configured to direct the first auxiliary flow layer downstream relative to the centerline in a generally axial direction into the turbine exit passage; and Wherein, the second auxiliary channel branch is configured to guide the second auxiliary flow layer into the turbine outlet channel in a direction that induces a vortex of the second auxiliary flow layer about the centerline in the positive angle direction.

106. A turbine according to any one of claims 74 to 105, wherein: The turbine outlet passage defines a diffuser portion, and wherein the turbine outlet passage surface is a surface of the diffuser portion.

107. A turbine according to any one of claims 74 to 106, wherein: The turbine includes a housing assembly having: a turbine housing defining the turbine inlet passage and the turbine wheel chamber; and A connection adapter defines at least a portion of the turbine outlet passage and the turbine outlet passage surface.

108. A turbocharger comprising a turbine according to any one of claims 74 to 107.

109. A method of operating a turbine for a turbocharger, comprising: receiving exhaust gas from an internal combustion engine into a turbine inlet passage, the exhaust gas received by the turbine inlet passage defining a turbine body flow; receiving the turbine body flow from the turbine inlet passage into a turbine wheel chamber configured to house a turbine wheel supported for rotation; receiving the turbine body flow from the turbine wheel chamber into a turbine outlet passage, the turbine outlet passage being at least partially defined by a turbine outlet passage surface, the turbine outlet passage defining a centerline; receiving a portion of the main turbine flow into an auxiliary passage, the portion of the main turbine flow received by the auxiliary passage defining an auxiliary flow; delivering a spray of aftertreatment fluid into the turbine outlet passage using a dosing module; as well as The secondary flow is directed along the turbine outlet passage surface in a secondary flow layer.

110. The method of claim 109, wherein: The dosing module includes a nozzle in fluid communication with the turbine outlet passage, the nozzle being configured to produce a spray of aftertreatment fluid; and Wherein, the nozzle is positioned on a side of the turbine outlet passage opposite to the auxiliary flow layer.

111. The method according to any one of claims 109 or 110, wherein: The secondary passage is configured to direct the secondary flow layer in a generally axial direction downstream relative to the centerline.

112. The method according to any one of claims 109 to 111, wherein: The turbine includes a shield structure protruding into the turbine outlet passage, the shield structure defining a portion of the auxiliary passage.

113. The method of any one of claims 109, 110 or 112, wherein: The turbine wheel imparts a swirl momentum to the turbine body flow, the swirl momentum of the turbine body flow defining a positive angular direction, and wherein the auxiliary passage is configured to deliver the auxiliary flow to the turbine outlet passage in a direction that induces a swirl of the auxiliary flow layer about the centerline along the positive angular direction.

114. The method according to any one of claims 109 to 113, wherein: The auxiliary passage is configured to deliver the auxiliary flow into the turbine outlet passage in a direction between 0° and about 60° relative to a direction normal to the centerline.

115. The method of claim 114, wherein: The auxiliary passage is configured to deliver the auxiliary flow to the turbine outlet passage at a swirl angle between about 30° and about 85°.

116. The method of any one of claims 113 to 115, wherein: The auxiliary passage is at least partially defined by an auxiliary passage surface, wherein the auxiliary passage surface and the turbine outlet passage surface define an interface therebetween, and Wherein, at the interface, the auxiliary channel surface is substantially tangent to the turbine outlet channel surface.

117. The method of claim 116, wherein: At the interface, the secondary duct surface is inclined at an angle of up to about 15° relative to a tangent to the turbine outlet duct surface in a plane normal to the centerline.

118. The method according to any one of claims 113 to 117, wherein: The turbomachine further includes a sensor arrangement including a sensor passage having a sensor passage inlet and a sensor passage outlet; wherein the sensor passage inlet is configured to receive a portion of the turbine body flow from the turbine outlet passage to define a sensor flow, and the sensor passage outlet is configured to deliver the sensor flow to the turbine outlet passage; and The auxiliary passage is configured to guide the auxiliary flow into the turbine outlet passage so that the auxiliary flow layer passes downstream of the sensor passage outlet.

119. The method according to any one of claims 113 to 118, wherein: the turbine being configured to be connected to a network of exhaust conduits downstream of the turbine outlet passage, the network including a curved portion configured to receive the turbine body flow from the turbine outlet passage; and The auxiliary passage is configured to guide the auxiliary flow into the turbine outlet passage so that the auxiliary flow layer passes through the outer top end of the curved portion.

120. The method of any one of claims 109 to 119, wherein: The auxiliary channel includes an auxiliary channel outlet configured to deliver the auxiliary flow into the turbine outlet channel such that the thickness of the auxiliary flow layer is between at least about 5% and at most about 25% of a distance defined between the turbine outlet channel surface and the centerline.

121. The method of any one of claims 109 to 120, wherein: The auxiliary channel includes an auxiliary channel outlet configured to deliver the auxiliary flow into the turbine outlet channel such that a width of the auxiliary flow layer is between about 50% and about 100% of a diameter of the turbine outlet channel defined by the turbine outlet channel surface.

122. The method of any one of claims 120 or 121, wherein: The secondary channel outlet defines a width and a depth, and wherein the depth is about 15% to about 50% of the width, and preferably about 25% of the width.

123. The method of any one of claims 121 or 122, wherein: The auxiliary passage includes a wastegate valve configured to selectively allow or prevent the auxiliary flow from traveling through the auxiliary passage; The wastegate valve includes a valve opening defining a valve flow area; The auxiliary passage outlet defines an auxiliary flow area in a plane normal to the direction of the auxiliary flow; and The auxiliary flow area is approximately 1.2 times the valve flow area.

124. The method of any one of claims 109 to 123, wherein: The auxiliary passage is configured to receive the portion of the turbine body flow from the turbine inlet passage.

125. The method of any one of claims 109 to 124, wherein: The auxiliary passage includes a valve configured to control a flow rate of an auxiliary stream through the auxiliary passage.

126. The method of claim 125, wherein: The auxiliary passage is sized such that when the valve is open, a flow rate of the auxiliary flow through the auxiliary passage is between at least about 25% of a flow rate of the main turbine flow received by the turbine inlet passage.

127. The method of claim 125 or 126, wherein: The auxiliary passage includes an auxiliary passage outlet configured to deliver the auxiliary flow into the turbine outlet passage, and wherein the valve is positioned at the auxiliary passage outlet.

128. The method of any one of claims 109 to 122, wherein: The auxiliary passage is configured to receive the portion of the turbine body flow from the turbine outlet passage.

129. The method of claim 128, wherein: The auxiliary channel is configured such that an auxiliary flow is always allowed to pass through the auxiliary channel.

130. The method of claim 129, wherein: The auxiliary passage is sized such that, during use, the flow rate of the auxiliary flow is about 0.5% to about 2% of the flow rate of the main turbine flow received by the turbine inlet passage.

131. The method of any one of claims 109 to 130, wherein: The auxiliary channel includes an auxiliary channel outlet and defines a flow area normal to a flow direction of an auxiliary flow through the auxiliary channel, and wherein the flow area narrows toward the auxiliary channel outlet.

132. The method of any one of claims 109 to 131, wherein: The auxiliary passage includes a plurality of auxiliary passage outlets configured to deliver the auxiliary flow into the turbine outlet passage.

133. The method of claim 132, wherein: The auxiliary passage includes a first branch defining the auxiliary passage outlet and a second branch defining a second auxiliary passage outlet, wherein the second auxiliary passage outlet is positioned on a side of the turbine outlet passage generally opposite the auxiliary passage outlet.

134. The method of claim 133, wherein: The auxiliary channel outlets are equidistantly distributed around the center line.

135. The method of any one of claims 109 to 134, wherein: The auxiliary channel includes a plenum and a plurality of branches fluidly connected to the plenum, wherein the plenum is configured to receive the auxiliary flow from an inlet of the auxiliary channel, and the branches are configured to deliver the auxiliary flow to an outlet of the auxiliary channel.

136. The method of claim 135, wherein: Each of the branches is configured to deliver the secondary flow to the turbine exit passage in a direction that induces a swirl in the secondary flow layer about the centerline.

137. The method of any one of claims 74 to 96, wherein: The auxiliary channel comprises: a first auxiliary channel branch configured to receive a first auxiliary flow portion and direct the first auxiliary flow portion into the turbine outlet channel as a first auxiliary flow layer; and A second auxiliary channel branch is configured to receive a second auxiliary flow portion and direct the second auxiliary flow portion into the turbine outlet channel in a second auxiliary flow layer.

138. The method of claim 137, wherein: The first auxiliary passage branch is configured to direct the first auxiliary flow layer downstream relative to the centerline in a generally axial direction into the turbine exit passage; and The second auxiliary channel branch is configured to guide the second auxiliary flow layer downstream in a substantially axial direction relative to the centerline into the turbine outlet channel.

139. The method of claim 138, wherein: the first auxiliary passage branch being configured to direct the first auxiliary flow layer into the turbine exit passage in a direction inducing a vortex of the first auxiliary flow layer about the centerline in a positive angular direction; and Wherein, the second auxiliary channel branch is configured to guide the second auxiliary flow layer into the turbine outlet channel in a direction that induces a vortex of the second auxiliary flow layer about the centerline in the positive angle direction.

140. The method of claim 139, wherein: The first auxiliary passage branch is configured to direct the first auxiliary flow layer downstream relative to the centerline in a generally axial direction into the turbine exit passage; and Wherein, the second auxiliary channel branch is configured to guide the second auxiliary flow layer into the turbine outlet channel in a direction that induces a vortex of the second auxiliary flow layer about the centerline in the positive angle direction.

141. The method of any one of claims 109 to 140, wherein: The turbine outlet passage defines a diffuser portion, and wherein the turbine outlet passage surface is a surface of the diffuser portion.

142. The method of any one of claims 109 to 141, wherein: The turbine includes a housing assembly having: a turbine housing defining the turbine inlet passage and the turbine wheel chamber; and A connection adapter defines the turbine outlet passage surface and at least a portion of the turbine outlet passage.

143. An aftertreatment system for an internal combustion engine system, comprising: a decomposition chamber configured to receive a bulk flow from the internal combustion engine, the decomposition chamber being at least partially defined by a decomposition chamber surface, and the decomposition chamber defining a centerline; an auxiliary channel configured to receive a portion of the main flow, the portion of the main flow received by the auxiliary channel defining an auxiliary flow; and a dispensing module configured to deliver a spray of post-treatment fluid into the decomposition chamber; Wherein, the auxiliary channel is configured to guide the auxiliary flow along the surface of the decomposition chamber in an auxiliary flow layer.

144. The aftertreatment system of claim 143, wherein: The dispensing module includes a nozzle in fluid communication with the decomposition chamber, the nozzle being configured to produce the spray of post-treatment fluid; and Wherein, the nozzle is positioned on a side of the decomposition chamber opposite to the auxiliary flow layer, so that during use, the auxiliary flow layer inhibits post-treatment fluid from reaching a portion of the decomposition chamber surface opposite to the nozzle.

145. The aftertreatment system of any one of claims 143 to 144, wherein: The secondary passage is configured to direct the secondary flow layer in a generally axial direction downstream relative to the centerline.

146. The aftertreatment system of any one of claims 143 to 144, wherein: The auxiliary channel is configured to deliver the auxiliary flow to the decomposition chamber in a direction that induces a vortex of the auxiliary flow layer about the centerline.

147. The aftertreatment system of claim 146, wherein: The auxiliary channel is configured to deliver the auxiliary flow to the decomposition chamber in a plane normal to the centerline along a tangential direction relative to a surface of the decomposition chamber.

148. The aftertreatment system of any one of claims 143 to 147, wherein: The internal combustion engine system includes a turbine having a turbine wheel, and the auxiliary passage receives the auxiliary flow from a location upstream of the turbine wheel.

149. The aftertreatment system of claim 148, wherein: The turbine imparts a vortex momentum to the main flow, the vortex momentum of the main flow defining a positive angular direction, and wherein the auxiliary channel is configured to deliver the auxiliary flow to the decomposition chamber in a direction that induces the auxiliary flow layer to swirl about the centerline along the positive angular direction.

150. The aftertreatment system of claim 149, wherein: The swirl momentum imparted by the turbine to the turbine body flow defines a first swirl angle, and wherein the auxiliary passage is configured to deliver the auxiliary flow to the decomposition chamber at a second swirl angle that is equal to or steeper than the first swirl angle.

151. The aftertreatment system of claim 150, wherein: The auxiliary channel is configured to deliver the auxiliary flow to the decomposition chamber at a swirl angle between about 30° and about 85°.

152. The aftertreatment system of any one of claims 149 to 151, wherein: The auxiliary channel is at least partially defined by an auxiliary channel surface, wherein the auxiliary channel surface and the decomposition chamber surface define an interface therebetween, and Wherein, at the interface, the auxiliary channel surface is substantially tangent to the decomposition chamber surface.

153. The aftertreatment system of claim 152, wherein: At the interface, the auxiliary channel surface is inclined at an angle of up to about 15° relative to a tangent line to the decomposition chamber surface in a plane normal to the centerline.

154. The aftertreatment system of any one of claims 149 to 153, wherein: The decomposition chamber further includes a sensor device, the sensor device including a sensor channel having a sensor channel inlet and a sensor channel outlet; wherein the sensor channel inlet is configured to receive a portion of the body flow from the decomposition chamber to define a sensor flow, and the sensor channel outlet is configured to deliver the sensor flow to the decomposition chamber; and The auxiliary channel is configured to guide the auxiliary flow into the decomposition chamber so that the auxiliary flow layer passes downstream of the sensor channel outlet.

155. The aftertreatment system of any one of claims 143 to 154, wherein: The decomposition chamber includes a curved portion, and the auxiliary channel is configured to guide the auxiliary flow into the decomposition chamber such that the auxiliary flow layer passes over an outer top end of the curved portion.

156. The aftertreatment system of any one of claims 143 to 155, wherein: The auxiliary channel includes an auxiliary channel outlet, which is configured to deliver the auxiliary flow into the decomposition chamber so that the thickness of the auxiliary flow layer is between at least about 5% and at most about 25% of the distance defined between the decomposition chamber surface and the centerline.

157. The aftertreatment system of any one of claims 143 to 156, wherein: The auxiliary channel includes an auxiliary channel outlet configured to deliver the auxiliary flow into the decomposition chamber such that a width of the auxiliary flow layer is between about 50% and about 100% of a diameter of the turbine outlet channel defined by the decomposition chamber surface.

158. The aftertreatment system of any one of claims 156 or 157, wherein: The secondary channel outlet defines a width and a depth, and wherein the depth is about 15% to about 50% of the width, and preferably about 25% of the width.

159. The aftertreatment system of any one of claims 143 to 158, wherein: The auxiliary passage includes a valve configured to control a flow rate of an auxiliary stream through the auxiliary passage.

160. The aftertreatment system of claim 159, wherein: The auxiliary channel includes an auxiliary channel outlet configured to deliver the auxiliary flow into the decomposition chamber, and wherein the valve is positioned at the auxiliary channel outlet.

161. The aftertreatment system of any one of claims 143 to 160, wherein: The auxiliary channel includes an auxiliary channel outlet and defines a flow area normal to a flow direction of an auxiliary flow through the auxiliary channel, and wherein the flow area narrows toward the auxiliary channel outlet.

162. The aftertreatment system of any one of claims 143 to 161, wherein: The auxiliary channel includes a plurality of auxiliary channel outlets configured to deliver the auxiliary flow into the decomposition chamber.

163. The aftertreatment system of claim 162, wherein: The auxiliary channel outlets are equidistantly distributed around the center line.

164. The aftertreatment system of any one of claims 143 to 163, wherein: The auxiliary channel includes a plenum and a plurality of branches fluidly connected to the plenum, wherein the plenum is configured to receive the auxiliary flow from an inlet of the auxiliary channel, and the branches are configured to deliver the auxiliary flow to an outlet of the auxiliary channel.

165. The aftertreatment system of claim 164, wherein: Each of the branches is configured to deliver the secondary flow to the turbine exit passage in a direction that induces a swirl in the secondary flow layer about the centerline.

166. The aftertreatment system of any one of claims 143 to 165, wherein: The auxiliary channel comprises: a first auxiliary channel branch configured to receive a first auxiliary flow portion and direct the first auxiliary flow portion into the decomposition chamber as a first auxiliary flow layer; and A second auxiliary channel branch is configured to receive a second auxiliary flow portion and guide the second auxiliary flow portion into the decomposition chamber in a second auxiliary flow layer.

167. The aftertreatment system of claim 166, wherein: The first auxiliary channel branch is configured to direct the first auxiliary flow layer downstream relative to the centerline in a generally axial direction into the decomposition chamber; and The second auxiliary channel branch is configured to guide the second auxiliary flow layer downstream relative to the center line in a substantially axial direction into the decomposition chamber.

168. The aftertreatment system of claim 166, wherein: The first auxiliary channel branch is configured to guide the first auxiliary flow layer into the decomposition chamber in a direction that induces a vortex of the first auxiliary flow layer about the centerline in a positive angle direction; and The second auxiliary channel branch is configured to guide the second auxiliary flow layer into the decomposition chamber in a direction that induces a vortex of the second auxiliary flow layer around the center line in the positive angle direction.

169. The aftertreatment system of claim 166, wherein: The first auxiliary channel branch is configured to direct the first auxiliary flow layer downstream relative to the centerline in a generally axial direction into the decomposition chamber; and The second auxiliary channel branch is configured to guide the second auxiliary flow layer into the decomposition chamber in a direction that induces a vortex of the second auxiliary flow layer around the center line in the positive angle direction.

170. A turbine for a turbocharger, comprising: a turbine inlet passage configured to receive exhaust gas from an internal combustion engine, the exhaust gas received by the turbine inlet passage defining a turbine body flow; a turbine wheel chamber configured to receive the turbine body flow from the turbine inlet passage, the turbine wheel chamber housing a turbine wheel supported for rotation; a turbine outlet passage configured to receive the turbine body flow from the turbine wheel chamber, the turbine outlet passage defining a centerline; an auxiliary passage configured to receive a portion of the turbine main body flow, the portion of the turbine main body flow received by the auxiliary passage defining an auxiliary flow, and wherein the turbine wheel is configured to discharge the turbine body flow into the turbine outlet passage so that the turbine body flow swirls about the centerline in a positive angular direction; and The auxiliary passage is configured to guide the auxiliary flow into the turbine outlet passage at a negative angle direction opposite to the positive angle direction.

171. The turbine of claim 170, further comprising a distribution module configured to deliver a spray of aftertreatment fluid into the turbine outlet passage.

172. A turbine according to claim 170 or 171, wherein The auxiliary flow collides with the turbine main flow within the turbine outlet passage to produce a turbulent region, and wherein the dosing module includes a nozzle configured to produce the spray of after-treatment fluid, wherein the nozzle is oriented to direct the after-treatment fluid into the turbulent region.

173. A turbine according to any one of claims 170 to 172, wherein: The swirl momentum imparted to the turbine body flow by the turbine impeller defines a first swirl angle, and wherein the auxiliary passage is configured to deliver the auxiliary flow to the turbine outlet passage at a second swirl angle that is equal to or steeper in magnitude than the first swirl angle.

174. The turbine according to claim 173, wherein: The auxiliary passage is configured to deliver the auxiliary flow to the turbine outlet passage in a direction between 0° and about 60° relative to a direction normal to the centerline.

175. A turbine according to any one of claims 170 to 174, wherein The auxiliary passage is at least partially defined by an auxiliary passage surface, wherein the auxiliary passage surface and the turbine outlet passage surface define an interface therebetween, and Wherein, at the interface, the auxiliary channel surface is substantially tangent to the turbine outlet channel surface.

176. A turbine according to any one of claims 170 to 175, wherein The auxiliary passage is configured to receive the portion of the turbine body flow from the turbine inlet passage.

177. The turbine according to claim 176, wherein The auxiliary passage includes a valve configured to control a flow rate of an auxiliary stream through the auxiliary passage.

178. The turbine according to claim 177, wherein: The auxiliary passage is sized such that when the valve is open, the flow rate of the auxiliary flow through the auxiliary passage is between at least about 25% and about 50% of the flow rate of the main turbine flow received by the turbine inlet passage.

179. A turbine according to any one of claims 170 to 175, wherein The auxiliary passage is configured to receive the portion of the turbine body flow from the turbine outlet passage.

180. The turbine of claim 179, wherein: The auxiliary channel is configured such that an auxiliary flow is always allowed to pass through the auxiliary channel.

181. The turbine according to claim 180, wherein: The auxiliary passage is sized such that, during use, the flow rate of the auxiliary flow is between about 0.1% and about 2% of the flow rate of the main turbine flow received by the turbine inlet passage.

182. A turbine according to any one of claims 170 to 181, wherein The auxiliary passage includes an auxiliary passage outlet configured to deliver the auxiliary flow into the turbine outlet passage.

183. A turbine according to any one of claims 170 to 182, wherein: The turbine outlet passage defines a diffuser portion.

184. The turbine according to claim 183, wherein: The secondary passage outlet is defined by a surface of the diffuser portion.

185. A turbine according to any one of claims 170 to 184, wherein The auxiliary passage includes a plurality of auxiliary passage outlets configured to deliver the auxiliary flow into the turbine outlet passage.

186. A turbine according to any one of claims 170 to 185, wherein The turbine includes a housing assembly having: a turbine housing defining the turbine inlet passage and the turbine wheel chamber; and A connection adapter defines at least a portion of the turbine outlet passage and the turbine outlet passage surface.

187. A turbocharger comprising a turbine according to any one of claims 170 to 186.

188. A method of operating a turbine for a turbocharger, comprising: receiving exhaust gas from an internal combustion engine into a turbine inlet passage, the exhaust gas received by the turbine inlet passage defining a turbine body flow; receiving the turbine body flow from the turbine inlet passage into a turbine wheel chamber, the turbine wheel chamber housing a turbine wheel, the turbine wheel supported for rotation; receiving the turbine body flow from the turbine wheel chamber into a turbine outlet passage, the turbine outlet passage defining a centerline; receiving a portion of the main turbine flow into an auxiliary passage, the portion of the main turbine flow received by the auxiliary passage defining an auxiliary flow; discharging the turbine body flow into the turbine outlet passage using the turbine impeller so that the turbine body flow swirls about the centerline in a positive angular direction; as well as The secondary flow is directed into the turbine outlet passage at a negative angular direction opposite to the positive angular direction.

189. The method of claim 188, further comprising delivering a spray of aftertreatment fluid into the turbine outlet passage using a dosing module.

190. The method of claim 188 or 189, wherein: The auxiliary flow collides with the turbine main flow within the turbine outlet passage to produce a turbulent region, and wherein the dosing module includes a nozzle configured to produce the spray of after-treatment fluid, wherein the nozzle is oriented to direct the after-treatment fluid into the turbulent region.

191. The method of any one of claims 188 to 190, wherein: The swirl momentum imparted to the turbine body flow by the turbine impeller defines a first swirl angle, and wherein the auxiliary passage is configured to deliver the auxiliary flow to the turbine outlet passage at a second swirl angle that is equal to or steeper in magnitude than the first swirl angle.

192. The method of claim 191, wherein: The auxiliary passage is configured to deliver the auxiliary flow to the turbine outlet passage in a direction between 0° and about 60° relative to a direction normal to the centerline.

193. The method of any one of claims 188 to 192, wherein: The auxiliary passage is at least partially defined by an auxiliary passage surface, wherein the auxiliary passage surface and the turbine outlet passage surface define an interface therebetween, and Wherein, at the interface, the auxiliary channel surface is substantially tangent to the turbine outlet channel surface.

194. The method of any one of claims 188 to 193, wherein: The auxiliary passage is configured to receive the portion of the turbine body flow from the turbine inlet passage.

195. The method of claim 194, wherein: The auxiliary passage includes a valve configured to control a flow rate of an auxiliary stream through the auxiliary passage.

196. The method of claim 195, wherein: The auxiliary passage is sized such that when the valve is open, the flow rate of the auxiliary flow through the auxiliary passage is between at least about 25% and about 50% of the flow rate of the main turbine flow received by the turbine inlet passage.

197. The method of any one of claims 188 to 193, wherein: The auxiliary passage is configured to receive the portion of the turbine body flow from the turbine outlet passage.

198. The method of claim 197, wherein: The auxiliary channel is configured such that an auxiliary flow is always allowed to pass through the auxiliary channel.

199. The method of claim 198, wherein: The auxiliary passage is sized such that, during use, the flow rate of the auxiliary flow is between about 0.1% and about 2% of the flow rate of the main turbine flow received by the turbine inlet passage.

200. The method of any one of claims 188 to 199, wherein: The auxiliary passage includes an auxiliary passage outlet configured to deliver the auxiliary flow into the turbine outlet passage.

201. The method of any one of claims 188 to 200, wherein: The turbine outlet passage defines a diffuser portion.

202. The method according to claim 201, wherein: The secondary passage outlet is defined by a surface of the diffuser portion.

203. The method of any one of claims 188 to 202, wherein: The auxiliary passage includes a plurality of auxiliary passage outlets configured to deliver the auxiliary flow into the turbine outlet passage.

204. The method of any one of claims 188 to 203, wherein: The turbine includes a housing assembly having: a turbine housing defining the turbine inlet passage and the turbine wheel chamber; and A connection adapter defines at least a portion of the turbine outlet passage and the turbine outlet passage surface.

205. A turbine for a turbocharger, comprising: a turbine inlet passage configured to receive exhaust gas from an internal combustion engine, the exhaust gas received by the turbine inlet passage defining a turbine body flow; a turbine wheel chamber configured to receive the turbine body flow from the turbine inlet passage, the turbine wheel chamber configured to house a turbine wheel supported for rotation; a turbine outlet passage configured to receive the turbine body flow from the turbine wheel chamber, the turbine outlet passage extending along a centerline, and the turbine outlet passage being at least partially defined by a first surface of a dividing wall; a distribution module configured to deliver a spray of aftertreatment fluid into the turbine outlet passage; and an auxiliary passage configured to receive a portion of the turbine main body flow, the portion of the turbine main body flow received by the auxiliary passage defining an auxiliary flow, the auxiliary passage being at least partially defined by the second surface of the dividing wall; Wherein the partition wall is configured to provide thermal communication from the auxiliary channel to the first surface via the second surface.

206. The turbine according to claim 205, wherein: The first surface is provided on a side of the partition wall opposite to the second surface.

207. A turbine according to any one of claims 205 or 206, wherein The dividing wall defines a thickness between the first surface and the second surface, wherein the turbine includes a turbine wheel having an inducer portion defining an inducer diameter, and wherein the thickness of the dividing wall is approximately 5% of the inducer diameter.

208. A turbine according to any one of claims 205 to 207, wherein: The auxiliary passage is configured to receive the auxiliary flow from the turbine outlet passage.

209. A turbine according to any one of claims 205 to 207, wherein The auxiliary passage is configured to receive the auxiliary flow from the turbine inlet passage.

210. The turbine according to claim 209, wherein: The auxiliary passage includes a valve device configured to selectively allow, prevent and / or regulate flow of the auxiliary fluid through the auxiliary passage.

211. The turbine according to claim 209, wherein: The auxiliary passage is configured such that flow is always allowed through the auxiliary passage.

212. A turbine according to any one of claims 205 to 211, wherein: The turbine includes a turbine wheel having an inducer defining an inducer diameter, and The dosing module includes a nozzle configured to inject the spray of aftertreatment fluid into the turbine outlet passage, and Wherein the nozzle of the dosing module is spaced apart from the outlet inducer of the turbine impeller along the centerline of the turbine outlet passage by a distance of at most about 10 times the outlet inducer diameter.

213. The turbine according to claim 212, wherein: The nozzle is positioned substantially flush with a side wall of the turbine outlet passage.

214. A turbine according to any one of claims 205 to 213, wherein The distribution module is configured to deliver the spray of after-treatment fluid into the turbine outlet passage in a direction facing the first surface.

215. A turbine according to any one of claims 212 to 214, wherein The auxiliary passage defines an auxiliary passage outlet configured to deliver the auxiliary flow into the turbine outlet passage, and wherein the auxiliary passage outlet is located at least about 0.5 outlet inducer diameters downstream of the nozzle along the centerline.

216. A turbine according to any one of claims 205 to 215, wherein The turbine includes a surface at least partially defining the turbine outlet passage, and wherein the nozzle is substantially aligned with or located radially outward of the surface in a radial direction relative to the centerline.

217. A turbine according to any one of claims 205 to 216, wherein The dividing wall extends circumferentially about the centerline.

218. The turbine according to claim 217, wherein: The partition wall is supported by a pair of elongated support columns, and wherein the auxiliary channel is at least partially defined between the support columns.

219. The turbine according to claim 217, wherein: The support posts are positioned on a side of the turbine outlet passage opposite the distribution module, and the auxiliary passage is defined between the support posts on a side of the turbine outlet passage opposite the distribution module.

220. A turbine according to any one of claims 217 to 219, wherein The secondary passage defines an annular nozzle.

221. A turbine according to any one of claims 217 to 220, wherein The turbine outlet passage includes a diffuser portion that is at least partially defined by the dividing wall.

222. A turbine according to claim 221, wherein The distribution module is configured to deliver an aftertreatment fluid into the diffuser portion.

223. A turbine according to any one of claims 217 to 222, wherein The turbine includes a support structure disposed in the auxiliary passage and configured to support the partition wall.

224. A turbine according to claim 223, wherein: The distribution module comprises a nozzle, and wherein the support structure is configured to shield the nozzle from the auxiliary flow and / or the turbine body flow.

225. A turbine according to any one of claims 205 to 223, wherein The dosing module comprises a nozzle positioned in fluid communication with the auxiliary channel such that, in use, the auxiliary flow passes through the nozzle of the dosing module.

226. A turbine according to any one of claims 205 to 225, wherein The turbine outlet passage comprises a curved portion defining a top end, and wherein the dosing module comprises a nozzle configured to deliver aftertreatment fluid into the turbine outlet passage, the nozzle being positioned at the top end of the curved portion or upstream of the top end of the curved portion.

227. A turbine according to claim 226, wherein: The first surface defines a surface of the curved portion, and the nozzle faces the first surface.

228. A turbine according to any one of claims 205 to 227, wherein The auxiliary channel includes an auxiliary channel outlet, which is configured to deliver a portion of the auxiliary flow to the turbine outlet channel at a position downstream of the nozzle of the distribution module, and wherein the partition wall includes an auxiliary orifice, which is configured to deliver a portion of the auxiliary flow to the turbine outlet channel at a position aligned with the nozzle or at a position upstream of the nozzle.

229. The turbine of any one of claims 205 to 228, further comprising a turbine housing assembly, the turbine housing assembly comprising: a turbine housing defining the turbine inlet passage, the turbine wheel chamber, and at least a portion of the turbine outlet passage; and a connection adapter defining at least a portion of the turbine outlet passage and at least a portion of the auxiliary passage, the connection adapter coupled to the turbine housing at a first interface; wherein the connection adapter is configured to support the partition wall to extend along the centerline; and Wherein, the partition wall extends axially along the center line through the first interface.

230. The turbine according to claim 229, wherein: The turbine housing assembly also includes a downtube adapter configured to be connected to the downtube, wherein the down tube adapter defines at least a portion of the auxiliary passage and / or the turbine outlet passage, and the down tube adapter is coupled to the connection adapter at a second interface; and Wherein, the partition wall extends axially along the center line through the second interface.

231. A turbine according to any one of claims 205 to 230, wherein The auxiliary channel is a first auxiliary channel, and the auxiliary flow is a first auxiliary flow, and wherein the turbine further comprises a second auxiliary passage configured to receive a portion of the turbine main flow from the turbine inlet passage, the portion of the turbine main flow received by the second auxiliary passage defining a second auxiliary flow, and Wherein, the second auxiliary passage is configured to deliver the second auxiliary flow to the turbine outlet passage.

232. The turbine according to claim 231, wherein: The second auxiliary channel includes a second auxiliary channel outlet, wherein the second auxiliary channel outlet is aligned with the nozzle of the distribution module relative to the center line or positioned upstream of the nozzle, and wherein the second auxiliary channel outlet is configured to guide the second auxiliary flow along the first surface of the partition wall in a second auxiliary flow layer.

233. A turbine according to any one of claims 231 to 232, wherein The second auxiliary passage includes a second auxiliary passage valve device configured to selectively allow, prevent and / or regulate flow of a second auxiliary fluid through the second auxiliary passage.

234. The turbine of any one of claims 205 to 233, further comprising a controller configured to selectively activate the dosing module to deliver aftertreatment fluid into the turbine outlet passage.

235. A method of operating a turbine for a turbocharger, comprising: receiving exhaust gas from an internal combustion engine into a turbine inlet passage, the exhaust gas received by the turbine inlet passage defining a turbine body flow; receiving the turbine body flow from the turbine inlet passage into a turbine wheel chamber configured to house a turbine wheel supported for rotation; receiving the turbine body flow from the turbine wheel chamber into a turbine outlet passage, the turbine outlet passage extending along a centerline and the turbine outlet passage being at least partially defined by a first surface of a dividing wall; delivering an atomized spray of aftertreatment fluid into the turbine outlet passage using a dosing module including a nozzle; receiving a portion of the turbine main body flow into an auxiliary passage, the portion of the turbine main body flow received by the auxiliary passage defining an auxiliary flow, the auxiliary passage being at least partially defined by a second surface of the dividing wall; Wherein the partition wall is configured to provide thermal communication from the auxiliary channel to the first surface via the second surface.

236. The method of claim 235, wherein: The first surface is provided on a side of the partition wall opposite to the second surface.

237. The method of any one of claims 235 or 236, wherein: The dividing wall defines a thickness between the first surface and the second surface, wherein the turbine includes a turbine wheel having an inducer portion defining an inducer diameter, and wherein the thickness of the dividing wall is approximately 5% of the inducer diameter.

238. The method of any one of claims 235 to 237, wherein: The auxiliary passage is configured to receive the auxiliary flow from the turbine outlet passage.

239. The method of any one of claims 235 to 237, wherein: The auxiliary passage is configured to receive the auxiliary flow from the turbine inlet passage.

240. The method of claim 239, wherein: The auxiliary passage includes a valve device configured to selectively allow, prevent and / or regulate flow of the auxiliary fluid through the auxiliary passage.

241. The method of claim 239, wherein: The auxiliary passage is configured such that flow is always allowed through the auxiliary passage.

242. The method of any one of claims 235 to 241, wherein: The turbine includes a turbine wheel having an outlet inducer defining an outlet inducer diameter, and the dosing module includes a nozzle configured to inject the atomized spray of aftertreatment fluid into the turbine outlet passage, and Wherein the nozzle of the dosing module is spaced apart from the outlet inducer of the turbine impeller along the centerline of the turbine outlet passage by a distance of at most about 10 times the outlet inducer diameter.

243. The method according to claim 242, wherein: The nozzle is positioned substantially flush with a side wall of the turbine outlet passage.

244. The method of any one of claims 235 to 243, wherein: The dosing module is configured to deliver the atomized spray of after-treatment fluid into the turbine outlet passage in a direction facing the first surface.

245. The method of any one of claims 242 to 244, wherein: The auxiliary passage defines an auxiliary passage outlet configured to deliver the auxiliary flow into the turbine outlet passage, and wherein the auxiliary passage outlet is located at least about 0.5 outlet inducer diameters downstream of the nozzle along the centerline.

246. The method of any one of claims 235 to 245, wherein: The turbine includes a surface at least partially defining the turbine outlet passage, and wherein the nozzle is substantially aligned with or located radially outward of the surface in a radial direction relative to the centerline.

247. The method of any one of claims 235 to 246, wherein: The dividing wall extends circumferentially about the centerline.

248. The method of claim 247, wherein: The partition wall is supported by a pair of elongated support columns, and wherein the auxiliary channel is at least partially defined between the support columns.

249. The method of claim 247, wherein: The support posts are positioned on a side of the turbine outlet passage opposite the distribution module, and the auxiliary passage is defined between the support posts on a side of the turbine outlet passage opposite the distribution module.

250. The method of any one of claims 247 to 249, wherein: The secondary passage defines an annular nozzle.

251. The method of any one of claims 247 to 250, wherein: The turbine outlet passage includes a diffuser portion that is at least partially defined by the dividing wall.

252. The method according to claim 251, wherein: The distribution module is configured to deliver an aftertreatment fluid into the diffuser portion.

253. The method of any one of claims 247 to 252, wherein: The turbine includes a support structure disposed in the auxiliary passage and configured to support the partition wall.

254. The method according to claim 253, wherein: The distribution module comprises a nozzle, and wherein the support structure is configured to shield the nozzle from the auxiliary flow and / or the turbine body flow.

255. The method of any one of claims 235 to 254, wherein: The dosing module comprises a nozzle positioned in fluid communication with the auxiliary channel such that, in use, the auxiliary flow passes through the nozzle of the dosing module.

256. The method of any one of claims 235 to 255, wherein: The turbine outlet passage comprises a curved portion defining a top end, and wherein the dosing module comprises a nozzle configured to deliver aftertreatment fluid into the turbine outlet passage, the nozzle being positioned at the top end of the curved portion or upstream of the top end of the curved portion.

257. The method of claim 256, wherein: The first surface defines a surface of the curved portion, and the nozzle faces the first surface.

258. The method of any one of claims 235 to 257, wherein: The auxiliary channel includes an auxiliary channel outlet, which is configured to deliver a portion of the auxiliary flow to the turbine outlet channel at a position downstream of the nozzle of the distribution module, and wherein the partition wall includes an auxiliary orifice, which is configured to deliver a portion of the auxiliary flow to the turbine outlet channel at a position aligned with the nozzle or at a position upstream of the nozzle.

259. The method of any one of claims 235 to 258, further comprising a turbine housing assembly, the turbine housing assembly comprising: a turbine housing defining the turbine inlet passage, the turbine wheel chamber, and at least a portion of the turbine outlet passage; and a connection adapter defining at least a portion of the turbine outlet passage and at least a portion of the auxiliary passage, the connection adapter coupled to the turbine housing at a first interface; wherein the connection adapter is configured to support the partition wall to extend along the centerline; and Wherein, the partition wall extends axially along the center line through the first interface.

260. The method of claim 259, wherein: The turbine housing assembly also includes a downtube adapter configured to be connected to the downtube, wherein the down tube adapter defines at least a portion of the auxiliary passage and / or the turbine outlet passage, and the down tube adapter is coupled to the connection adapter at a second interface; and Wherein, the partition wall extends axially along the center line through the second interface.

261. The method of any one of claims 235 to 260, wherein: The auxiliary channel is a first auxiliary channel, and the auxiliary flow is a first auxiliary flow, and wherein the turbine further comprises a second auxiliary passage configured to receive a portion of the turbine main flow from the turbine inlet passage, the portion of the turbine main flow received by the second auxiliary passage defining a second auxiliary flow, and Wherein, the second auxiliary passage is configured to deliver the second auxiliary flow to the turbine outlet passage.

262. The method according to claim 261, wherein: The second auxiliary channel includes a second auxiliary channel outlet, wherein the second auxiliary channel outlet is aligned with the nozzle of the distribution module relative to the center line or positioned upstream of the nozzle, and wherein the second auxiliary channel outlet is configured to guide the second auxiliary flow along the first surface of the partition wall in a second auxiliary flow layer.

263. The method of any one of claims 261 to 262, wherein: The second auxiliary passage includes a second auxiliary passage valve device configured to selectively allow, prevent and / or regulate flow of a second auxiliary fluid through the second auxiliary passage.

264. The method of any one of claims 235 to 263, further comprising a controller configured to selectively activate the dosing module to deliver aftertreatment fluid into the turbine outlet passage.

265. The method of any one of claims 235 to 264, wherein: The step of delivering an atomized spray of aftertreatment fluid into the turbine outlet passage is performed as a function of time from engine ignition and / or temperature of the first surface.

266. A turbine for a turbocharger, comprising: a turbine inlet passage configured to receive exhaust gas from an internal combustion engine, the exhaust gas received by the turbine inlet passage defining a turbine body flow; a turbine wheel chamber configured to receive the turbine body flow from the turbine inlet passage, the turbine wheel chamber housing a turbine wheel supported for rotation about a turbine axis; a turbine outlet passage configured to receive the turbine body flow from the turbine wheel chamber; a distribution module configured to deliver an atomized spray of aftertreatment fluid into the turbine outlet passage; an auxiliary passage configured to receive a portion of the turbine main body flow from a location upstream of the turbine outlet passage, the portion of the turbine main body flow received by the auxiliary passage defining an auxiliary flow; and an exhaust gas sensor, the exhaust gas sensor being located in the auxiliary passage; Therein, the exhaust gas sensor is configured to sense one or more physical parameters of the auxiliary flow.

267. The turbine according to claim 266, wherein The exhaust gas sensor is configured to measure a concentration of nitrogen oxides (NOx) in the secondary flow.

268. A turbine according to claim 266 or 267, wherein: The auxiliary passage is sized to receive at least about 0.1% of the turbine body flow received by the turbine inlet passage.

269. A turbine according to any one of claims 266 to 268, wherein The auxiliary passage is sized to receive at most about 10% of the turbine body flow received by the turbine inlet passage.

270. A turbine according to any one of claims 266 to 269, wherein The auxiliary passage is configured such that the auxiliary flow is always allowed to flow through the auxiliary passage during all operating conditions of the turbine.

271. A turbine according to any one of claims 266 to 270, wherein The auxiliary passage includes a valve assembly configured to control a flow rate of the auxiliary fluid through the auxiliary passage.

272. The turbine according to claim 271, wherein The valve assembly defines an open configuration and a closed position, wherein in the open configuration, the auxiliary flow is allowed to pass through the valve assembly, and in the closed position, the auxiliary flow is substantially blocked by the valve assembly, and wherein the valve assembly includes a leakage channel, which is configured to allow leakage from one side of the valve assembly to the other side when the valve is in the closed configuration.

273. A turbine according to any one of claims 266 to 272, wherein The auxiliary passage is configured to deliver the auxiliary flow to the turbine outlet passage.

274. A turbine according to any one of claims 266 to 272, wherein The auxiliary passage is configured to deliver the auxiliary flow to the turbine inlet passage.

275. A turbine according to any one of claims 266 to 274, wherein The dosing module includes a nozzle configured to generate the spray of aftertreatment fluid.

276. The turbine according to claim 275, wherein The turbine outlet passage is at least partially defined by a surface, and the turbine outlet passage defines a centerline, and wherein the nozzle is substantially aligned with the surface or located radially outward of the surface relative to the centerline.

277. A turbine according to claim 275 or 276, wherein: The turbine includes a turbine wheel having an inducer, the inducer defining an inducer diameter, The turbine outlet passage defines a centerline, and The nozzle is spaced apart from the outlet inducer of the turbine wheel along the centerline of the turbine outlet passage by a distance of at most about 10 outlet inducer diameters.

278. A turbine according to any one of claims 275 to 277, wherein The auxiliary passage is configured to deliver the auxiliary flow into the turbine outlet passage upstream of the nozzle.

279. A turbine according to any one of claims 275 to 278, wherein The secondary passage is configured to direct the secondary flow through the nozzle.

280. A turbine according to any one of claims 266 to 279, wherein The auxiliary passage is configured to receive the auxiliary flow from the turbine inlet passage.

281. The turbine according to claim 280, wherein: The turbine inlet passage includes a first volute and a second volute, and the auxiliary passage is configured to receive the auxiliary flow from the first volute.

282. A turbocharger comprising a turbine according to any one of claims 266 to 281.

283. An exhaust aftertreatment system comprising: A turbine according to any one of claims 266 to 281 or a turbocharger according to claim 282; and A catalyst device is configured to receive the turbine body flow downstream of the turbine outlet passage.

284. The system of claim 283, wherein: The system also includes a controller in communication with the exhaust gas sensor and configured to determine measurements of the one or more physical parameters of the auxiliary flow sensed by the exhaust gas sensor; The controller is further configured to generate a control signal according to the measurement results of the one or more physical parameters, and The dosing module is in communication with the controller to receive the control signal, and the dosing module is operable to adjust a delivery rate of the aftertreatment fluid to the turbine outlet passage in accordance with the control signal.

285. A method of operating a turbine for a turbocharger, comprising: receiving exhaust gas from an internal combustion engine into a turbine inlet passage, the exhaust gas received by the turbine inlet passage defining a turbine body flow; receiving the turbine body flow from the turbine inlet passage into a turbine wheel chamber, the turbine wheel chamber housing a turbine wheel supported for rotation about a turbine axis; receiving the turbine body flow from the turbine wheel chamber into a turbine outlet passage; receiving a portion of the main turbine flow into an auxiliary passage, the portion of the main turbine flow received by the auxiliary passage defining an auxiliary flow; delivering an atomized spray of aftertreatment fluid into the turbine outlet passage using a dosing module; as well as One or more physical parameters of the auxiliary flow are sensed using an exhaust gas sensor in fluid communication with the auxiliary flow.

286. The method of claim 285, wherein: The exhaust gas sensor is configured to measure a concentration of nitrogen oxides (NOx) in the secondary flow.

287. The method of any one of claims 285 or 286, wherein: The auxiliary passage is sized to receive at least about 0.1% of the turbine body flow received by the turbine inlet passage.

288. The method of any one of claims 285 to 287, wherein: The auxiliary passage is sized to receive at most about 10% of the turbine body flow received by the turbine inlet passage.

289. The method of any one of claims 285 to 288, wherein: The auxiliary passage is configured such that the auxiliary flow is always allowed to flow through the auxiliary passage during all operating conditions of the turbine.

290. The method of any one of claims 285 to 289, wherein: The auxiliary passage includes a valve assembly configured to control a flow rate of the auxiliary fluid through the auxiliary passage.

291. The method of claim 290, wherein: The valve assembly defines an open configuration and a closed position, wherein in the open configuration, the auxiliary flow is allowed to pass through the valve assembly, and in the closed position, the auxiliary flow is substantially blocked by the valve assembly, and wherein the valve assembly includes a leakage channel, which is configured to allow leakage from one side of the valve assembly to the other side when the valve is in the closed configuration.

292. The method of any one of claims 285 to 291, wherein: The auxiliary passage is configured to deliver the auxiliary flow to the turbine outlet passage.

293. The method of any one of claims 285 to 292, wherein: The auxiliary passage is configured to deliver the auxiliary flow to the turbine inlet passage.

294. The method of any one of claims 285 to 293, wherein: The dosing module includes a nozzle configured to generate the spray of aftertreatment fluid.

295. The method of claim 294, wherein: The turbine outlet passage is at least partially defined by a surface, and the turbine outlet passage defines a centerline, and wherein the nozzle is substantially aligned with the surface or located radially outward of the surface relative to the centerline.

296. The method of claim 294 or 295, wherein: The turbine includes a turbine wheel having an inducer, the inducer defining an inducer diameter, The turbine outlet passage defines a centerline, and The nozzle is spaced apart from the outlet inducer of the turbine wheel along the centerline of the turbine outlet passage by a distance of at most about 10 outlet inducer diameters.

297. The method of any one of claims 294 to 296, wherein: The auxiliary passage is configured to deliver the auxiliary flow into the turbine outlet passage upstream of the nozzle.

298. The method of any one of claims 294 to 297, wherein: The secondary passage is configured to direct the secondary flow through the nozzle.

299. The method of any one of claims 285 to 298, wherein: The auxiliary passage is configured to receive the auxiliary flow from the turbine inlet passage.

300. The method of claim 299, wherein: The turbine inlet passage includes a first volute and a second volute, and the auxiliary passage is configured to receive the auxiliary flow from the first volute.

301. The method of any one of claims 285 to 300, further comprising: determining, using a controller, measurements of the one or more physical parameters of the auxiliary flow sensed by the exhaust gas sensor; and generating, using the controller, a control signal based on the measurement of the one or more physical parameters of the auxiliary flow; The dosing module is used to regulate a delivery rate of aftertreatment fluid to the turbine outlet based on the control signal.

302. An exhaust aftertreatment system comprising: A turbine configured to receive an exhaust gas flow from an internal combustion engine, the turbine comprising: a turbine inlet passage configured to receive exhaust gas from an internal combustion engine, the exhaust gas received by the turbine inlet passage defining a bulk flow; - a turbine wheel chamber configured to receive the bulk flow from the turbine inlet passage, the turbine wheel chamber configured to house a turbine wheel supported for rotation about a turbine axis; - a turbine outlet passage configured to receive the bulk flow from the turbine wheel chamber; and - a distribution module configured to deliver a spray of aftertreatment fluid into the turbine outlet channel; an exhaust passage configured to receive the bulk flow from the turbine outlet passage; and an auxiliary channel configured to receive a portion of the main flow, the portion of the main flow received by the auxiliary channel defining an auxiliary flow; wherein the exhaust passage includes a predicted aftertreatment fluid concentration region, and Wherein, the auxiliary passage is configured to deliver the auxiliary flow to the exhaust passage into the predicted aftertreatment fluid concentration area.

303. The exhaust aftertreatment system of claim 302, wherein: the exhaust passage defines a centerline and includes a non-linear portion that causes a change in momentum of the bulk flow, The turbine includes a turbine wheel having an inducer defining an inducer diameter; and The auxiliary passage is configured to deliver the auxiliary flow into the predicted aftertreatment fluid concentration area at a location within about 5 outlet inducer diameters from the non-linear portion along the centerline.

304. An exhaust aftertreatment system according to claim 302 or 303, wherein: The non-linear portion includes a curved portion.

305. An exhaust aftertreatment system according to any one of claims 302 to 304, wherein: The exhaust passage includes a curved portion having an inner curved surface and an outer curved surface, the inner curved surface defining an inner curved radius, the outer curved surface defining an outer curved radius, the outer curved radius being greater than the inner curved radius, A portion of the predicted post-treatment fluid concentration area covers at least a portion of the outer curved surface; and The auxiliary channel is configured to deliver the auxiliary flow into the portion of the predicted after-treatment fluid concentration area covering the outer curved surface.

306. The exhaust aftertreatment system of claim 305, wherein: The auxiliary passage includes an auxiliary passage outlet configured to deliver the auxiliary flow to the exhaust passage, and The auxiliary passage outlet is defined by an opening formed in the outer curved surface.

307. The exhaust aftertreatment system of claim 306, wherein: The outer curved surface defines a proximal end and a distal end relative to the direction of the bulk flow, and The auxiliary channel outlet is positioned at the distal end of the outer curved surface.

308. An exhaust aftertreatment system according to any one of claims 304 to 307, wherein: The bend defines a centerline having an inlet vector and an outlet vector, and The exit vector is inclined at an angle of at least about 30° relative to the entry vector.

309. An exhaust aftertreatment system according to any one of claims 302 to 308, wherein: The exhaust passage defines a centerline; and The auxiliary passage is configured to deliver the auxiliary flow to the exhaust passage in an auxiliary flow direction that is inclined at least about 15° relative to the centerline.

310. The exhaust aftertreatment system of claim 309, wherein: The auxiliary flow direction faces upstream relative to the direction of the main flow.

311. The exhaust aftertreatment system of claim 308, wherein: The auxiliary flow direction faces downstream relative to the direction of the main flow.

312. An exhaust aftertreatment system according to any one of claims 302 to 311, wherein: The geometry of the predicted post-treatment fluid concentration area is determined using a computational model.

313. The exhaust aftertreatment system of claim 312, wherein: The predicted after-treatment fluid concentration region includes a spatial region in which a concentration of the after-treatment fluid is at least about 50% greater than an expected concentration of the after-treatment fluid in the exhaust passage when the after-treatment fluid is uniformly distributed.

314. The exhaust aftertreatment system of claim 313, wherein: The predicted post-treatment fluid concentration region includes a spatial region in which a concentration of post-treatment fluid is at least about 2.25% by volume of the bulk flow.

315. An exhaust aftertreatment system according to any one of claims 302 to 314, wherein: The auxiliary passage receives the auxiliary flow from a location upstream of the turbine outlet passage.

316. An exhaust aftertreatment system according to any one of claims 302 to 315, wherein: The auxiliary passage includes a valve configured to allow, prevent or regulate a flow rate of the auxiliary stream.

317. An exhaust aftertreatment system according to any one of claims 302 to 316, wherein: The auxiliary passage is configured such that the auxiliary flow is always allowed to travel through the auxiliary passage.

318. An exhaust aftertreatment system comprising: A turbine configured to receive an exhaust gas flow from an internal combustion engine, the turbine comprising: a turbine inlet passage configured to receive exhaust gas from an internal combustion engine, the exhaust gas received by the turbine inlet passage defining a bulk flow; a turbine wheel chamber configured to receive the bulk flow from the turbine inlet passage, the turbine wheel chamber housing a turbine wheel supported for rotation about a turbine axis, the turbine having an inducer defining an inducer diameter; - a turbine outlet passage configured to receive the bulk flow from the turbine wheel chamber; and - a distribution module configured to deliver a spray of aftertreatment fluid into the turbine outlet channel; an exhaust passage configured to receive the bulk flow from the turbine outlet passage, the exhaust passage defining a centerline and including a non-linear portion; and an auxiliary channel configured to receive a portion of the main flow, the portion of the main flow received by the auxiliary channel defining an auxiliary flow; The auxiliary passage is configured to deliver the auxiliary flow into the exhaust passage at a position within about 5 times the outlet guide diameter from the non-linear portion along the center line.

319. An exhaust aftertreatment system according to claim 318, wherein: The non-linear portion includes a curved portion.

320. An exhaust aftertreatment system according to claim 318 or 319, wherein: The curved portion includes an inner curved surface and an outer curved surface, the inner curved surface defines an inner curved radius, the outer curved surface defines an outer curved radius, and the outer curved radius is greater than the inner curved radius. the auxiliary passage comprising an auxiliary passage outlet configured to deliver the auxiliary flow to the exhaust passage; and The auxiliary passage outlet is defined by an opening formed in the outer curved surface.

321. The exhaust aftertreatment system of claim 320, wherein: The outer curved surface defines a proximal end and a distal end relative to the direction of the bulk flow, and The auxiliary channel outlet is positioned at the distal end of the outer curved surface.

322. An exhaust aftertreatment system according to any one of claims 318 to 321, wherein: The bend defines a centerline having an inlet vector and an outlet vector, and The exit vector is inclined at an angle of at least about 30° relative to the entry vector.

323. An exhaust aftertreatment system according to any one of claims 318 to 322, wherein: The auxiliary passage is configured to deliver the auxiliary flow to the exhaust passage in an auxiliary flow direction that is inclined at least about 15° relative to the centerline.

324. An exhaust aftertreatment system according to claim 323, wherein: The auxiliary flow direction faces upstream relative to the direction of the main flow.

325. The exhaust aftertreatment system of claim 323, wherein: The auxiliary flow direction faces downstream relative to the direction of the main flow.

326. An exhaust aftertreatment system comprising: A turbine configured to receive an exhaust gas flow from an internal combustion engine, the turbine comprising: a turbine inlet passage configured to receive exhaust gas from an internal combustion engine, the exhaust gas received by the turbine inlet passage defining a bulk flow; - a turbine wheel chamber configured to receive the bulk flow from the turbine inlet passage, the turbine wheel chamber configured to house a turbine wheel supported for rotation about a turbine axis; - a turbine outlet passage configured to receive the bulk flow from the turbine wheel chamber; and - a distribution module configured to deliver a spray of aftertreatment fluid into the turbine outlet channel; an exhaust passage configured to receive the bulk flow from the turbine outlet passage; and an auxiliary channel configured to receive a portion of the main flow, the portion of the main flow received by the auxiliary channel defining an auxiliary flow; wherein the inner surface of the exhaust passage includes a predicted aftertreatment fluid impact risk area, and Wherein, the auxiliary channel is configured to direct the auxiliary flow in an auxiliary flow layer along a portion of the inner surface defining the predicted post-treatment fluid impact risk zone.

327. An exhaust aftertreatment system according to claim 326, wherein: The exhaust passage defines a centerline and includes a non-linear portion that causes a change in momentum of the bulk flow, the non-linear portion being defined at least in part by a portion of the interior surface that includes the after-treatment fluid impingement risk zone.

328. An exhaust aftertreatment system according to claim 326 or 327, wherein: The non-linear portion includes a curved portion of the exhaust passage.

329. The exhaust aftertreatment system of claim 328, wherein: The curved portion includes an inner curved surface and an outer curved surface, the inner curved surface defines an inner curved radius, the outer curved surface defines an outer curved radius, the outer curved radius is greater than the inner curved radius, and The outer curved surface includes a portion of the inner surface that defines the predicted after-treatment fluid impact risk zone.

330. The exhaust aftertreatment system of claim 329, wherein: The auxiliary passage includes an auxiliary passage outlet configured to deliver the auxiliary flow to the exhaust passage, and The auxiliary passage outlet is defined by an opening formed in the outer curved surface.

331. The exhaust aftertreatment system of claim 330, wherein: The outer curved surface defines a proximal end and a distal end relative to the direction of the bulk flow, and The auxiliary channel outlet is positioned at the distal end of the outer curved surface.

332. An exhaust aftertreatment system according to any one of claims 328 to 331, wherein: The bend defines a centerline having an inlet vector and an outlet vector, and The exit vector is inclined at an angle of at least about 30° relative to the entry vector.

333. An exhaust aftertreatment system according to any one of claims 326 to 332, wherein: The geometry of the predicted aftertreatment fluid impact risk zone is determined using a computational model.

334. An exhaust aftertreatment system according to claim 333, wherein: The predicted aftertreatment fluid impact risk zone includes an area of ​​the inner surface of the exhaust passage where an aftertreatment fluid impact rate by mass is more than about 50% higher than an average aftertreatment fluid impact rate by mass of the surface of the exhaust passage as a whole.

335. An exhaust aftertreatment system according to any one of claims 326 to 334, wherein: The auxiliary passage receives the auxiliary flow from a location upstream of the turbine outlet passage.

336. An exhaust aftertreatment system according to any one of claims 326 to 335, wherein: The auxiliary passage includes a valve configured to allow, prevent or regulate a flow rate of the auxiliary stream.

337. An exhaust aftertreatment system according to any one of claims 326 to 336, wherein: The auxiliary passage is configured such that the auxiliary flow is always allowed to travel through the auxiliary passage. 338.An exhaust aftertreatment system comprising: A turbine configured to receive an exhaust gas flow from an internal combustion engine, the turbine comprising: a turbine inlet passage configured to receive exhaust gas from an internal combustion engine, the exhaust gas received by the turbine inlet passage defining a bulk flow; - a turbine wheel chamber configured to receive the bulk flow from the turbine inlet passage, the turbine wheel chamber configured to house a turbine wheel supported for rotation about a turbine axis; - a turbine outlet passage configured to receive the bulk flow from the turbine wheel chamber; and - a distribution module configured to deliver a spray of aftertreatment fluid into the turbine outlet channel; an exhaust passage configured to receive the bulk flow from the turbine outlet passage, the exhaust passage including a non-linear portion defined by an inner surface of the exhaust passage; and an auxiliary channel configured to receive a portion of the main flow, the portion of the main flow received by the auxiliary channel defining an auxiliary flow; The auxiliary channel is configured to guide the auxiliary flow along the inner surface of the non-linear portion in an auxiliary flow layer.

339. An exhaust aftertreatment system according to claim 338, wherein: The non-linear portion includes a curved portion of the exhaust passage.

340. An exhaust aftertreatment system according to claim 338 or 339, wherein: The curved portion includes an inner curved surface and an outer curved surface, the inner curved surface defines an inner curved radius, the outer curved surface defines an outer curved radius, the outer curved radius is greater than the inner curved radius, and the outer curved surface includes the inner surface; and The auxiliary channel is configured to direct the auxiliary flow layer along the outer curved surface.

341. An exhaust aftertreatment system according to any one of claims 338 to 340, wherein: The auxiliary passage includes an auxiliary passage outlet configured to deliver the auxiliary flow to the exhaust passage; and The auxiliary passage outlet is defined by an opening formed in the outer curved surface.

342. The exhaust aftertreatment system of claim 341, wherein: The outer curved surface defines a proximal end and a distal end relative to the direction of the bulk flow, and The auxiliary channel outlet is positioned at the distal end of the outer curved surface.

343. An exhaust aftertreatment system according to any one of claims 338 to 342, wherein: The bend defines a centerline having an inlet vector and an outlet vector, and The exit vector is inclined at an angle of at least about 30° relative to the entry vector.

344. An exhaust aftertreatment system comprising: A turbine configured to receive an exhaust gas flow from an internal combustion engine, the turbine comprising: a turbine inlet passage configured to receive exhaust gas from an internal combustion engine, the exhaust gas received by the turbine inlet passage defining a bulk flow; a turbine wheel chamber configured to receive the bulk flow from the turbine inlet passage, the turbine wheel chamber configured to house a turbine wheel supported for rotation about a turbine axis; a turbine outlet passage configured to receive the bulk flow from the turbine wheel chamber; and a distribution module configured to deliver a spray of aftertreatment fluid into the turbine outlet passage; an exhaust passage configured to receive the bulk flow from the turbine outlet passage; and an auxiliary channel configured to receive a portion of the main flow, the portion of the main flow received by the auxiliary channel defining an auxiliary flow; wherein the exhaust passage is at least partially defined by a first surface of a partition wall, and the auxiliary passage is at least partially defined by a second surface of the partition wall, the partition wall being configured to provide thermal communication from the auxiliary passage to the first surface via the second surface; and Wherein, at least a portion of the first surface of the partition wall includes a post-treatment fluid impact risk area.

345. An exhaust aftertreatment system according to claim 344, wherein: The first surface is provided on a side of the partition wall opposite to the second surface.

346. An exhaust aftertreatment system according to claim 344 or 345, wherein: The dividing wall defines a thickness between the first surface and the second surface, wherein the turbine includes a turbine wheel having an outlet inducer portion, the outlet inducer portion defining an outlet inducer diameter, and wherein the thickness of the dividing wall is about 1% to about 10% of the outlet inducer diameter.

347. An exhaust aftertreatment system according to any one of claims 344 to 346, wherein: The exhaust passage includes a non-linear portion defined at least in part by a portion of the first surface including the after-treatment fluid impingement risk zone.

348. An exhaust aftertreatment system according to any one of claims 344 to 346, wherein: The non-linear portion includes a curved portion.

349. The exhaust aftertreatment system of claim 348, wherein: The curved portion includes an inner curved surface and an outer curved surface, the inner curved surface defines an inner curved radius, the outer curved surface defines an outer curved radius, the outer curved radius is greater than the inner curved radius, and The outer curved surface includes a portion of the first surface that defines the post-treatment fluid impact risk zone.

350. The exhaust aftertreatment system of claim 349, wherein: The auxiliary passage includes an auxiliary passage outlet configured to deliver the auxiliary flow to the exhaust passage; and The auxiliary passage outlet is defined by an opening formed in the outer curved surface.

351. The exhaust aftertreatment system of claim 350, wherein: The outer curved surface defines a proximal end and a distal end relative to the direction of the bulk flow, and The auxiliary channel outlet is positioned at the distal end of the outer curved surface.

352. An exhaust aftertreatment system according to any one of claims 344 to 351, wherein: The geometry of the post-treatment fluid impact risk zone is determined using a computational model.

353. An exhaust aftertreatment system according to claim 352, wherein: The predicted aftertreatment fluid impact risk zone includes an area of ​​the inner surface of the exhaust passage where an aftertreatment fluid impact rate by mass is more than about 50% higher than an average aftertreatment fluid impact rate by mass of the surface of the exhaust passage as a whole.

354. An exhaust aftertreatment system according to any one of claims 344 to 353, wherein: The auxiliary passage receives the auxiliary flow from a location upstream of the turbine outlet passage.

355. An exhaust aftertreatment system according to any one of claims 344 to 354, wherein: The auxiliary passage includes a valve configured to allow, prevent or regulate a flow rate of the auxiliary stream.

356. An exhaust aftertreatment system according to any one of claims 344 to 355, wherein: The auxiliary passage is configured such that the auxiliary flow is always allowed to travel through the auxiliary passage. 357.An exhaust aftertreatment system comprising: A turbine configured to receive an exhaust gas flow from an internal combustion engine, the turbine comprising: a turbine inlet passage configured to receive exhaust gas from an internal combustion engine, the exhaust gas received by the turbine inlet passage defining a bulk flow; a turbine wheel chamber configured to receive the bulk flow from the turbine inlet passage, the turbine wheel chamber configured to house a turbine wheel supported for rotation about a turbine axis; a turbine outlet passage configured to receive the bulk flow from the turbine wheel chamber; and a distribution module configured to deliver a spray of aftertreatment fluid into the turbine outlet passage; an exhaust passage configured to receive the bulk flow from the turbine outlet passage, the exhaust passage defining a bend; and an auxiliary channel configured to receive a portion of the main flow, the portion of the main flow received by the auxiliary channel defining an auxiliary flow; The bend of the exhaust passage is at least partially defined by a first surface of a partition wall, and the auxiliary passage is at least partially defined by a second surface of the partition wall, and the partition wall is configured to provide thermal connectivity from the auxiliary passage to the first surface via the second surface.

358. An exhaust aftertreatment system according to claim 357, wherein: The first surface is disposed on a side of the partition wall opposite to the second surface.

359. An exhaust aftertreatment system according to claim 357 or 358, wherein: The dividing wall defines a thickness between the first surface and the second surface, wherein the turbine includes a turbine wheel having an outlet inducer portion, the outlet inducer portion defining an outlet inducer diameter, and wherein the thickness of the dividing wall is about 1% to about 10% of the outlet inducer diameter.

360. An exhaust aftertreatment system according to any one of claims 357 to 359, wherein: The curved portion includes an inner curved surface and an outer curved surface, the inner curved surface defines an inner curved radius, the outer curved surface defines an outer curved radius, the outer curved radius is greater than the inner curved radius, and The outer curved surface includes the first surface of the partition wall.

361. The exhaust aftertreatment system of claim 360, wherein: The auxiliary passage includes an auxiliary passage outlet configured to deliver the auxiliary flow to the exhaust passage; and The auxiliary passage outlet is defined by an opening formed in the outer curved surface.

362. The exhaust aftertreatment system of claim 361, wherein: The outer curved surface defines a proximal end and a distal end relative to the direction of the bulk flow, and the auxiliary channel outlet is positioned at the distal end of the outer curved surface.

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