Mixer for mixing exhaust gas

Abstract

Methods and systems for exhaust mixers are disclosed. In one example, a system may include an outer annular portion outside an exhaust pipe and an inner annular portion inside the exhaust pipe, wherein the outer annular portion includes helical fins extending around the exhaust pipe in a downstream direction.

Description

Technical Field

[0001] The present description generally relates to methods and systems for exhaust gas mixers. Background Art

[0002] In order to meet stringent U.S. federal government emission standards, engine systems may be configured with a variety of technologies for reducing emissions. Specifically, it may be desirable to address nitrogen oxides (NO x ) emissions. Used to reduce NO x Two exemplary technologies for reducing NOx may include exhaust gas recirculation (EGR) and selective catalytic reduction (SCR) devices. x This involves recirculating a controlled proportion of the engine exhaust gas back into the intake passage to be combined with the intake air. The addition of EGR may not chemically participate in combustion (e.g., the gas is substantially inert) and may reduce the amount of cylinder contents available for combustion. This may result in correspondingly lower peak cylinder temperatures and heat release. In this way, NO x Emissions. Reduce NO through SCR device x Including NO promoted by SCR device x With ammonia (NH 3 ) between the two, wherein the reduction reaction converts NO x Converted into nitrogen (N 2 ) and water (H 2 O). By injecting urea into the exhaust path, NH 3 Introduced into the engine exhaust system upstream of the SCR catalyst, or NH 3 Under high temperature conditions, urea entropy decomposes into NH 3 .

[0003] However, as recognized by the inventors herein, problems may arise when flowing EGR into the intake passage and / or injecting urea into the exhaust passage. In one example, EGR is introduced into the intake passage before the intake passage is split upstream of a multi-cylinder engine. The desired mixing of EGR with intake air may be difficult to achieve at various engine speeds / loads, which may result in an uneven distribution of the EGR / intake air mixture. For example, one cylinder may receive too much EGR, which may result in increased particulate emissions, and another cylinder may receive too little EGR, which may result in increased NO x As a second example, urea may mix poorly with the exhaust (e.g., a first region of the exhaust has a higher urea concentration than a second region of the exhaust in the exhaust passage), which may result in poor coating of the SCR and emissions (e.g., NO x) and SCR. In addition, excessive mixing and agitation of urea in the exhaust gas may also cause problems, such as increased deposits. Therefore, the introduction of EGR into the intake passage and the introduction of urea into the exhaust passage may succumb to poor mixing.

[0004] Attempts to address the inadequate mixing include introducing a mixing device at the junction between the EGR outlet and the intake passage, and / or introducing a mixing device downstream of the urea injector and upstream of the SCR device so that the dispersion of the EGR or urea can be more uniform. Further attempts include one or more of the following: adjusting valve function to introduce back pressure into the intake and / or exhaust passages, and / or including an injector with a swirler and / or other turbulence generating feature.

[0005] However, the inventors herein have recognized potential problems with such methods. As an example, the mixing potential of the device may be limited. As an example, a static mixer may be limited in gas velocity due to its lack of vacuum or other mixing assisting features. Therefore, the size of the mixer may be increased to overcome the reliance on gas velocity. However, increasing the size of the mixer may result in increasing the size of the gas passage, which ultimately requires significant modifications to the design of the gas passage. This may increase the production cost of the vehicle. Summary of the invention

[0006] In one example, the above problem can be solved by a mixer that can include an outer annular portion outside the exhaust pipe and an inner annular portion inside the exhaust pipe, wherein the outer annular portion includes a spiral fin extending around the exhaust pipe in a downstream direction. In this way, the exhaust gas can interact with the inner and outer portions of the mixer to increase exhaust gas uniformity.

[0007] As an example, the outer annular portion may include an outer passage between the exhaust pipe and the outer surface. The spiral fins may adjust the exhaust flow through the outer passage before directing the exhaust flow to the inner annular portion in the exhaust passage. The inner annular portion may constrict the exhaust passage, wherein an annular perforation along the inner annular portion creates a vacuum. The vacuum may facilitate exhaust flow into the outer annular portion and the inner annular portion. In this way, exhaust mixing may be increased as the exhaust flows through various portions of the mixer. This may also occur in conjunction with reductant injection. Thus, reductant mixed into the exhaust upstream of the exhaust device may be increased.

[0008] It should be understood that the above summary is provided to introduce a simple form of a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is solely defined by the claims attached to the detailed description. Furthermore, the claimed subject matter is not limited to implementations that address any disadvantages noted above or in any part of this disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 An engine having a single cylinder is shown with a mixer arranged in an exhaust passage coupled to the cylinder.

[0010] Figure 2 A first embodiment of a mixer is shown.

[0011] Figure 3 A perspective view of a first embodiment is shown.

[0012] Figure 4 A spiral fin is shown traversing around the outer surface of the exhaust pipe.

[0013] Figure 5 An exemplary exhaust flow is shown in cross section through the first embodiment.

[0014] Figure 6 A second embodiment of a mixer is shown.

[0015] Fig. 7A and Figure 7B A second embodiment of twisted blades is shown.

[0016] Figure 8 An exemplary exhaust flow is shown in cross section through the second embodiment.

[0017] Figure 2-8 Shown approximately to scale. DETAILED DESCRIPTION

[0018] The following description relates to systems and methods for a mixer disposed in an exhaust passage, such as Figure 1 In a first embodiment, the mixer includes an outer annular portion positioned around the outer perimeter of the exhaust pipe and an inner annular portion positioned around the inner perimeter of the exhaust pipe. Figure 2 As shown, both the outer annular portion and the inner annular portion are configured to receive exhaust gas from the exhaust passage. Figure 3 As shown, a cross section of the mixer and exhaust pipe reveals a spiral fin disposed between the exhaust pipe and the outer annular portion. The outer annular portion also includes a reductant injector positioned to inject into the space between each of the outer annular surface, the exhaust pipe, and the fin. Figure 4The outer annular portion is omitted in to better illustrate the structure of the spiral fin. The outer annular portion and the inner annular portion may work in tandem to not only increase the flow path of the exhaust gas, but also impart swirl and / or turbulence to the exhaust gas so that a greater amount of exhaust gas mixing may occur. Figure 5 An example of exhaust gas mixing by a first embodiment of a mixer is shown in FIG.

[0019] In a second embodiment, the mixer includes an outer annular portion having a U-shaped flow path. The flow path directs the exhaust gas in a first direction and then redirects the exhaust gas in a second direction opposite to the first direction. The outer annular portion receives the exhaust gas from the exhaust passage at a location directly upstream of one or more twisted blades. Figure 6 As shown, the outer annular portion discharges exhaust gas into the exhaust passage at a location between one or more twisted blades. Fig. 7A and Figure 7B The twisted blades are shown in more detail in FIG, wherein the twisted blades include an upstream blade and a downstream blade. In one example, the upstream blade is oriented and / or twisted in a direction opposite to the orientation and / or twist of the downstream blade. The mixer is configured to increase exhaust gas mixing by increasing the exhaust gas flow path and imparting swirl and / or turbulence to the exhaust gas. Figure 8 An exemplary exhaust gas flow through a mixer is shown in FIG.

[0020] Figure 1-8An exemplary configuration is shown by the relative positioning of various components. If shown as being in direct contact or direct coupling with each other, then at least in one example, such elements can be referred to as being in direct contact or direct coupling respectively. Similarly, at least in one example, the elements shown as being continuous or adjacent to each other can be respectively continuous or adjacent to each other. As an example, the components in face-sharing contact with each other can be referred to as face-sharing contact. As another example, in at least one example, the elements that are spaced apart from each other and positioned and have only space without other components can be referred to as such. As another example, the elements shown as being above / below each other, on opposite sides of each other, or on the left and right of each other can be referred to as such relative to each other. In addition, as shown in the figure, in at least one example, the topmost element or the topmost element point can be referred to as the "top" of the component, and the bottommost element or the bottommost element point can be referred to as the "bottom" of the component. As used herein, top / bottom, up / down, above / below can be relative to the vertical axis (axis) of the accompanying drawings, and can be used to describe the positioning of the elements relative to each other in the figure. Therefore, in one example, the element shown to be located above other elements is vertically positioned above other elements. As yet another example, the shapes of elements depicted in the figures may be referred to as having those shapes (e.g., as being round, straight, planar, curved, rounded, chamfered, angled, etc.). Additionally, in at least one example, elements shown as intersecting one another may be referred to as intersecting elements or intersecting one another. Additionally, in one example, elements shown within another element or shown outside another element may be referred to as such. It should be understood that one or more components referred to as "substantially similar and / or identical" may differ from one another based on manufacturing tolerances (e.g., within a 1-5% deviation).

[0021] Continue turning Figure 1 , which shows a schematic diagram illustrating one cylinder of a multi-cylinder engine 10 in an engine system 100 that may be included in a propulsion system of an automobile. Engine 10 may be controlled at least in part by a control system including controller 12, and by input from a vehicle operator 132 via an input device 130. In this example, input device 130 includes an accelerator pedal and a pedal position sensor 134 for generating a proportional pedal position signal. Combustion chamber 30 of engine 10 may include a cylinder formed by cylinder walls 32, with piston 36 positioned in the cylinder. Piston 36 may be coupled to crankshaft 40 so that reciprocating motion of the piston is converted into rotational motion of the crankshaft. Crankshaft 40 may be coupled to at least one drive wheel of the vehicle via an intermediate transmission system. Additionally, a starter motor may be coupled to crankshaft 40 via a flywheel to enable a starting operation of engine 10.

[0022] Combustion chamber 30 may receive intake air from intake manifold 44 via intake passage 42 and may exhaust combustion gases via exhaust passage 48. Intake manifold 44 and exhaust passage 48 may selectively communicate with combustion chamber 30 via respective intake valve 52 and exhaust valve 54. In some examples, combustion chamber 30 may include two or more intake valves and / or two or more exhaust valves.

[0023] In this example, intake valve 52 and exhaust valve 54 may be controlled by cam actuation via respective cam actuation systems 51 and 53. Cam actuation systems 51 and 53 may each include one or more cams, and may utilize one or more of: cam profile switching (CPS), variable cam timing (VCT), variable valve timing (VVT), and / or variable valve lift (VVL) systems, which may be operated by controller 12 to vary valve operation. The positions of intake valve 52 and exhaust valve 54 may be determined by position sensors 55 and 57, respectively. In an alternative example, intake valve 52 and / or exhaust valve 54 may be controlled by electric valve actuation. For example, cylinder 30 may alternatively include an intake valve controlled by electric valve actuation and an exhaust valve controlled by cam actuation including a CPS and / or VCT system.

[0024] Fuel injector 69 is shown coupled directly to cylinder chamber 30 for injecting fuel directly therein in proportion to the pulse width of the signal received from controller 12. In this manner, fuel injector 69 provides so-called direct injection of fuel into combustion chamber 30. For example, the fuel injector may be mounted in the side of the combustion chamber or in the top of the combustion chamber. Fuel may be delivered to fuel injector 69 by a fuel system (not shown) including a fuel tank, a fuel pump, and a fuel rail. In some examples, combustion chamber 30 may alternatively or additionally include a fuel injector arranged in intake manifold 44, such a configuration providing so-called port injection of fuel into the intake port upstream of combustion chamber 30.

[0025] Spark is provided to combustion chamber 30 via spark plug 66. The ignition system may further include an ignition coil (not shown) for increasing the voltage supplied to spark plug 66. In other examples, such as a diesel engine, spark plug 66 may be omitted.

[0026] Intake passage 42 may include throttle valve 62 having throttle plate 64. In this particular example, controller 12 may vary the position of throttle plate 64 via a signal provided to an electric motor or actuator included with throttle valve 62, a configuration that is commonly referred to as electronic throttle control (ETC). In this manner, throttle valve 62 may be operated to vary intake air provided to combustion chamber 30 among other engine cylinders. The position of throttle plate 64 may be provided to controller 12 via a throttle position signal. Intake passage 42 may include a mass air flow sensor 120 and a manifold air pressure sensor 122 to sense the amount of air entering engine 10.

[0027] Exhaust gas sensor 126 is shown coupled to exhaust passage 48 upstream of emission control device 72 according to the direction of exhaust gas flow. Sensor 126 may be any suitable sensor for providing an indication of exhaust air-fuel ratio, such as a linear oxygen sensor or UEGO (Universal or Wide Range Exhaust Gas Oxygen), a two-state oxygen sensor or EGO, HEGO (Heated EGO), NO x , HC or CO sensor. In one example, upstream exhaust gas sensor 126 is a UEGO configured to provide an output (such as a voltage signal) proportional to the amount of oxygen present in the exhaust gas. Controller 12 converts the oxygen sensor output into exhaust gas air-fuel ratio via an oxygen sensor transfer function.

[0028] Emission control device 72 is shown arranged along exhaust passage 48 downstream of exhaust gas sensor 126. Device 72 may be a three way catalyst (TWC), NO x A trap, a selective catalytic reductant (SCR), various other emission control devices, or combinations thereof. In some examples, during operation of engine 10 , emission control device 72 may be periodically reset by operating at least one cylinder of the engine at a particular air / fuel ratio.

[0029] Exhaust gas recirculation (EGR) system 140 may direct a desired portion of exhaust gas from exhaust passage 48 to intake manifold 44 via EGR passage 152. Controller 12 may vary the amount of EGR provided to intake manifold 44 via EGR valve 144. Under some conditions, EGR system 140 may be used to regulate the temperature of the air-fuel mixture within the combustion chamber, thereby providing a method of controlling spark timing during some combustion modes.

[0030] The mixer 80 is arranged in the exhaust passage 48 downstream of the EGR system 140 and upstream of the aftertreatment device 72. The mixer 80 can be fluidly coupled to the injector 82, which is coupled to the reductant reservoir 84. The reductant in the reservoir 84 can be one or more of urea, fuel, etc. The mixer 80 can include an inner portion and an outer portion relative to the exhaust passage 48, so that the mixer 80 is configured to direct a portion of the exhaust gas out of the exhaust passage. The exhaust gas can be circulated in the mixer outside the exhaust passage and then flow back into the exhaust passage 48. In one example, in this way, the mixer receives the exhaust gas from the exhaust passage 48 and directs the exhaust gas only to the exhaust passage 48.

[0031] The controller 12 Figure 1 1 is shown as a microcomputer, which includes a microprocessor unit 102, input / output ports 104, an electronic storage medium for executable programs and calibration values, shown in this particular example as a read-only memory chip 106 (e.g., non-volatile memory), a random access memory 108, a non-fail memory 110, and a data bus. In addition to those signals previously discussed, the controller 12 can also receive various signals from sensors coupled to the engine 10, including the following measurements: intake mass air flow (MAF) from a mass air flow sensor 120; engine coolant temperature (ECT) from a temperature sensor 112 coupled to a cooling jacket 114; an engine position signal from a Hall effect sensor 118 (or other type) sensing the position of the crankshaft 40; throttle position from a throttle position sensor 65; and a manifold absolute pressure (MAP) signal from a sensor 122. The controller 12 can generate an engine speed signal based on the crankshaft position sensor 118. The manifold pressure signal also provides an indication of the vacuum or pressure in the intake manifold 44. It should be noted that various combinations of the above sensors may be used, such as a MAF sensor without a MAP sensor, or vice versa. During engine operation, engine torque may be inferred based on the output of the MAP sensor 122 and the engine speed. Additionally, this sensor, along with the detected engine speed, may be the basis for estimating charge (including air) inducted into the cylinder. In one example, the crankshaft position sensor 118, which is also used as an engine speed sensor, may produce a predetermined number of equally spaced pulses every revolution of the crankshaft.

[0032] Storage medium read-only memory 106 can be programmed with computer readable data representing non-transitory instructions executable by processor 102 for performing the methods described below as well as other variants that are anticipated but not specifically listed.

[0033] The controller 12 is Figure 1 Various sensors receive signals and use Figure 1Various actuators are controlled to adjust engine operation based on received signals and instructions stored in the controller's memory.

[0034] Now go to Figure 2 , which shows a perspective view of a first embodiment of a mixer 200 arranged along the exhaust passage 48. In one example, Figure 1 The mixer 80 of FIG. 1 is similarly used with the mixer 200. Therefore, previously introduced components may be similarly numbered in subsequent figures. The mixer 200 is shown coupled to an inner portion and an outer portion of an exhaust pipe 202, which may house the exhaust passage 48. As will be described herein, the mixer 200 and the exhaust pipe 202 include various contours and / or cutouts that may cooperate to increase exhaust gas mixing.

[0035] The axis system 290 includes three axes, namely an x-axis parallel to the horizontal direction, a y-axis parallel to the vertical direction, and a z-axis perpendicular to both the x-axis and the y-axis. The direction of gravity is shown by arrow 299. Therefore, arrow 299 is referred to as gravity 299 herein. Dashed line 292 indicates the central axis of one or more of the exhaust pipe 202 and the exhaust passage 48. Here, dashed line 292 is referred to as central axis 292. In one example, central axis 292 is parallel to the x-axis. Arrow 294 indicates the approximate direction of the exhaust flow through the exhaust passage 48. In one example, the direction of the exhaust flow 294 is parallel to the central axis 292. The length of the mixer 200 can describe the distance of the mixer 200 along the x-axis. The height of the mixer 200 can describe the distance of the mixer 200 along the y-axis. Finally, the thickness of the mixer 200 can describe the distance of the mixer 200 along the z-axis.

[0036] The mixer 200 may include one or more of aluminum, carbon fiber, magnesium, iron, steel, plastic, and combinations thereof. The mixer 200 may be physically coupled to the exhaust pipe 202 by one or more of welding, fusing, adhesives, and screws. In this way, the mixer 200 is immovable. In addition, the mixer 200 may not be hydraulically driven, electrically driven, and mechanically driven. Therefore, the mixer 200 may be a static mixer and may not slide, rotate, vibrate, or perform any other type of movement during vehicle operation. In one example, the mixer 200 is fixed and immovable.

[0037] The outer annular portion 210 is physically coupled to the outer perimeter 204 and / or outer surface 204 of the exhaust pipe 202. The outer annular portion 210 is outside of the exhaust passage 48 located within the exhaust pipe 202. As such, the exhaust pipe 202 separates the outer annular portion 210 from the exhaust passage.

[0038] The reductant injector 82 is physically coupled to the upstream surface 212 of the outer annular portion 210. The injector 82 is positioned to inject into the space between the outer surface 204 of the exhaust pipe 202 and the outer annular portion 210.

[0039] The upstream outer surface 212 can be angled relative to the exhaust pipe 202. The angle is less than 90°. In one example, the angle is exactly 60°. In this way, the upstream outer surface 212 is angled in the downstream direction. The upstream outer surface 212 is flush with the outer surface 204 of the exhaust pipe 202 at the outer upstream position 211. The distance between the upstream outer surface 212 and the outer surface 204 of the exhaust pipe 202 increases from the outer upstream position 211 in the downstream direction and reaches a maximum value at the outer downstream position 213. In one example, the length of the upstream outer surface is substantially equal to the distance between the outer upstream position 211 and the outer downstream position 213.

[0040] In this document, upstream and downstream may be used to describe the positioning of components. In one example, upstream and downstream are described relative to the direction of exhaust flow. Additionally or alternatively, upstream and downstream may be used to describe the distance of a component from an engine, wherein an upstream component is closer to the engine than a downstream component. For example, an outer upstream position 211 is located upstream of an outer downstream position 213. In other words, the outer downstream position 213 is located downstream of the outer upstream position 211.

[0041] The mixer 200 also includes an outer annular wall 214 that is physically coupled to the upstream outer surface 212 at an outer upstream position 211 and physically coupled to the exhaust pipe 202 at an extreme end 215 of the outer annular portion 210. The outer annular wall 214 is concentric with the exhaust pipe 202 about the central axis 292. The difference between the diameter of the outer annular wall 214 and the diameter of the exhaust pipe 202 is substantially equal to the thickness of the outer annular portion 210. In other words, the diameter of the outer annular wall 214 is greater than the diameter of the exhaust pipe 202 by the thickness of the outer annular portion 210.

[0042] Inner annular portion 220 is physically coupled to inner perimeter 206 and / or inner surface 206 of exhaust pipe 202. In one example, the difference between outer perimeter 204 and inner perimeter 206 is substantially equal to the thickness of exhaust pipe 202. In this manner, inner annular portion 220 is in direct contact with exhaust gas flowing through exhaust passage 48.

[0043] The inner upstream surface 222 is flush with the inner surface 206 at the inner upstream position 221. The inner upstream surface 222 is spaced apart from the inner surface 206 downstream of the inner upstream position 221. In this way, the inner upstream surface 222 restricts the flow of exhaust gas through the exhaust passage 48 by reducing the diameter of the flow area corresponding to the position of the inner upstream surface 222. In other words, the inner upstream surface 222 extends farther from the inner surface 206 of the exhaust pipe 202 in the downstream direction starting from the inner upstream position 221. This results in a reduction in the cross-sectional flow area of ​​the exhaust passage 48. In this way, the cross-sectional flow area of ​​the exhaust passage 48 is reduced downstream of the inner upstream position 221, resulting in a more restricted exhaust passage 48.

[0044] In the case of any portion along the outer annular portion 210 in the x-direction, the cross section of the outer annular portion 210 along the y-axis may be circular. Similarly, in the case of any portion along the inner annular portion 220 in the x-direction, the cross section of the inner annular portion 220 along the y-axis may be circular. Figure 5 As shown, cross sections taken along the y-axis of the outer annular portion 210 and the inner annular portion 220 may overlap in the x-direction.

[0045] The outer annular portion 210 and the inner annular portion 220 are both hollow. Therefore, there is space for gas to flow through in both the outer annular portion 210 and the inner annular portion 220. The outer annular portion 210 can receive exhaust gas from the exhaust passage 48 via the upstream exhaust pipe perforation 208. The upstream exhaust pipe perforation 208 is located in a portion of the exhaust pipe 202 upstream of the inner upstream position 221 and downstream of the outer downstream position 213. The upstream exhaust pipe perforation 208 can be flush with the inner surface 206 of the exhaust pipe 202 and extend through the entire thickness of the exhaust pipe 202. In this regard, the upstream exhaust pipe perforation 208 can be perpendicular to the direction of the exhaust flow 294. In this way, the upstream exhaust pipe perforation 208 couples the outer annular portion 210 fluidly to the exhaust passage 48. Each upstream exhaust pipe perforation 208 can be spaced apart from each other and positioned along the entire perimeter of the inner surface 206. Each upstream exhaust pipe perforation 208 is substantially the same as each other in size and shape. In one example, each upstream exhaust pipe perforation 208 is oval. However, without departing from the scope of the present disclosure, the upstream exhaust pipe perforations 208 can be of other shapes and sizes. For example, some upstream exhaust pipe perforations 208 can be square, rectangular, triangular, pentagonal, hexagonal, etc.

[0046] The inner annular portion 220 can receive exhaust gas from the exhaust passage 48 via the inner upstream surface perforations 224. The inner upstream surface perforations 224 are located on a portion of the inner upstream surface 222 downstream of the inner upstream position 221. Each inner upstream surface perforation 224 is spaced apart from one another. The inner upstream surface perforations 224 can be flush with the inner upstream surface 222 and located around the entire perimeter of the inner upstream surface. In this regard, the inner upstream surface perforations 224 are angled relative to the direction of the incoming exhaust gas flow 294. The inner upstream surface perforations 224 extend through the entire thickness of the inner upstream surface 222 so that the space between the inner annular portion 220 and the inner surface 206 can receive exhaust gas from the exhaust passage 48. In one example, each inner upstream surface perforation 224 is substantially the same as the upstream exhaust pipe perforation 208 in terms of size and shape. However, it should be understood that each inner upstream surface perforation 224 can be different from one another or from the upstream exhaust pipe perforation 208 in terms of size and / or shape without departing from the scope of the present disclosure.

[0047] Now go to Figure 3 , which shows that along Figure 2 The cross-sectional view 300 of the first embodiment of the mixer 200 is taken along the cutting plane AA' of FIG. The cross-sectional view 300 omits some portions of the outer annular portion 210 and the exhaust pipe 202 to reveal the exhaust pipe 202 and the inner portion of the outer annular portion 210. In addition, the shape of the inner annular portion 220 is revealed. In the cross-sectional view 300, the inner annular portion 220 is not cross-sectioned so as to show the inner annular wall 328.

[0048] The inner annular wall 328 may be in coplanar contact and hermetically sealed with the inner surface 206 of the exhaust pipe 202. As such, gas may not be able to flow between the inner surface 206 and the inner annular wall 328. The inner annular wall 328 may be physically coupled to the inner surface 206 of the exhaust pipe using welding, fusing, adhesives, etc.

[0049] The inner annular wall 328 may include a length along the x-axis that is equal to the entire length of the inner annular portion 220. Specifically, the inner annular wall 328 extends from the inner upstream position 221 of the inner annular portion 220 to the inner downstream position 321. The inner downstream position 321 may be substantially similar to the inner upstream position 221, in that both positions are flush with and / or smooth to the inner surface 206 of the exhaust pipe. The circumference of the inner downstream position 321 is substantially equal to the circumference of the inner upstream position 221.

[0050] The inner upstream surface 222 extends from the inner upstream position 221 in a downward direction and may intersect with the inner downstream surface 322, which extends from the inner downstream position 321 in an upstream direction. In one example, the inner upstream surface 222 and the inner downstream surface 322 are equal in length and shape so that the inner annular portion 220 is symmetrical about the central axis 294 and the vertical axis 392. The distance between the inner upstream surface and the inner surface 206 of the exhaust pipe 202 increases from the inner upstream position 221 to the annular intersection 324, where the inner upstream surface 222 and the inner downstream surface 322 meet. The distance between the inner downstream position 322 and the inner surface 206 of the exhaust pipe 202 decreases from the annular intersection 324 to the inner downstream position 321. The inner upstream surface 222 and the inner downstream surface 322 may be convex or concave relative to the direction of the exhaust flow 294. Additionally or alternatively, the inner upstream surface 222 and the inner downstream surface 322 may be differently contoured and / or curved such that the inner upstream surface 222 is concave and the inner downstream surface 322 is convex, or vice versa. In some embodiments, the inner upstream surface 222 and the inner downstream surface 322 may be linear and inclined relative to the direction of the exhaust gas flow 294.

[0051] In this way, the inner annular portion 220 can contract and / or block a portion of the exhaust passage 48 between the inner upstream position 221 and the inner downstream position 321. The maximum contraction area can coincide with the annular intersection 324. Therefore, the diameter of the cross-sectional flow area of ​​the exhaust passage 48 taken along a plane parallel to the y-axis and the z-axis is smallest at the annular intersection 324. The annular intersection 324 is arranged along the vertical axis 392 of the inner annular portion 220.

[0052] As described above, the inner upstream surface 222 includes the inner upstream surface perforations 224 configured to allow gas to enter the space of the inner annular portion 220. Similarly, the inner downstream surface 322 includes the inner downstream surface perforations 323 arranged between the annular intersection 324 and the inner downstream position 321, and the inner downstream surface perforations 323 can be configured to allow gas to enter the space of the inner annular portion 220 and / or discharge gas outside the space of the inner annular portion 220. The inner downstream surface perforations 323 can be spaced apart from each other along the perimeter of the inner downstream surface 322. Similarly, the annular intersection 324 includes the annular intersection perforations 326 configured to discharge gas from the space of the inner annular portion 220 to the exhaust passage 48. The annular intersection perforations 326 can be spaced apart from each other and arranged along the entire perimeter of the annular intersection 324. In one example, the inner upstream surface perforations 224, the inner downstream surface perforations 323, and the annular intersection perforations 326 can have similar shapes and sizes (e.g., elliptical). It should be understood that one or more of the inner upstream surface perforations 224, the inner downstream surface perforations 323, and the annular intersection perforations 326 may have shapes and / or sizes that are different from one another (such as square, rectangular, triangular, hexagonal, and other suitable shapes) without departing from the scope of the present disclosure. Each of the inner upstream surface perforations 224, the inner downstream surface perforations 323, and the annular intersection perforations 326 may be arranged such that their openings are angled and / or perpendicular to the direction of the exhaust flow 294. Additionally, each of the inner upstream surface perforations 224 and the inner downstream surface perforations 323 may be radially aligned about the central axis 292. It should be understood that the perforations may be misaligned without departing from the scope of the present disclosure.

[0053] The space of the inner annular portion 220 is defined by the inner annular wall 328, the inner upstream surface 222 and the inner downstream surface 322. Each of these surfaces is impervious to the air flow. Therefore, the gas can enter and leave the inner annular portion via the inner upstream surface perforations 224, the inner downstream surface perforations 323 and the annular intersection perforations 326.

[0054] As will be described below, the inner annular portion 220 and the outer annular portion 210 are configured to function cooperatively to facilitate exhaust gas flow. Figure 5 As shown, the outer annular portion 210 and the inner annular portion 220 may be in fluid communication via one or more openings spaced about the spiral fin 312 disposed between the outer annular portion 210 and the outer surface 204 of the exhaust pipe 202 .

[0055] The spiral fin 312 may be physically coupled to one or more of the outer surface 204 and the outer annular wall 214. The height of the spiral fin 312 may be substantially equal to the distance between the outer annular wall 214 and the outer surface 204. The spiral fin 312 may be wrapped around the outer surface 204 in a downstream direction so that the first end 314 and the second end 316 of the spiral fin 312 are spaced apart and do not contact each other. The first end 314 is located upstream of the second end 316. In one example, the spiral fin 312 is wrapped around the outer surface 204 exactly 360° so that the first end 314 and the second end 316 are aligned with each other along the x-axis. In some examples, the spiral fin 312 is wrapped greater than or less than 360° so that the first end 314 and the second end 316 are not aligned along the x-axis. The spiral fin 312 is wrapped around the outer surface 204 in a counterclockwise direction. However, without departing from the scope of the present disclosure, the spiral fin 312 may be wrapped around the outer surface 204 in a clockwise direction. The spiral fin 312 may be a single continuous piece that is impermeable to airflow. Additionally or alternatively, the spiral fin 312 may include one or more openings configured to allow gas to pass through the spiral opening 312. The spiral fin 312 may not include a flow space therein, and therefore, the spiral fin 312 may be solid.

[0056] The upstream portion of the spiral fin 312 is located downstream of the reductant injector 82. In this way, the injection space and / or injection area is located between the injector 82 and the spiral fin 312. This can limit the reductant from impinging on the surface of the spiral fin 312 before mixing with the exhaust gas, as will be described below. Figure 5 Described in. Reference below Figure 4 The helical fin 312 is shown in greater detail.

[0057] Now go to Figure 4 , which shows a perspective view 400 of a spiral fin 312 positioned around the outer surface 204 of the exhaust pipe 202. The outer annular portion 210 is omitted from the view 400 to illustrate the shape and orientation of the spiral fin 312. The spiral fin 312 is shown traversing the outer surface 204 in a clockwise direction. The fin 312 is curved in the downstream direction along the x-axis. The cross-section of the spiral fin 312 along a plane parallel to the y-axis and the z-axis can be generally rectangular (e.g., similar to the shape of the first end 314 and the second end 316). The front surface 412 of the spiral fin 312 is shown facing in a direction opposite to the direction of the exhaust flow 294. The rear surface (not shown) is opposite the front surface 412 and faces in a direction parallel to the direction of the exhaust flow 294.

[0058] As shown, the first end 314 and the second end 316 are spaced apart from each other. The first end 314 can be positioned about the first axis 492, and the second end 316 can be positioned about the second axis downstream of the first axis 492. The fin 312 wraps around the exhaust pipe 202 between the first axis 492 and the second axis 494. Gas can flow freely between the first end 314 and the second end 316 without interacting with the spiral fin 312. As described above, the spiral fin 312 is physically coupled to the outer annular wall (e.g., Figure 3 Specifically, the outer fin surface 414 is hermetically sealed with the outer annular wall so that gas cannot flow therebetween. Figure 3 The exhaust gas in the outer annular portion 210) can follow the path of the spiral fin 312. In this way, the spiral fin can impart swirl and / or turbulence to the exhaust gas in the outer annular portion.

[0059] Therefore, the mixer includes an outer annular portion outside the exhaust pipe and an inner annular portion inside the exhaust pipe, wherein the outer annular portion includes a spiral fin extending around the exhaust pipe in a downstream direction. The spiral fin includes a first end arranged along a first axis and a second end arranged along a second axis, and wherein the first axis is spaced apart from the second axis, and the first axis is located upstream of the second axis relative to the direction of the exhaust flow from the engine. The outer annular portion is fluidly coupled to the exhaust passage of the exhaust pipe upstream of the first axis, and wherein the outer annular portion is fluidly coupled to the inner annular portion downstream of the second axis. The outer annular portion and the inner annular portion are hollow and symmetrical about the central axis of the exhaust pipe. The outer annular portion includes an outer surface that is angled relative to the exhaust pipe, and wherein the ejector is coupled to the outer surface and is positioned to eject into a flow space formed between the outer annular portion and the exhaust pipe. The inner annular portion is curved and includes a C-shaped cross section in the downstream direction, and wherein the inner annular portion includes a venturi channel positioned along its central axis. The inner annular portion is fluidly coupled to the exhaust passage at each of the venturi inlet, the venturi throat, and the venturi outlet of the venturi channel. The outer annular portion and the inner annular portion are fluidly coupled via one or more perforations.

[0060] Now go to Figure 5 , which shows that along Figure 2 500 of the embodiment of the mixer 200 taken along the cutting plane AA' of FIG. Specifically, the mixer 200 is divided into two along the central axis 294. In this way, the internal flow space of the outer annular portion 210 and the inner annular portion 220 through which the exhaust gas flows is illustrated. The embodiment 500 is intended as one example among many examples of the exhaust gas flowing through the mixer 200 when the reductant is injected from the injector 82. In addition, the exhaust gas can flow through the mixer 200 without the injection of the reductant and experience similar mixing.

[0061] The axis system 590 includes two axes, namely an x-axis parallel to the horizontal direction and a y-axis parallel to the vertical direction, including a central axis 294 and a vertical axis 392. As shown in the figure, the central axis 294 is perpendicular to the vertical axis 394.

[0062] In the embodiment 500, the unlabeled arrows indicate where there is a space for exhaust flow, while the solid lines represent boundaries that block the exhaust flow. The gaps and / or spaces and / or interruptions between the solid lines may illustrate one or more perforations suitable for receiving or discharging exhaust gas from the outer annular portion 210 and the inner annular portion 220 as described above. It should be understood that the direction of one or more arrows depicted in the embodiment 500 may be reversed and / or flipped without departing from the scope of the present disclosure.

[0063] The downstream exhaust duct penetrations 508 are shown as being positioned between the endmost 215 and the spiral fin 312. Specifically, each of the downstream exhaust duct penetrations 508 is located downstream of the second end 316 of the spiral fin 312. The downstream exhaust duct penetrations 508 may be substantially similar in size and shape to the upstream exhaust duct penetrations 208. However, it should be understood that the downstream exhaust duct penetrations 508 may differ in size and shape from the upstream exhaust duct penetrations 208 without departing from the scope of the present disclosure.

[0064] The downstream exhaust pipe perforations 508 may extend around the entire perimeter of the exhaust pipe 202. The downstream exhaust pipe perforations 508 are spaced apart from one another. Figure 5 In the example of FIG. 5 , each of the downstream exhaust pipe perforations 508 is radially aligned with each of the upstream exhaust pipe perforations 208, the inner upstream surface perforations 224, the annular intersection perforations 326, and the inner downstream surface perforations 323. In one example, there are exactly eight each of the upstream exhaust pipe perforations 208, the inner upstream surface perforations 224, the annular intersection perforations 326, the inner downstream surface perforations 323, and the downstream exhaust pipe perforations 508. Each perforation may have other numbers (e.g., less than or more than eight) without departing from the scope of the present disclosure.

[0065] Downstream exhaust pipe perforations 508 fluidly couple outer annular portion 210 to inner annular portion 220. Thus, outer annular portion 210 may receive and discharge exhaust gas via upstream exhaust pipe perforations 208 and downstream exhaust pipe perforations 508. Inner annular portion 220 may receive and discharge exhaust gas via one or more of inner upstream surface perforations 224, annular intersection perforations 326, and inner downstream surface perforations 323. Exhaust flow through each of these perforations and exhaust passage 48 is described below.

[0066] The exhaust passage 48 and the mixer 200 are separated by six dashed lines A through F, which may divide the embodiment 500 into multiple regions. Exhaust flow is described with respect to each of these dashed lines.

[0067] Upstream of the dashed line A, the exhaust gas may flow in a generally linear direction parallel to the central axis 292. The exhaust gas may be undisturbed and has not yet reached the mixer 200. The exhaust gas upstream of the dashed line A does not contain a reductant. In this context, the reductant may include urea, fuel, etc. suitable for reducing an SCR catalyst located downstream of the mixer 200.

[0068] Between dashed line A and dashed line B, the exhaust gas may continue to flow through the exhaust passage 48 uninterruptedly without interacting with the mixer 200. In one example, the exhaust gas adjacent to the central axis 292 continues to flow through the portion of the exhaust passage between dashed line A and dashed line B without interacting with the mixer 200. Exhaust gas approaching the exhaust pipe 202 may flow through the upstream exhaust pipe perforations 208 and enter the outer annular portion 210. In one example, the exhaust gas flowing through the upstream exhaust pipe perforations 208 flows in a radially outward direction perpendicular to the direction of the exhaust flow 294. As shown, the exhaust gas flows into the portion of the outer annular portion 210 upstream of the spiral fin 312. In this way, the exhaust gas between dashed line A and dashed line B does not interact with the spiral fin 312.

[0069] The reductant injector 82 is positioned to inject the reductant into the outer annular portion 210 upstream of the spiral fin 312 between the dotted line A and the dotted line B. As shown, the reductant injector 82 is fixedly coupled to the outer upstream surface 212 and injects the reductant in a direction substantially perpendicular to the outer upstream surface 212 and inclined relative to the direction of the exhaust gas flow 294. It should be understood that, without departing from the scope of the present disclosure, the injector 82 may be positioned at other angles greater than or less than vertical. The exhaust gas flowing into the top of the outer annular portion 210 adjacent to the reductant injector 82 can be mixed with the injected reductant. In one example, the reductant is already in a gaseous state before mixing with the exhaust gas. Alternatively, the reductant is a liquid and evaporates after mixing with the exhaust gas.

[0070] As described above, the inner annular portion 220 constricts the exhaust passage 48. Here, the constriction may be described as a venturi passage 520, wherein the venturi passage 520 includes a venturi inlet 522 located between dashed lines B and C, a venturi throat 524 located between dashed lines C and D, and a venturi outlet 526 located between dashed lines D and E. The venturi passage 520 may provide a vacuum to the outer annular portion 210 and the inner annular portion 220 of the mixer 200 while adjusting the exhaust flow velocity and / or rate through the exhaust passage. The combination of these effects may work synergistically to improve exhaust mixing.

[0071] Between dotted line B and dotted line C, exhaust gas can enter and flow through the venturi inlet 522 of the venturi passage 520. The venturi inlet 522 corresponds to the inner upstream surface 222 of the inner annular portion 220. In this way, the cross-sectional flow area of ​​the venturi inlet 522 decreases along the y-axis in the downstream direction parallel to the x-axis. Therefore, as the exhaust gas flows through the venturi inlet 522, its flow rate can increase. The exhaust gas flows from the venturi inlet 522 to the venturi throat 524 located between the dotted line C and the dotted line D. The venturi throat 524 corresponds to the annular intersection of the inner annular portion 220. As the exhaust gas flows from the venturi inlet 522 to the venturi throat 524, the exhaust gas flow speed and / or velocity can increase. In one example, the exhaust gas flow speed and / or velocity in the venturi passage 520 is the highest at the venturi throat 524. In this way, as the exhaust flows from the venturi inlet 522 to the venturi throat 524, the pressure of the exhaust can be reduced accordingly. In this way, a vacuum is generated at the venturi throat 524, where the vacuum can be supplied to the interior space of the inner annular portion 220 via the annular intersection perforations 326. The vacuum in the interior space of the inner annular portion 220 can also flow to the outer annular portion 210 via the downstream exhaust pipe perforations 508. The vacuum can promote the exhaust flow from the exhaust passage 48 to the outer annular portion 210 and the inner annular portion 220. In one example, the vacuum can promote the exhaust flow through the inner upstream surface perforations 224 to the interior space of the inner annular portion 220 between the dashed line B and the dashed line C. The exhaust flow through the inner upstream surface perforations 224 can flow in a direction oblique and / or parallel to the direction of the exhaust flow 294. In addition, the vacuum can promote the exhaust flow through the upstream exhaust pipe perforations 208 to the outer annular portion 210. In this way, turbulence and / or spin are imparted to the exhaust gas, thereby increasing exhaust uniformity regardless of the occurrence of reductant injection. Exhaust gas may also bounce off inner upstream surface 222 when flowing through venturi inlet 522 , thereby increasing misdirection of exhaust gas flow through exhaust passage 48 .

[0072] Between dashed line B and dashed line D, the exhaust gas in outer annular portion 210 may follow the flow path of spiral fin 312. This is shown by the solid arrows. In this way, the exhaust gas may flow around exhaust pipe 202 and along the body of spiral fin 312 in a 360° direction. Alternatively, as shown by the dashed arrows, the exhaust gas in outer annular portion 210 may avoid spiral fin 312. As shown, the exhaust gas may flow through the space between outer annular portion 210 and exhaust pipe 202 around first end 314 of spiral fin 312. Figure 3 and Figure 4 These spaces are further shown in FIG.

[0073] Between dashed line D and dashed line E, the exhaust gas from the outer annular portion 210 and the inner annular portion 220 can be mixed. For example, the exhaust gas mixed with the reductant from between dashed line A and dashed line B can flow around the outer annular portion 210 and follow the flow path of the spiral fin 312. After flowing around the entire length of the spiral fin 312, the exhaust gas mixed with the reductant can flow into the interior space of the inner annular portion 220 via the downstream exhaust pipe perforations 508 and mix with the exhaust gas without the reductant. Alternatively, the exhaust gas from the interior space of the inner annular portion 220 can flow into the outer annular portion 210 via the downstream exhaust pipe perforations 508. The exhaust gas between dashed line D and dashed line E in the inner annular portion 220 can flow toward one or more of the annular intersection perforations 328 and the inner downstream surface perforations 323. The exhaust gas in the inner annular portion 220 can flow to the venturi throat 224 through the annular intersection perforations 326 in a radially inward direction perpendicular to the direction of the exhaust gas flow 294. Additionally, exhaust gas exiting the annular intersection perforations 326 may flow along the central axis 292 of the exhaust passage 48. Exhaust gas in the inner annular portion may flow through the inner downstream surface perforations 323 approaching the exhaust pipe 202 in a direction that is angled to the direction of the exhaust gas flow 294, wherein the direction may be oblique, parallel, or perpendicular to the direction of the exhaust gas flow 294.

[0074] Between dashed lines E and F, the exhaust continues to mix due to the swirl, spin, and turbulence imparted to the exhaust from the mixer 200. As such, between dashed lines A and B, the reductant injection occurring in the top of the outer annular portion 210 can be dispersed by the various exhaust flows described above. In this way, the reductant delivery to the SCR located downstream of the mixer 200 can be more efficient compared to other exhaust mixing systems.

[0075] A method includes causing exhaust gas to flow from an exhaust passage to an outer passage of a mixer located outside the exhaust passage, and wherein the outer passage surrounds an exhaust pipe of the exhaust passage, wherein the outer passage receives and discharges the exhaust gas at one or more perforations upstream and downstream of one or more curved fins. A reductant injector is positioned to inject into a position between a surface of the mixer and one or more fins. Flowing the exhaust gas also includes causing the exhaust gas to flow through an exhaust passage constriction formed by the interior of the exhaust passage, wherein the interior of the exhaust passage is fluidly coupled to a downstream portion of the outer passage. The mixer is fixed and immovable, and wherein the mixer does not rotate or slide. The mixer has no additional inlet or other outlet other than the perforations that fluidly couple the mixer to the exhaust passage.

[0076] Now go to Figure 6 , which shows a second embodiment of the mixer 600. In some examples, Figure 1Mixer 600 is similarly used with mixer 80 of FIG. As such, previously introduced components may be similarly numbered in subsequent figures. Mixer 600 is shown coupled to an inner portion and an outer portion of an exhaust pipe 602, which may house exhaust passage 48. As will be described herein, mixer 600 and exhaust pipe 602 include various contours and / or cutouts that may cooperate to increase exhaust gas mixing.

[0077] The axis system 690 includes three axes, namely an x-axis parallel to the horizontal direction, a y-axis parallel to the vertical direction, and a z-axis perpendicular to both the x-axis and the y-axis. The direction of gravity is shown by an arrow 699. Therefore, arrow 699 is referred to as gravity 699 herein. A dotted line 692 indicates the central axis of one or more of the exhaust pipe 602 and the exhaust passage 48. Here, the dotted line 692 is referred to as the central axis 692. In one example, the central axis 692 is parallel to the x-axis. Arrow 694 indicates the approximate direction of the exhaust flow through the exhaust passage 48. In one example, the direction of the exhaust flow 694 is parallel to the central axis 692. The length of the mixer 600 can describe the distance of the mixer 600 along the x-axis. The height of the mixer 600 can describe the distance of the mixer 600 along the y-axis. Finally, the thickness of the mixer 600 can describe the distance of the mixer 600 along the z-axis.

[0078] Mixer 600 may include one or more of aluminum, carbon fiber, magnesium, iron, steel, plastic, and combinations thereof. Mixer 600 may be physically coupled to exhaust pipe 602 by one or more of welding, fusing, adhesives, and screws. In this way, mixer 600 is immovable. In addition, mixer 600 may not be hydraulically driven, electrically driven, and mechanically driven. Therefore, mixer 600 may be a static mixer and may not slide, rotate, vibrate, or perform any other type of movement during vehicle operation. In one example, mixer 600 is fixed and immovable.

[0079] The mixer 600 is located downstream of the reductant injector 82. The injector 82 is positioned to inject directly into the exhaust passage 48 in a direction that is oblique relative to the direction of the exhaust flow 694. In one example, the injection angle is less than 90° relative to the exhaust flow direction. Alternatively, the injection angle can be exactly 90° without departing from the scope of the present disclosure.

[0080] The mixer 600 includes an outer portion 610 that is physically coupled to and located outside the outer surface 604 of the exhaust pipe 602. The outer portion 610 may include an upstream surface 612 that is located upstream of a downstream surface 614 relative to the direction of the exhaust flow. The upstream surface 612 may be perpendicular to the outer surface 604. The downstream surface 614 may be angled relative to the outer surface 604. The upstream surface 612 and the downstream surface 614 may span the entire perimeter of the exhaust pipe 602. In this way, the upstream surface 612 and the downstream surface 614 may be symmetrical about the central axis 692. In one example, the coupling between the upstream surface and the outer surface 604 of the exhaust pipe 602 may be airtightly sealed. Similarly, the coupling between the downstream surface 614 and the outer surface 604 of the exhaust pipe 602 may also be airtightly sealed. In this way, the exhaust gas may not be able to flow to the engine and / or the ambient atmosphere between the outer surface 604 and one or more of the upstream surface 612 and the downstream surface 614.

[0081] The outer annular surface 616 can be physically coupled to the upstream surface 612 at the upstream extreme end. In one example, the outer annular surface 616 is hermetically sealed to the upstream surface 612. Similarly, the outer annular surface 616 can be physically coupled to the downstream surface 614 at the downstream extreme end. In this way, the outer annular surface 616 is fixed to the upstream surface 612 and the downstream surface 614 at the opposite extreme ends. In one example, the outer annular surface 616 is hermetically sealed to the downstream surface 614.

[0082] The outer annular surface 616 can be spaced apart from the outer surface 604 of the exhaust pipe 602. The inner portion 620 can be disposed between the outer annular surface 616 and the outer surface 604. In one example, the surface of the inner portion 620 is spaced apart from each of the upstream surface 612, the downstream surface 614, the outer annular surface 616, and the outer surface 604. The inner portion 620 includes a free end 622, a downstream wall 624, and an inner annular surface 626. The inner annular surface 626 can be concentric with the exhaust pipe 602 and the outer annular surface 616. The downstream wall 624 is adjacent to the downstream surface 614 and parallel to the upstream surface 612. The free end 622 is adjacent to the upstream surface 612 and is spaced apart from it. Therefore, in one example, the inner portion 620 is cantilevered from the outer surface 604 of the exhaust pipe 602.

[0083] The flow space 630 is located between the outer portion 610 and the exhaust pipe 602. The flow space 630 can be divided into two channels, namely, an inner channel 632 and an outer channel 634. The inner channel 632 can be located between the inner portion 620 and the outer surface 604. The height of the inner channel 632 can be similar to one-sixth of the diameter of the exhaust pipe 602. The height of the outer channel 634 can be substantially equal to one-eighth of the diameter of the exhaust pipe 602. The inner channel 632 can be fluidly coupled to the outer channel 634 at the intersection of the channel between the free end 622 and the upstream surface 612. Due to the arrangement of the inner portion 620, the inner channel 632 can be configured to guide the exhaust gas in a direction opposite to the direction of the exhaust gas 694. When the exhaust gas flows from the inner channel 632 to the outer channel 634, the exhaust gas in the flow space 630 turns in a direction perpendicular to the direction of the exhaust gas flow 694. The exhaust gas in the outer channel 634 can flow in a direction parallel to the direction of the exhaust gas flow 694. In this way, the exhaust gas in the flow space 630 may flow in a substantially U-shaped direction.

[0084] The flow space 630 can be coupled to the exhaust passage 48 through one or more perforated fluids. In one example, the inner passage 632 is directly coupled to the exhaust passage 48 through the upstream perforation 642. Similarly, the outer passage 634 is directly coupled to the exhaust passage through the downstream perforation 644. The upstream perforation 642 and the downstream perforation 644 can be used as the inlet and outlet of the inner passage 632 and the outer passage 634, respectively. In one example, the upstream perforation 642 and the downstream perforation 644 are elliptical. However, without departing from the scope of the present disclosure, the upstream perforation 642 and the downstream perforation 644 can be other suitable shapes, such as circular, rectangular, triangular, etc. Each of the upstream perforation 642 and the downstream perforation 644 can have similar shapes and sizes. In one example, each of the upstream perforation 642 and the downstream perforation 644 is circular and has a diameter of 8-12 mm. However, without departing from the scope of the present disclosure, each of the upstream perforation 642 and the downstream perforation 644 can have different shapes and / or sizes. For example, one or more of the upstream perforations 642 and the downstream perforations 644 may be triangular in shape, while the remainder of the upstream perforations 642 and the downstream perforations 644 may be elliptical in shape. The upstream perforations 642 and the downstream perforations 644 may be radially aligned along the exhaust passage 48. Alternatively, the upstream perforations 642 and the downstream perforations 644 may be radially non-aligned.

[0085] The upstream perforations 642 and the downstream perforations 644 extend through the entire thickness of the exhaust pipe 602 and are arranged adjacent to the upstream blades 652 and / or fins 652 and the downstream blades 662 and / or fins 662. Specifically, the upstream perforations 642 are located just upstream of the upstream blades 652. Similarly, the downstream perforations 652 are located just upstream of the downstream blades 662. In addition, the downstream perforations 644 are arranged between the upstream blades 652 and the downstream blades 662. The upstream blades 652 and the downstream blades 662 extend from the inner surface 606 of the exhaust pipe 602 toward the central axis 692. The upstream blades 652 and the downstream blades 662 are fixedly coupled to the inner surface 606. In one example, the upstream blades 652 and the downstream blades 662 are immovable and impermeable to the airflow.

[0086] Each of the upstream blades 652 may be spaced apart from one another at different tangent points along a single perimeter of the exhaust pipe 602. Two or more upstream blades 652 are arranged around the exhaust pipe 602. In one example, the number of upstream blades 652 is equal to the number of upstream perforations 642. Alternatively, there may be different numbers of upstream blades 652 and upstream perforations 642. For example, there may be eight upstream perforations 642 and two upstream blades 652.

[0087] Similarly, each of the downstream blades 662 can be spaced apart from each other along different tangent points of a single perimeter of the exhaust pipe 602. The perimeter around which the downstream blades 662 are arranged is located downstream of the perimeter around which the upstream blades 652 are arranged. Two or more downstream blades 662 are arranged around the exhaust pipe 602. In one example, the number of downstream blades 662 is equal to the number of downstream perforations. Alternatively, the number of downstream blades 662 is different from the number of downstream perforations. In one example, the number of upstream perforations and downstream perforations is equal, and the number of upstream blades and downstream blades is equal. As an example, the number of each of the upstream perforations and downstream is equal to twelve, and the number of each of the upstream blades and downstream blades is equal to two. In this way, there are 24 perforations and four blades in total.

[0088] Upstream blade 652 and downstream blade 662 may be radially aligned with each other along exhaust passage 48. In one example, the blades are cascaded along exhaust passage 48 with upstream blade 652 located just upstream of downstream blade 662. In this manner, upstream blade 652 eclipses downstream blade 662. In some examples, upstream blade 652 and downstream blade 662 may be radially non-aligned such that upstream blade 652 does not eclipse downstream blade 662.

[0089] The upstream blades 652 may extend in an upstream direction opposite to the direction of the exhaust flow 694. The downstream blades 662 may extend in a downstream direction parallel to the direction of the exhaust flow 694. In one example, the upstream blades 652 and the downstream blades 662 are twisted. However, the upstream blades 652 and the downstream blades 662 may be curved, bent, wavy, etc. without departing from the scope of the present disclosure. Fig. 7A and Figure 7B 65 and 662 are described in more detail in each of FIG.

[0090] Therefore, a system includes an annular mixing channel located outside an exhaust pipe, wherein the mixing channel is divided into an inner channel and an outer channel, the inner channel is fluidly coupled to the exhaust channel at a position upstream of one or more first blades, and wherein the outer channel is fluidly coupled to the exhaust channel at a position downstream of one or more first blades and upstream of one or more second blades. The first blade is twisted in a counterclockwise direction, and the second blade is twisted in a clockwise direction. The first blade and the second blade include free ends close to the central axis of the exhaust channel. The inner channel is located between the inner annular surface and the exhaust pipe, and wherein the inner annular surface is cantilevered from the exhaust pipe. The outer channel is located between the outer annular surface and the inner annular surface, and wherein the outer annular surface and the inner annular surface extend completely around the circumference of the exhaust pipe. The first blade and the second blade are fixedly coupled to the exhaust pipe and extend in an upstream direction and a downstream direction, respectively.

[0091] Now go to Fig. 7A and Figure 7B , which show perspective views 700 and 750 of upstream blade 652 and downstream blade 662, respectively. In one example, perspective view 700 is a perspective view of upstream blade 652 parallel to the exhaust flow (e.g., Figure 6 700 is a front view of the exhaust flow 694 parallel to the positive x-axis. Similarly, the perspective view 750 is a view of the downstream blade 662 in relation to the exhaust flow (eg, Figure 6 A front view 750 is shown in the opposite direction of the exhaust flow 694 (which is parallel to the positive x-axis).

[0092] In views 700 and 750, upstream blade 652 and downstream blade 662 extend toward the viewer in upstream and downstream directions, respectively. Upstream blade 652 and downstream blade 662 are twisted so that the blades can impart vortices when exhaust gas contacts one or more of upstream blade 652 and downstream blade 662. Specifically, upstream blade 652 is twisted so that free end 702 creates first angle θ, respectively. 1 and the second angle θ 2 The first angle θ 1 and the second angle θ 2With respect to the initial plane about which the blade extends. Thus, the upstream blade 652 forms a first angle θ above the initial plane. 1 And below the plane, a second angle θ is formed 2 Similarly, the downstream blade 662 forms a first angle θ above the initial plane. 1 And below the plane, a second angle θ is formed 2 In one example, the first angle θ 1 and the second angle θ 2 In this way, the upstream blade 652 and the downstream blade 662 are symmetrical about the x-axis. In one example, the first angle θ 1 and the second angle θ 2 is substantially equal to 30°. Alternatively, the corresponding first angle θ 1 and the second angle θ 2 can be different, so that the upstream blade 652 and the downstream blade 662 are asymmetric. Therefore, the first angle θ 1 can be greater or less than the second angle θ 2 .

[0093] Now go to Figure 8 , which illustrates embodiment 800, thereby illustrating an exemplary exhaust gas flow through mixer 600 while reductant injection is occurring. However, the exhaust gas may flow through mixer 600 and mix without reductant injection. At any rate, mixer 600 is configured to increase the amount of reductant injected into the exhaust (e.g., Figure 1 The uniformity of the exhaust gas flowing through the exhaust passage 48 upstream of the post-treatment device 72) wherein the exhaust device may be an SCR, a particulate filter, a three-way catalyst, an exhaust gas sensor, NO x Catcher, etc.

[0094] The exhaust is shown flowing from the left side to the right side of the drawing. The large dashed arrows depict the portion of the exhaust that initially flows above the central axis 692 upstream of the mixer 600. The small dashed arrows depict the portion of the exhaust that initially flows below the central axis 692 upstream of the mixer 600. The large dashed line is larger than the small dashed line. The solid arrows depict the portion of the exhaust that initially flows along the central axis 692 upstream of the mixer 600.

[0095] The exhaust gas upstream of the injection 882 from the reductant injector 82 contains no reductant. In one example, the reductant is urea. However, the reductant may be a fuel or the like without departing from the scope of the present disclosure.

[0096] The large dashed arrows may flow into one or more upstream blades 652 located above the central axis 692, where the exhaust may be directed through one or more upstream perforations 642 located above the central axis. The large dashed arrows flow into a portion of the inner passage 632 located above the central axis 692. However, as described above with respect to Figure 6 As described above, the inner passage 632 traverses the entire circumference of the exhaust pipe 602 .

[0097] The large dashed arrow can flow through the inner passage 632 in a direction substantially opposite to the direction of the exhaust gas flow 694. Once the large dashed arrow reaches the portion of the inner passage 632 adjacent to the upstream surface 612, the large dashed arrow can turn 180° and flow upward into the outer passage 634. Therefore, in one example, the exhaust gas does not flow through the inner annular surface 626. The large dashed arrow flows through the portion of the outer passage 634 located above the central axis 692 in a direction substantially parallel to the direction of the exhaust gas flow 694. However, it should be understood that the exhaust gas in the outer passage 634 can turn to a direction oblique and / or perpendicular to the direction of the exhaust gas flow 694 and flow around the exhaust pipe 602. In one example, the exhaust gas in the portion of the outer passage 634 located above the central axis 692 can turn and flow into a portion of the outer passage 634 located below the central axis 692.

[0098] When the large dashed exhaust arrow in the outer passage 634 reaches the downstream surface 614, the arrow may turn in a direction perpendicular to the exhaust flow. The exhaust flows between the downstream wall 624 and the downstream surface 614 toward the one or more downstream perforations 644. The large dashed exhaust arrow may flow through the one or more downstream perforations 644 in a radially inward direction perpendicular to the exhaust flow 694 before turning and flowing in a direction parallel to the direction of the exhaust flow 694. The large dashed exhaust arrow may merge with the solid exhaust arrow in the region of the exhaust passage 48 between the upstream vane 652 and the downstream vane 662.

[0099] The small dashed exhaust arrow can flow similarly to the large dashed exhaust arrow described above. It should be understood that the small dashed exhaust arrow can mix with the large dashed exhaust arrow in one or more of the inner channel 632 and the outer channel 634. In this way, the exhaust gas can be transferred from the exhaust passage 48 and flow out of the exhaust pipe 602 to one or more of the inner channel 632 and the outer channel 632, wherein the exhaust gas can mix and flow around the outside of the exhaust pipe 602 and then return to the exhaust passage 48. The small dashed exhaust arrow can also flow through one or more downstream perforations 644 and merge with the solid exhaust arrow at a position between the upstream blade 652 and the downstream blade 662. In this way, the exhaust portion that does not contain the reductant can be combined and mixed with the exhaust portion that includes the reductant. In addition, due to the increase in the exhaust flow path located outside the exhaust passage 48 and fluidly coupled to the exhaust passage 48, the uniformity of the exhaust gas can be increased when it flows through the mixer 600. In addition, increased turbulence can be introduced into the exhaust gas flowing through the mixer 600 via upstream blades 652 and downstream blades 662, which can apply vortices in the radial direction, and upstream perforations 642 and downstream perforations 644, which can receive and discharge the exhaust gas in a direction that is angled to the general direction of the exhaust flow.

[0100] In this way, the exhaust mixer can increase the uniformity of the exhaust gas flowing through the exhaust passage. In a first embodiment, the mixer includes fins surrounding the outer surface of the exhaust pipe. The fins can change the exhaust flow in the outer channel located outside the exhaust pipe. Therefore, when the exhaust returns to the exhaust channel in the exhaust pipe, the exhaust may increase turbulence and increase exhaust mixing. In a second embodiment, the mixer includes blades twisted in the exhaust channel. The blades can apply swirls to the exhaust and / or guide the exhaust into the channel of the mixer located outside the exhaust pipe. The exhaust gas in the channel outside the exhaust pipe can flow around the exhaust pipe before returning to the exhaust channel in the exhaust pipe. The technical effect of causing the exhaust gas to flow to the exhaust channel outside and / or outside the exhaust pipe is to increase the exhaust mixing space and increase the exhaust uniformity. By doing so, when the reductant flows through the above-mentioned one or more mixers, the reductant can be gradually mixed with the exhaust gas.

[0101] One embodiment of a mixer includes an outer annular portion outside the exhaust pipe and an inner annular portion inside the exhaust pipe, wherein the outer annular portion includes a spiral fin extending around the exhaust pipe in a downstream direction. The first example of the mixer also includes: wherein the spiral fin includes a first end arranged along a first axis and a second end arranged along a second axis, and wherein the first axis is spaced apart from the second axis, and the first axis is located upstream of the second axis relative to the direction of the exhaust flow from the engine. The second example of the mixer optionally includes the first example, and also includes: wherein the outer annular portion is fluidly coupled to the exhaust passage of the exhaust pipe upstream of the first axis, and wherein the outer annular portion is fluidly coupled to the inner annular portion downstream of the second axis. The third example of the mixer optionally includes the first example and / or the second example, and also includes: wherein the outer annular portion and the inner annular portion are hollow and symmetrical about the central axis of the exhaust pipe. The fourth example of the mixer optionally includes one or more of the first to third examples, and also includes: wherein the outer annular portion includes an outer surface that is angled relative to the exhaust pipe, and wherein the injector is coupled to the outer surface and positioned to inject into the flow space between the outer annular portion and the exhaust pipe. A fifth example of the mixer optionally includes one or more of the first to fourth examples, further comprising: wherein the inner annular portion is curved and includes a C-shaped cross-section in the downstream direction, and wherein the inner annular portion includes a venturi passage positioned along its central axis. A sixth example of the mixer optionally includes one or more of the first to fifth examples, further comprising: wherein the inner annular portion is fluidly coupled to the exhaust passage at each of the venturi inlet, the venturi throat, and the venturi outlet of the venturi passage. A seventh example of the mixer optionally includes one or more of the first to sixth examples, further comprising: wherein the outer annular portion and the inner annular portion are fluidly coupled via one or more perforations.

[0102] An embodiment of a system includes an annular mixing passage located outside an exhaust pipe, wherein the mixing passage is divided into an inner passage and an outer passage, the inner passage being fluidly coupled to the exhaust passage at a position upstream of one or more first blades, and wherein the outer passage being fluidly coupled to the exhaust passage at a position downstream of one or more first blades and upstream of one or more second blades. The first example of the system also includes: wherein the first blade is twisted in a counterclockwise direction and the second blade is twisted in a clockwise direction. The second example of the system optionally includes the first example, and further includes: wherein the first blade and the second blade include free ends proximate to a central axis of the exhaust passage. The third example of the system optionally includes the first example and / or the second example, and further includes: wherein the inner passage is located between the inner annular surface and the exhaust pipe, and wherein the inner annular surface is cantilevered from the exhaust pipe. The fourth example of the system optionally includes one or more of the first to third examples, and further includes: wherein the outer passage is located between the outer annular surface and the inner annular surface, and wherein the outer annular surface and the inner annular surface extend completely around the circumference of the exhaust pipe. The fifth example of the system optionally includes one or more of the first to fourth examples, and further includes: wherein the first blade and the second blade are fixedly coupled to the exhaust pipe and extend in an upstream direction and a downstream direction, respectively.

[0103] An embodiment of a method includes causing exhaust gas to flow from an exhaust passage to an outer passage of a mixer located outside the exhaust passage, and wherein the outer passage surrounds an exhaust pipe of the exhaust passage, wherein the outer passage receives and discharges exhaust gas at one or more perforations upstream and downstream of one or more curved fins. The first example of the method also includes: wherein the reductant injector is positioned to inject into a position between the surface of the mixer and the one or more fins. The second example of the method optionally includes the first example, and further includes: wherein causing the exhaust gas to flow also includes causing the exhaust gas to flow through a constriction of the exhaust passage formed by an inner portion of the exhaust passage, wherein the inner portion of the exhaust passage is fluidly coupled to a downstream portion of the outer passage. The third example of the method optionally includes the first example and / or the second example, and further includes: wherein the exhaust gas flows through the outer passage in a U-shape. The fourth example of the method optionally includes one or more of the first to third examples, and further includes: wherein the mixer is fixed and immovable, and wherein the mixer does not rotate and slide. The fifth example of the method optionally includes one or more of the first to fourth examples, and further includes: wherein the mixer has no additional inlet or other outlet except for the perforations that fluidly couple the mixer to the exhaust passage.

[0104] Note that the exemplary control and estimation routines included herein can be used with various engine and / or vehicle system configurations. The control methods and routines disclosed herein can be stored as executable instructions in a non-volatile memory and can be executed by a control system including a controller combined with various sensors, actuators, and other engine hardware. The specific routines described herein can represent one or more of any number of processing strategies, such as event-driven, interrupt-driven, multi-tasking, multi-threading, etc. Therefore, the various actions, operations, and / or functions shown may be performed in parallel in the order shown, or omitted in some cases. Similarly, in order to achieve the features and advantages of the exemplary embodiments described herein, the processing order is not necessarily required, but the processing order is provided for ease of illustration and description. One or more of the actions, operations, and / or functions shown may be repeatedly performed depending on the specific strategy used. In addition, the described actions, operations, and / or functions can graphically represent the code in the non-volatile memory of a computer-readable storage medium that will be programmed into the engine control system, wherein the described actions are performed by executing instructions in a system including various engine hardware components combined with an electronic controller.

[0105] It should be understood that the configurations and routines disclosed herein are exemplary in nature, and these specific embodiments should not be considered limiting, as many variations are possible. For example, the above-described technology can be applied to V-6, I-4, I-6, V-12, opposed 4, and other engine types. The subject matter of the present disclosure includes all novel and non-obvious combinations and sub-combinations of the various systems and configurations and other features, functions, and / or properties disclosed herein.

[0106] It should be noted that Figure 5 and Figure 8 Arrows are shown indicating where there is room for gas flow, and solid lines of device walls show where flow is blocked and communication is not possible due to the lack of fluid communication created by the device walls spanning from one point to another. The walls create separation between areas except for openings in the walls that allow for the described fluid communication.

[0107] The following claims particularly point out certain combinations and subcombinations regarded as novel and non-obvious. The claims may refer to "an" element or a "first" element or the equivalent thereof. Such claims should be understood to include incorporation of one or more such elements, neither requiring nor excluding two or more such elements. Other combinations and subcombinations of the disclosed features, functions, elements, and / or properties may be claimed by amendment of the present claims or by presentation of new claims in this or a related application. Such claims, whether broader, narrower, equal, or different in scope to the original claims, are deemed to be included in the subject matter of the present disclosure.

Claims

1. A mixer, comprising: An outer annular portion on the exterior of the exhaust pipe; as well as an inner annular portion inside the exhaust pipe, wherein the outer annular portion includes a spiral fin extending around the exhaust pipe in a downstream direction relative to the exhaust gas flow, wherein the inner annular portion is curved and includes a C-shaped cross-section in the downstream direction, and wherein the inner annular portion includes a venturi passage positioned along its central axis.

2. The mixer of claim 1 , wherein the spiral fin comprises a first end portion arranged along a first axis and a second end portion arranged along a second axis, and wherein the first axis is spaced apart from the second axis, and wherein the first axis is located upstream of the second axis relative to the direction of exhaust flow from the engine, wherein the outer annular portion is fluidly coupled to the exhaust passage of the exhaust pipe upstream of the first axis, and wherein the outer annular portion is fluidly coupled to the inner annular portion downstream of the second axis. 3 . The mixer of claim 1 , wherein the outer annular portion and the inner annular portion are hollow and symmetrical about a central axis of the exhaust pipe.

4. The mixer of claim 1, wherein the outer annular portion includes an outer surface that is angled relative to the exhaust pipe, and wherein an injector is coupled to the outer surface and positioned to inject into a flow space between the outer annular portion and the exhaust pipe. 5 . The mixer of claim 1 , wherein the inner annular portion is fluidly coupled to the exhaust passage at each of a venturi inlet, a venturi throat, and a venturi outlet of the venturi passage.

6. The mixer of claim 1, wherein the outer annular portion and the inner annular portion are fluidly coupled via one or more perforations.

7. A method for exhausting gas, comprising: causing exhaust gas to flow from an exhaust passage to an outer passage of a mixer located outside the exhaust passage, wherein the outer passage surrounds an exhaust pipe of the exhaust passage, and wherein the outer passage receives and discharges exhaust gas at one or more perforations upstream and downstream of one or more curved fins, a reductant injector being positioned to inject reductant into a location between a surface of the mixer and one or more of the curved fins, Exhaust gas is caused to flow through a constriction of the exhaust passage formed by an interior portion of the exhaust passage, the constriction being a venturi passage. 8 . The method of claim 7 , wherein the inner portion of the exhaust passage is fluidly coupled to a downstream portion of the outer passage.

9. The method of claim 7, wherein the exhaust gas flows through the outer passage in a U-shape.

10. The method of claim 7, wherein the mixer is fixed and immovable, and wherein the mixer does not rotate and slide.

11. The method of claim 7, wherein the mixer has no additional inlets or outlets other than the perforations fluidly coupling the mixer to the exhaust passage.

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