Aftertreatment module with replaceable catalyst housing

Abstract

Post-treatment module (12) with: an inlet housing (18) which at least partially defines an inlet passage (32) for the exhaust gas, at least one mixer (38) provided in the inlet passage (32), an outlet housing (20) which at least partially defines an outlet passage (44) for the exhaust gas, a catalyst housing (22) which is detachably connected between the inlet housing (18) and the outlet housing (20), and several catalyst substrates (52) designed to be mounted in the catalyst housing (22), to receive the exhaust gas from the inlet passage (32) in parallel and to discharge the exhaust gas to the outlet housing (20) in parallel.

Description

[0001] The present disclosure relates to a post-treatment module and in particular to a post-treatment module with an interchangeable catalyst housing. background

[0002] Internal combustion engines, including diesel engines, gasoline engines, gas-powered engines, and other known engines, emit a complex mixture of air pollutants. These air pollutants consist of gaseous components, including, among others, nitrogen oxides (NOx). X Due to increased environmental awareness, exhaust emission standards have become stricter and the amount of NOₓ has been reduced. X The amount of emissions released into the atmosphere by a power engine can be regulated depending on the type of power engine, the size of the power engine and / or the class of the power engine.

[0003] To the NO XTo comply with regulations, some engine manufacturers have implemented a strategy called selective catalytic reduction (SCR). SCR is an exhaust gas treatment process in which a reducing agent, most commonly urea ((NH₂)₂CO) or a water / urea solution, is selectively injected into the exhaust stream of an engine and adsorbed onto a downstream substrate. The injected urea solution decomposes into ammonia (NH₃), which reacts with the NOₓ to reduce emissions. X in the exhaust gas it reacts to form water (H2O) and diatomic nitrogen (N2).

[0004] In some applications, it may be necessary for the substrate used for SCR purposes to be very large, ensuring that it has sufficient surface area or effective volume to adsorb enough ammonia for adequate NO reduction. XThe required substrates can be expensive and require significant amounts of space in the engine exhaust system. Additionally, the substrate must be positioned far enough downstream of the urea injection point to allow sufficient time for decomposition into the ammonia gas and uniform distribution within the exhaust stream for efficient NO reduction. X is available. This distance can further increase the packing difficulties of the exhaust system.

[0005] Exhaust backpressure caused by the use of the SCR substrate described above can be problematic in some situations. Specifically, the SCR substrate can restrict the exhaust flow to a certain extent, thereby increasing the pressure of the exhaust gas leaving the engine. If this exhaust backpressure is too high, the engine's breathing capacity and, consequently, its performance can be negatively affected. Therefore, measures should be taken to avoid excessive restriction of the exhaust flow when implementing SCR.

[0006] An exemplary aftertreatment module is disclosed in U.S. patent US 8,747,788 B1 (the “788 patent”). In particular, the 788 patent discloses an aftertreatment module comprising a housing with an inlet and an outlet, and a catalyst bank separating the inlet from the outlet. The catalyst bank has a surface arranged at an oblique angle relative to a flow direction through the inlet and the outlet. Passages with decreasing cross-sectional areas extend from the inlet to the catalyst bank and from the catalyst bank to the outlet.

[0007] Although the post-treatment module of patent 788 may be functional in many applications, it may still be suboptimal. In particular, the catalyst bank may wear out over time, and it may not be easily maintainable.

[0008] From DE 3608371 A1, an exhaust aftertreatment module with a particulate filter and a housing with inlet and exhaust channels is also known.

[0009] The post-treatment module of the present disclosure addresses one or more of the needs mentioned above and / or other problems of the prior art. The invention aims to provide a post-treatment module that is more compact and easier to maintain. Summary

[0010] According to a first aspect, the present disclosure relates to an aftertreatment module. The aftertreatment module can comprise an inlet housing that at least partially defines an inlet passage for the exhaust gas, and at least one mixer provided in the inlet passage. The aftertreatment module can also comprise an outlet housing that at least partially defines an outlet passage for the exhaust gas, and a catalyst housing that is detachably connected between the inlet housing and the outlet housing. The aftertreatment module can further comprise several catalyst substrates configured to be mounted in the catalyst housing, to receive the exhaust gas from the inlet passage in parallel, and to discharge the exhaust gas to the outlet housing in parallel.

[0011] According to another aspect, the present disclosure relates to a different aftertreatment module. The aftertreatment module may comprise an inlet housing that at least partially defines an inlet passage with a first axis, and a first mounting flange oriented at an oblique angle relative to the first axis. The aftertreatment module may also comprise an outlet housing that at least partially defines an outlet passage with a second axis, and a second mounting flange oriented at an oblique angle relative to the second axis. The aftertreatment module may further comprise a catalyst housing that is detachably connected between the first mounting flange and the second mounting flange.

[0012] According to another aspect, the present disclosure relates to an aftertreatment module for a vehicle with a mounting platform configured to be substantially parallel to a base surface supporting the vehicle. The aftertreatment module may comprise an inlet housing, an outlet housing, and a catalyst housing detachably connected between the inlet housing and the outlet housing. The aftertreatment module may further comprise a mounting bracket with a base support device configured to connect a base of the outlet housing to the mounting platform, and a side support device projecting from the base support device at an oblique angle and configured to hold a side of the outlet housing and a side of the catalyst housing. Brief description of the drawings Fig. Figure 1 is a pictorial representation of an exemplary disclosed performance system, Fig. 2 is an exemplary assembly arrangement of two exemplary post-treatment modules, which are connected to the power system of Fig. 1 can be used, Fig. 3 is an exploded view of another exemplary post-treatment module disclosed, which is used in conjunction with the power system of Fig. 1 can be used, Fig. Figure 4 is a cross-sectional view of the post-treatment module of Fig. 3. Detailed description

[0013] Fig. Figure 1 represents an exemplary power system 10. For the purposes of this disclosure, the power system 10 is represented and described as a mobile machine, for example, a truck with one or more multi-cylinder internal combustion engines (not shown). Each engine can be configured to burn a mixture of air and fuel, for example, diesel, gasoline, or a gaseous fuel, and to produce a mechanical output. The mechanical output from the engine(s) can be directed to drive the mobile machine. Alternatively, if desired, the engine(s) can be configured as the primary or auxiliary power source of a stationary power system 10, such as a pump.

[0014] The power system 10 can be equipped with one or more (exhaust) aftertreatment modules (“modules”) 12 with components that work together to promote power production and simultaneously control the emission of pollutants from the engine(s) to the atmosphere. In the embodiment of Fig. In this embodiment, the power system 10 comprises a single module 12 mounted on a platform 14, which is configured to be substantially parallel to a ground surface on which the power system 10 is supported. In this embodiment, the platform 14 is positioned with respect to gravity above any associated power machine(s), and a channel system (not shown) can connect the module 12 to the power machine(s). A mounting bracket (or system of brackets) 16 can be used to connect the module 12 to the platform 14.

[0015] An exemplary assembly arrangement module 12 is shown in Fig. Figure 1 shows that in this arrangement, the mounting bracket 16 is configured to hold or grip two main surfaces of a single module 12 and to hold the module 12 in an orientation that avoids interference with other features of the power system 10. In particular, the mounting bracket 16 can have a base support 16a configured to be connected to a housing base or the lowest part of the module 12, and a side support 16b configured to be connected to a housing side or a vertical part of the module 12. The side support 16b can project at an oblique angle from the base support 16a, so that the module 12 is inclined forward (relative to a normal direction of movement of the power system 10) and away from a bed or foundation of the power system 10.A gap can be maintained between the module 12 and the bed of the power system 10 during operation. The base and side support devices 16a, 16b can be formed in one piece or integrally as a single component by a casting or manufacturing process. In some embodiments, several mounting brackets 16 (for example, one at each end) can be used to secure the module 12 to the platform 14.

[0016] An alternative mounting arrangement is in Fig. Figure 2 shows two modules 12 packed or bundled together, thus accommodating a power engine configuration with an increased exhaust flow and / or pollutant concentration. In this arrangement, the modules 12 can be stacked (for example, side by side or next to each other) and mounted in a vertical orientation at any suitable location on board the power system 10, for example, on the top of a fuel tank (not shown). Four substantially identical mounting brackets 16 (two on each side of the modules 12, with one at each end of the corresponding module 12), each having only side support devices 16b, can be used in this embodiment. It is intended that any number of modules 12 can be packed or bundled together at any position and / or in any orientation on board the power system 10, as desired.

[0017] As in Fig. As shown in Figure 3, each module 12 can be an assembly of components that are detachably connected to one another. For the purposes of this disclosure, the term "detachably connected" can refer to a connecting element that does not require a deforming or destructive process (for example, cutting, tearing, grinding, bending, melting, etc.) for removal or detachment. The module 12 can, among other things, comprise an inlet housing 18, an outlet housing 20, and a catalyst housing 22 arranged between the inlet and outlet housings 18 and 20. One or more gaskets or sealing rings 24 can be positioned between adjacent housings (for example, between mounting flanges or mounting collars 25 of adjacent housings), and several fasteners 26 can be used to detachably connect the housings.

[0018] As in Fig. 3 and Fig. As can be seen in Figure 4, the inlet and outlet housings 18 and 20 can each have a height h1 and h2, respectively, which varies in a longitudinal direction, while the catalyst housing 22 can have a height h3 that remains essentially constant along its length. In particular, a cross-section (shown in Figure 4) can be shown in Figure 4. Fig. 4) The inlet and outlet housings 18, 20 may be essentially triangular, while a cross-section of the catalyst housing 22 may be essentially quadrilateral or rectangular. The triangular shapes of the inlet and outlet housings 18, 20 may be inverted both vertically and horizontally (relative to the perspective of Fig. 3 and Fig. 4), so that the overall cross-section of the module 12 can be essentially square or rectangular. With this configuration, the mounting flanges or collars 25 can be oriented at an oblique angle relative to axes 28 and 30. Once the catalyst housing 22 is assembled between the collars or flanges 25, the catalyst housing 22 can be inclined relative to the top, bottom, and sides of the module 12.

[0019] In the Fig. 3 and Fig. In the embodiment shown in Figure 4, exhaust gas can flow into the module 12 in a first direction and flow out of the module 12 in a second direction, which is essentially perpendicular to the first direction. In particular, the incoming exhaust gas flow can be aligned with an axis 28 extending through a side of the module 12, while the outgoing exhaust gas flow can be aligned with an axis 30 extending through a base of the module 12. However, it is provided that, if desired, the incoming and outgoing exhaust gas flows can alternatively flow in the same or opposite directions (see Figure 4). Fig. 2) can be aligned to take into account different power machine / power system management requirements.

[0020] The inlet housing 18 can at least partially define an inlet passage 32 and a distribution space 34, which is positioned below the inlet passage 32 (that is, closer to an open bottom of the inlet housing 18). Exhaust gas can enter the inlet passage 32 on one side of the inlet housing 18 and travel along the length of the inlet housing 18 to the opposite side. On the opposite side, the exhaust gas flow can reverse direction as it enters the distribution space 34.

[0021] In the disclosed embodiment, the inlet passage 32 is a cylindrical conduit or pipe with a cross-sectional area that remains substantially constant along its length. One or more reducing agent injectors 36 (for example, two to four injectors spaced apart in different axial and / or circumferential positions) can be positioned at an inlet to the inlet passage 32, and one or more mixers 38 (for example, three mixers of different types and / or orientations) can be provided within the inlet passage 32 at different positions downstream of the injectors 36. The mixers 38 can be configured to uniformly mix the injected reducing agent with the exhaust gas as it flows into the module 12 and to prevent the reducing agent from impacting and / or condensing on its walls. In the example of Fig. 3 and Fig. In the following sections, the injector(s) 36 are arranged and oriented for directly spraying a reducing agent into a portion of the most upstream mixer 38. However, it should be noted that other configurations and arrangements of the injectors 36 and the mixer 38 are possible.

[0022] The distribution chamber 34 can be designed to distribute the exhaust gas received from the inlet passage 32 evenly across the open bottom of the inlet housing 18. In particular, the distribution chamber 34 can have a decreasing cross-sectional area along a flow direction. This flow area can decrease to such an extent that pressure is maintained along the length and width of the distribution chamber 34. In the disclosed embodiment, a diffuser 40 (e.g., a perforated plate) can be arranged at an intersection or connection point of the inlet passage 32 and the distribution chamber 34 (e.g., at a point where the exhaust gas flow reverses direction). The diffuser 40 can function such that a large portion of the exhaust gas flow is deflected toward the opposite end of the distribution chamber 34, where the cross-sectional area decreases.The length and / or porosity of the diffuser 40 can be adjusted to provide a desired exhaust gas distribution for a specific application. Additionally, in some applications, a restrictor or flow restrictor 42 (for example, a solid strip) can project from the inlet passage 32 downwards into the distribution chamber 34 at a downstream end of the diffuser 40. The position, height, and / or width of the restrictor 42 can be adjusted to provide desired exhaust gas distribution characteristics.

[0023] The outlet housing 20 can at least partially have an outlet passage 44 centered along a longitudinal and transverse direction, and a collection chamber 46 positioned above the outlet passage 44 (i.e., closer to an open top of the outlet housing 20). The exhaust gas can enter the collection chamber 46 along the length of the outlet housing 20 and move inwards towards the outlet passage 44 in the center of the outlet housing 20.

[0024] In the illustrated embodiment, the outlet passage 44 is a cylindrical conduit or pipe with a cross-sectional area that remains substantially constant along its length. A swirl end cap or vortex end cap 48 can be positioned at an inlet to the outlet passage 44, and one or more sensor flutes 50 can be provided within the outlet passage 44 at positions downstream of the swirl end cap 48. The swirl end cap 48 can be a perforated plate having vanes or wings on an outlet side designed to generate a vortex or swirl in the exhaust gas as it exits the module 12. The vortex can help improve the consistency of the readings or measurements taken by the sensors (not shown) provided within or otherwise connected to the sensor flutes 50.

[0025] The collection chamber 46 can be configured to collect exhaust gas along the open top of the outlet housing 20 while maintaining a substantially constant pressure and flow rate along its length. For this reason, the collection chamber 46 can have a decreasing cross-sectional area along its length. In particular, at an axial position essentially corresponding to the inlet of the distribution chamber 34 (i.e., where the flows and pressures are higher), the flow area within the distribution chamber 46 can be smallest. Conversely, at an axial position essentially corresponding to the end of the distribution chamber 34 (i.e., where the flows and pressures are lower), the flow area within the distribution chamber 46 can be largest. This flow area profile can promote a uniform exhaust gas flow through the catalyst housing 22.

[0026] The catalyst housing 22 can be a substantially four-walled structure with an open top facing the inlet housing 18 and an open bottom facing the outlet housing 20. A tube support device 51 can be formed within the catalyst housing 22, configured to accommodate several catalyst substrates or catalyst supports (“substrates” or “supports”) 52. In particular, the support device 51 can have several tubes (for example, six) arranged parallel to one another relative to the exhaust gas flow passing through the catalyst housing 22, each tube being configured to accommodate one or more (for example, two) substrates 52 arranged in series.Each of the substrates 52 can be an SCR-type substrate 52, and by arranging several substrates 52 within each pipe, the distribution of the exhaust gas over the end faces of the substrates 52 and the effectiveness or efficiency of the substrates 52 can be improved. However, it should be noted that in other embodiments, the substrates 52 contained in a common pipe can alternatively be other types of substrates. For example, the upstream substrates 52 can be diesel oxidation catalyst (DOC) substrates, while the downstream substrates 52 can be SCR substrates. Other configurations are also possible.

[0027] As an SCR substrate type, each substrate 52 can be made of a ceramic material such as titanium oxide, a base metal oxide such as vanadium and tungsten, zeolites, and / or precious metals, or it can be coated. This allows decomposed reducing agent, which flows along or is carried away with the exhaust gas flowing through the mixers 38 and the distribution chamber 34, to be adsorbed on the surface and / or absorbed within each substrate 52. The reducing agent can then be combined with the NO X (NO and NO2) react in the exhaust gas to form water (H2O) and diatomic nitrogen (N2), which may be unregulated substances.

[0028] As a DOC substrate type, each substrate 52 can be made of a precious metal such as palladium, platinum, vanadium, or a mixture thereof, or alternatively, it can be coated. With this structure, the substrate 52 can catalyze a chemical reaction to modify the exhaust gas flowing through the aftertreatment module 12. For example, the substrates 52 can help convert CO, NO, HC, and / or other components of the exhaust gas from the engine(s) into harmless substances such as CO2, NO2, and H2O. In another embodiment, the substrates 52 can, if desired, alternatively or additionally perform particulate filtering or particle trapping functions (i.e., the substrates 52 can act as catalytic particle traps).

[0029] The catalyst housing 22 can be inclined to accommodate the triangular shapes of the inlet and outlet housings 18, 20 (i.e., to form the stepped or changing flow surfaces that promote a uniform exhaust gas flow through the substrates 52). In particular, the substrates 52 can each have an upstream end surface lying in a common plane and oriented at an oblique angle relative to the flow direction through the inlet passage 32 (i.e., relative to the axis 28), and a downstream end surface lying in a common plane and oriented at an oblique angle relative to a flow direction through the outlet passage 44 (i.e., relative to the axis 30). Commercial applicability

[0030] The aftertreatment module of the present disclosure can be applied to any power system configuration requiring exhaust component treatment, where component packing and maintainability are important considerations. The disclosed aftertreatment module can improve the packing by using multiple small substrates and by efficiently utilizing the available onboard space. The disclosed aftertreatment module can improve maintainability by providing for separate replacement of the catalyst housing 22. The operation of the power system 10 will now be described.

[0031] With reference to the Fig. 3 and Fig.4. The exhaust gas generated by the engine(s) of the power system 10 can flow horizontally inwards through the inlet housing 18 in a first direction via the inlet passage 32. As the exhaust gas flows through the inlet passage 32, a reducing agent can be injected into the exhaust gas by the injectors 36 and mixed with the exhaust gas by the mixers 38. When the exhaust gas loaded with the reducing agent reaches the end of the inlet passage 32, it can be deflected downwards by approximately 180° to enter the distribution chamber 34. Part of the exhaust gas can impinge on the diffuser 40, and part can flow through the diffuser 40 to the substrate 52, which is positioned directly below it. The exhaust gas impinging on the diffuser 40 can be deflected in a second direction, which is essentially opposite to the first direction.The exhaust gas can then flow downwards along the length of the distribution space 34 and be forced downwards through the remaining substrates 52 by narrowing the cross-sectional area of ​​the distribution space 34.

[0032] As the exhaust gas flows through the substrates 52, the reducing agent flowing with it can decompose into NH3 and be adsorbed and / or absorbed within it. This can enable a catalytic reaction within the substrates 52, which reduces the NO Xin the exhaust gas, the gas is converted into harmless substances. The exhaust gas can then flow from the substrates 52 into the collection chamber 46 and be deflected inwards towards the outlet passage 44. The exhaust gas can then flow through the vortex end cap 48, whose blades generate a vortex or swirl of the exhaust gas to produce a substantially homogeneous exhaust gas mixture. This mixing can be advantageous because the exhaust gas flowing through each tube of the substrates 52 may have a slightly different composition. To obtain reliable and consistent sensor measurements at the measuring tubes 50, it may be necessary to mix the different exhaust gas streams into a more homogeneous stream. The exhaust gas can then exit the outlet passage 44 in a direction that is substantially perpendicular to the first and second directions.

[0033] The catalyst housing 22, together with the tube support device 51 and the substrates 52, can be designed to be easily replaced as a single unit (for example, in the field or in the workshop). In particular, the efficiency of the substrates 52 may decrease over time. Therefore, to ensure that the power system 10 continues to comply with government regulations, it may be necessary to replace the substrates 52. In a conventional aftertreatment module, when this occurs, the entire module is replaced with a completely new one. This can be expensive and labor-intensive. However, in the disclosed aftertreatment module, it may be possible to replace only the catalyst housing 22.

[0034] To replace the catalyst housing 22, the fasteners 26 can be loosened or removed, and the inlet and outlet housings 18, 20 can be separated from the catalyst housing 22. A new (or remanufactured) catalyst housing 22 can then be positioned between the flanges 25 of the existing inlet and outlet housings 18, 20, and the fasteners 26 can be reinstalled. In some applications, the sealing rings 24 can also be replaced at this time. One or more lifting ports (not shown) may be associated with the catalyst housing 22 and may be connected, for example, to the tube support device 51. The lifting ports can be used to lift the catalyst housing 22 during removal and installation. This maintenance can be quick and easy, with minimal associated costs.

[0035] The aftertreatment module 12 can be configured for use in many different applications, although some applications require more exhaust gas treatment than others. In particular, the catalyst housing 22 can be configured to accommodate substrates 52 of different lengths, the lengths being selected to suit the specific application. For example, if the aftertreatment module 12 is used in a power system 10 with lower exhaust gas flow rates and / or pollutant concentrations, shorter substrates 52 can be installed within the tube support device 51 of the catalyst housing 22. Conversely, if the aftertreatment module 12 is used in a power system 10 with higher exhaust gas flow rates and / or pollutant concentrations, longer substrates 52 can be installed within the tube support device 51 of the catalyst housing 22.The post-treatment module 12 can be designed such that its overall size and shape remain unchanged when used with substrates of different lengths. This increases part commonality across applications, resulting in a unit that requires fewer parts to be kept in stock. This can lead to cost reductions in most situations. It should also be noted that, if desired, catalyst housings 22 with different heights can be used interchangeably with the same inlet and outlet housings 18, 20.

[0036] Those skilled in the art will recognize that different modifications and variations to the post-treatment module of the present disclosure can be made without departing from the scope of the disclosure. Other embodiments will be recognizable to those skilled in the art from considering the description and application of the module disclosed herein. The description and examples are intended to be considered merely exemplary, with the true scope of the disclosure being specified by the subsequent claims and their equivalents. Reference symbol list: 10 Performance system 12 Module 14 Platform 18 Inlet housings 20 outlet housings 22 Catalyst housings 24 Sealing ring / gasket 25 mounting flanges / mounting collars 26 Fastening element 28 axle 30 axis 32 Admission lane 34 Distribution area 36 Reducing agent injector / injector 38 mixers 40 Diffuser 42 Flow restrictors 44 Outlet passage 46 Collection room 48 Outlet swivel cap 50 Measuring tube / perforated tube section 51 Tube carrying device / carrying device 52 substrates

Claims

Aftertreatment module (12) comprising: an inlet housing (18) which at least partially defines an inlet passage (32) for the exhaust gas, at least one mixer (38) which is provided in the inlet passage (32), an outlet housing (20) which at least partially defines an outlet passage (44) for the exhaust gas, a catalyst housing (22) which is detachably connected between the inlet housing (18) and the outlet housing (20), and several catalyst substrates (52) which are designed to be mounted in the catalyst housing (22), to receive the exhaust gas from the inlet passage (32) in parallel and to discharge the exhaust gas to the outlet housing (20) in parallel. Post-treatment module (12) according to claim 1, wherein the at least one mixer (38) has several mixers (38) arranged in series. Post-treatment module (12) according to claim 2, further comprising a reducing agent injector (36) which is connected to the inlet housing (18) and is configured to inject a reducing agent into an upstream mixer of the multiple mixers (38). Post-treatment module (12) according to one of claims 1 to 3, further comprising a diffuser (40) which is arranged within the inlet housing (18) and is arranged downstream of the at least one mixer (38). Aftertreatment module (12) according to claim 4, wherein the diffuser (40) is provided outside the inlet passage (32) and in an exhaust gas flow path that leads only to one upstream catalyst substrate of the several catalyst substrates (52). Aftertreatment module (12) according to one of claims 1 to 5, wherein each of the several catalyst substrates (52) has an upstream end surface which is oriented at an oblique angle relative to an exhaust gas flow through the inlet passage (32). Aftertreatment module (12) according to claim 6, wherein each of the multiple catalyst substrates (52) has a downstream end surface which is oriented at an oblique angle relative to an exhaust gas flow through the outlet passage (44). Post-treatment module (12) according to one of the preceding claims, further comprising an outlet vortex cap (48) arranged at an inlet of the outlet passage (44). Aftertreatment module (12) according to one of the preceding claims, further comprising a measuring tube (50) extending into the outlet passage (44) and designed to provide a mounting position for an exhaust gas sensor. Aftertreatment module (12) according to one of the preceding claims, further comprising: a seal (24) provided between the catalyst housing (22) and both the inlet housing (18) and the outlet housing (20), and / or several fastening elements (26) designed to detachably connect the catalyst housing (22) to both the inlet housing (18) and the outlet housing (20).

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