Aftertreatment system, exhaust duct assembly, mounting plate and method for increasing the mixing of reducing agent with an exhaust gas stream in an exhaust duct

Abstract

Aftertreatment system (100), comprising: a selective catalytic reduction system (150) comprising at least one catalyst for decomposing components of an exhaust gas produced by an engine (10); an exhaust passage (102) fluidly coupled to the selective catalytic reduction system (150) and configured to conduct the exhaust gas from the engine (10) to the selective catalytic reduction system (150), the exhaust passage (102) having an exhaust passage opening on a side wall (104) of the exhaust passage (102); and a mounting plate (120) positioned in the exhaust duct opening, the mounting plate (120) comprising a plurality of fluid channels (124a, 124b) defined therein, the plurality of fluid channels being positioned in an exhaust flow path of the exhaust gas flowing through the exhaust duct (102), at least one mounting plate opening (129) being defined by the mounting plate (120), the at least one mounting plate opening (129) being in fluid communication with at least one pair of fluid channels (124) of the plurality of fluid channels downstream of an inlet (122) of each fluid channel of the plurality of fluid channels, wherein the at least one pair of fluid channels (124) of the plurality of fluid channels is configured to receive at least one pair of exhaust gas streams from the inlets of the pair of fluid channels (124) and to direct them to the at least one mounting plate opening (129) such that exhaust gas streams of the at least one pair of exhaust gas streams arrive at the corresponding mounting plate opening (129) from different directions, wherein the at least one pair of exhaust gas streams is combined with a reducing agent supplied through the at least one mounting plate opening (129) before being supplied to the exhaust gas flow path.

Description

TECHNICAL FIELD

[0001] The present disclosure relates generally to aftertreatment systems for use with internal combustion (IC) engines, an exhaust passage assembly for conveying an exhaust gas from an engine to at least one aftertreatment component, a mounting plate for mounting a plurality of reductant delivery units, and a method for enhancing mixing of a reductant with an exhaust gas in an exhaust passage. BACKGROUND

[0002] Aftertreatment systems are used to capture and treat exhaust gas produced by engines, such as internal combustion engines. Conventional aftertreatment systems include any number of different components to reduce the proportion of harmful exhaust emissions in the exhaust. For example, certain aftertreatment systems for diesel-powered internal combustion engines include a selective catalytic reduction (SCR) catalyst system to convert NOx (NO and NO2 in minor proportions) into harmless nitrogen gas (N2) and water vapor (H2O) in the presence of ammonia (NH3).

[0003] Generally, a reductant, such as a diesel exhaust fluid (e.g., an aqueous urea solution), is supplied to the aftertreatment system as an ammonia source. The reductant facilitates the decomposition of exhaust gas components by the catalyst contained in the SCR system. Typically, the delivery of the reductant into the aftertreatment system's channels is assisted by the exhaust gas flow to achieve effective mixing of the reductant with the exhaust gas and reduce reductant deposits.

[0004] One or more injectors, which may be incorporated into a reductant delivery component, are used to deliver the reductant to the exhaust stream. Large engines produce enormous amounts of exhaust gases and therefore require that large amounts of reductant be delivered to the exhaust stream. This is generally achieved by multiple injectors delivering multiple reductant streams to the exhaust stream at multiple points. However, the exhaust-assisted delivery of reductant, which is commonly used for reductant delivery and has been optimized for reductant injection via a single injector, is not equally applicable to multi-point reductant delivery.

[0005] Simply increasing the number of injection points can lead to poor reductant spray characteristics, inadequate delivery, and inefficient mixing of the reductant with the exhaust stream, for example, caused by crossflow at the injection points and adverse interactions between a first reductant injection at a first injection point and a second reductant injection at a second injection point. This can lead to increased reductant deposits in the aftertreatment system components and thus increased backpressure. The increased backpressure and inadequate mixing can ultimately reduce NOx conversion efficiency, increase maintenance costs, and ultimately lead to aftertreatment system failure. SUMMARY

[0006] An aftertreatment system according to the present invention is set out in claim 1. An exhaust duct assembly according to the present invention is set out in claim 10. A mounting plate according to the present invention is set out in claim 17. A method according to the present invention is set out in claim 22. Further preferred embodiments are set out in the dependent claims. Embodiments described herein generally relate to systems and methods for increasing the mixing of reductant with an exhaust gas stream in an exhaust duct and reducing reductant deposits. In particular, the various embodiments described herein provide a mounting plate mounted to a sidewall of an exhaust duct.The mounting plate is configured to support one or more injectors and to divide at least a portion of an exhaust stream entering one or more fluid channels of the mounting plate into at least one pair of exhaust streams directed in opposite directions. The at least one pair of exhaust streams is combined with one or more reductant streams introduced through openings defined in the mounting plate before being fed to an exhaust flow path of the exhaust channel.

[0007] In a first set of embodiments, an aftertreatment system comprises an SCR system including at least one catalyst for separating components of an exhaust gas produced by an engine. An exhaust passage is fluidly coupled to the SCR system and configured to conduct the exhaust gases from the engine to the SCR system. The exhaust passage defines an exhaust passage opening on a sidewall of the exhaust passage. A mounting plate is positioned within the exhaust passage opening. The mounting plate includes a plurality of fluid channels defined therein. The plurality of fluid channels is positioned within an exhaust flow path of the exhaust gas flowing through the exhaust passage. At least one mounting plate opening is defined by the mounting plate.The mounting plate opening is in fluid communication with at least one pair of fluid channels of the plurality of fluid channels located downstream of an inlet of each of the plurality of fluid channels. Each of the plurality of fluid channels is configured to receive at least one pair of exhaust streams from the inlet of the plurality of fluid channels and direct them to a corresponding mounting plate opening, such that the at least one pair of exhaust streams arrive at the corresponding outlet from different directions. The at least one pair of exhaust streams is combined with a reductant introduced through the mounting plate opening before being supplied to the exhaust flow path.

[0008] In a second set of embodiments, an exhaust passage assembly for conveying exhaust gas from an engine to at least one aftertreatment component includes an exhaust passage. The exhaust passage is configured to fluidly couple the engine to the at least one aftertreatment component. The exhaust passage defines an exhaust passage opening on a sidewall of the exhaust passage. A mounting plate is positioned within the exhaust passage opening. The mounting plate includes a plurality of fluid channels defined therein. The plurality of fluid channels is positioned within an exhaust flow path of exhaust gas flowing through the exhaust passage. At least one mounting plate opening is defined by the mounting plate. The mounting plate opening is in fluid communication with at least one pair of fluid channels of the plurality of fluid channels located downstream of an inlet of each fluid channel of the plurality of fluid channels.Each fluid channel of the plurality of fluid channels is configured to receive and direct at least one exhaust stream pair from an inlet to an outlet such that at least one exhaust stream pair flows from the inlet of the plurality of fluid channels to the at least one mounting plate opening, such that the at least one exhaust stream pair arrives at the corresponding mounting plate opening from different directions. The at least one exhaust stream pair is combined with a reductant introduced through the at least one mounting plate opening before being supplied to the exhaust flow path.

[0009] In a third set of embodiments, a mounting plate configured for mounting a plurality of reductant delivery units comprises a plurality of mounting plate openings defined by the mounting plate. A plurality of fluid channels are defined within the mounting plate. The plurality of mounting plate openings are fluidly coupled to at least a portion of the plurality of fluid channels downstream of an inlet of at least a portion of the plurality of fluid channels. The mounting plate is positionable in an exhaust duct opening of an exhaust duct such that the inlet of each fluid channel of the plurality of fluid channels is positioned within an exhaust flow path of an exhaust gas stream defined by the exhaust duct.Each mounting plate opening of the plurality of mounting plate openings is configured to receive a reductant from at least one reductant supply unit of the plurality of reductant supply units. Furthermore, the plurality of fluid channels is configured to receive at least two exhaust gas streams from the inlet of each fluid channel of the plurality of fluid channels and direct them to the corresponding mounting plate opening, such that the pair of exhaust gas streams arrive at the corresponding mounting plate opening from different directions. The two exhaust gas streams are combined with a reductant supplied by at least one supply unit of the plurality of reductant supply units into the corresponding mounting plate opening before being supplied to the exhaust gas flow path.

[0010] In a fourth set of embodiments, a method for enhanced mixing of a reductant with an exhaust gas within an exhaust duct comprises providing an exhaust duct opening in the exhaust duct. A mounting plate is positioned within the exhaust duct opening. The mounting plate includes a plurality of fluid channels defined therein. The plurality of fluid channels is disposed within an exhaust flow path of the exhaust duct. At least one mounting plate opening is defined by the mounting plate. The mounting plate opening is in fluid communication with at least one pair of fluid channels of the plurality of fluid channels located downstream of an inlet of each of the plurality of fluid channels. At least one reductant delivery unit is mounted on the mounting plate.The assembly of the at least one reductant supply unit fluidly couples the at least one reductant supply unit to the at least one mounting plate opening. A reductant is supplied into the mounting plate opening via the at least one reductant supply unit. An exhaust gas flows through the exhaust channel. The flow results in at least a portion of the exhaust gas flowing into each fluid channel of the plurality of fluid channels. The portion of the exhaust gas is split into at least one exhaust stream pair, which flows through each fluid channel of the plurality of fluid channels. The plurality of fluid channels are configured to direct the at least one exhaust stream pair from the inlet of the respective plurality of fluid channels to a corresponding mounting plate opening such that at least one exhaust stream pair arrives at the corresponding mounting plate opening from different directions.The exhaust stream pair is combined with a reductant before being fed into the exhaust flow path.

[0011] It should be understood that all combinations of the above concepts and additional concepts discussed in more detail below (provided these concepts are not mutually incompatible) are intended to be part of the inventive subject matter disclosed herein. In particular, all combinations of the claimed subject matter listed at the end of this disclosure are intended to be part of the inventive subject matter disclosed herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The foregoing and other features of the present disclosure will become more apparent from the following description and appended claims, which should be read in conjunction with the accompanying drawings. While these drawings merely illustrate several embodiments in accordance with the disclosure and are therefore not to be considered limiting its scope, the disclosure will be described in greater detail and detail using the accompanying drawings. Fig. 1A is a schematic representation of an aftertreatment system including an exhaust duct with a mounting plate positioned therein, according to one embodiment; and Fig. 1B is a bottom view of the mounting plate included in the aftertreatment system made of Fig. 1A. Fig. 2 is a perspective view of a portion of another embodiment of an aftertreatment system. Fig. 3 is an enlarged view of a portion of the aftertreatment system of Fig. 2, with arrow A in Fig. 2, which shows a mounting plate mounted on the exhaust duct that has been removed from the exhaust duct. Fig. 4 is a cross-sectional view of the mounting plate from the Fig. 2 and Fig. 3, which shows a plurality of fluid channels defined therein. Fig. 5 is a front view of a first mixer installed in the exhaust duct of Fig. 2, at the position indicated by arrow B in Fig. 2 displayed position. Fig. Figure 6 is a front view of a second mixer installed in the exhaust duct of Fig. 2, at the position indicated by arrow C in Fig. 2 displayed position. Fig. 7 is a computer-aided fluid dynamics (CFD) model of the exhaust duct and the mounting plate from Fig. 2 and the flow path of the exhaust gas flows flowing through the fluid channels and the reducing agent flowing through the mounting plate openings of the mounting plate from the Fig. 2 to 3, so that the exhaust gas is combined with the reducing agent before it is introduced into the exhaust gas duct from Fig. 2 defined exhaust gas flow path. Fig. 8 is another CFD model of a flow path of different exhaust gas flows mixed with the exhaust gas flowing through the mounting plate of Fig. 2 supplied reducing agent in the exhaust gas flow path of the exhaust duct from Fig. 2 and after flowing through the first and second mixer. Fig. 9 is a schematic flow diagram of an embodiment of a method for reducing the droplet size and improving the mixing of a reducing agent supplied into the exhaust duct via a mounting plate.

[0013] Throughout the following detailed description, reference is made to the accompanying drawings. In the drawings, like symbols normally refer to like components unless the context dictates otherwise. The illustrative embodiments described in the detailed description, drawings, and claims are not intended to be limiting. Other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented herein. It is to be understood that the aspects of the present disclosure generally described and illustrated in the figures may be arranged, substituted, combined, and embodied in a wide variety of different configurations, all of which are expressly proposed as being incorporated by reference and are incorporated herein by reference. DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS

[0014] Embodiments described herein generally relate to systems and methods for increasing the mixing of reductant with an exhaust gas stream in an exhaust passage and reducing reductant deposits. In particular, the various embodiments described herein provide a mounting plate mounted to a sidewall of an exhaust passage. The mounting plate is configured to support one or more fuel injectors and to split at least a portion of an exhaust gas stream entering one or more fluid channels of the mounting plate into at least two exhaust gas streams directed in opposite directions. The at least two exhaust gas streams are combined with one or more reductant streams delivered through openings defined in the mounting plate before being delivered to an exhaust flow path of the exhaust passage.

[0015] Embodiments of the exhaust duct, including the mounting plate coupled thereto, may provide, for example, the following advantages, among others: (1) providing a dedicated mounting plate for mounting a plurality of injectors; (2) receiving a portion of the exhaust gas flow flowing through the exhaust duct and splitting the exhaust gas into at least two exhaust gas streams, which are combined with the reductant supplied through a mounting plate opening in the mounting plate before being directed into the exhaust duct, thereby hindering the impingement of the reductant on the sidewalls of the exhaust duct and reducing reductant deposits; (3) causing an exhaust-assisted crossflow of the reductant into an exhaust flow path of the exhaust duct, thereby enhancing the penetration of droplets or other spray of the reductant into the exhaust gas flowing through the exhaust duct;(4) reducing the interaction between multiple reductant feeds delivered by a plurality of injectors mounted on the mounting plate; and (5) reducing the droplet size and providing one or more mixers downstream of the mounting plate that improve the mixing of the reductant with the exhaust gas.

[0016] Fig. 1 is a schematic representation of an aftertreatment system 100 according to one embodiment. The aftertreatment system 100 is configured to receive exhaust gas (e.g., diesel exhaust) from an engine 10 (e.g., a diesel engine, a gasoline engine, a natural gas engine, a biodiesel engine, a dual-fuel engine, etc.) and decompose constituents (e.g., NOx gases) present in the exhaust gas produced by the engine 10. The aftertreatment system 100 includes an exhaust duct 102, a mounting plate 120, an SCR system 150, and optionally a mixer 140.

[0017] The SCR system 150 includes one or more catalysts designed to selectively reduce the exhaust gas. Any suitable catalyst may be used, such as a platinum-, palladium-, rhodium-, cerium-, iron-, manganese-, copper-, vanadium-based catalyst, any other suitable catalyst, or a combination thereof. The catalyst may be disposed on a suitable substrate, such as a ceramic (e.g., cordierite) or metallic (e.g., kanthal) monolith core, which may, for example, have a honeycomb structure. A washcoat (intermediate layer) may also be used as a support material for the catalysts. Such washcoat materials may, for example, be alumina, titania, silica, any other suitable washcoat material, or a combination thereof. The exhaust gas (e.g.,Diesel exhaust gas) can flow over and around the catalyst in such a way that any NOx gases contained in the exhaust gas are further reduced, resulting in an exhaust gas that is essentially free of carbon monoxide and NOx gases.

[0018] Although the aftertreatment system 100 is illustrated herein as including the SCR system 150, it may also include other components, such as the mixer 140 described herein, a particulate filter, an oxidation catalyst (e.g., a diesel oxidation catalyst or an ammonia oxidation catalyst), temperature sensors, oxygen sensors, NOx sensors, ammonia sensors, and / or any other components.

[0019] The exhaust passage 102 is fluidly coupled to the SCR system 150 and the engine 10. The exhaust passage may comprise a metallic (e.g., aluminum, stainless steel, iron, alloys, etc.) tube or pipe and is configured to conduct exhaust gases from the engine 10 to the SCR system 150. For example, the exhaust passage 102 may be fluidly coupled to an exhaust manifold (not shown) of the engine 10 to receive exhaust gases produced by the engine 10. Fig. 1 shows a single exhaust passage 102 fluidly coupled to the engine 10. In other embodiments, a plurality of exhaust passages 102 may be fluidly coupled to the engine 10. For example, the aftertreatment system 100 may have multiple compartments, each compartment including the exhaust passage 102, the SCR system 150, and any other components described herein.

[0020] An exhaust duct opening is defined in the side wall 104 of the exhaust duct 102, wherein the mounting plate 120 is positioned. Fig. 1B shows a bottom view of the mounting plate 120. The mounting plate 120 may be coupled to the exhaust duct opening defined in the exhaust duct 102 using any suitable coupling mechanism, for example, welded (e.g., by arc welding, spot welding, gas welding, hot air welding, etc.), fusion bonded, glued, or coupled with snap-fit fasteners or fasteners (e.g., screws, bolts, rivets, etc.). The coupling of the mounting plate 120 to the sidewall of the exhaust duct 102 forms a substantially leak-tight seal such that the exhaust gas cannot escape the junction between the mounting plate 120 and the exhaust duct opening of the exhaust duct 102.

[0021] The term "leak-tight" as used herein encompasses both a hermetic seal (i.e., the seal is impermeable to gases) and a liquid-tight seal. The term "substantially," when used in conjunction with "leak-tight," is intended to convey that, although complete impermeability to liquids is desired, minimal leaks may occur even in a "substantially liquid-tight" seal due to manufacturing tolerances or other practical considerations (such as the pressure acting on the seal and / or the liquid). In other embodiments, the mounting plate 120 may be monolithically formed with the exhaust duct 102.

[0022] The mounting plate 120 includes a mounting plate opening 129, a first fluid channel 124a, and a second fluid channel 124b (collectively referred to herein as the "fluid channel pair 124"). Each of the fluid channels of the fluid channel pair 124 defines an inlet 122 for receiving at least a portion of the exhaust gas flowing through the exhaust flow path of the exhaust channel 102. The mounting plate opening 129 is positioned downstream of the inlets 122 and fluidly coupled to each fluid channel of the fluid channel pair 124.

[0023] While Fig. 1 shows the mounting plate 120 having a mounting plate opening 129 and a pair of fluid channels 124. In other embodiments, the mounting plate 120 may include a plurality of mounting plate openings 129 (e.g., 2, 3, 4, or more). Furthermore, each of the plurality of mounting plate openings 129 may be fluidly coupled to at least a portion of the plurality of fluid channels 124. For example, each of the plurality of mounting plate openings 129 may be fluidly coupled to a plurality of fluid channels, for example, two, three, four, or even more fluid channels.

[0024] As in Fig. 1B, the fluid channel pair 124 divides the exhaust flowing through the inlets 122 of the fluid channel pair 123 into two exhaust streams or into one exhaust stream pair. For example, the aftertreatment system 100 may also include an injector 130 (or other reductant delivery unit) positioned on the mounting plate 120 (e.g., coupled via a connector). The injector 130 is fluidly connected to the mounting plate opening 129 of the mounting plate 120. The injector 130 is configured to receive a reductant from a reductant tank 110 via a reductant delivery unit 112, which may include, for example, pumps, valves, channels, etc. configured to convey the reductant from the reductant tank 110 to the injector 130.

[0025] Any suitable reductant may be used. In some embodiments, the exhaust gas may comprise diesel exhaust, and the reductant may comprise a diesel emission fluid. The diesel emission fluid may comprise urea, an aqueous urea solution, or any other ammonia-containing fluid, byproducts, or any other diesel emission fluids known in the art (e.g., the diesel emission fluid marketed under the name ADBLUE®).

[0026] The injector 130 is configured to inject or otherwise deliver the reductant (e.g., as a reductant jet or spray) into the exhaust flow path of the exhaust passage 102 through the mounting plate opening 129 of the mounting plate 120. In the various embodiments in which the mounting plate 120 includes a plurality of mounting plate openings 129, a plurality of injectors 130 may be disposed on the mounting plate 120. Each injector 130 of the plurality of injectors may be in fluid communication with at least one of the plurality of mounting plate openings 129 of the mounting plate 120, such that numerous jets or sprays of the reductant are introduced into the exhaust passage through the mounting plate 120, as described herein.

[0027] The fluid channel pair 124 (or plurality of fluid channels) is structured to receive at least a portion of the exhaust flowing through the exhaust flow path and to direct a pair of exhaust streams from the fluid channel inlets 122 to the mounting plate openings 129 such that the pair of exhaust streams arrive at the opening 129 from opposite directions. For example, in a particular embodiment, the fluid channel pair 124 is structured such that the pair of exhaust streams arrive at the mounting plate opening 129 from opposite directions, i.e., at an angle of 180 degrees relative to each other. In other embodiments, the fluid channel pair 124 may be structured so that the exhaust stream pair arrives at the mounting plate opening 129 at any other angle relative to each other, for example, 30 degrees, 45 degrees, 60 degrees, 75 degrees, 90 degrees, 105 degrees, 120 degrees, 135 degrees, 150 degrees, or 165 degrees relative to each other, including all ranges and values therebetween.

[0028] The fluid channel pair 124 is arranged parallel to each other, as in Fig. 1B. In embodiments where the mounting plate 120 includes a plurality of fluid channels 124, all of the fluid channels 124 may be arranged parallel to one another. Introducing the pair of exhaust streams in different directions, for example, in opposite directions, results in the pair of exhaust streams arriving at the mounting plate opening 129 from opposite directions and combining with the reductant introduced through the mounting plate opening 129 before being delivered to the exhaust flow path defined by the exhaust channel 102. The exhaust flowing through the two fluid channels 124 combines with the reductant delivered through the mounting plate opening 129 and forces the reductant into the exhaust flow path, thereby improving mixing and preventing the reductant from impinging on the sidewalls 104 of the exhaust channel 102.Since the impingement of the reductant onto the side walls 104 of the exhaust passage 102 can lead to increased deposits of the reductant, the exhaust-assisted delivery of the reductant into the exhaust flow path provided by the mounting plate 120 hinders or prevents said impingement to a significant extent and thus reduces reductant deposits.

[0029] Combining the pair of exhaust streams arriving from opposite directions with the reductant delivered into the mounting plate opening 129 can create a crossflow of the exhaust reductant into the exhaust flow path. The crossflow can increase the mixing of the droplets or other spray of the reductant with the exhaust stream flowing through the exhaust passage 102. The exhaust flow-assisted delivery of the reductant through the mounting plate 120 reduces the interactions between multiple reductant sprays delivered by a plurality of injectors 130 mounted on the mounting plate 120. Combining the pair of exhaust streams with the reductant also reduces the droplet size of the reductant spray delivered to the exhaust flow path defined by the exhaust passage 102, thereby improving the mixing of the reductant with the exhaust gas.

[0030] The mounting plate 120 may be formed from any suitable material, such as stainless steel, iron, etc., and using any suitable method, such as casting, molding, etc. In various embodiments, the mounting plate 120 may include a first part and a second part that are coupled, e.g., welded, together to form the mounting plate 120. The mounting plate opening 129 or a plurality of mounting plate openings 129 may be defined by the first part and the second part, such that the mounting plate opening 129 is defined by the mounting plate 120. The pair of fluid channels 124 or the plurality of fluid channels 124 may be defined in the first part and / or in the second part. By coupling the first part to the second part, the inlet 122 of the plurality of fluid channels is fluidly coupled to the outlet.

[0031] In some embodiments, a mixer 140 upstream of the SCR system 150 may also be disposed in the exhaust duct 102. The mixer 140 may include a tab mixer, a swirl device, any other mixer, or a combination thereof. The mixer 140 may include plates, vanes, sidewalls, vortex generators, swirl-generating passages, protrusions, or any other feature designed to promote mixing of the reductant with the exhaust gas. For example, the mixer may include a tab mixer designed to distribute the flow of the reductant across the cross-section of the exhaust duct and / or reduce a droplet size of the reductant. The mixer 140 may also include a swirl device designed to increase the residence time of the reductant and the exhaust gas in the exhaust duct, thereby promoting mixing of the exhaust gas with the reductant.

[0032] Fig. 2 is a perspective view of a portion of another embodiment of an aftertreatment system 200. The aftertreatment system includes a first aftertreatment section 200a and a second aftertreatment section 200b that are substantially similar to one another. The aftertreatment system 200 is configured to receive exhaust gas (e.g., diesel exhaust) from an engine, such as engine 10, and decompose constituents (e.g., NOx gases) present in the exhaust gas produced by the engine. Both the first aftertreatment section 200a and the second aftertreatment section 200a of the aftertreatment system 200 include an exhaust passage 202, a mounting plate 220, a first injector 230a, a second injector 230b, and a third injector 230c (collectively referred to herein as “the injectors 230”), a first mixer 240, and a second mixer 242 (see Fig. 6) The aftertreatment system 200 may also include one or more components, such as an SCR system (e.g., the SCR system 150), that is part of both the first aftertreatment section 200a and the second aftertreatment section 200b of the aftertreatment system 200, or is configured to receive exhaust gas from both the first aftertreatment section 200a and the second aftertreatment section 200b of the aftertreatment system 200.

[0033] The exhaust duct 202 includes an inlet 201 configured to be coupled to an engine (e.g., engine 10) to receive an exhaust gas (e.g., diesel exhaust) from the engine. An outlet 203 of the exhaust duct 202 is coupled to the first mixer 240. Fig. Figure 2 shows the exhaust ducts 202 belonging to the first aftertreatment section 200a and the second aftertreatment section 200b as having a substantially "U-shape," such that the exhaust gas entering the exhaust duct 202 via the inlet 201 is redirected at an angle of approximately 180 degrees to the outlet 203. In other embodiments, the exhaust ducts 202 may have a substantially straight, curved, bent, angled, or any other suitable shape. The respective exhaust ducts 202, as well as the first mixers 240 and the second mixers 242, are attached to a frame 206. The frame 206 may include crossbars, rods, coupling means (e.g., openings or through-holes to accommodate fasteners or welds), or any other attachment mechanisms to enable attachment of the exhaust ducts 202, the first mixer 240, the second mixer 242, and / or other components of the aftertreatment system 200 thereto.

[0034] Fig. 3 is an enlarged view of the area indicated by arrow A in Fig. 3. An exhaust duct opening 204 is defined in a sidewall of the exhaust duct 202, wherein the mounting plate 220 is positioned. The mounting plate 220 includes a first portion 221 and a second portion 223 that are coupled together (e.g., welded, bolted, fastened, fusion bonded, glued, etc.) to form the mounting plate 220. The mounting plate 220 may be coupled to the exhaust duct opening 204 defined in the exhaust duct 102 using any suitable coupling means, for example, welded (e.g., by arc welding, spot welding, gas welding, hot air welding, etc.), fusion bonded, glued, or coupled with snap hooks or fasteners (e.g., screws, bolts, rivets, etc.).The coupling of the mounting plate 120 to the sidewall of the exhaust duct 102 forms a substantially leak-tight seal, so that the exhaust gas cannot escape the junction between the mounting plate 120 and the exhaust duct opening 204, as previously described herein. In various embodiments, the mounting plate 220 may be monolithically formed, for example, cast.

[0035] The mounting plate 220 may be formed from any suitable material, such as stainless steel, iron, etc., and using any suitable process, such as casting, molding, stamping, etc. The mounting plate 220 includes a first mounting plate opening 229a, a second mounting plate opening 229b, and a third mounting plate opening 229c (collectively referred to herein as "the plurality of mounting plate openings 229") defined in the first portion 221 and the second portion 223 of the mounting plate 220, such that the plurality of mounting plate openings 229 are defined by the mounting plate 220. The plurality of mounting plate openings 229 are arranged parallel to one another along a longitudinal axis of the mounting plate 220, which may be substantially parallel to an exhaust flow path of the exhaust gas flowing through the exhaust duct 202.A first injector 230a, a second injector 230b, and a third injector 230c (collectively referred to herein as “the plurality of injectors 230”) are disposed on the first portion 221 of the mounting plate 220 and fluidly coupled to the first mounting plate opening 229a, the second mounting plate opening 229b, and the third mounting plate opening 229c, and each configured to supply reductant through the corresponding mounting plate opening 229.

[0036] Fasteners 225 are defined on the first portion 221 of the mounting plate 220 proximate the plurality of mounting plate openings 229. The fasteners 225 may include, for example, pins, openings, through-holes (e.g., threaded holes), grooves, notches, recesses, detents, slots, or any other suitable fastening means to securely mount or couple the plurality of injectors 230 to the first portion 221 of the mounting plate 220. A seal 232 is disposed between each injector 230 of the plurality of injectors 230 and the first portion 221.Each of the seals 225 is disposed around each of the mounting plate openings of the plurality of mounting plate openings 229 and is configured to provide a leak-tight seal between each injector 230 of the plurality of injectors 230 and the corresponding mounting plate opening 229 to prevent reductant from leaking between the plurality of injectors 230 and the plurality of mounting plate openings 229.

[0037] Each injector of the plurality of injectors 230 is designed to deliver the reducing agent, for example any one, in conjunction with Fig. 1, into the corresponding mounting plate opening 229 of the plurality of mounting plate openings 229 such that at least three reductant streams are supplied through the mounting plate 220 to an exhaust flow path of the exhaust duct 202 as described herein. Fig. 4 is a front view of the second (bottom) portion 223 of the mounting plate 220. The first mounting plate opening 229a, the second mounting plate opening 229b, and the third mounting plate opening 229c are defined by the bottom portion so that the reductant introduced by the plurality of injectors 230 is delivered through the mounting plate 220. A first fluid channel pair 224a, a second fluid channel pair 224b, and a third fluid channel pair 224c (collectively referred to herein as "fluid channel pairs 224") are defined in the second portion 223 and / or the first portion 221.

[0038] The first fluid channel pair 224a includes a first inlet 222a, the second fluid channel pair 224b includes a second inlet 222b, and the third fluid channel pair 224c includes a third inlet 222c (collectively referred to herein as the "inlets 222"). The inlets 222 are configured to receive a portion of a portion of the exhaust gas through the fluid channel pairs 224. The fluid channel pairs 224 are fluidly connected to a corresponding one of the plurality of mounting plate openings 229 such that the pairs of exhaust gas flows are directed through the fluid channel pairs 224 to the corresponding mounting plate openings 229.

[0039] As in Fig. 4, the plurality of mounting plate openings 229 are parallel to each other and along a longitudinal axis A Lthe mounting plate 220. Furthermore, the plurality of fluid channels 224 are also arranged parallel to one another. The first fluid channel pair 224a is parallel to one another and directly along the longitudinal axis A L and on each side of the longitudinal axis A L The second fluid channel pair 224b is arranged parallel to each other distal to the longitudinal axis A L relative to the first fluid channel pair 224a and on both sides of the first fluid channel pair 224a. Furthermore, the third fluid channel pair 224c is also parallel to each other and most distal from the longitudinal axis A L arranged on both sides of the second fluid channel pair 224b.

[0040] The fluid channel pairs 224 may be defined only in the second portion 223 or in both the first portion 221 and the second portion 223 of the mounting plate 220. A plurality of alignment features 227, including pairs of uniquely shaped grooves and protrusions, are defined in both the first portion 221 and the second portion 223 of the mounting plate 220. The plurality of alignment features 227 may be used to align the first portion 221 with the second portion 223 to facilitate the desired positioning of the fluid channels 224 and the plurality of mounting plate openings 229 relative to one another once the first portion 221 is coupled to the second portion 223 to form the mounting plate 220.

[0041] As in Fig. 4, each fluid channel pair 224 divides the exhaust flowing into the mounting plate 220 into two exhaust streams or into one exhaust stream pair. Each fluid channel of the fluid channel pair 224 includes a curved portion leading to a corresponding mounting plate opening 229. The fluid channel pair 224 is configured to direct the exhaust stream pair from each inlet of the plurality of inlets 222 to a corresponding mounting plate opening 229 of the plurality of mounting plate openings 229, such that the two exhaust streams of a pair arrive at the corresponding mounting plate opening 229 from different directions. As shown in Fig. 4, the fluid channel pairs 224 are structured such that the exhaust stream pair arrives at the mounting plate opening 229 from opposite directions, i.e., at an angle of 180 degrees relative to each other. In other embodiments, the fluid channel pair 224 may be structured such that the two exhaust streams of an exhaust stream pair arrive at the outlet at any other angle relative to each other, for example, at an angle of 30 degrees, 45 degrees, 60 degrees, 75 degrees, 90 degrees, 105 degrees, 120 degrees, 135 degrees, 150 degrees, or 165 degrees relative to each other.

[0042] Introducing two exhaust streams of an exhaust stream pair in different directions, for example, in opposite directions, via the fluid channel pairs 224 results in the two exhaust streams of a pair arriving at the corresponding mounting plate opening 229 from opposite directions and combining with the reductant introduced through the corresponding mounting plate opening 229 before being fed to the exhaust flow path defined by the exhaust channel 202. The exhaust-assisted delivery of the reductant into the exhaust flow path through the mounting plate 220 via the mounting plate openings 229 significantly reduces the shear effect of the exhaust stream at the mounting plate openings 229.

[0043] Combining the exhaust stream pair with the reductant prior to introducing it into the exhaust flow path can create a crossflow of the exhaust reductant into the exhaust flow path. The crossflow can increase the mixing of the reductant droplets or other spray with the exhaust flow flowing through the exhaust passage 202. Delivering the reductant through the mounting plate 220 reduces the interactions between multiple reductant streams or sprays delivered by a plurality of injectors 230 mounted on the mounting plate 220. Combining the exhaust stream pair with the reductant to introduce the reductant into the exhaust flow path through the mounting plate openings 229 also reduces the size of the droplets forming the reductant spray introduced into the exhaust flow path, thereby improving the mixing of the reductant with the exhaust gas.

[0044] For example, Fig. 7 shows a CFD analysis of the exhaust-assisted introduction of multiple reductant streams introduced through the mounting plate 220 into the exhaust duct 202. The reductant droplets mix quickly with the exhaust stream and do not impinge on the sidewalls of the exhaust duct 202, thereby reducing the formation of reductant deposits on the sidewalls. A first mixer 240 is arranged in the exhaust duct 202 downstream of the mounting plate 220. Fig. 5 shows a front view of the first mixer 240. The first mixer 240 comprises a tab mixer comprising a plurality of tabs 241 designed to distribute the flow across the cross section of the exhaust duct 202 and / or to reduce the droplet size of the reducing agent.

[0045] The second mixer 242 is arranged downstream of the first mixer 240 and includes a swirling device. The second mixer 242 includes vanes 243 or blades 243 designed to create vortexes or eddies in the exhaust gas stream with the reducing agent mixed therein. This increases the residence time of the reducing agent and the exhaust gas in the exhaust duct 202, thereby promoting the mixing of the exhaust gas with the reducing agent.

[0046] Fig. Figure 8 is a CFD model of the reductant droplets delivered to the exhaust flow path of the exhaust duct by the plurality of reductant sprays. The CFD model shows that the reductant droplets are efficiently dispersed and mixed with the exhaust gas after passing through the mixer 240. Furthermore, turbulence is generated in the exhaust flow path after passing through the second mixer 242. While the first mixer 240 comprising a tab mixer and the second mixer 242 comprising a swirl device are shown, any other mixer or swirl device may be incorporated into the aftertreatment system in addition to or instead of the first mixer 240 and the second mixer 242.

[0047] Fig.9 is a schematic flow diagram of an example method 300 for promoting mixing of a reductant with an exhaust gas and reducing reductant deposits of a reductant introduced into an exhaust passage, such as exhaust passage 102 or 202, fluidly coupled to an engine, such as engine 10. Method 300 includes providing an exhaust passage opening in an exhaust passage 302. For example, exhaust passage opening 204 is provided in exhaust passage 202, which may include a cutout.

[0048] A mounting plate is positioned within the exhaust duct opening at 302. For example, mounting plate 120 or 220 is positioned within the exhaust duct opening defined in a sidewall of exhaust duct 102 or 202. The mounting plate (e.g., mounting plate 120 or 220) includes a plurality of fluid channels defined therein (e.g., fluid channels 124 or 224). The plurality of fluid channels are disposed within an exhaust flow path of the exhaust duct. At least one mounting plate opening (e.g., mounting plate opening 129 or 229) is defined through the mounting plate. The at least one mounting plate opening is in fluid communication with at least one pair of fluid channels of the plurality of fluid channels located downstream of an inlet (e.g., inlets 122 or 222) of the respective plurality of fluid channels, as described herein.

[0049] At least one injector is mounted on the outer surface of the mounting plate at 306. The positioning of the at least one injector fluidly couples the at least one injector to the at least one mounting plate opening. For example, the plurality of injectors 230 are arranged on the first portion 221 of the mounting plate 220 such that each of the plurality of injectors 230 is fluidly coupled to a corresponding mounting plate opening 229 of the mounting plate 220.

[0050] A reductant is introduced into the exhaust passage 308 via the at least one injector through the mounting plate. The injector introduces the reductant through the mounting plate into an exhaust flow path of the exhaust passage. For example, the plurality of injectors 230 introduces the reductant into the exhaust flow path through the corresponding mounting plate opening 229 from the plurality of mounting plate openings 229.

[0051] An exhaust gas flows through the exhaust channel at 310. The flow of the exhaust gas causes at least a portion of the exhaust gas to enter each of the plurality of fluid channels (e.g., the plurality of fluid channels 124 or 224) via an inlet of the plurality of fluid channels. The portion of the exhaust gas is split into at least one exhaust stream pair, each flowing through the plurality of fluid channels. The plurality of fluid channels is configured to direct the at least one exhaust stream pair from the inlet of the respective plurality of fluid channels to a corresponding mounting plate opening (e.g., the mounting plate openings 129 or 229) such that at least one exhaust stream pair arrives at the corresponding mounting plate opening from different directions. The exhaust stream pair is combined with the reductant at the mounting plate opening before being supplied to the exhaust flow path.In this way, the reducing agent is supplied from each of the plurality of mounting plate openings to the exhaust flow path, assisted by the exhaust flow.

[0052] In various embodiments, the exhaust stream pair comprises two exhaust streams that can be directed in opposite directions to each other. Combining the exhaust stream pair with the reducing agent prior to its introduction into the exhaust flow path creates a crossflow of the reducing agent into the exhaust flow path.

[0053] The crossflow can increase the mixing of the droplets or other spray of the reductant with the exhaust stream flowing through the exhaust passage (e.g., exhaust passage 102 or 220). Delivery of the reductant through the mounting plate reduces the interactions between multiple reductant sprays delivered by a plurality of injectors mounted on the mounting plate. Combining the two exhaust streams with the reductant also reduces the droplet size of the reductant spray delivered to the exhaust flow path defined by the exhaust passage, thereby improving the mixing of the reductant with the exhaust gas. Furthermore, the exhaust-assisted reductant delivery into the exhaust flow path also reduces the impingement of the reductant on the sidewalls of the exhaust passage, thereby reducing the formation of reductant deposits on the sidewalls, as described herein.

[0054] The terms "coupled," "connected," and the like, as used herein, mean the direct or indirect connection of two elements to one another. This connection can be stationary (e.g., permanent) or movable (e.g., removable or detachable). This connection can be achieved by the two elements, or the two elements and any other intermediate elements, being integrally formed as a unitary body, or by the two elements, or the two elements and any other intermediate elements, being secured to one another.

[0055] It should be understood that the structure and arrangement of the various exemplary embodiments are for illustrative purposes only. Although only a few embodiments have been described in detail in this disclosure, those skilled in the art will readily recognize upon reading this disclosure that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes, and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter described herein. Other substitutions, modifications, changes, and omissions may also be made in the construction, operating conditions, and arrangement of the various exemplary embodiments without departing from the scope of the present invention.

Claims

[1] Aftertreatment system (100) comprising: a selective catalytic reduction system (150) comprising at least one catalyst for decomposing components of an exhaust gas produced by an engine (10); an exhaust passage (102) fluidly coupled to the selective catalytic reduction system (150) and configured to conduct the exhaust gas from the engine (10) to the selective catalytic reduction system (150), the exhaust passage (102) having an exhaust passage opening on a side wall (104) of the exhaust passage (102); and a mounting plate (120) positioned in the exhaust duct opening, the mounting plate (120) comprising a plurality of fluid channels (124a, 124b) defined therein, the plurality of fluid channels being positioned in an exhaust flow path of the exhaust gas flowing through the exhaust duct (102), at least one mounting plate opening (129) being defined by the mounting plate (120), the at least one mounting plate opening (129) being in fluid communication with at least one pair of fluid channels (124) of the plurality of fluid channels downstream of an inlet (122) of each fluid channel of the plurality of fluid channels, wherein the at least one pair of fluid channels (124) of the plurality of fluid channels is configured to receive at least one pair of exhaust gas streams from the inlets of the pair of fluid channels (124) and to direct them to the at least one mounting plate opening (129) such that exhaust gas streams of the at least one pair of exhaust gas streams arrive at the corresponding mounting plate opening (129) from different directions, wherein the at least one pair of exhaust gas streams is combined with a reducing agent supplied through the at least one mounting plate opening (129) before being supplied to the exhaust gas flow path. [2] The aftertreatment system of claim 1, wherein the different directions are opposite directions. [3] Aftertreatment system according to one of the preceding claims, in particular according to claim 1, wherein combining the at least one exhaust stream pair with the reductant creates a crossflow of the reductant into the exhaust flow path. [4] Aftertreatment system according to one of the preceding claims, in particular according to claim 1, wherein the at least one mounting plate opening (129) has a plurality of mounting plate openings. [5] Aftertreatment system according to one of the preceding claims, in particular according to claim 1, wherein the at least one exhaust gas stream pair comprises two exhaust gas streams. [6] Aftertreatment system according to one of the preceding claims, in particular according to claim 4, wherein a plurality of injectors (130) are arranged on the mounting plate (120), each of the injectors (130) of the plurality of injectors being fluidly coupled to a mounting plate opening (129) of the plurality of mounting plate openings and being adapted to supply the reductant to the exhaust passage through the mounting plate (120). [7] Aftertreatment system according to one of the preceding claims, in particular according to claim 1, further comprising: at least one mixer (140) arranged downstream of the mounting plate (120) and upstream of the selective catalytic reduction system (150). [8] The aftertreatment system of claim 7, wherein the at least one mixer (140) comprises a tab mixer, the tab mixer being configured to distribute the flow of the reducing agent across the cross section of the exhaust duct (102) and / or to reduce the droplet size of the reducing agent. [9] Aftertreatment system according to claim 7 or 8, wherein the mixer (140) comprises a swirling device designed to increase the residence time of the reducing agent and the exhaust gas in the exhaust duct (102). [10] Exhaust duct assembly for conveying an exhaust gas from an engine (10) to at least one aftertreatment component, comprising: an exhaust duct (102) configured to fluidly couple the engine (10) to at least one aftertreatment component, the exhaust duct having an exhaust duct opening in the sidewall (104) of the exhaust duct; and a mounting plate (120) positioned in the exhaust duct opening, the mounting plate comprising a plurality of fluid channels (124a, 124b) defined therein, the plurality of fluid channels being positioned in an exhaust flow path of the exhaust gas flowing through the exhaust duct (102), at least one mounting plate opening (129) defined by the mounting plate, the at least one mounting plate opening (129) being in fluid communication with at least one pair of fluid channels (124) of the plurality of fluid channels downstream of an inlet (122) of each of the at least one pair of fluid channels (124) of the plurality of fluid channels, wherein the at least one pair of fluid channels (124) of the plurality of fluid channels is configured to receive at least one pair of exhaust gas streams from the inlets of the pair of fluid channels (124) and to direct them to the at least one mounting plate opening (129) such that exhaust gas streams of the at least one pair of exhaust gas streams arrive at the corresponding mounting plate opening (129) from different directions, wherein the at least one pair of exhaust gas streams is combined with a reducing agent supplied through the corresponding mounting plate opening (129) before being supplied to the exhaust gas flow path. [11] The exhaust passage assembly of claim 10, wherein combining the at least one exhaust stream pair with the reductant creates a crossflow of the reductant into the exhaust flow path. [12] The exhaust duct assembly of claim 10 or 11, wherein the at least one mounting plate opening (129) comprises a plurality of mounting plate openings. [13] An exhaust duct assembly according to any one of claims 10 to 12, wherein the plurality of fluid channels are arranged parallel to each other. [14] An exhaust duct assembly according to any one of claims 10 to 13, wherein the plurality of fluid channels (124a, 124b) includes a curved portion leading to one of the at least one mounting plate opening (129). [15] The exhaust duct assembly of claim 12, wherein each of the mounting plate openings (129) of the plurality of mounting plate openings (129) is arranged along a longitudinal axis of the mounting plate (120). [16] An exhaust duct assembly according to any one of claims 10 to 15, wherein the different directions are opposite directions. [17] Mounting plate for mounting a plurality of reducing agent supply units (112), comprising: a plurality of mounting plate openings (129) defined by the mounting plate (120); and a plurality of fluid channels (124a, 124b) defined in the mounting plate (120), wherein the plurality of mounting plate openings (129) are fluidly coupled to at least a portion of the plurality of fluid channels downstream of an inlet (122) of at least a portion of the plurality of fluid channels, wherein the mounting plate (120) is positionable in an exhaust duct opening of an exhaust duct (102) such that the inlet (122) of each fluid duct (124a, 124b) of the plurality of fluid ducts is positioned within an exhaust flow path of an exhaust gas stream defined by the exhaust duct (102), wherein each mounting plate opening (129) of the plurality of mounting plate openings is adapted to receive a reducing agent from at least one of the reducing agent supply units (112) of the plurality of reducing agent supply units, and wherein at least one fluid channel pair (124) of the plurality of fluid channels is configured to receive a pair of exhaust gas streams from the inlets of the fluid channel pair (124) and to direct them to the corresponding mounting plate opening (129) such that exhaust gas streams of the pair of exhaust gas streams arrive at the corresponding mounting plate opening from different directions, wherein the pair of exhaust gas streams is combined with a reductant supplied by at least one reductant supply unit of the plurality of reductant supply units into the corresponding mounting plate opening (129) before being supplied to the exhaust gas flow path. [18] Mounting plate according to claim 17, wherein the plurality of fluid channels are arranged parallel to each other. [19] A mounting plate according to claim 17 or 18, wherein each of the plurality of fluid channels has a curved portion leading to a corresponding outlet. [20] The mounting plate of any one of claims 17 to 19, wherein each of the mounting plate openings (129) of the plurality of mounting plate openings is arranged along a longitudinal axis of the mounting plate (120). [21] Mounting plate according to one of claims 17 to 20, wherein the different directions are opposite directions. [22] A method for improving the mixing of a reducing agent with an exhaust gas in an exhaust gas duct (102), comprising: Providing an exhaust duct assembly comprising: an exhaust duct (102) configured to fluidly couple the engine (10) to at least one aftertreatment component, the exhaust duct having an exhaust duct opening in the sidewall (104) of the exhaust duct; and a mounting plate (120) positioned in the exhaust duct opening, the mounting plate comprising a plurality of fluid channels (124a, 124b) defined therein, the plurality of fluid channels being positioned in an exhaust flow path of the exhaust gas flowing through the exhaust duct (102), at least one mounting plate opening (129) defined by the mounting plate, the at least one mounting plate opening (129) being in fluid communication with at least one pair of fluid channels (124) of the plurality of fluid channels downstream of an inlet (122) of each of the at least one pair of fluid channels (124) of the plurality of fluid channels, wherein the at least one pair of fluid channels (124) of the plurality of fluid channels is configured to receive at least one pair of exhaust gas streams from the inlets of the pair of fluid channels (124) and to direct them to the at least one mounting plate opening (129) such that exhaust gas streams of the at least one pair of exhaust gas streams arrive at the corresponding mounting plate opening (129) from different directions, wherein the at least one pair of exhaust gas streams is combined with a reducing agent supplied through the corresponding mounting plate opening (129) before being supplied to the exhaust gas flow path; Supplying a reducing agent via at least one reducing agent supply unit (112) into the at least one mounting plate opening (129); and Flowing an exhaust gas through the exhaust duct (102), wherein the flow causes at least a portion of the exhaust gas to enter each fluid channel of the plurality of fluid channels, wherein the portion of the exhaust gas is divided into the at least one exhaust stream pair flowing through the fluid channel pair (124) of the plurality of fluid channels, wherein the plurality of fluid channels is configured to direct the at least one exhaust stream pair from inlets (122) of the fluid channel pair (124) of the plurality of fluid channels (124) to a corresponding mounting plate opening (129) such that exhaust streams of the at least one exhaust stream pair arrive at the corresponding mounting plate opening (129) from different directions, wherein the at least one exhaust stream pair is combined with the reductant before being supplied to the exhaust flow path. [23] The method of claim 22, wherein combining the exhaust gas streams creates a cross flow of the reductant into the exhaust gas flow path. [24] The method of claim 22 or 23, wherein the at least one mounting plate opening (129) comprises a plurality of mounting plate openings, and the plurality of mounting plate openings are arranged along a longitudinal axis of the mounting plate (120). [25] A method according to any one of claims 22 to 24, wherein the at least one exhaust gas stream pair comprises two exhaust gas streams. [26] A method according to any one of claims 22 to 25, wherein the different directions are opposite directions.

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