WO2014172866A1

WO2014172866A1 - Perforated tube exhaust mixing device

Info

Publication number: WO2014172866A1
Application number: PCT/CN2013/074701
Authority: WO
Inventors: Wei Mao; Jianqiang FAN; Feng Shen; Zhiguo ZHAO; Lin Zhou
Original assignee: Tenneco Automotive Operating Company Inc.
Priority date: 2013-04-25
Filing date: 2013-04-25
Publication date: 2014-10-30
Also published as: CN205025535U

Abstract

An exhaust after-treatment component for treating an exhaust stream produced by an engine. The component includes a housing having an inlet and an outlet, an exhaust treatment substrate provided within the housing between the inlet and the outlet, a dosing module for dosing an exhaust treatment fluid into the exhaust stream proximate the inlet, and a mixing assembly located within the housing between the dosing module and the exhaust treatment substrate. The mixing assembly includes an outer perforated pipe and an inner perforated pipe, wherein the inner perforated pipe is located within and co-axially aligned with the outer perforated pipe, and a plurality of first perforations of the inner perforated pipe are provided at a position that forces the exhaust stream to flow in a reverse direction before exiting the mixing assembly through a plurality of second perforations of the outer perforated pipe.

Description

PERFORATED TUBE EXHAUST MIXING DEVICE

FIELD

[0001 ] The present disclosure relates to an exhaust after-treatment system including an exhaust gas mixing device.

BACKGROUND

[0002] This section provides background information related to the present disclosure which is not necessarily prior art.

[0003] Exhaust after-treatment systems may dose a reagent exhaust treatment fluid into the exhaust stream before the exhaust stream passes through various exhaust after-treatment components. A urea exhaust treatment fluid, for example, may be dosed into the exhaust stream before the exhaust passes through a selective catalytic reduction (SCR) catalyst. The SCR catalyst is most effective, however, when the exhaust has sufficiently mixed with the urea exhaust treatment fluid.

SUMMARY

[0004] This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.

[0005] The present disclosure according to a first configuration provides an exhaust after-treatment component for treating an exhaust stream produced by an engine. The exhaust after-treatment component may include a housing having an inlet and an outlet; an exhaust treatment substrate may be provided within the housing between the inlet and the outlet; an exhaust treatment fluid port may be in communication with the exhaust stream and positioned proximate the inlet; and a mixing assembly may be located within the housing downstream of the port and upstream of the exhaust treatment substrate. The mixing assembly may include an outer perforated pipe, an inner perforated pipe, and an end cap coupled to first ends of the pipes, wherein the inner perforated pipe may be located within and co-axially aligned with the outer perforated pipe. The inner perforated pipe may include a plurality of first perforations to force the exhaust stream to flow in a reverse direction, and the outer perforated pipe may include a plurality of second perforations through which the exhaust flows after passing through the first perforations.

[0006] In the exhaust after-treatment component according to the first configuration, the first perforations may not axially overlap with the second perforations.

[0007] In the exhaust after-treatment component according to the first configuration, the first perforations may be formed over half of a circumference of the inner perforated pipe and face in a first direction, and the second perforations may be formed over half of a circumference of the outer perforated pipe and face in a second and opposite direction.

[0008] In the exhaust after-treatment component according to the first configuration, the inlet and mixing assembly may be arranged parallel with a longitudinal axis of the housing. [0009] In the exhaust after-treatment component according to the first configuration, the inlet and the mixing assembly may be arranged orthogonal to a longitudinal axis of the housing.

[0010] In the exhaust after-treatment component according to the first configuration, the mixing assembly may be fixedly coupled to the inlet.

[001 1 ] In the exhaust after-treatment component according to the first configuration, the end cap may have an axially-extending flange that couples to the first end of the outer perforated pipe.

[0012] In the exhaust after-treatment component according to the first configuration, the end of the outer perforated pipe may include a saw- toothed edge defined by a plurality of recesses, and the recesses may have a length greater than a length of the axially-extending flange to define a plurality of exit ports.

[0013] The present disclosure according to a second configuration provides an exhaust after-treatment system for treating an exhaust stream produced by an engine. The exhaust after-treatment system may include a housing for carrying the exhaust stream, a dosing port may extend through the housing for dosing an exhaust treatment fluid into the exhaust stream, and an exhaust treatment component may be positioned within the housing and located downstream from the dosing port. The exhaust treatment component may include at least one exhaust treatment substrate or filter located between an inlet and an outlet. A mixing assembly may be coupled to the inlet of the housing. The mixing assembly may include a first pipe including a plurality of first perforations about a circumference thereof, and may include a second pipe including a plurality of second perforations about a circumference thereof. The second pipe may be disposed within and co-axially aligned with the first pipe, and the second pipe may be coupled to the first pipe via a funnel-shaped collar. The first perforations may not axially overlap with the second perforations, and the mixing assembly is configured to receive the exhaust stream through the second pipe, direct the exhaust stream through the second perforations into the first pipe, reverse a flow of the exhaust stream toward the first perforations, and direct the exhaust stream through the first perforations into an interior of the housing.

[0014] In the exhaust after-treatment component according to the second configuration, the inlet and mixing assembly may be arranged parallel with a longitudinal axis of the housing.

[0015] In the exhaust after-treatment component according to the second configuration, the outlet may include a first end disposed within an interior of the housing, the first end may be supported by a perforated baffle, and the first end may include a plurality of third perforations.

[0016] In the exhaust after-treatment component according to the second configuration, the mixing assembly may include an end cap having an axially-extending flange that couples to an end of the first pipe.

[0017] In the exhaust after-treatment component according to the second configuration, the end of the first pipe may include a saw-toothed edge defined by a plurality of recesses, and the recesses may have a length greater than a length of the axially-extending flange to define a plurality of exit ports. [0018] The present disclosure according to a third configuration provides an exhaust after-treatment system for treating an exhaust stream produced by an engine. The exhaust after-treatment system may include a housing for carrying the exhaust stream, a dosing port may extend through the housing for dosing an exhaust treatment fluid into the exhaust stream, and an exhaust treatment component may be positioned within the housing and located downstream from the dosing port. The exhaust treatment component may include at least one exhaust treatment substrate or filter located between an inlet and an outlet. A mixing assembly may be coupled to the inlet. The mixing assembly may include a first pipe including a plurality of first perforations about half of a circumference thereof, and may include a second pipe including a plurality of second perforations about half of a circumference thereof. The second pipe may be disposed within and co-axially aligned with the first pipe, and the second pipe may be coupled to the first pipe via a funnel-shaped collar. The first perforations may face in a first direction and the second perforations may face in a second and opposite direction. The mixing assembly is configured to receive the exhaust stream through the second pipe, direct the exhaust stream through the second perforations into the first pipe, reverse a flow of the exhaust stream toward the first perforations, and direct the exhaust stream through the first perforations into an interior of the housing.

[0019] In the exhaust after-treatment component according to the third configuration, the inlet and mixing assembly may be arranged orthogonal to a longitudinal axis of the housing. [0020] In the exhaust after-treatment component according to the third configuration, the outlet may include a first end disposed within an interior of the housing, the first end may be supported by a perforated baffle, and the first end may include a plurality of third perforations.

[0021 ] In the exhaust after-treatment component according to the third configuration, the mixing assembly may include an end cap having an axially-extending flange that couples to an end of the first pipe.

[0022] In the exhaust after-treatment component according to the third configuration, the end of the first pipe may include a saw-toothed edge defined by a plurality of recesses, and the recesses may have a length greater than a length of the axially-extending flange to define a plurality of exit ports.

[0023] Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

DRAWINGS

[0024] The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.

[0025] Figure 1 schematically illustrates an exhaust system according to a principle of the present disclosure; [0026] Figure 2 is an inlet-side perspective view of an exhaust treatment component according to a first principle of the present disclosure;

[0027] Figure 3 is an outlet-side perspective view of the exhaust treatment component illustrated in Figure 2;

[0028] Figure 4 is a right-side perspective view of the exhaust treatment component illustrated in Figure 2;

[0029] Figure 5 is a left-side perspective view of the exhaust treatment component illustrated in Figure 2;

[0030] Figure 6 is an inlet-side exploded perspective view of the exhaust treatment component illustrated in Figure 2;

[0031 ] Figure 7 is an outlet-side exploded perspective view of the exhaust treatment component illustrated in Figure 2;

[0032] Figure 8 is an inlet-side front perspective view of the exhaust treatment component illustrated in Figure 2;

[0033] Figure 9 is a cross-sectional view of the exhaust treatment component taken along line 9-9 in Figure 8;

[0034] Figure 10 is an outlet-side cross-sectional perspective view of the exhaust treatment component illustrated in Figure 2;

[0035] Figure 1 1 is an inlet-side perspective view of an exhaust treatment component according to a second principle of the present disclosure;

[0036] Figure 12 is an outlet-side perspective view of the exhaust treatment component illustrated in Figure 1 1 ; [0037] Figure 13 is a right-side perspective view of the exhaust treatment component illustrated in Figure 1 1 ;

[0038] Figure 14 is a left-side perspective view of the exhaust treatment component illustrated in Figure 1 1 ;

[0039] Figure 15 is an inlet-side exploded perspective view of the exhaust treatment component illustrated in Figure 1 1 ;

[0040] Figure 16 is an outlet-side exploded perspective view of the exhaust treatment component illustrated in Figure 1 1 ;

[0041 ] Figure 17 is a cross-sectional view of the exhaust treatment component illustrated in Figure 1 1 ; and

[0042] Figure 18 is an outlet-side cross-sectional perspective view of the exhaust treatment component illustrated in Figure 1 1 .

[0043] Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.

DETAILED DESCRIPTION

[0044] Example embodiments will now be described more fully with reference to the accompanying drawings.

[0045] Figure 1 schematically illustrates an exhaust system 10 according to the present disclosure. Exhaust system 10 can include at least an engine 12 in communication with a fuel source (not shown) that, once consumed, will produce exhaust gases that are discharged into an exhaust passage 14 having an exhaust after-treatment system 16. Downstream from engine 12 can be disposed an exhaust treatment component 18, which can include a catalyst- coated substrate or filter 20. Catalyst-coated substrate or filter 20 can be a diesel oxidation catalyst (DOC), a diesel particulate filter (DPF) component or, as illustrated, a selective catalytic reduction (SCR) component. Although only a single catalyst-coated substrate or filter 20 is illustrated in Figure 1 , it should be understood that exhaust treatment component 18 may house a pair of catalyst- coated substrates or filters 20 and 21 (e.g., Figures 9 and 17). In this regard, any combination of the above-noted substrates or filters can be used. In addition, other substrates and filters include ammonia slip catalysts, lean NOx catalysts, and the like.

[0046] Although not required by the present disclosure, exhaust after- treatment system 16 can further include components such as a thermal enhancement device or burner 22 to increase a temperature of the exhaust gases passing through exhaust passage 14. Increasing the temperature of the exhaust gas is favorable to achieve light-off of the catalyst in the exhaust treatment component 18 in cold-weather conditions and upon start-up of engine 12, as well as initiate regeneration of the exhaust treatment component 18 when the exhaust treatment component 18 is a DPF.

[0047] To assist in reduction of the emissions produced by engine 12, exhaust after-treatment system 16 can include a dosing module 24 for periodically dosing an exhaust treatment fluid into the exhaust stream. As illustrated in Figure 1 , dosing module 24 can be located upstream of exhaust treatment component 18, and is operable to inject an exhaust treatment fluid into the exhaust stream. In this regard, dosing module 24 is in fluid communication with a reagent tank 26 and a pump 28 by way of inlet line 30 to dose an exhaust treatment fluid such as diesel fuel or urea into the exhaust passage 14 upstream of exhaust treatment component 18. Dosing module 24 can also be in communication with reagent tank 26 via return line 32. Return line 32 allows for any exhaust treatment fluid not dosed into the exhaust stream to be returned to reagent tank 26. Flow of the exhaust treatment fluid through inlet line 30, dosing module 24, and return line 32 also assists in cooling dosing module 24 so that dosing module 24 does not overheat. Although not illustrated in the drawings, dosing module 24 can be configured to include a cooling jacket that passes a coolant around dosing module 24 to cool it.

[0048] The amount of exhaust treatment fluid required to effectively treat the exhaust stream may vary with load, engine speed, exhaust gas temperature, exhaust gas flow, engine fuel injection timing, desired NO_x reduction, barometric pressure, relative humidity, EGR rate and engine coolant temperature. A NO_x sensor or meter 34 may be positioned downstream from exhaust treatment component 18. NO_x sensor 34 is operable to output a signal indicative of the exhaust NO_x content to an engine control unit 36. All or some of the engine operating parameters may be supplied from engine control unit 36 via the engine/vehicle databus to a reagent electronic dosing controller 38. The reagent electronic dosing controller 38 could also be included as part of the engine control unit 36. Exhaust gas temperature, exhaust gas flow and exhaust back pressure and other vehicle operating parameters may be measured by respective sensors, as indicated in Figure 1 .

[0049] The amount of exhaust treatment fluid required to effectively treat the exhaust stream can also be dependent on the size of the engine 12. In this regard, large-scale diesel engines used in locomotives, marine applications, and stationary applications can have exhaust flow rates that exceed the capacity of a single dosing module 24. Accordingly, although only a single dosing module 24 is illustrated for dosing exhaust treatment fluid, it should be understood that multiple dosing modules 24 for reagent injection are contemplated by the present disclosure.

[0050] To ensure proper mixing of the exhaust produced by engine 12 and the exhaust treatment fluid, the present disclosure provides an exhaust treatment component 18 having a mixing assembly 40 disposed therein. A first exemplary embodiment of exhaust treatment component 18 including mixing assembly 40 is illustrated in Figures 2-10. As best shown in Figures 2-5, 9, and 10, exhaust treatment component 18 includes a cylindrical inlet 42 and a cylindrical outlet 44 disposed on opposing ends of a cylindrical housing 46.

[0051 ] A first portion 48 of inlet 42 may include an attachment flange 50 for securing exhaust treatment component 18 to exhaust passage 14. A second portion 52 of inlet 42 can radially expand to provide a mounting surface 54 for dosing module 24 (not shown). Mounting surface 54 may define a circular aperture 56 that receives a mounting device 58 that supports dosing module 24 (not shown). An inlet sensor boss 60 may be disposed adjacent aperture 56 for receipt of a sensor (not shown) that may be, for example, a NOx sensor, a temperature sensor, a pressure sensor, ammonia sensor, or any other type of sensor known in the art of exhaust after-treatment.

[0052] Outlet 44 may include a first portion 62 disposed within an interior 64 of housing 46. A perforated baffle 66 may support first portion 62 within housing 46. Perforated baffle 66 can include an axially-extending flange 68 that may be welded, brazed, or secured to an inner surface 70 of housing 46 (Figure 9). A second portion 72 of outlet 44 extends from housing 46 and includes a terminal end 74 that is operable to be slip-fit with exhaust passage 14. A clamp (not shown) may secure second portion 72 to exhaust passage 14. An outlet sensor boss 76 for receipt of another sensor (not shown) may be located at second portion 72 of outlet 44. The sensor may be, for example, a NOx sensor, a temperature sensor, a pressure sensor, an ammonia sensor, or any other type of sensor known to one skilled in the art of exhaust after-treatment. First and second solid baffles 78 and 80 that are welded or brazed to housing 46 may be used to seal the opposing ends of housing 46.

[0053] It should be understood that although inlet 42 and outlet 44 are not illustrated as being axially aligned in Figure 9, the present disclosure contemplates a configuration where inlet 42 and outlet 44 are axially aligned. When inlet 42 and outlet 44 are not axially aligned, second baffle 80 may include an axially-extending bulge 82 that directs exhaust flow toward a plurality of perforations 84 that may be formed about an entire circumference of first portion 62 of outlet 44. In this regard, exhaust that does not directly enter outlet 44 may, at flared end 86, first pass through perforated baffle 66. After passing through perforated baffle 66, the exhaust can be directed by bulge 82 toward the perforations 84 formed in outlet 44 where the exhaust may then enter outlet 44 and exit exhaust treatment component 18.

[0054] Mixing assembly 40 inter-mixes exhaust produced by engine 12 and the reagent dosed into the exhaust by dosing module 24. To increase the amount of time that the exhaust and reagent may interact before reaching a catalyst-coated substrate such as SCR 20, mixing assembly 40 is designed to allow the mixture of exhaust and reagent to flow in a first direction and then reverse the mixture of exhaust reagent to a second direction before allowing the mixture to enter the interior 64 of housing 46 and reach catalyst-coated substrates or filters 20 and 21 . To reverse the flow direction of the mixture of exhaust and reagent, mixing assembly 40 may include a pair of co-axially aligned perforated pipes 88 and 90.

[0055] An outer perforated pipe 88 includes a first end 92 that receives second portion 52 of inlet 42. First end 92 of outer perforated pipe 88 may be located outside of housing 46, while first solid baffle 78 supports outer perforated pipe 88 at a location proximate first end 92. A second end 94 of outer perforated pipe 88 extends into housing 46. A third baffle 96 having a plurality of through- holes 98 formed therein is located proximate second end 94. Through-holes 98 of third baffle 96 are designed to allow exhaust to flow toward SCR 20 after exiting mixing assembly 40. [0056] A curved end cap 100 may be secured to second end 94 of outer perforated pipe 88. End cap 100 may be curved to force exhaust flow in a direction back toward inlet 42. End cap 100 may be secured to second end 94 in a manner (e.g., by welding or brazing) where second end 94 is completely sealed and the entire exhaust flow is forced to reverse direction toward inlet 42. Alternatively, as best illustrated in Figures 6, 7, and 10, second end 94 may include a saw-toothed edge 102. A plurality of recesses 104 form saw-toothed edge 102, and each recess 104 has a length that is greater than a length of an axially-extending flange 106 formed on end cap 100. Because each recess 104 has a length that is greater than the length of axially-extending flange 106, each recess 104 will not be completely covered by axially-extending flange 106 when end cap 100 is secured to second end 94, which results in the formation of an exit port 108 that allows a portion of the exhaust to leave mixing assembly 40 before being directed in a reverse direction back toward inlet 42. Such a configuration assists in preventing backpressures from developing in exhaust treatment component 18.

[0057] Mixing assembly 40 also includes an inner perforated pipe 90. Inner perforated pipe 90 has a diameter D2 that is less than a diameter D1 of outer perforated pipe 88 such that inner perforated pipe 90 may be located entirely within, and co-axially aligned with, outer perforated pipe 88. A collar 1 10 may be used to secure inner perforated pipe 90 within outer perforated pipe 88. Collar 1 10 can be secured to outer perforated pipe 88 at a location proximate first end 92. Collar 1 10 includes a first cylindrical surface 1 12 secured to first end 92 of outer perforated pipe 88, and a second cylindrical surface 1 14 secured to inner perforated pipe 90. Between first and second cylindrical surfaces 1 12 and 1 14 may be a radially-narrowing portion 1 16 that provides collar 1 10 with a funnel- shape. The velocity of the exhaust flow will tend to slow at a location where reagent is dosed into the exhaust stream because inlet 42 radially expands to provide mounting surface 54. To offset the decrease in velocity, the funnel- shape of collar 1 10 assists increasing the velocity of the exhaust flow as it enters inner perforated pipe 90. The increase in velocity also assists in inter-mixing the reagent and exhaust.

[0058] Inner perforated pipe 90 includes a free end 1 18 located proximate end cap 100. Free end 1 18 may abut end cap 100, or may be spaced apart from end cap 100. If free end 1 18 abuts end cap 100, free end 1 18 can be formed to have a saw-toothed configuration like outer perforated pipe 88 to assist in alleviating back pressure in mixing assembly 40. Inner perforated pipe 90 may include a plurality of perforations 120 at a location proximate free end 1 18. Perforations 120 can be formed about an entire circumference of inner perforated pipe 90.

[0059] As exhaust enters inlet 42, the reagent exhaust treatment fluid will be dosed into the exhaust stream by dosing module 24. After the exhaust treatment fluid is dosed into the exhaust, the mixture of exhaust and exhaust treatment fluid will pass through collar 1 10 and into inner perforated pipe 90 where a flow rate of the mixture may increase. At a position proximate free end 1 18, the mixture may exit inner perforated pipe 90 through perforations 120 and enter outer perforated pipe 88. Due to the curved surface of end cap 100, the mixture may be forced to reverse direction back toward inlet 42 while in outer perforated pipe 88. As the mixture travels back toward inlet 42, the mixture will then be able to exit outer perforated pipe 88 through a plurality of perforations 122 and enter interior 64 of exhaust treatment component 18. Perforations 122 can be formed about an entire circumference of outer perforated pipe 88. The mixture may then pass through through-holes 98 of third baffle 96 toward catalyst-coated substrates or filters 20 and 21 . After passing through substrates 20 and 21 , the treated exhaust may directly enter outlet 44, or enter outlet 44 after passing through perforated baffle 66 and perforations 84. The exhaust may then exit exhaust treatment component 18 through outlet 44.

[0060] It should be understood that perforations 120 of inner perforated pipe 90 do not axially overlap with perforations 122 of outer perforated pipe 88. Rather, the exhaust mixture is required to flow through inner perforated pipe 90 and then reverse direction before exiting outer perforated pipe 88. By causing the exhaust mixture to reverse direction, the exhaust and reagent exhaust treatment fluid can inter-mix to a greater degree. Further, such a configuration allows for a smaller and more compact exhaust treatment component because the co-axially aligned inner and outer perforated pipes 88 and 90 allow for flow path having an increased length.

[0061 ] A second exemplary embodiment according to the present disclosure will now be described. The second exemplary embodiment is similar to the first exemplary embodiment. Accordingly, description of features that are common between each embodiment will be omitted. Referring to Figures 1 1 -18, an exhaust treatment component 124 is illustrated. The primary difference between exhaust treatment component 124 and exhaust treatment component 18 is that inlet 42 of exhaust treatment component 124 is arranged orthogonal to a longitudinal axis A of housing 126. To account for inlet 42 being arranged orthogonal to longitudinal axis A of housing 126, housing 126 may be provided with an annular flange 128 that receives second portion 52 of inlet 42. Inlet 42 can be secured to annular flange 128 by any attachment method known to one skilled in the art, including welding, brazing, and the like. Because inlet 42 and outlet 44 are no longer located at opposing ends of housing 126, a housing cap 130 may be used to seal housing 126 (via, e.g., welding, brazing, or the like) at the end opposite to where outlet 44 is located.

[0062] Exhaust treatment component 124 includes a mixing assembly 132 located adjacent inlet 42. Mixing assembly 132 inter-mixes exhaust produced by engine 12 and the reagent dosed into the exhaust by dosing module 24. To increase the amount of time that the exhaust and reagent may interact before reaching a catalyst-coated substrate such as SCR 20, mixing assembly 132 is designed to allow the mixture of exhaust and reagent to flow in a first direction and then reverse the mixture of exhaust and reagent to a second direction before allowing the mixture to enter the interior 64 of housing 126 and reach catalyst-coated substrates or filters 20 and 21 . To change the flow direction of the mixture of exhaust and reagent, similar to the first embodiment, mixing assembly 132 may include a pair of co-axially aligned perforated pipes 134 and 136.

[0063] An outer perforated pipe 134 includes a first end 138 that receives second portion 52 of inlet 42. A curved end cap 140 may be secured to second end 142 of outer perforated pipe 134. Although end cap 140 is illustrated as being curved, it should be understood that end cap 140 may be planar without departing from the scope of the present disclosure. End cap 140 may be secured to second end 142 in a manner (e.g., by welding or brazing) where second end 142 is completely sealed and the entire exhaust flow is forced to reverse direction toward inlet 42. Alternatively, as best illustrated in Figures 15- 18, second end 142 may include a saw-toothed edge 102. A plurality of recesses 104 form saw-toothed edge 102, and each recess 104 has a length that is greater than a length of an axially-extending flange 106 formed on end cap 140. Because each recess 104 has a length that is greater than the length of axially- extending flange 106, each recess 104 will not be completely covered by axially- extending flange 106 when end cap 140 is secured to second end 142, which results in the formation of an exit port 108 that allows a portion of the exhaust to leave mixing assembly 132 before passing through a plurality of perforations 144 formed in outer perforated pipe 134. Such a configuration assists in preventing backpressures from developing in exhaust treatment component 124.

[0064] Mixing assembly 132 also includes an inner perforated pipe 136. Inner perforated pipe 136 has a diameter D2 that is less than a diameter D1 of outer perforated pipe 134 such that inner perforated pipe 136 may be located entirely within, and co-axially aligned with, outer perforated pipe 134. A funnel shaped collar 1 10 may be used to secure inner perforated pipe 136 within outer perforated pipe 134.

[0065] Inner perforated pipe 136 includes a free end 1 18 located proximate end cap 140. Free end 1 18 may abut end cap 140 or, as illustrated in Figures 17 and 18, may pass through end cap 140 such that free end 1 18 may be spaced apart from end cap 140. Free end 1 18 can be formed to have a saw- toothed configuration including teeth 146 that correspond to and pass through elongate apertures 148 formed in end cap 140. Due to the corresponding arrangement between teeth 146 and elongate apertures 148 of end cap 140, inner perforated pipe 136 is not required to be fixedly secured to end cap 140. Rather, end cap 140 may be fixedly secured to outer perforated pipe 134. Inner perforated pipe 136 may include a plurality of perforations 150 that allow the mixture of exhaust and reagent exhaust treatment fluid to exit inner perforated pipe 136 and enter outer perforated pipe 134.

[0066] It should be understood that perforations 150 of inner perforated pipe 136 can be formed along substantially the entire length of inner perforated pipe 136, but are only formed about half of a circumference of the inner perforated pipe 136. In this manner, the exhaust mixture can only exit inner perforated pipe 136 in a first direction. Similar to inner perforated pipe 136, perforations 144 of outer perforated pipe 134 are also formed along substantially an entire length thereof, and only about half of a circumference of the outer perforated pipe 134. The portion of the circumference of outer perforated pipe 134 that includes perforations 144, however, should face a direction that is opposite to that of perforations 150 of inner perforated pipe 136.

[0067] For example, referring to Figure 17, it can be seen that perforations 150 of inner perforated pipe 136 face toward outlet 44, while perforations 144 of outer perforated pipe 134 face toward housing cap 130. In this manner, the exhaust mixture can only exit outer perforated pipe 134 in a second direction that is opposite the first direction in which perforations 150 face. Such an orientation requires a reversing of flow through mixing assembly 132 that can inter-mix the exhaust and reagent exhaust treatment fluid to a greater degree. Further, such a configuration allows for a smaller and more compact exhaust treatment component because the co-axially aligned inner and outer pipes 134 and 136 allow for flow path having an increased length.

[0068] As exhaust enters inlet 42, the reagent exhaust treatment fluid will be dosed into the exhaust stream by dosing module 24. After the exhaust treatment fluid is dosed into the exhaust, the mixture of exhaust and exhaust treatment fluid will pass through collar 1 10 and into inner perforated pipe 136 where a flow rate of the mixture may increase. At a position proximate free end 1 18, the mixture may exit inner perforated pipe 136 through perforations 150 in the first direction toward outlet 44, and enter outer perforated pipe 134. After entering outer perforated pipe 134, the flow is required to reverse toward perforations 144 where the exhaust mixture may then exit outer perforated pipe 134 and enter interior 64 of housing 126. The mixture may then pass through catalyst-coated substrates or filters 20 and 21 . After passing through substrates 20 and 21 , the treated exhaust may directly enter outlet 44, or enter outlet 44 after passing through perforated baffle 66 and perforations 84. The exhaust may then exit exhaust treatment component 124 through outlet 44.

[0069] The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.

Claims

CLAIMS What is claimed is:

1 . An exhaust after-treatment component for treating an exhaust stream produced by an engine, comprising:

a housing having an inlet and an outlet;

an exhaust treatment substrate provided within the housing between the inlet and the outlet;

an exhaust treatment fluid port in communication with the exhaust stream and positioned proximate the inlet; and

a mixing assembly located within the housing downstream of the port and upstream of the exhaust treatment substrate, the mixing assembly including an outer perforated pipe, an inner perforated pipe, and an end cap coupled to first ends of the pipes,

wherein the inner perforated pipe is located within and co-axially aligned with the outer perforated pipe, the inner perforated pipe including a plurality of first perforations to force the exhaust stream to flow in a reverse direction, and the outer perforated pipe includes a plurality of second perforations through which the exhaust flows after passing through the first perforations.

2. The exhaust after-treatment component of Claim 1 , wherein the first perforations do not axially overlap with the second perforations.

3. The exhaust after-treatment component of Claim 1 , wherein the first perforations are formed over half of a circumference of the inner perforated pipe and face in a first direction, and the second perforations are formed over half of a circumference of the outer perforated pipe and face in a second and opposite direction.

4. The exhaust after-treatment component of Claim 2, wherein the inlet and mixing assembly are arranged parallel with a longitudinal axis of the housing.

5. The exhaust after-treatment component of Claim 3, wherein the inlet and the mixing assembly are arranged orthogonal to a longitudinal axis of the housing.

6. The exhaust after-treatment component of Claim 1 , wherein the mixing assembly is fixedly coupled to the inlet.

7. The exhaust after-treatment component of Claim 1 , wherein the end cap includes an axially-extending flange that couples to the first end of the outer perforated pipe.

8. The exhaust after-treatment component of Claim 7, wherein the end of the outer perforated pipe includes a saw-toothed edge defined by a plurality of recesses, the recesses having a length greater than a length of the axially-extending flange to define a plurality of exit ports.

9. An exhaust after-treatment system for treating an exhaust stream produced by an engine, comprising:

a housing for carrying the exhaust stream;

a dosing port extending through the housing for dosing an exhaust treatment fluid into the exhaust stream;

an exhaust treatment component positioned downstream within the housing and located downstream from the dosing port, the exhaust treatment component including at least one exhaust treatment substrate or filter located between an inlet and an outlet of the housing; and

a mixing assembly coupled to the inlet, the mixing assembly including a first pipe including a plurality of first perforations about a circumference thereof, and including a second pipe including a plurality of second perforations about a circumference thereof, the second pipe being disposed within and co-axially aligned with the first pipe, and the second pipe being coupled to the first pipe via a funnel-shaped collar,

wherein the first perforations do not axially overlap with the second perforations, and the mixing assembly is configured to receive the exhaust stream through the second pipe, direct the exhaust stream through the second perforations into the first pipe, reverse a flow of the exhaust stream toward the first perforations, and direct the exhaust stream through the first perforations into an interior of the housing.

10. The exhaust after-treatment system of Claim 9, wherein the inlet and mixing assembly are arranged parallel with a longitudinal axis of the housing.

1 1 . The exhaust after-treatment system of Claim 9, wherein the outlet includes a first end disposed within an interior of the housing, the first end is supported by a perforated baffle, and the first end includes a plurality of third perforations.

12. The exhaust after-treatment component of Claim 9, wherein the mixing assembly includes an end cap having an axially-extending flange that couples to an end of the first pipe.

13. The exhaust after-treatment component of Claim 12, wherein the end of the first pipe includes a saw-toothed edge defined by a plurality of recesses, the recesses having a length greater than a length of the axially- extending flange to define a plurality of exit ports.

14. An exhaust after-treatment system for treating an exhaust stream produced by an engine, comprising:

a housing for carrying the exhaust stream;

an exhaust treatment component positioned within the housing and located downstream from the dosing port, the exhaust treatment component including at least one exhaust treatment substrate or filter located between an inlet and an outlet of the housing; and

a mixing assembly coupled to the inlet, the mixing assembly including a first pipe including a plurality of first perforations about half of a circumference thereof, and including a second pipe including a plurality of second perforations about half of a circumference thereof, the second pipe being disposed within and co-axially aligned with the first pipe, and the second pipe being coupled to the first pipe via a funnel-shaped collar,

wherein the first perforations face in a first direction and the second perforations face in a second and opposite direction, and

the mixing assembly is configured to receive the exhaust stream through the second pipe, direct the exhaust stream through the second perforations into the first pipe, reverse a flow of the exhaust stream toward the first perforations, and direct the exhaust stream through the first perforations into an interior of the housing.

15. The exhaust after-treatment system of Claim 14, wherein the inlet and mixing assembly are arranged orthogonal to a longitudinal axis of the housing.

16. The exhaust after-treatment system of Claim 14, wherein the outlet includes a first end disposed within an interior of the housing, the first end is supported by a perforated baffle, and the first end includes a plurality of third perforations.

17. The exhaust after-treatment component of Claim 14, wherein the mixing assembly includes an end cap having an axially-extending flange that couples to an end of the first pipe.

18. The exhaust after-treatment component of Claim 17, wherein the end of the first pipe includes a saw-toothed edge defined by a plurality of recesses, the recesses having a length greater than a length of the axially- extending flange to define a plurality of exit ports.