Patent Publication Number: US-2015071826-A1

Title: Axial flow atomization module with mixing device

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part of U.S. patent application Ser. No. 14/165,923 filed Jan. 28, 2014, which is a continuation-in-part of U.S. patent application Ser. No. 13/958,955 filed Aug. 5, 2013, which is a continuation-in-part of U.S. patent application Ser. No. 13/888,861 filed May 7, 2013. The entire disclosure of each of the above applications is incorporated herein by reference. 
    
    
     FIELD 
     The present disclosure relates to an exhaust after-treatment system including an exhaust gas mixing device. 
     BACKGROUND 
     This section provides background information related to the present disclosure which is not necessarily prior art. 
     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 
     This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features. 
     The present disclosure provides an engine exhaust after-treatment system including an exhaust conduit for carrying an engine exhaust; a dosing module for dosing the engine exhaust with a reagent exhaust treatment fluid, the dosing module dispersing the reagent exhaust treatment fluid into plurality of conical spray paths; and a mixing device positioned in the exhaust conduit downstream from the dosing module for intermixing the reagent exhaust treatment fluid and the engine exhaust, the mixing device including a plurality of mixing blades in a number that is equal to a number of the conical spray paths, wherein the mixing device is oriented in the exhaust conduit based on an orientation of each of the conical spray paths. 
     The present disclosure also provides an exhaust treatment component for treating an engine exhaust, including a housing including an inlet and an outlet; a dosing module coupled to the housing for dosing the engine exhaust with a reagent exhaust treatment fluid, the dosing module dispersing the reagent exhaust treatment fluid into plurality of conical spray paths; and a mixing assembly located within the housing downstream from the dosing module. The mixing assembly includes a decomposition tube having a first end and a second end, the first end being configured to receive the exhaust from the inlet and being configured to receive the reagent exhaust treatment fluid from the dosing module; a static mixer positioned within the decomposition tube between the first end and the second end; and a flow reversing device disposed proximate the second end, the flow reversing device configured to direct a mixture of the exhaust and reagent exhaust treatment fluid as the mixture exits the second end of the decomposition tube in a direction back toward the first end, wherein the static mixer includes a plurality of mixing blades in a number that is equal to a number of the conical spray paths, and the static mixer is oriented in the decomposition tube based on an orientation of each of the conical spray paths. 
     The present disclosure also provides an exhaust treatment system for treating an exhaust produced by an engine, including a first exhaust treatment component; a second exhaust treatment component; a common hood that fluidly and mechanically connects the first and second exhaust treatment components; a dosing module mounted to the common hood at a position downstream from the first exhaust treatment component, the dosing module operable to dose the exhaust with a reagent exhaust treatment fluid, and the dosing module dispersing the reagent exhaust treatment fluid into plurality of conical spray paths; and a mixing assembly located within the housing and positioned downstream from the dosing module. 
     The mixing device includes a decomposition tube having a first end and a second end, the first end being configured to receive the exhaust from the common hood and being configured to receive the reagent exhaust treatment fluid; a static mixer positioned within the decomposition tube between the first end and the second end; and a flow reversing device disposed proximate the second end, the flow reversing device configured to direct a mixture of the exhaust and reagent exhaust treatment fluid as the mixture exits the second end of the decomposition tube in a direction back toward the first end, wherein the static mixer includes a plurality of mixing blades in a number that is equal to a number of the conical spray paths, and the static mixer is oriented in the decomposition tube based on an orientation of each of the conical spray paths. 
     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 
       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. 
         FIG. 1  is a schematic representation of an exhaust system according to a principle of the present disclosure; 
         FIG. 2  is a perspective view of an exhaust treatment component according to a principle of the present disclosure; 
         FIG. 3  is a side-perspective view of the exhaust treatment component illustrated in  FIG. 2 ; 
         FIG. 4  is a front-perspective view of the exhaust treatment component illustrated in  FIG. 2 ; 
         FIG. 5  is a cross-sectional view along line  5 - 5  in  FIG. 4 ; 
         FIG. 6  is a cross-sectional view along line  6 - 6  in  FIG. 4 ; 
         FIG. 7  is a perspective view of a mixing assembly according to a first exemplary embodiment of the present disclosure; 
         FIG. 8  is an exploded perspective view of the mixing assembly illustrated in  FIG. 7 ; 
         FIG. 9  is a cross-sectional view of the mixing assembly illustrated in  FIG. 7 ; 
         FIG. 10  is a perspective view of a mixing assembly according to a second exemplary embodiment of the present disclosure; 
         FIG. 11  is a perspective view of a flow-reversing device and dispersion device of the mixing assembly illustrated in  FIG. 10 ; 
         FIG. 12  is a perspective view of the dispersion device illustrated in  FIG. 11  in an assembled state; 
         FIG. 13  is another perspective view of the dispersion device illustrated in  FIG. 11  in an un-assembled state; 
         FIG. 14  is a perspective view of a mixing assembly according to a third exemplary embodiment of the present disclosure; 
         FIG. 15  is a perspective view of a flow-reversing device and dispersion device of the mixing assembly illustrated in  FIG. 14 ; 
         FIG. 16  is a perspective view of the dispersion device illustrated in  FIG. 15 ; 
         FIG. 17  is a perspective view of a mixing assembly according to a fourth exemplary embodiment of the present disclosure; 
         FIG. 18  is a partial-perspective view of the mixing assembly illustrated in  FIG. 17 ; 
         FIG. 19  is a perspective cross-sectional view of  FIG. 17 ; 
         FIG. 20  is a perspective view of a mixing assembly according to a fifth exemplary embodiment of the present disclosure; 
         FIG. 21  is an exploded perspective view of the mixing assembly illustrated in  FIG. 10 ; 
         FIG. 22  is a perspective view of an exhaust treatment component according to a principle of the present disclosure; 
         FIG. 23  is a cross-sectional view of the exhaust treatment component illustrated in  FIG. 22 ; 
         FIG. 24  is a perspective view of an exhaust after-treatment system according to a principle of the present disclosure; 
         FIG. 25  is a perspective view of an exhaust treatment component that forms part of the exhaust after-treatment system illustrated in  FIG. 24 ; 
         FIG. 26  is another perspective view of the exhaust treatment component illustrated in  FIG. 25 ; 
         FIG. 27  is a top-perspective view of the exhaust treatment component illustrated in  FIG. 25 ; 
         FIG. 28  is a side-perspective view of the exhaust treatment component illustrated in  FIG. 25 ; 
         FIG. 29  is a cross-sectional perspective view of the exhaust treatment component illustrated in  FIG. 25 ; 
         FIG. 30  is a cross-sectional view of the exhaust treatment component illustrated in  FIG. 25 ; 
         FIG. 31  is a side-perspective view of an exhaust treatment component according to a principle of the present disclosure; 
         FIG. 32  is a cross-sectional view of the exhaust treatment component illustrated in  FIG. 31 ; 
         FIG. 33  is a cross-sectional view of a mixing assembly according to a principle of the present disclosure; 
         FIG. 34  is a perspective partial cross-sectional view of an exhaust treatment system according to a principle of the present disclosure; 
         FIG. 35  is a perspective view of a mixing assembly according to a principle of the present disclosure; 
         FIG. 36  is a perspective view of a mixing assembly according to a principle of the present disclosure; 
         FIG. 37  is a perspective cross-sectional view of a mixing assembly according to a principle of the present disclosure; 
         FIG. 38  is a perspective partial cross-sectional view of an exhaust treatment system according to a principle of the present disclosure; 
         FIG. 39  is a side-perspective view of a mixing assembly according to a principle of the present disclosure; 
         FIG. 40  is a cross-sectional view of the mixing assembly illustrated in  FIG. 39 ; 
         FIG. 41  is a perspective view of a mixing assembly according to a principle of the present disclosure; 
         FIG. 42  is a bottom perspective view of the mixing assembly illustrated in  FIG. 41 ; 
         FIG. 43  is a is a perspective view of a mixing assembly according to a principle of the present disclosure; 
         FIG. 44  is a perspective view of a flow-reversing device according to a principle of the present disclosure; 
         FIG. 45  illustrates an exhaust treatment component according to a principle of the present disclosure; 
         FIGS. 45A and 45B  each illustrate an injector mount according to a principle of the present disclosure; 
         FIG. 46  illustrates an exhaust treatment component according to a principle of the present disclosure; 
         FIG. 47  illustrates an exhaust treatment component according to a principle of the present disclosure; 
         FIG. 48  is a perspective partial cross-sectional view of an exhaust treatment system according to a principle of the present disclosure; 
         FIG. 49  is a perspective partial cross-sectional view of an exhaust treatment system according to a principle of the present disclosure; 
         FIG. 50  is a perspective view of a perforated swirl device according to a principle of the present disclosure; 
         FIG. 51  is another perspective view of a perforated swirl device according to a principle of the present disclosure; 
         FIG. 52  is a perspective view of another perforated swirl device according to a principle of the present disclosure; 
         FIG. 53  is a perspective view of another perforated swirl device according to a principle of the present disclosure; 
         FIG. 54  is a perspective view of another perforated swirl device according to a principle of the present disclosure 
         FIG. 55  is a partial perspective view of an exhaust treatment device according to a principle of the present disclosure; 
         FIG. 56  is a perspective view of a flow reversing device according to a principle of the present disclosure; 
         FIG. 57  is a partial perspective view of an exhaust treatment device according to a principle of the present disclosure; 
         FIG. 58  is a perspective view of an exhaust treatment device according to a principle of the present disclosure; 
         FIG. 59  is a cross-sectional view of an exhaust treatment device according to a principle of the present disclosure; 
         FIG. 60  is a perspective partial cross-sectional view of an exhaust treatment device according to a principle of the present disclosure; 
         FIG. 60A  is a sectional view of an exhaust treatment component according to a principle of the present disclosure; 
         FIG. 61  is a perspective view of a mixing assembly according to a principle of the present disclosure; 
         FIG. 62  is a perspective view of a mixing assembly according to a principle of the present disclosure; 
         FIG. 63  is a perspective view of a decomposition tube according to a principle of the present disclosure; and 
         FIG. 64  is a perspective view of another decomposition tube according a principle of the present disclosure. 
     
    
    
     Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings. 
     DETAILED DESCRIPTION 
     Example embodiments will now be described more fully with reference to the accompanying drawings. 
       FIG. 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 a pair of exhaust treatment components  18  and  20 , which can include catalyst-coated substrates or filters  22  and  24 . Catalyst-coated substrates or filters  22  and  24  can be any combination of a diesel particulate filter (DPF), a diesel oxidation catalyst (DOC), a selective catalytic reduction (SCR) component, a lean NO x  catalyst, an ammonia slip catalyst, or any other type of exhaust treatment device known to one skilled in the art. If a DPF is used, it may be catalyst-coated. 
     Although not required by the present disclosure, exhaust after-treatment system  16  can further include components such as a thermal enhancement device or burner  26  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 substrate  22  or  24  is a DPF. 
     To assist in reduction of the emissions produced by engine  12 , exhaust after-treatment system  16  can include a dosing module  28  for periodically dosing an exhaust treatment fluid into the exhaust stream. As illustrated in  FIG. 1 , dosing module  28  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  28  is in fluid communication with a reagent tank  30  and a pump  32  by way of inlet line  34  to dose an exhaust treatment fluid such as diesel fuel or urea into the exhaust passage  14  upstream of exhaust treatment components  18  and  20 . Dosing module  28  can also be in communication with reagent tank  30  via return line  36 . Return line  36  allows for any exhaust treatment fluid not dosed into the exhaust stream to be returned to reagent tank  30 . Flow of the exhaust treatment fluid through inlet line  34 , dosing module  28 , and return line  36  also assists in cooling dosing module  28  so that dosing module  28  does not overheat. Although not illustrated in the drawings, dosing module  28  can be configured to include a cooling jacket that passes a coolant around dosing module  28  to cool it. 
     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  38  may be positioned downstream from exhaust treatment component  18 . NO x  sensor  38  is operable to output a signal indicative of the exhaust NO x  content to an engine control unit  40 . All or some of the engine operating parameters may be supplied from engine control unit  40  via the engine/vehicle databus to a reagent electronic dosing controller  42 . The reagent electronic dosing controller  42  could also be included as part of the engine control unit  40 . Exhaust gas temperature, exhaust gas flow and exhaust back pressure and other vehicle operating parameters may be measured by respective sensors, as indicated in  FIG. 1 . 
     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  28 . Accordingly, although only a single dosing module  28  is illustrated for dosing exhaust treatment fluid, it should be understood that multiple dosing modules  28  for reagent injection are contemplated by the present disclosure. 
     Referring to  FIGS. 2-6 , an exemplary configuration of exhaust treatment components  18  and  20  is illustrated. As best shown in  FIG. 2 , exhaust treatment components  18  and  20  are arranged parallel to one another. It should be understood, however, that exhaust treatment components  18  and  20  can be arranged substantially co-axially, without departing from the scope of the present disclosure. 
     Exhaust treatment component  18  may include a housing  44 , an inlet  46 , and an outlet  48 . Inlet  46  may be in communication with exhaust passage  14 , and outlet  48  may be in communication with exhaust treatment component  20 . Although outlet  48  is illustrated as being directly connected to exhaust treatment component  20 , it should be understood that an additional conduit (not shown) may be positioned between outlet  48  and exhaust treatment component  20 . The additional conduit can be non-linear such that the flow of exhaust through the conduit must turn before entering exhaust treatment component  20 . Housing  44  can be cylindrically-shaped and may include a first section  50  supporting a DOC  52 , and a second section  54  supporting DPF  56 . Although DOC  52  is illustrated as being upstream of DPF  56 , it should be understood that DPF  56  can be positioned upstream of DOC  52  without departing from the scope of the present disclosure. Opposing ends of housing  44  can include end caps  58  and  60  to hermetically seal housing  44 . End caps  58  and  60  can be slip-fit and welded to first and second sections  50  and  54 , respectively. First and second sections  50  and  54  may be secured by clamps  62 . The use of clamps  62  allows for easy removal of DOC  52  or DPF  56  for maintenance, cleaning, or replacement of these components. Exhaust from exhaust passage  14  will enter inlet  46 , pass through DOC  52  and DPF  56 , and exit outlet  48  before entering exhaust treatment component  20 . 
     Exhaust treatment component  20  is substantially similar to exhaust treatment component  18 . In this regard, exhaust treatment component  20  may include a housing  64 , an inlet  66 , and an outlet  68 . Inlet  66  communicates with outlet  48  of exhaust treatment component  18 , and outlet  68  may be in communication with a downstream section of exhaust passage  14 . 
     Housing  64  can be cylindrically-shaped and may support an SCR  70  and ammonia slip catalyst  72 . SCR is preferably located upstream of ammonia slip catalyst  72 . Opposing ends of housing  64  can include end caps  74  and  76  to hermetically seal housing  64 . End caps  74  and  76  can be slip-fit and welded to housing  64 . Alternatively, end caps  74  and  76  can be secured to housing  64  by clamps (not shown). Exhaust from outlet  48  of exhaust treatment component  18  will enter inlet  66 , pass through SCR  70  and ammonia slip catalyst  72 , and exit outlet  68  before entering the downstream section of exhaust passage  14 . 
     Dosing module  28  may be positioned on end cap  74  at a location proximate inlet  66 . Dosing module  28  is operable to inject a reductant such as a urea exhaust treatment fluid into the exhaust stream before the exhaust stream passes through SCR  70 . A sufficient intermingling of the exhaust and exhaust treatment fluid should occur to optimize the removal of NO x  from the exhaust stream during as the mixture passes through SCR  70 . To assist in intermingling of the exhaust stream and the urea exhaust treatment fluid, a mixing assembly  80  may be positioned downstream from inlet  66  and upstream of SCR  70 . Mixing assembly  80  is positioned proximate dosing module  28  such that dosing module  28  may dose the urea exhaust treatment fluid directly into mixing assembly  80  where it may intermingle with the exhaust stream. 
       FIGS. 7-9  illustrate a first exemplary embodiment of mixing assembly  80 . Mixing assembly  80  includes a decomposition tube  82  including a first end portion  84  that may be secured to end cap  74  and a second end portion  86  that is positioned proximate SCR  70 . Decomposition tube  82  may be substantially cylindrical, with a radially expanded portion  88  positioned between the first and second end portions  84  and  86 . Radially expanded portion  88  includes a conically-expanding portion  90  that expands the decomposition tube  82 , a cylindrical portion  92  downstream from the conically-expanding portion  90  having a diameter that is greater than that of first and second end portions  84  and  86 , and a conically-narrowing portion  94  that narrows decomposition tube  82 . It should be understood that first and second end portions  84  and  86  may have different diameters, without departing from the scope of the present disclosure. It should also be understood that the present disclosure does not require conically-narrowing portion  94 . That is, radially expanded portion  88  may extend over the entire length of second end portion  86 . 
     First end portion  84  may be perforated such that first end portion  84  includes a plurality of first perforations  96 . First perforations  96  can vary in size around the circumference of first end portion  84 , and assist in creating turbulence and increasing a velocity of the exhaust stream as it enters decomposition tube  82 . Although not required by the present disclosure, a perforated collar  98  including a plurality of second perforations formed as elongate slots  100  may be positioned around and secured to first end portion  84 . Perforated collar  98  includes a cylindrical portion  102  having a diameter greater than that of first end portion  84 . Cylindrical portion  102  radially narrows into an axially-extending flange  104  that may be fixedly coupled to decomposition tube  82  at a position proximate radially expanded portion  88  by welding, brazing, or any other secure attachment method known to one skilled in the art. 
     Elongate slots  100  may be dimensioned larger than first perforations  96 . Elongate slots  100  can be oriented in various directions including directions parallel with an axis of decomposition tube  82 , and directions arranged orthogonal to the axis of decomposition tube  82 . It should be understood, however, that each elongate slot  100  can be oriented in the same direction without departing from the scope of the present disclosure. Similar to first perforations  96 , elongate slots  100  assist in creating turbulence and increasing a velocity of the exhaust stream as it enters decomposition tube  82 . 
     Mixing assembly  80  includes a flow reversing device  106  at second end portion  86 . Flow reversing device  106  may be fixed to second end portion  86 , or may be supported by a baffle (not shown) that secures flow reversing device  106  to end cap  74  at a position proximate terminal edge  108  of second end portion  86 . Flow reversing device  106  is a substantially cup-shaped member  110  having a central bulge  112  formed therein. Flow reversing device  106  has a diameter greater than that of second end portion  86  of decomposition tube  82  such that as the exhaust flow enters the cup-shaped member  110 , the exhaust flow will be forced to flow in a reverse direction back toward inlet  66  of housing  64 . The reversing of the exhaust flow assists in intermingling of the reagent exhaust treatment fluid and the exhaust stream before the exhaust stream reaches SCR  70 . 
     Flow reversing device  106  may include a plurality of deflecting members  114  to further assist in intermingling the reagent exhaust treatment fluid and the exhaust stream. Deflecting members  114  may be formed as a plurality of vanes that extend radially inward from an inner surface  116  of outer wall  118  of flow reversing device  106 . In addition to extending radially inward, vanes  114  may also be angled relative to an axis of decomposition tube  82  to further direct the exhaust flow as it exits flow reversing device  106 . Vanes  114  may be planar members, or may be slightly curved. Although vanes  114  are illustrated as being secured to inner surface  116  of flow-reversing device  106 , it should be understood that vanes  114  may be secured to second end portion  86  of decomposition tube  82 . 
     As illustrated in  FIG. 6 , mixing assembly  80  may be arranged in a direction orthogonal to an axis of inlet  66 . The exhaust stream, therefore, will enter mixing assembly  80  orthogonally before being directed toward SCR  70 . As the exhaust stream enters first end  84  of decomposition tube  82 , a velocity of the exhaust stream may increase and the flow of the exhaust stream will become tortuous due to first and second perforations  96  and  100 . As the exhaust enters radially expanded portion  88 , the flow may tend to stay along the axis of the decomposition tube  82 . Although the velocity of the exhaust stream may slow, the velocity only slows to a minimal extent that ensures satisfactory intermingling of the exhaust and reagent exhaust treatment fluid. In this regard, radially expanded portion  88  diffuses the turbulence in the exhaust flow created by perforations  96  and  100 , which aids in minimizing any potential loss in velocity. Table 1, below, summarizes the peak velocity of the exhaust stream at various regions within exhaust treatment component  20 . 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                 Region 
                 Peak Velocity (m/S) 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                   
                 A 
                 84 
               
               
                   
                 B 
                 120 
               
               
                   
                 C 
                 102 
               
               
                   
                 D 
                 102 
               
               
                   
                 E 
                 120 
               
               
                   
                 F 
                 120 
               
               
                   
                 G 
                 25 
               
               
                   
                   
               
            
           
         
       
     
     As can be seen in Table 1 and  FIG. 6 , as the exhaust stream enters from inlet  66 , the exhaust may have a peak velocity of 84 m/s (Region A). As the exhaust enters mixing assembly  80  through collar  98  and first end portion  84  of decomposition tube  82 , the velocity may increase (Region B). The increase in velocity at region B creates a large velocity differential between a velocity of the exhaust treatment fluid injected by dosing module  28  and the exhaust gas flowing through perforations  96  and  100 . The velocity differential of the bulk exhaust flow results in aerodynamic forces greater than the surface tension characteristic of the exhaust treatment fluid, which leads to droplet breakup and atomization of the exhaust treatment fluid. 
     Then, as the exhaust enters radially expanded portion  88 , the exhaust may slightly slow (Regions C and D). As the exhaust exits radially expanded portion and enters flow reversing device  106 , the velocity may then increase (Regions E and F). The exhaust velocity may then decrease as the exhaust reaches SCR  70  (Region G). Because the exhaust velocity increases at a location (Region B) where the exhaust treatment fluid is dosed into the exhaust stream, and increases as it exits flow reversing device  106 , the exhaust and exhaust treatment fluid can be sufficiently intermingled to ensure satisfactory atomization of the exhaust treatment fluid. 
     Regardless, while the exhaust stream is in radially expanded portion  88  (Region D), zones  120  of low velocity flow are present at positions adjacent inner walls  122  of decomposition tube  82  ( FIG. 9 ). These zones  120  surround the exhaust stream as it passes through radially expanded portion  88 , and assist in preventing wetting of inner walls  122  with the reagent exhaust treatment fluid. The prevention of the inner walls  122  being wetted prevents, or at least substantially minimizes, the build-up of solid urea deposits on the inner walls  122 . 
     As the exhaust stream enters second end portion  86  of decomposition tube  82 , a velocity of the exhaust stream will again increase and remain increased as it enters and exits flow reversing device  106 . Upon entry into flow reversing device  106 , the flow direction of the exhaust stream will be reversed back toward inlet  66 . As the exhaust flow exits flow reversing device  106 , the exhaust will be directed by vanes  114 , which will assist in further intermingling of the exhaust and reagent exhaust treatment fluid. Additionally, the exhaust stream may impinge upon conically-narrowing portion  94  of decomposition tube  82 , which can further assist in directing the exhaust stream away from mixing assembly  80 . The exhaust stream is then free to flow towards SCR  70 . It should be understood that the above-noted velocities may vary in later-described embodiments. In this regard, the velocities may be increased anywhere from 10%-20%. 
     Now referring to  FIGS. 10 to 13 , a second exemplary mixing assembly  200  will be described. Mixing assembly  200  is similar to mixing assembly  80  illustrated in  FIGS. 7 to 9 . Description of components that are common to each assembly, therefore, is omitted herein for clarity. Mixing assembly  200  includes deflecting device  202  including a plurality of deflecting members  204 . As best shown in  FIG. 13 , deflecting device  202  may be formed from an elongate strip  206  of metal such as aluminum, steel, titanium, or any other material known to one skilled in the art. Deflecting members  204  are integral (i.e., unitary) with elongate strip  206  and are formed as planar tabs that are bent radially outward from elongate strip  206  from a plurality of cut-outs  208  formed in elongate strip  206 . 
     Deflecting members  204  may be designed to function in a manner similar to vanes  114 . In this regard, as the exhaust flow exits flow reversing device  106 , the exhaust will be directed by deflecting members  204 , which will assist in further intermingling of the exhaust and reagent exhaust treatment fluid. As best shown in  FIGS. 12 and 13 , cut-outs  208  are angled relative to a length of elongate strip  206 . When deflecting members  204  are bent outward from elongate strip  206 , deflecting members  204  will also be angled relative to an axis of mixing assembly  200 , which may be used to direct the exhaust flow in predetermined directions upon exiting flow reversing device  106 . 
     Deflecting members  204  may have a length that is substantially equal to a distance between second end portion  86  of decomposition tube  82  and outer wall  118  of flow reversing device  106 . Alternatively, deflecting members  204  may have a length that is less than the distance between second end portion  86  and outer wall  118 . In another alternative, deflecting members  204  may each have a terminal projection  210  that provides deflecting members  204  with a length that is greater than the distance between second end portion  86  and outer wall  118 . Terminal projection  210  may then abut a terminal end  212  of outer wall  118  of flow reversing device  106 , which assists in positioning deflecting device  202  relative to flow reversing device  106 . Terminal projections  210  may also assist in securing deflecting device  202  to flow reversing device  106 , by providing a location to weld, braze, or secure each tab to flow reversing device  106 , if desired. 
     Now referring to  FIGS. 14 to 16 , a third exemplary mixing assembly  300  is illustrated. Mixing assembly  300  is substantially similar to mixing assembly  80  illustrated in  FIGS. 7 to 9 . Description of components that are common to each assembly, therefore, is omitted herein for clarity. Although collar  98  is not illustrated in  FIG. 14 , it should be understood that mixing assembly  300  may include collar  98 . Mixing assembly  300  includes deflecting device  302  including a plurality of deflecting members  304 . As best shown in  FIG. 15 , deflecting device  302  may be formed from an annular ring  306  of metal such as aluminum, steel, titanium, or any other material known to one skilled in the art. Deflecting members  304  are integral (i.e., unitary) with annular ring  306  and are formed as planar tabs that may be bent axially outward from annular ring from a plurality of cut-outs  308  formed in annular ring  306 . Although deflecting members  304  are illustrated as being bent in a direction toward an interior  310  of flow reversing device  106 , it should be understood that deflecting members  304  can be bent in a direction away from interior  310 . 
     Deflecting members  304  may be designed to function in a manner similar to vanes  114 . In this regard, as the exhaust flow exits flow reversing device  106 , the exhaust will be directed by deflecting members  304 , which will assist in further intermingling of the exhaust and reagent exhaust treatment fluid. Deflecting members  304  may also be angled relative to an axis of mixing assembly  300 , which may be used to direct the exhaust flow in predetermined directions upon exiting flow reversing device  106 . 
     Once deflecting members  304  are bent into the desired orientation, an inner ring  312  and an outer ring  314  of deflecting device will be defined. Inner ring  312  may be used to secure deflecting device  302  to second end portion  86  of decomposition tube  82  by welding, brazing, or any other fixing method known in any manner known to one skilled in the art. Deflecting device  302  may also include an axially-extending flange  316  that extends outward from outer ring  314 . Axially-extending flange  316  may correspond to terminal end  212  of flow reversing device  106  ( FIG. 11 ), and overlap terminal end  212  such that axially-extending flange  316  may be secured to flow reversing device  106  by welding, brazing, or any other attachment method known. 
     Now referring to  FIGS. 17 to 19 , a fourth exemplary embodiment is illustrated. Mixing assembly  400  is similar to mixing assembly  80  illustrated in  FIGS. 7 to 9 . Description of components that are common to each assembly, therefore, is omitted herein for clarity. Mixing assembly  400  includes flow reversing device  106  at second end portion  86 , which is a substantially cup-shaped member having a central bulge formed therein. In contrast to deflecting members  204  and  304  described above, mixing assembly  400  may include a flow-dispersing cap  402  coupled between flow reversing device  106  and decomposition tube  82 . 
     Flow-dispersing cap  402  includes a first axially-extending lip  404  that couples flow-dispersing cap  402  to flow reversing device  106 , and a second axially-extending lip  406  that couples flow-dispersing cap  402  to decomposition tube  82 . Between axially-extending lips  404  and  406  is a perforated conically-shaped ring  408  having a plurality of through-holes  410 . Similar to first and second perforations  96  and  100 , through-holes  410  assist in creating turbulence and increasing a velocity of the exhaust stream as it exits flow reversing device  106 . Through-holes  410  can be sized and shaped in any manner desired. In this regard, although through-holes  410  are illustrated as being circular, it should be understood that through-holes can be any shape including square, rectangular, triangular, oval, and the like. Conically-shaped ring  408  can include a first portion  412  adjacent first axially-extending lip  404 , and a second portion  414  adjacent second axially-extending lip  406 . 
     A diverter ring  416  may be positioned between second portion  414  and decomposition tube  82 . As best shown in  FIG. 19 , diverter ring  416  includes a cylindrical portion  418  coupled to decomposition tube  82 , and an angled flange  420  extending away from cylindrical portion  418  between decomposition tube  82  and conically-shaped ring  408 . Angled flange  420  may be positioned at any angle desired to further assist in diverting flow out from mixing assembly  400 . In this regard, angled flange may be angled relative to cylindrical portion  418  in the range of 25 to 75 degrees, preferably in the range of 35 to 65 degrees, and most preferably at an angle of degrees. 
     Upon entry into flow reversing device  106 , the flow direction of the exhaust stream will be reversed back toward inlet  66 . As the exhaust flow exits flow reversing device  106 , the exhaust will be directed by diverter ring  416  out through through-holes  410 , which will assist in further intermingling of the exhaust and reagent exhaust treatment fluid. The exhaust stream is then free to flow towards SCR  70 . 
     Now referring to  FIGS. 20 and 21 , a fifth exemplary embodiment is illustrated. Mixing assembly  500  is substantially similar to mixing assembly  80  illustrated in  FIGS. 7 to 9 . Description of components that are common to each assembly, therefore, is omitted herein for clarity. Mixing assembly  500  includes flow reversing device  502  at second end portion  86  of decomposition tube  82 , which is a substantially cup-shaped member having a central bulge  503  formed therein. Flow reversing device  502  may include a plurality of flow deflecting members  504  formed in an outer wall  506  thereof. Deflecting members  504  are integral (i.e., unitary) with flow reversing device  502  and are formed as planar tabs that are that are bent radially outward from outer wall  506  from a plurality of cut-outs  508  formed in outer wall  506 . Deflecting members  504  may be designed to function in a manner similar to vanes  114 . In this regard, as the exhaust flow exits flow reversing device  502  through cut-outs  508 , the exhaust flow will become turbulent and deflected by deflecting members  504 , which will assist in further intermingling of the exhaust and reagent exhaust treatment fluid. 
     Mixing assembly  500  may further include a dispersing ring  510  positioned between a terminal end  512  of flow reversing device  502  and decomposition tube  82 . Dispersing ring  510  may be formed from an annular ring  514  of metal such as aluminum, steel, titanium, or any other material known to one skilled in the art. A cylindrical flange  516  may extend axially away from annular ring  514 . Cylindrical flange  516  may be welded, brazed, or secured in any manner known, to decomposition tube  82 . Annular ring  514  includes a plurality of scallop-shaped recesses  518  formed therein. Recesses  518  serve as exit ports to allow the exhaust stream to exit mixing assembly  500 . Accordingly, the exhaust stream may exit through cut-outs  508 , or may exit through recesses  518 . Adjacent recesses  518  may be separated by a land portion  520  of the annular ring  514 . A terminal end  522  of each land portion  520  located opposite to cylindrical flange  516  may be bent in the axial direction to provide an abutment surface that can position dispersing ring  510  relative to flow reversing device  502  before dispersing ring  510  is secured to decomposition tube  82 . 
     Upon entry into flow reversing device  502 , the flow direction of the exhaust stream will be reversed back toward inlet  66 . As the exhaust flow exits flow reversing device  502 , the exhaust may exit through cut-outs  508  and be deflected in a desired direction by deflecting members  504 , or the exhaust stream may exit through recesses  518  formed in dispersing ring  510 . Regardless of the location at which the exhaust stream exits mixing assembly  500 , the exhaust stream is further intermingled with the reagent exhaust treatment fluid before flowing toward SCR  70 . 
     Although each mixing assembly has been described relative to use in an exhaust treatment component  20  including a single SCR  70 , the present disclosure should not be limited thereto. As best shown in  FIGS. 22 and 23 , mixing assemblies can be used in an exhaust treatment component  20  having a pair of SCRs  70 .  FIG. 22  illustrates a pair of exhaust treatment components  18  and  20 , arranged in parallel. Exhaust treatment component  18  is similar to the previously-described embodiments so description thereof will be omitted. 
     Exhaust treatment component  20 , as best shown in  FIG. 23 , includes mixing assembly  80  (or any other mixing assembly described above) for intermingling exhaust treatment fluid dosed into the exhaust stream by dosing module  28 . Exhaust treatment component  20  includes a pair of housings  600  in communication with a pair of end caps  602  and  604 . End caps  602  and  604  may be secured to housings  600  by welding, or may be secured to housings  600  by clamps (not shown). Mixing assembly  80  and dosing module  28  are secured in a conduit  606  that provides communication between exhaust treatment component  18  and exhaust treatment component  20 . Conduit  606  may include a first portion  608  and a second portion  610  each including a flange  612  and  614 , respectively, that may be secured by welding, or by a clamp (not shown). Each housing  600  supports a plurality of exhaust treatment component substrates  618 , which may be a combination of SCRs, ammonia slip catalysts, and filters for treating the mixture of exhaust and exhaust treatment fluid. 
     As the exhaust enters mixing assembly  80 , the urea exhaust treatment fluid may be dosed directly into mixing assembly  80  by dosing module  28 . As the mixture of exhaust and exhaust treatment fluid travels through decomposition tube  82  and flow reversing device  106 , the exhaust treatment fluid and exhaust stream will be sufficiently intermingled before passing through exhaust treatment component substrates  618 . Mixing assembly  80  may include deflecting members or vanes  114  to assist in intermingling the exhaust and exhaust treatment fluid. Because a pair of housings  600  each including exhaust treatment component substrates  618  is used in the exemplary embodiment, vanes  114  may be positioned within flow reversing device  106  to ensure that a substantially equal amount of the exhaust stream is directed to each housing  600 . That is, it should be understood that deflecting members  114  (and the deflecting members in each exemplary embodiment) can be oriented and positioned to direct the exhaust in the desired direction. In this manner, the exhaust can be properly treated by exhaust treatment component substrates  618 . 
     Now referring to  FIGS. 24-30 , an exemplary exhaust treatment assembly  700  including exhaust treatment components  702  and  704  is illustrated. As best shown in  FIG. 24 , exhaust treatment components  702  and  704  are arranged parallel to one another. It should be understood, however, that exhaust treatment components  702  and  704  can be arranged substantially co-axially, without departing from the scope of the present disclosure. 
     Exhaust treatment component  702  may include a housing  706 , an inlet  708 , and an outlet  710 . Inlet  708  may be in communication with exhaust passage  14 , and outlet  710  may be in communication with exhaust treatment component  704 . Although outlet  710  is illustrated as being directly connected to exhaust treatment component  704 , it should be understood that an additional conduit (not shown) may be positioned between outlet  710  and exhaust treatment component  704 . The additional conduit can be non-linear such that the flow of exhaust through the conduit must turn before entering exhaust treatment component  704 . 
     Housing  706  can be cylindrically-shaped and may include a first section  712  supporting a DOC  714 , and a second section  716  supporting a mixing assembly  718  ( FIGS. 29 and 30 ). DOC  714  may be replaced by for example, a DPF or catalyst-coated DPF without departing from the scope of the present disclosure. Opposing ends of housing  706  can include end caps  720  and  722  to hermetically seal housing  706 . End caps  720  and  722  can be slip-fit and welded to first and second sections  712  and  716 , respectively. First and second sections  712  and  716  may be secured by a clamp  724 . Alternatively, first and second sections  712  and  716  may be slip fit or welded, without departing from the scope of the present disclosure. The use of clamp  724  allows for easy removal of DOC  714  or mixing assembly  718  for maintenance, cleaning, or replacement of these components. A perforated baffle  725  may be positioned immediately downstream from inlet  708  and upstream for DOC  714 . Exhaust from exhaust passage  14  will enter inlet  708 , pass through perforated baffle  725 , DOC  714 , and mixing assembly  718 , and exit outlet  710  before entering exhaust treatment component  704 . 
     Exhaust treatment component  704  is substantially similar to exhaust treatment component  702 . In this regard, exhaust treatment component  704  may include a housing  726 , an inlet  728 , and an outlet  730 . Inlet  728  communicates with outlet  710  of exhaust treatment component  702 , and outlet  730  may be in communication with a downstream section of exhaust passage  14 . 
     Housing  726  can be cylindrically-shaped and may support an SCR  732  and ammonia slip catalyst  734 . SCR  732  is preferably located upstream of ammonia slip catalyst  734 . Opposing ends of housing  726  can include end caps  736  and  738  to hermetically seal housing  726 . End caps  736  and  738  can be slip-fit and welded to housing  726 . Alternatively, end caps  736  and  738  can be secured to housing  726  by clamps (not shown). Exhaust from outlet  710  of exhaust treatment component  702  will enter inlet  728 , pass through SCR  732  and ammonia slip catalyst  734 , and exit outlet  730  before entering the downstream section of exhaust passage  14 . 
     Dosing module  28  may be positioned on end cap  722  at a location proximate outlet  710 . As in previously described embodiments, dosing module  28  is operable to inject a reductant such as a urea exhaust treatment fluid into the exhaust stream before the exhaust stream passes through SCR  732 . A sufficient intermingling of the exhaust and exhaust treatment fluid should occur to optimize the removal of NO x  from the exhaust stream before the mixture passes through SCR  732 . To assist in intermingling of the exhaust stream and the urea exhaust treatment fluid, mixing assembly  718  may be positioned downstream from DOC  714  and upstream of SCR  732 . Mixing assembly  718  is positioned proximate dosing module  28  such that dosing module  28  may dose the urea exhaust treatment fluid directly into mixing assembly  718  where it may intermingle with the exhaust stream. 
       FIGS. 29 and 30  best illustrate mixing assembly  718 . Similar to previously described embodiments, mixing assembly  718  includes a decomposition tube  82  including first end portion  84  that may be secured to end cap  722  and second end portion  86  that is positioned proximate DOC  714 . Decomposition tube  82  may be substantially cylindrical, with radially expanded portion  88  positioned between the first and second end portions  84  and  86 . A flow reversing device  740  at second end portion  86 . In addition to decomposition tube  82  being fixed to end cap  722 , mixing assembly  718  may be supported within housing  706  by a perforated support plate  742 . 
     Support plate  742  includes an annular central portion  744  surrounding an aperture  746  defined by an axially extending flange  748  that is fixed to decomposition tube  82 . An annular outer portion  750  of support plate  742  includes a plurality of through-holes  752  for allowing the exhaust to flow therethrough. Outer portion  750  also includes an axially-extending flange  754  for fixing support plate  742  to housing  706 . An axially-extending shoulder portion  756  may be positioned between the annular central portion  744  and annular outer portion  750 . Shoulder portion  756  provides a mounting surface for a cylindrical shell  758  of mixing assembly  718 . Shell  758  includes a proximal end  760  fixed to shoulder portion  756  and a distal end  762  fixed to flow reversing device  740 . A radially extending mounting flange  764  receives an end  766  of outlet  710 . 
     As best shown in  FIG. 30 , the exhaust flow will enter inlet  708 , pass through perforated baffle  725 , and enter DOC  714 . After the exhaust exits DOC  714 , the exhaust will approach mixing assembly  718 . Although not required by the present disclosure, mixing assembly  718  may cup-shaped nose  768  fixed to an outer surface  770  of flow-reversing device  740 . Cup-shaped nose  768  may include a conical, hemispherical, or ellipsoid outer surface  772  that, upon contact by the exhaust, directs the exhaust around mixing assembly  718 . Cup-shaped nose  768  may also have a concave surface relative to the direction of the exhaust. In addition, cup-shaped nose  768  may have raised or recessed features (e.g., bumps or dimples, not shown) formed on outer surface  772 . Although cup-shaped nose  768  is illustrated as being fixed to flow-reversing device  740 , it should be understood that cup-shaped nose  768  can be supported by a support plate (not shown) at a position proximate flow-reversing device  740 . For example, a support plate similar to support plate  742  having through-holes  752  to allow for exhaust flow may be used, with annular central portion  744  defining cup-shaped nose  768  rather than aperture  746 . 
     After passing around mixing assembly  718 , the exhaust will pass through through-holes  752  of support plate  742 . After passing through support plate  742 , the exhaust may enter mixing assembly  718  through perforations  96  and  100 . To assist in feeding the exhaust gas into mixing assembly  718 , end cap  722  may define curved surfaces (i.e., similar to flow-reversing device  740 , not shown) that direct the exhaust into mixing assembly  718 . After entering decomposition tube  82 , the exhaust flow will be exposed to the exhaust treatment fluid (e.g., urea) dosed into mixing assembly  718  by dosing module  28 . As the exhaust flows through decomposition tube  82 , the exhaust will be directed in a reverse direction by flow reversing device  740  into shell  758 . The exhaust may then exit shell  758  through outlet  710  and enter exhaust treatment component  704  where SCR  732  and ammonia slip catalyst  734  are located. 
     According the above-described configuration, the exhaust flow will be forced to reverse direction within exhaust treatment component  702  twice. That is, the exhaust flow will firstly reverse direction as it enters mixing assembly  718 , and the exhaust will secondly reverse direction due to contact with flow-reversing device  740 . Due to the exhaust flow reversing in direction twice as it travels through exhaust treatment component  702 , the exhaust flow will become tortuous, which increases the ability to intermingle the exhaust treatment fluid with the exhaust before the exhaust enters SCR  732 . Due to the increased intermingling of the exhaust treatment fluid and the exhaust, the efficacy of SCR  732  in removing NO x  from the exhaust can be increased. 
     Although not illustrated in  FIGS. 29 and 30 , it should be understood that flow-reversing device  740  may include deflecting members such as vanes  114 . Alternatively, any of mixing assemblies  200 ,  300 ,  400 , and  500  may be used in exhaust treatment component  702  without departing from the scope of the present disclosure. 
     Now referring to  FIGS. 31 and 32 , an exhaust treatment component  800  is illustrated. Exhaust treatment component  800  includes a housing  802 , an inlet  804 , and an outlet  806 . Housing  802  may include an inner shell  807  and an outer shell  808 . An insulating material  810  may be disposed between inner shell  806  and outer shell  808 . Inlet  804  may be coupled to exhaust passage  14 , and includes an inner cone  812  and an outer cone  814 . Insulating material  810  may be disposed between inner cone  812  and outer cone  814 . Inner cone  812  may be fixed to inner shell  807 , and outer cone  814  may be fixed to outer shell  808 . Inner cone  812  may first be fixed to outer cone  814 , and then inlet  804  may be fixed to inner and outer shells  807  and  808 . Outlet  806  may include an outer sleeve  816  fixed to outer shell  808 , and an inner sleeve  818 . Inner sleeve  818  may be constructed of one or more sections that are hermetically sealed. Insulating material  810  may be disposed between inner sleeve  818  and outer sleeve  816 . Outlet  806  may extend radially outward from housing  802 , while inlet  804  may be co-axial with housing  802 . 
     An end cap  820  may be coupled to housing  802  at an end of housing  802  opposite to inlet  804 . Dosing module  28  may be positioned on end cap  820  (or on an additional flange (not shown) at a location proximate outlet  806 . As in previously described embodiments, dosing module  28  is operable to inject a reductant such as a urea exhaust treatment fluid into the exhaust stream before the exhaust stream passes through an SCR (not shown). A sufficient intermingling of the exhaust and exhaust treatment fluid should occur to optimize the removal of NO x  from the exhaust stream before the mixture passes through the SCR. To assist in intermingling of the exhaust stream and the urea exhaust treatment fluid, mixing assembly  718  may be positioned between inlet  804  and outlet  806 . Mixing assembly  718  is positioned proximate dosing module  28  such that dosing module  28  may dose the exhaust treatment fluid directly into mixing assembly  718  where it may intermingle with the exhaust stream. 
       FIG. 32  best illustrates mixing assembly  718  within exhaust treatment component  800 . Mixing assembly  718  includes a decomposition tube  82  including first end portion  84  that may be secured to end cap  820  and second end portion  86  that is positioned proximate inlet  804 . The exhaust flow will enter inlet  804  and approach mixing assembly  718 . Although not required by the present disclosure, mixing assembly  718  may include cup-shaped nose  768  fixed to an outer surface  770  of flow-reversing device  740 . Cup-shaped nose  768  may include a conical, hemispherical, or ellipsoid outer surface  772  that, upon contact by the exhaust, directs the exhaust around mixing assembly  718 . Cup-shaped nose  768  may also have a concave surface relative to the direction of the exhaust. In addition, cup-shaped nose  768  may have raised or recessed features (e.g., bumps or dimples, not shown) formed on outer surface  772 . After passing around mixing assembly  718 , the exhaust will pass through through-holes  752  of support plate  742 . After passing through support plate  742 , the exhaust may enter mixing assembly  718  through perforations  96 . Although mixing assembly  718  is illustrated in  FIG. 32  as not including perforated collar  98 , it should be understood that the illustrated embodiment may include perforated collar  98  without departing from the scope of the present disclosure. 
     After entering decomposition tube  82 , the exhaust flow will be exposed to the exhaust treatment fluid (e.g., urea) dosed into mixing assembly  718  by dosing module  28 . As the exhaust flows through decomposition tube  82 , the exhaust will be directed in a reverse direction by flow reversing device  740  into shell  758 . The exhaust may then exit shell  758  through outlet  806  and enter another exhaust treatment component (e.g., exhaust treatment component illustrated in  FIG. 24 ) where an SCR may be located. 
     Although not illustrated in  FIG. 32 , it should be understood that flow-reversing device  740  may include deflecting members such as vanes  114 . Alternatively, any of mixing assemblies  200 ,  300 ,  400 , and  500  may be used in exhaust treatment component  800  without departing from the scope of the present disclosure. 
     According the above-described configuration, the exhaust flow will be forced to reverse direction within exhaust treatment component  800  twice. That is, the exhaust flow will firstly reverse direction as it enters mixing assembly  718 , and the exhaust will secondly reverse direction due to contact with flow-reversing device  740 . Due to the exhaust flow reversing in direction twice as it travels through exhaust treatment component  800 , the exhaust flow will become tortuous, which increases the ability to intermingle the exhaust treatment fluid with the exhaust before the exhaust enters an SCR. Due to the increased intermingling of the exhaust treatment fluid and the exhaust, the efficacy of the SCR in removing NO x  from the exhaust can be increased. 
     Moreover, it should be understood that exhaust treatment component  800  does not include a DOC, DPF, SCR, or some other type of exhaust treatment substrate. Without any of these devices, component  800  may be made to be compact. Such a design allows for existing exhaust after-treatment systems including an SCR to be retro-fit with component  800  to assist in increasing intermingling of the exhaust and urea exhaust treatment fluid. 
     It should be understood that each of the above-described configurations may be modified, as desired. For example, although inlet  708  illustrated in  FIG. 24  is illustrated as having a 90 degree bend, the present disclosure contemplates a co-axial inlet like that illustrated in  FIG. 31  (i.e., inlet  804 ) or a radially-positioned inlet like inlet  728 . Similarly, outlet  710  may be replaced by a co-axial outlet (similar to co-axial inlet  804 ) or an outlet having a 90 degree bend (similar to inlet  708 ). Similar modifications may be made in component  800 , without departing from the scope of the present disclosure. 
       FIG. 33  illustrates another mixing assembly  900  according to the present disclosure. Similar to previously described embodiments, mixing assembly  90  includes a decomposition tube  82  including a first end portion  84  that may be secured to end cap  74  and a second end portion  86  that is positioned proximate SCR  70 . Decomposition tube  82  may be substantially cylindrical, with a radially narrowed portion  902  positioned between the first and second end portions  84  and  86 . 
     Radially narrowed portion  902  includes a conically-narrowing portion  904  that narrows decomposition tube  82 , a cylindrical portion  92  downstream from the first conically-narrowing portion  904  having a diameter that is less than that of first and second end portions  84  and  86 , and a conically-expanding portion  906  that radially expands decomposition tube  82 . It should be understood that first and second end portions  84  and  86  may have different diameters, without departing from the scope of the present disclosure. It should also be understood that the present disclosure does not require conically-expanding portion  906 . That is, radially narrowed portion  902  may extend over the entire length of second end portion  86 . Radially narrowing decomposition tube  82  results in an increase in the velocity of the exhaust gas as it travels through decomposition tube  82 . The increase in velocity assists in atomization of the reagent exhaust treatment fluid. 
     Although mixing assemblies such as mixing assembly  80  (see e.g.,  FIG. 9 ) and mixing assembly  900  (see e.g.,  FIG. 33 ) have been described as including either a radially expanded portion  88  or a radially narrowed portion  902 , the present disclosure should not be limited thereto. In this regard, it should be understood that the present disclosure contemplates a mixing assembly including an entirely cylindrical decomposition tube  82  where decomposition tube  82  has the same diameter along the entire length thereof. An entirely cylindrical decomposition tube  82  is illustrated, for example, in  FIG. 33  at  908 . 
     Now referring to  FIGS. 34-37 , another exhaust treatment system  1000  will be described. Exhaust treatment system  1000  includes exhaust treatment components  18  and  20 , where exhaust treatment component  18  may include a DOC  52  and/or a DPF  56  positioned within a housing  44  and exhaust treatment component  20  may include an SCR  70  and/or an ammonia slip catalyst  72  within a housing  64 . A common hood  1002  fluidly and mechanically connects exhaust treatment components  18  and  20 . 
     Hood  1002  includes a peripheral outer surface  1004  defining a connection flange  1006  for connecting to each housing  44  and  64 . Connection flange  1006  may be welded to each housing  44  and  64 , or connection flange  1006  may be secured to each housing  44  and  64  using a clamp  1005 . To prevent exhaust gases from escaping hood  1002  as the exhaust gases travel from exhaust treatment component  18  to exhaust treatment component  20 , a solid connection plate  1008  may be positioned between exhaust treatment component  18  and exhaust treatment component  20 . Connection plate  1008  may include apertures  1010  for receipt of housings  44  and  64 . To ensure a gas-tight fit between connection plate  1008  and housings  44  and  64 , connection plate  1008  may be welded to each housing  44  and  64 , or a gasket (not shown) may be positioned between housings  44  and  64  and apertures  1010 . An end plate  1012  of hood  1002  is integral with peripheral outer surface  1004 . End plate  1012  may include a contoured surface  1014  at exhaust treatment component  18  that assists in directing the exhaust gases toward exhaust treatment component  20 . In addition, hood  1002  may include a mounting device  1016  for receipt of a dosing module  28  operable to dose reagent exhaust treatment fluid into the exhaust gases. 
     To assemble exhaust treatment system  1000 , connection plate  1008  may be secured to each exhaust treatment component  18  and  20  by welding, or with a gasket (not shown) that allows connection plate  1008  and exhaust treatment components  18  and  20  to be secured by an interference fit therebetween. After connection plate  1008  is secured to exhaust treatment components  18  and  20 , hood  1002  may then be secured to exhaust treatment components  18  and  20  and connection plate  1008  by welding or by a clamp (not shown). 
     Exhaust treatment system  1000  includes a mixing assembly  1100  positioned upstream from SCR  70  that assists in intermixing the exhaust gases and reagent exhaust treatment fluid. As illustrated in  FIG. 34 , mixing assembly  1100  extends between hood  1002  and exhaust treatment component  20 . To secure mixing assembly  1100  between hood  1002  and exhaust treatment component  20 , a solid partition plate  1018  that axially aligns mixing assembly  1100  with SCR  70  may be used. Partition plate  1018  includes a central axially extending flange  1020  that is coupled to decomposition tube  82  of mixing assembly  1100  by welding or any other attachment method known to one skilled in the art. Partition plate  1018  may be secured to housing  64  or may be secured to connection plate  1008 . After the exhaust exits mixing assembly  1100 , the exhaust gas may pass through a perforated baffle ring  1022  positioned upstream from SCR  70  that further assists in intermingling the exhaust gases and reagent exhaust treatment fluid. Baffle ring  1022  may be secured to an interior surface  1024  of housing  64 . Alternatively, baffle ring  1022  can be secured in a separate housing that is coupled to an end of housing  64 . 
     As illustrated in  FIGS. 35 and 36 , mixing assembly  1100  includes decomposition tube  82  with radially expanded portion  88 . It should be understood, however, that decomposition tube  82  can be entirely cylindrical or include a radially narrowed portion like mixing assembly  900  illustrated in FIG.  33 . Regardless, mixing assembly  1100  is not fixed to end plate  1012  of hood  1002 . Rather, mixing assembly  1100  is spaced apart from end plate  1012  of hood  1002 . 
     In accordance with the present disclosure, first end portion  84  of decomposition tube  82  includes a flared edge  1102 . Flared edge  1102  increases the diameter of first end  84  of decomposition tube  82 , and is designed to increase the ease with which the exhaust gases may enter mixing assembly  1100 . By increasing the ease with which the exhaust gases may enter mixing assembly  1100 , backpressures within exhaust treatment system  1000  may also be reduced. It should be understood that although  FIG. 35  illustrates first end  84  of decomposition tube  82  as being devoid of perforations  96 , the present disclosure contemplates the use of perforations  96  in first end  84  as illustrated in  FIG. 36 . 
     As in previously described embodiments, perforations  96  can vary in size around the circumference of first end  84 , and assist in creating turbulence and increasing velocity of the exhaust stream as it enters decomposition tube  82 . Moreover, although not illustrated in  FIGS. 35 and 36 , it should be understood that mixing assemblies  1100  may also include a perforated collar  98  like that shown in  FIG. 9  without departing from the scope of the present disclosure. Similar to previously described embodiments, mixing assemblies  1100  include a flow reversing device  106  at second end  86 . Any of the flow reversing devices  106  such as those illustrated in  FIGS. 7 ,  11 ,  15 ,  19 , and  21  may be used. 
     Although exhaust treatment system  1000  has been described above as including a mixing assembly  1100  spaced apart from end plate  1012 , it should be understood that the present disclosure should not be limited thereto. Specifically, as best shown in  FIG. 37 , it can be seen that hood  1002  can include an aperture  1026  for receipt of first end portion  84  of decomposition tube  82  such that decomposition tube  82  can be directly attached to end plate  1012  of hood  1002 . To mount dosing module (not shown) relative to end plate  1012  and decomposition tube  82 , a mounting ring  1028  can be secured to first end portion  84  such that dosing module can dose the reagent exhaust treatment fluid directly into decomposition tube  82 . 
     As illustrated in  FIG. 37 , a flow distribution plate  1030  can be positioned in hood  1002  relative to first end portion  84  of decomposition tube  82 . Flow distribution plate  1030  can be a solid plate, or flow distribution plate  1030  can include a plurality of perforations  1032  as show in phantom. Flow distribution plate  1030  can be secured to either hood  1002  or first end portion  84  of decomposition tube by welding, brazing, or the like. Regardless, flow distribution plate  1030  assists in preventing the exhaust flow from swirling about first end portion  84  of decomposition tube  82  before entering perforations  96  of decomposition tube  82 . In other words, flow distribution plate  1030  blocks the flow of exhaust around first end portion  84  and assists in forcing the exhaust to enter decomposition tube  82 . 
     Now referring to  FIG. 38 , it can be seen that mixing assembly  1100  may additionally include a static mixer  1104  positioned within decomposition tube  82  at a location upstream from flow reversing device  106 . Static mixer  1104  may include a plurality of mixing blades  1106  secured within a mounting ring  1108  that is secured by an interference fit or welding to an interior surface  1110  of decomposition tube  82 . Preferably, static mixer  1104  is positioned between first end  84  and second end  86  at radially expanded portion  88 . Mixing blades  1106  may be slightly twisted to swirl the mixture of exhaust gas and reagent exhaust treatment fluid as the mixture passes through decomposition tube  82 . It should be understood, however, that any type of static mixer can be used as is known in the art. Regardless, static mixer  1104  further assists in the intermingling of the exhaust gas and the reagent exhaust treatment fluid. 
     Static mixer  1104  can include a support rod  1112  that axially extends from mixing blades  1106  in a direction toward flow reversing device  106 . Support rod  1112  provides an attachment point for flow reversing device  106  such that flow reversing device  106  may be secured to support rod  1112  by welding, brazing, or the like. The use of support rod  1112  to secure flow reversing device  106  relative to decomposition tube  82  removes the need for a separate support baffle (now shown) that secures flow reversing device  106  to an interior surface of housing  64 . It should be understood, however, that static mixer  1104  is not required to include support rod  1112 . 
     Now referring to  FIGS. 39 and 40 , yet another configuration of mixing assembly  1100  is illustrated. Similar to the mixing assemblies illustrated in  FIGS. 35-37 , mixing assembly  1100  illustrated in  FIGS. 39 and 40  is designed to be spaced apart from end plate  1012  of hood  1002 . Mixing assembly  1100  differs from those illustrated in  FIGS. 35-37  in that first end portion  84  is truncated. In other words, a length L of first end portion  84  is variable in an axial direction along a circumference thereof. More specifically, a length of first end portion  84  along a circumference thereof decrease from flared edge  1102  in a direction toward second end portion  86  such that a length L1 at terminal end of first end portion  84  at flared edge  1102  is greater than a length L2 at a location closer to second end portion  86 . The amount that the length of first end portion  84  decreases along a circumference thereof is variable, and can be tuned as necessary. The truncation of first end portion  84  allows the exhaust gases to more easily enter decomposition tube  82 , assists in reducing backpressure in exhaust treatment system  1000 , and increases the turbulence with which the exhaust gases enter the decomposition tube  82 . 
     Although not required by the present disclosure, the use of a mixing assembly  1100  with a truncated first end portion  84  can be in combination with a cylindrical spray guide  1032  attached to end plate  1012 . Spray guide  1032  ensures that the reagent exhaust treatment fluid fed into the exhaust by dosing module  28  will enter decomposition tube  92 . This can be particularly important with the truncated first end portion  84 , which has a larger opening in comparison to previously described embodiments and is spaced apart from end plate  1012 . It should be understood, however, that cylindrical spray guide  1026  may be used in combination with any mixing assembly that is spaced apart from end plate  1012  to ensure proper entry of the reagent exhaust treatment fluid into decomposition tube  82 . 
     Now referring to  FIGS. 41 and 42 , a flow reversing device  1200  will be described. Flow reversing device  1200  is similar to previously described flow reversing device  106  in that flow reversing device  1200  is a substantially cup-shaped member  110  having a central bulge  112  formed therein. Flow reversing device  1200  has a diameter greater than that of second end portion  86  of decomposition tube  82  such that as the exhaust flow enters the cup-shaped member  110 , the exhaust flow will be forced to flow in a reverse direction. Reversing the flow direction assists in intermingling of the reagent exhaust treatment fluid and the exhaust stream before the exhaust stream reaches SCR  70 . Flow reversing device  1200  may also be configured to include deflecting members like those illustrated in  FIGS. 7 ,  11 ,  15 ,  19 , and  21 . 
     In accordance with the present disclosure, flow reversing device  1200  may include a plurality of through-holes  1202  formed in a bottom surface  1204  of cup-shaped member  110 . Although through-holes  1202  allow a small portion of the exhaust stream to pass through cup-shaped member  110  without reversing direction, through-holes  1202  are designed to allow any reagent exhaust treatment fluid that has not atomized to flow therethrough. By allowing liquid reagent exhaust treatment fluid to pass through cup-shaped member  110 , the prevention of urea deposits can be prevented from forming within cup-shaped member  110 . In this regard, if liquid reagent exhaust treatment fluid collects within cup-shaped member  110  and subsequently evaporates, urea deposits may form within cup-shaped member  110  that may eventually obstruct exhaust flow from decomposition tube  82  and through flow reversing device  1200 . Although flow reversing device  1200  is illustrated as having through-holes  1202 , it should be understood that any type of perforation i.e. such as elongate slots is acceptable so long as any liquid reagent exhaust treatment fluid is allowed to pass therethrough. 
     Now referring to  FIGS. 43 and 44 , a flow reversing device  1300  will be described. Flow reversing device  1300  is similar to previously described flow reversing device  106  in that flow reversing device  1300  is a substantially cup-shaped member  110  having a central bulge  112  formed therein. Flow reversing device  1300  has a diameter greater than that of second end portion  86  of decomposition tube  82  such that as the exhaust flow enters the cup-shaped member  110 , the exhaust flow will be forced to flow in a reverse direction. Reversing the flow direction assists in intermingling of the reagent exhaust treatment fluid and the exhaust stream before the exhaust stream reaches SCR  70 . 
     Flow reversing device  1300  includes a plurality of deflecting members  1302  coupled to an axially extending ring  1304  that is fixed to second end portion  86  of decomposition tube  82 . Deflecting members  1302  further assist in intermingling the reagent exhaust treatment fluid and the exhaust stream. Deflecting members  1302  may be formed as a plurality of helically curved vanes  1306  that extend radially outward from ring  1304 . Although vanes  1306  are illustrated as being secured to ring  1304 , it should be understood that vanes  1306  may be secured to second end portion  86  of decomposition tube  82 , without departing from the scope of the present disclosure. 
     Vanes  1306  induce a high turbulence swirl of the exhaust stream to increase intermingling of the reagent exhaust treatment fluid and the exhaust gases. The high turbulence swirl generated by vanes  1306  results in the reagent exhaust treatment fluid being circumferentially distributed throughout the exhaust stream as it is swirled by vanes  1306 . Although six vanes  1306  are illustrated, it should be understood that the number of vanes  1306  is variable. Moreover, the helical pitch of vanes  1306  may also be varied dependent on the amount of swirl desired to be generated. Lastly, it should be understood that flow reversing device  1300  can be used in conjunction with any of the decomposition tubes  82  described including tubes  82  with a radially expanded portion  88 , a radially narrowed portion  902 , a flared edge  1102 , and a truncated first portion  84  ( FIG. 39 ). 
       FIG. 45  illustrates another exhaust treatment component  1400  according to the present disclosure. Exhaust treatment component  1400  is substantially similar to exhaust treatment component  20  illustrated in  FIG. 6 . In this regard, exhaust treatment component  1400  may include a housing  64 , an inlet  66 , and an outlet  68 . Inlet  66  communicates with outlet  48  of exhaust treatment component  18 , and outlet  68  may be in communication with a downstream section of exhaust passage  14 . 
     Housing  64  can be cylindrically-shaped and may support an SCR  70  and ammonia slip catalyst  72 . SCR is preferably located upstream of ammonia slip catalyst  72 . Opposing ends of housing  64  can include end caps  74  and  76  to hermetically seal housing  64 . End caps  74  and  76  can be slip-fit and welded to housing  64 . Alternatively, end caps  74  and  76  can be secured to housing  64  by clamps (not shown). Exhaust from outlet  48  of exhaust treatment component  18  will enter inlet  66 , pass through SCR  70  and ammonia slip catalyst  72 , and exit outlet  68  before entering the downstream section of exhaust passage  14 . 
     In contrast to exhaust treatment component  20  illustrated in  FIG. 6 , dosing module  28  may be positioned on a dosing module mount  1402  that is fixed to end cap  74  at a location proximate inlet  66 . Although dosing module mount  1402  is illustrated in  FIGS. 45 and 45A  as being fixed to end cap  74  by welding, brazing, or the like, it should be understood that dosing module mount  1402  can be unitarily formed with end cap  74  without departing from the scope of the present disclosure. 
     Dosing module mount  1402  includes an aperture  1404  for receipt of dosing module  28 , which is operable to inject a reductant such as a urea exhaust treatment fluid into the exhaust stream before the exhaust stream passes through SCR  70 . A sufficient intermingling of the exhaust and exhaust treatment fluid should occur to optimize the removal of NO x  from the exhaust stream during as the mixture passes through SCR  70 . To assist in intermingling of the exhaust stream and the urea exhaust treatment fluid, mixing assembly  80  may be positioned downstream from inlet  66  and upstream of SCR  70 . Mixing assembly  80  is positioned proximate dosing module  28  such that dosing module  28  may dose the urea exhaust treatment fluid directly into mixing assembly  80  where it may intermingle with the exhaust stream. 
     As previously described, region A experiences low peak exhaust stream velocities in comparison to regions B, C, D, E, and F. Although mixing assembly  80  assists in intermingling the exhaust with the urea exhaust treatment fluid to overcome the low velocities at region A, it is desirable to further mitigate the effect of the initial low velocities at region A on the atomization of the urea exhaust treatment fluid. Exhaust treatment component  1400 , therefore, includes ultrasonic transducers  1406  that assist in atomizing the urea exhaust treatment fluid immediately after dosing module  28  doses the exhaust treatment fluid into dosing module mount  1402  and before the urea exhaust treatment fluid enters mixing assembly  80 . It should be understood that any mixing assembly previously described may be used in conjunction with exhaust treatment component  1400  without departing from the scope of the present disclosure. 
     As best shown in  FIG. 45A , ultrasonic transducers  1406  are positioned on opposing sides of dosing module mount  1402 , and are configured to emit ultrasonic waves  1408  into dosing module mount  1402  in a direction transverse to a direction in which the urea exhaust treatment fluid is dosed into dosing module mount  1402 . In this manner, as ultrasonic waves  1408  propagate through dosing module mount  1402 , ultrasonic waves  1408  will pass through the urea exhaust treatment fluid and the energy of the ultrasonic waves  1408  will be transferred to the urea exhaust treatment fluid. This assists in atomizing the urea exhaust treatment fluid. Although it is preferable that ultrasonic transducers  1406  emit ultrasonic waves in a direction transverse to the dosing direction, the present disclosure contemplates that ultrasonic transducers  1406  can be configured to emit ultrasonic waves  1408  in directions toward or away from dosing module  28  as well. 
     Further, it should be understood that the number of ultrasonic transducers  1406  can be greater than two. As shown in  FIG. 45B , the ultrasonic transducers  1406  are arranged in rows  1403   a  and  1403   b  along dosing module mount  1402  in the axial direction. In addition, although only a pair of rows  1403   a  and  1403   b  are illustrated it should be understood than more than two rows  1403  are contemplated. Still further, it should be understood that each row  1403   a  and  1403   b  can include a number of ultrasonic transducers  1406  greater than two (e.g., 3, 4, 5, etc.). For example, three ultrasonic transducers  1406  can form each row  1403   a  and  1403   b , with each transducer  1406  being spaced apart by 60 degrees. In addition, the transducers  1406  of upper row  1403   a  can be offset relative to the transducers  1406  in the lower row  1403   b  by thirty degrees such that the upper row  1403   a  is staggered around a periphery of dosing module mount  1402  relative to the transducers  1406  in lower row  1403   b . These configurations are desirable when a larger diameter exhaust pipe is used. It should also be understood that dosing module mount  1402  is not necessarily required by the present disclosure. In contrast, it should be understood that ultrasonic transducers  1406  may be mounted to along any position of decomposition tube  82  where it is determined using computational flow dynamics (CFD) that the spray from injector  28  starts to break up due to interaction with the exhaust at high flow conditions. See the transducers  1406  illustrated in phantom in  FIG. 45 . 
     Ultrasonic transducers  1406  may communicate with controller  42  so that upon actuation of dosing module  28 , ultrasonic transducers  1406  can propagate ultrasonic waves  1408  into dosing module mount  1402 . Ultrasonic transducers  1406  can be operated simultaneously with dosing module  28 , or may be operated immediately before or following actuation of dosing module  28 . 
     In addition, ultrasonic transducers  1406  can be operated to increase or decrease the amount of ultrasonic energy provided to each ultrasonic wave  1408  based on various exhaust treatment system operating conditions. For example, atomization of the urea exhaust treatment fluid at cold exhaust temperatures is more difficult in comparison to atomization of the exhaust treatment fluid at hot exhaust temperatures. Ultrasonic transducers  1406 , therefore, can propagate ultrasonic waves  1408  having a greater amplitude (i.e., energy) or frequency when the exhaust temperatures are low to further assist in atomization. In contrast, when exhaust temperatures are higher, ultrasonic transducers  1406  can propagate ultrasonic waves  1408  having a lower amplitude (i.e., energy) or frequency when the need for assistance in atomizing the urea exhaust treatment fluid is not as great. 
     Other operating conditions include an amount of NOx in the exhaust stream, a temperature of the exhaust treatment fluid, and the exhaust flow conditions that are based flow uniformity conditions or pipe geometry that are determined using CFD. Regardless, when ultrasonic transducers  1406  are to increase or decrease the amplitude or frequency of the ultrasonic waves  1408  based on a particular exhaust treatment system operating condition, controller  42  receives a signal indicative of the particular operating condition from the respective sensor (e.g., exhaust temperature sensor, NOx sensor, or exhaust treatment fluid sensor). Upon receipt of the signal from the respective sensor, controller  42  is configured to instruct ultrasonic transducers  1406  accordingly. 
     Now referring to  FIG. 46 , an exhaust treatment component  1500  substantially similar to exhaust treatment component  20  illustrated in  FIGS. 22 and 23  is illustrated. In contrast to exhaust treatment component  20  illustrated in  FIGS. 22 and 23 , however, dosing module  28  may be positioned on a dosing module mount  1502  that is fixed to second portion  610  of conduit  606 . Although dosing module mount  1502  is illustrated in  FIG. 46  as being fixed to second portion  610  by welding, brazing, or the like, it should be understood that dosing module mount  1502  can be unitarily formed with second portion  610  without departing from the scope of the present disclosure. 
     Dosing module mount  1502  includes an aperture  1504  for receipt of dosing module  28 , which is operable to inject a reductant such as a urea exhaust treatment fluid into the exhaust stream before the exhaust stream passes through SCR  618 . Ultrasonic transducers  1506  are positioned on opposing sides of dosing module mount  1502 , and are configured to emit ultrasonic waves  1508  into dosing module mount  1502  in a direction transverse to a direction in which the urea exhaust treatment fluid is dosed into dosing module mount  1502 . In this manner, as ultrasonic waves  1508  propagate through dosing module mount  1502 , ultrasonic waves  1508  will pass through the urea exhaust treatment fluid and the energy of the ultrasonic waves  1508  will be transferred to the urea exhaust treatment fluid. This assists in atomizing the urea exhaust treatment fluid before travelling through mixing assembly  80 . It should be understood that any mixing assembly previously described may be used in conjunction with exhaust treatment component  1500  without departing from the scope of the present disclosure. 
     Similar to ultrasonic transducers  1406 , ultrasonic transducers  1506  may communicate with controller  42  so that upon actuation of dosing module  28 , ultrasonic transducers  1506  can propagate ultrasonic waves  1508  into dosing module mount  1502 . Ultrasonic transducers  1406  can be operated simultaneously with dosing module  28 , or may be operated immediately before or following actuation of dosing module  28 . In addition, ultrasonic transducers  1506  can be operated to increase or decrease the amount of ultrasonic energy provided to each ultrasonic wave  1508  based on various exhaust treatment system operating conditions as previously described. 
     Now referring to  FIG. 47 , an exhaust treatment component  1600  substantially similar to exhaust treatment component  702  illustrated in  FIGS. 25-30  is illustrated. In contrast to exhaust treatment component  702  illustrated in  FIGS. 25-30 , however, dosing module  28  may be positioned on a dosing module mount  1602  that is fixed to second portion end cap  722  of housing  706 . Although dosing module mount  1602  is illustrated in  FIG. 47  as being fixed to second portion end cap  722  by welding, brazing, or the like, it should be understood that dosing module mount  1602  can be unitarily formed with second portion end cap  722  without departing from the scope of the present disclosure. 
     Dosing module mount  1602  includes an aperture  1604  for receipt of dosing module  28 , which is operable to inject a reductant such as a urea exhaust treatment fluid into the exhaust stream before the exhaust stream passes through SCR  732 . Ultrasonic transducers  1606  are positioned on opposing sides of dosing module mount  1602 , and are configured to emit ultrasonic waves  1608  into dosing module mount  1602  in a direction transverse to a direction in which the urea exhaust treatment fluid is dosed into dosing module mount  1602 . In this manner, as ultrasonic waves  1608  propagate through dosing module mount  1602 , ultrasonic waves  1608  will pass through the urea exhaust treatment fluid and the energy of the ultrasonic waves  1608  will be transferred to the urea exhaust treatment fluid. This assists in atomizing the urea exhaust treatment fluid before travelling through mixing assembly  718 . It should be understood that any mixing assembly previously described may be used in conjunction with exhaust treatment component  1600  without departing from the scope of the present disclosure. 
     Similar to ultrasonic transducers  1406  and  1506 , ultrasonic transducers  1606  may communicate with controller  42  so that upon actuation of dosing module  28 , ultrasonic transducers  1606  can propagate ultrasonic waves  1608  into dosing module mount  1602 . Ultrasonic transducers  1606  can be operated simultaneously with dosing module  28 , or may be operated immediately before or following actuation of dosing module  28 . In addition, ultrasonic transducers  1606  can be operated to increase or decrease the amount of ultrasonic energy provided to each ultrasonic wave  1608  based on various exhaust treatment system operating conditions as previously described. 
     Now referring to  FIG. 48 , an exhaust treatment component  1700  substantially similar to exhaust treatment component  1000  illustrated in  FIG. 34  is illustrated. In contrast to exhaust treatment component  1000  illustrated in  FIG. 34 , however, dosing module  28  may be positioned on a dosing module mount  1702  that is fixed to end plate  1012  of hood  1002 . Although dosing module mount  1702  is illustrated in  FIG. 48  as being fixed to second portion end plate  1012  by welding, brazing, or the like, it should be understood that dosing module mount  1702  can be unitarily formed with end plate  1012  without departing from the scope of the present disclosure. 
     Dosing module mount  1702  includes an aperture  1704  for receipt of dosing module  28 , which is operable to inject a reductant such as a urea exhaust treatment fluid into the exhaust stream before the exhaust stream passes through SCR  70 . Ultrasonic transducers  1706  are positioned on opposing sides of dosing module mount  1702 , and are configured to emit ultrasonic waves  1708  into dosing module mount  1702  in a direction transverse to a direction in which the urea exhaust treatment fluid is dosed into dosing module mount  1702 . In this manner, as ultrasonic waves  1708  propagate through dosing module mount  1702 , ultrasonic waves  1708  will pass through the urea exhaust treatment fluid and the energy of the ultrasonic waves  1708  will be transferred to the urea exhaust treatment fluid. This assists in atomizing the urea exhaust treatment fluid before travelling through mixing assembly  1100 . It should be understood that any mixing assembly previously described may be used in conjunction with exhaust treatment component  1700  without departing from the scope of the present disclosure. 
     Similar to ultrasonic transducers  1406 ,  1506 , and  1606 , ultrasonic transducers  1706  may communicate with controller  42  so that upon actuation of dosing module  28 , ultrasonic transducers  1706  can propagate ultrasonic waves  1708  into dosing module mount  1702 . Ultrasonic transducers  1706  can be operated simultaneously with dosing module  28 , or may be operated immediately before or following actuation of dosing module  28 . In addition, ultrasonic transducers  1706  can be operated to increase or decrease the amount of ultrasonic energy provided to each ultrasonic wave  1708  based on various exhaust treatment system operating conditions as previously described. 
     Now referring to  FIGS. 49-51 , another exhaust treatment system  1800  will be described. Exhaust treatment system  1800  is similar to exhaust treatment system  1000  illustrated in  FIG. 34 . In this regard, exhaust treatment system  1800  includes exhaust treatment components  18  and  20 , where exhaust treatment component  18  may include a DOC  52  and/or a DPF  56  positioned within a housing  44  and exhaust treatment component  20  may include an SCR  70  and/or an ammonia slip catalyst  72  within a housing  64 . A common hood  1002  fluidly and mechanically connects exhaust treatment components  18  and  20 . 
     Hood  1002  includes a peripheral outer surface  1004  defining a connection flange  1006  for connecting to each housing  44  and  64 . Connection flange  1006  may be welded to each housing  44  and  64 , or connection flange  1006  may be secured to each housing  44  and  64  using a clamp  1005 . To prevent exhaust gases from escaping hood  1002  as the exhaust gases travel from exhaust treatment component  18  to exhaust treatment component  20 , a solid connection plate  1008  may be positioned between exhaust treatment component  18  and exhaust treatment component  20 . Connection plate  1008  may include apertures  1010  for receipt of housings  44  and  64 . To ensure a gas-tight fit between connection plate  1008  and housings  44  and  64 , connection plate  1008  may be welded to each housing  44  and  64 , or a gasket (not shown) may be positioned between housings  44  and  64  and apertures  1010 . An end plate  1012  of hood  1002  is integral with peripheral outer surface  1004 . End plate  1012  may include a contoured surface  1014  at exhaust treatment component  18  that assists in directing the exhaust gases toward exhaust treatment component  20 . In addition, hood  1002  may include a mounting device  1016  for receipt of a dosing module  28  operable to dose reagent exhaust treatment fluid into the exhaust gases. 
     Exhaust treatment system  1800  includes a mixing assembly  1802  positioned upstream from SCR  70  that assists in intermixing the exhaust gases and reagent exhaust treatment fluid. As illustrated in  FIG. 49 , mixing assembly  1802  extends between hood  1002  and exhaust treatment component  20 . To secure mixing assembly  1802  between hood  1002  and exhaust treatment component  20 , a solid partition plate  1018  that axially aligns mixing assembly  1802  with SCR  70  may be used. Partition plate  1018  includes a central axially extending flange  1020  that is coupled to decomposition tube  1804  of mixing assembly  1802  by welding or any other attachment method known to one skilled in the art. Partition plate  1018  may be secured to housing  64  or may be secured to connection plate  1008 . After the exhaust exits mixing assembly  1802 , the exhaust gas may pass through a perforated baffle ring  1022  positioned upstream from SCR  70  that further assists in intermingling the exhaust gases and reagent exhaust treatment fluid. Baffle ring  1022  may be secured to an interior surface  1024  of housing  64 . Alternatively, baffle ring  1022  can be secured in a separate housing that is coupled to an end of housing  64 . 
     As illustrated in  FIG. 49 , mixing assembly  1802  includes decomposition tube  1804  that is devoid of the perforated first end portion  84  utilized in previously-described embodiments (e.g.,  FIG. 8 ). Decomposition tube  1804 , rather, includes a radially expanded portion  1806  as an inlet at a first end portion  1808  thereof. Radially expanded portion  1806  includes a conically-expanding portion  1810  that expands the decomposition tube  1802 , a cylindrical portion  1812  downstream from the conically-expanding portion  1810 , and a conically-narrowing portion  1814  that radially narrows decomposition tube  1804 . A second end portion  1816  is connected to conically-narrowing portion  1814 , and extends toward a flow-reversing device  1818 . Although not illustrated, it should be understood that flow-reversing device  1818  can include deflecting members like those in the previously-described above embodiments that assist in creating turbulent flow in the exhaust stream as the exhaust stream flows through flow-reversing device  1818 . 
     In lieu of decomposition tube  1804  including perforated first end portion  84 , mixing assembly  1802  includes a perforated swirl device  1820 . As best shown in  FIGS. 50 and 51 , perforated swirl device  1820  includes a perforated cylindrical tube defining an inlet  1822  that includes a plurality of perforations or apertures  1824 . Perforations  1824  are illustrated as being staggered about a circumference of inlet  1822 , but it should be understood that the arrangement of perforations  1824  and size of the perforations  1824  can vary to assist in creating turbulence and increasing velocity of the exhaust stream as it enters perforated swirl device  1820 . In addition, as the exhaust enters inlet  1822 , the exhaust will be begin to swirl which, as the reagent exhaust treatment fluid is dosed into the exhaust stream by injector  28 , will keep the reagent exhaust treatment fluid suspended along axis A of swirl device  1820  as it travels along axis A toward exhaust treatment component  70 ,  72 . Although not illustrated in  FIGS. 50 and 51 , it should be understood that perforated swirl device  1820  may also include a perforated collar  98  like that shown in  FIG. 9  without departing from the scope of the present disclosure. 
     A terminal end  1826  of inlet  1822  is configured to be fixed to end plate  1012  at aperture  1026  by welding or the like where injector mounting device  1016  is located so that the urea exhaust treatment fluid can be injected directly into inlet  1822 . Alternatively, terminal end  1826  may be spaced apart from end plate  1012  and include a flared edge (not shown) similar to the embodiment illustrated in  FIG. 36 . Another alternative is for exhaust treatment system  1800  to include dosing module mount that includes ultrasonic transducers like that shown in  FIG. 48 . In such a configuration, inlet  1822  may be fixed to an opposing surface of end plate  1012  at a location where dosing module mount is fixed to end plate  1012 . 
     A swirl member  1828  is attached to inlet  1822 . Swirl member  1828  may be unitary with inlet  1822 , or swirl member  1828  can be separately manufactured and then fixed to inlet  1822  by welding, brazing, or the like. Swirl member  1828  is preferably fixed to first end portion  1808  of decomposition tube  1804  by welding, brazing, or the like. Alternatively, swirl member  1828  may extend into decomposition tube  1804  (not shown). In such a configuration, however, it should be understood that a support baffle (not shown) will be required to support swirl device  1820 . Regardless, swirl member  1828  is a collar-like member that conically expands outward from inlet  1822  and includes a plurality of apertures that allows a portion of the exhaust to bypass inlet  1822  and enter decomposition tube  1804 . Specifically, swirl member  1828  includes a plurality of tabs  1830  separated by elongate slots  1832 . Slots  1832  are illustrated in  FIGS. 50 and 51  as including a first portion  1832   a  and a second portion  1832   b , with an obtuse angle being defined between first portion  1832   a  and  1832   b . It should be understood, however, that slot  1832  can be linear or extend substantially co-axially with an axis A of swirl member  1828  without departing from the scope of the present disclosure. 
     Tabs  1830  each include a main body portion  1834  that assists in defining the conical expansion of swirl member  1828  outward from inlet  1822 . Main body portions  1834  include a first end  1836  attached to inlet  1822 , and a second end  1838  distal from inlet  1822 . As illustrated in  FIGS. 50 and 51 , second ends  1838  are bent relative to first ends  1836  in a radially inward direction. 
     Tabs  1830  also each include a swirl portion  1840  that extend in the circumferential direction about swirl member  1828 . In other words swirl portions  1840  extend axially away from main body portion  1834  in a downstream direction. Swirl portions  1840  are bent in an axially downward direction relative to main body portions  1834 , and are designed to induce a swirl in the exhaust stream as it passes over swirl portions  1840 . Each swirl portion  1840  can be identically bent relative main body portions  1834 , or each swirl portion  1840  can be bent to a different degree relative to main body portion  1834  in comparison to other tabs  1830  of swirl device  1822 . That is, it should be understood that the orientation of each swirl portion  1840  can be individually tailored, as desired. Further, it should be understood that swirl portions  1840  may be helically twisted to swirl the mixture of exhaust gas and reagent exhaust treatment fluid as the mixture passes through decomposition tube  1804 . Regardless, swirl member  1828  further assists in the intermingling of the exhaust gas and the reagent exhaust treatment fluid as it passes through decomposition tube before reaching flow-reversing device  1818 , and also maintains the reagent exhaust treatment fluid suspended along axis A away from walls of decomposition tube  1804 . This prevents, or at least substantially minimizes, the build-up of deposits in decomposition tube  1804 . 
     Alternatively, swirl device  1820  may be replaced by swirl device  1820   a  illustrated in  FIG. 52 . The swirl device  1820   a  may include a tubular portion  1821  defining an inlet portion  1822   a , and a swirl member  1828   a . A first portion of the exhaust gas flowing through the exhaust pipe  12  may flow into the tubular portion  1821  and a second portion of the exhaust gas may flow around the tubular portion  1821  and through the swirl member  1828   a . The tubular portion  1821  may include a plurality of openings  1823  and a plurality of deflectors  1825  arranged in rows extending around the diameter of the tubular portion  1821  and in columns extending along an axial length of the tubular portion  1821 . The deflectors  1825  may be partially cut or stamped out of the tubular portion  1821  (thereby forming the openings  1823 ) and bent inward into the tubular portion  1821 . 
     Some of the exhaust may enter the tubular portion  1821  through the openings  1823  and may be directed by the deflectors  1825  in a rotational direction to generate a first swirling flow pattern (e.g., in a clockwise direction) within the tubular portion  1821 . This swirling flow pattern facilitates atomization of the reagent exhaust treatment fluid and mixing of the reagent exhaust treatment fluid with the exhaust gas. The swirling flow pattern also restricts or prevents impingement of the reagent exhaust treatment fluid on the surfaces of the tubular portion  1821 , which reduces the formation and/or buildup of reductant deposits on the tubular portion  1821 . As the reagent/exhaust mixture reaches swirl member  1828   a , the tabs  1830   a  will generate a second swirling flow pattern that may be opposite to that of the first swirling flow pattern (e.g., in a counter-clockwise direction). The opposite flow pattern balances the flow through swirl device  1820   a . In some embodiments, the swirl device  1820   a  may include a hydrolysis coating to further reduce the formation and/or buildup of reductant deposits thereon. 
     While the deflectors  1825  are shown in  FIG. 52  as extending inward into the tubular portion  1821 , in some embodiments, the deflectors  1825  may be formed to extend outward from the tubular portion  1821  (not shown). With the deflectors  1825  extending radially outward, the opportunity for reductant deposits to form on the deflectors  1825  may be further reduced, while the swirling flow pattern within the tubular portion  1821  is still able to be effectively generated. 
     With reference to  FIG. 53 , another swirl device  1820   b  is illustrated that may be used instead of the swirl devices  1820  and  1820   a . The structure and function of the swirl device  1820   b  may be similar or identical to that of swirl devices  1820  and  1820   a , apart from any differences described below and/or shown in the figure. The swirl device  1820   b  may include a tubular portion  1821   b  including a plurality of blades  1827  extending from a downstream end  1829  of the tubular portion  1821   b , as well as an upstream portion  1831 . As described above with respect to the swirl devices  1820  and  1820   a , the swirl device  1820   b  may induce turbulence in the flow of exhaust gas to facilitate mixing of the reductant with the exhaust gas. 
     The tubular portion  1821   b  may a plurality of openings  1823   b . While the openings  1823   b  shown in  FIG. 53  have a circular shape, it will be appreciated that the openings  1823   b  could have any shape, such as rectangular, square, or oval, for example. Furthermore, the size of each opening  1823   b  and the total number of openings  1823   b  can vary, as well. The openings  1823   b  may be arranged in a plurality of parallel rows extending circumferentially around the tubular portion  1821   b , or may be misaligned with each other. 
     The blades  1827  may extend downstream away from the downstream end  1829  of the tubular portion  1821   b  and radially outward therefrom. The blades  1827  curve as they extend downstream. As shown in  FIG. 53 , the blades  1827  and the tubular portion  1821   b  may define a unitary body integrally formed from a common sheet of material. Transitions  1833  between the tubular portion  1821   b  and the blades  1827  may be smooth, edgeless and/or seamless. That is, the transitions  1833  may not include steps or ridges, for example. The smooth, edgeless transitions  1833  may reduce backpressure in the flow of exhaust through the swirl device  1820   b . The smooth, edgeless transitions  1833  may also reduce or prevent the buildup of reductant deposits and/or other deposits on the swirl device  1820   b.    
     In some embodiments, the blades  1827  may include a generally L-shaped cross section or profile. In this manner, a first portion  1835  of each blade  1827  may extend substantially radially outwardly and a second portion  1837  of each blade  1827  may extend substantially in the downstream direction. In some embodiments, the blades  1827  may have a generally helical shape. In some embodiments, the blades  1827  may be generally flattened and angled, rather than helical. The precise number, shape and spacing of the blades  1827  may be varied. The shape and configuration of the blades  127  promote turbulence in the exhaust gas flow while reducing backpressure relative to other blade configurations. That is, the blades  1827  may be designed so that most or all of the structure that increases backpressure will also generate turbulence (i.e., the swirl device  1820   b  has very little structure that increases backpressure without also increasing turbulence). It will be appreciated that any suitable number, shape and/or spacing may be employed to suit a given application. 
     With reference to  FIG. 54 , another swirl device  1820   c  is illustrated that may be used instead of swirl devices  1820 ,  1820   a , and  1820   b . The structure and function of the swirl device  1820   c  may be similar or identical to that of either of the swirl devices  1820 ,  1820   a , and  1820   b , apart from any differences described below and/or shown in the figure. Therefore, similar features will not be described again in detail. 
     The mixing pipe  1820   c  may include a tubular portion  1821   c  and a plurality of blades  1827   c . The tubular portion  1821   c  may include a plurality of openings  1823   c . Deflectors  1825   c  may be partially cut or stamped out of the tubular portion  1821   c  (thereby forming the openings  1823   c ) and may extend generally radially outward from the tubular portion  1823   c  and in a generally upstream direction. As described above, the deflectors  1825   c  may increase the turbulence of the fluid flow and promote a swirling motion in the fluid flow. 
     Now referring to  FIGS. 55-58 , a flow reversing device  1900  will be described. Flow reversing device  1900  is similar to previously described flow reversing device  1300  in that flow reversing device  1900  is a substantially cup-shaped member  110  having a central bulge  112  formed therein. Flow reversing device  1900  has a diameter greater than that of second end portion  86  of decomposition tube  82  such that as the exhaust flow enters the cup-shaped member  110 , the exhaust flow will be forced to flow in a reverse direction. Reversing the flow direction assists in intermingling of the reagent exhaust treatment fluid and the exhaust stream before the exhaust stream reaches SCR  70 . 
     Flow reversing device  1900  can include a plurality of deflecting members  1302  coupled to second end portion  86  of decomposition tube  82 . Deflecting members  1302  further assist in intermingling the reagent exhaust treatment fluid and the exhaust stream. Deflecting members  1302  may be formed as a plurality of helically curved vanes  1306 . Vanes  1306  induce a high turbulence swirl of the exhaust stream to increase intermingling of the reagent exhaust treatment fluid and the exhaust gases. The high turbulence swirl generated by vanes  1306  results in the reagent exhaust treatment fluid being circumferentially distributed throughout the exhaust stream as it is swirled by vanes  1306 . It should be understood that the number of vanes  1306  is variable. Moreover, the helical pitch of vanes  1306  may also be varied dependent on the amount of swirl desired to be generated. It should also be understood that flow reversing device  1900  can be used in conjunction with any of the decomposition tubes  82  described previously, including tubes  82  with a radially expanded portion  88 , a radially narrowed portion  902 , a flared edge  1102  ( FIG. 26 ), a truncated first portion  84  ( FIG. 39 ), and a perforated swirl device  1802  ( FIGS. 50-54 ). 
     Although the high turbulence swirl generated by vanes  1306  is efficient at intermingling the exhaust treatment fluid with the exhaust stream, the velocity distribution of the exhaust stream after passing over vanes  1306  is affected. To normalize the velocity distribution of the exhaust stream after passing over vanes  1306  in cup-shaped member  110 , flow reversing device  1900  includes swirl arrester device  1910  positioned downstream from vanes  1306  in cup-shaped member  110 . Swirl arrester device  1910  includes a cylindrical ring  1912  that includes a plurality of radially inwardly extending blade members  1914 . Blade members  1914  can be unitary with cylindrical ring  1912  such that blade members  1914  are punched from the material that forms cylindrical ring  1912 , or blade members  1914  can be separately manufactured and attached to cylindrical ring  1912  by welding, brazing, or the like. Regardless, blade members  1914  are angled or helically twisted relative to cylindrical ring  1912  and are configured to reduce the swirl generated by vanes  1306 . The number of blade members  1914  can be varied, dependent on the velocity profiles of the exhaust gases as the exhaust stream exits cup-shaped member  110 . 
     More specifically, it should be understood that blade members  1914  are not configured to reverse the swirl generated by vanes  1306 . Rather, blade members  1914  are configured to reduce, stop, or arrest the swirl generated by vanes  1306 . In this manner, the velocity profiles of the exhaust gases can be more evenly distributed throughout the exhaust stream, which assists in conducting the selective catalytic reduction of NOx in the exhaust stream as it passes through the SCR substrate. Accordingly, the number of blade members  1914  used to reduce, stop, or arrest the swirl generated by vanes  1306  can be selected such that a reverse swirl is not generated by blade members  1914  during high flow conditions. The number of blade members  1914  selected is based on high flow conditions because the blade members  1914  influence the exhaust flow to a greater extent during high flow conditions in comparison to low flow conditions. 
     Cylindrical ring  1912  can be coupled to an interior surface of exhaust treatment component  20  with blade members extending radially inward toward cup-shaped member  110  including vanes  1306 . Alternatively, blade members  1914  can be coupled to an exterior surface  1916  of cup-shaped member  110  such that cylindrical ring  1912  is spaced apart from the interior surface of exhaust treatment component  20 . 
     Alternatively, as shown in  FIGS. 57 and 58 , blade members  1914  can be separately manufactured and attached about an interior circumference of exhaust treatment component  20 . In this regard, blade members  1914  can be prefabricated and helically twisted (or twisted like a ribbon with 360 degree rotation) as desired before being attached to the interior surface of exhaust treatment component  20  by welding, brazing, or any other attachment method known to one skilled in the art. Blade members  1914  may also include a reinforcing rib  1915  ( FIG. 57 ) that prevents deformation of blade members  1914  during high flow conditions, or a plurality of through holes  1917  that increase turbulence in the exhaust flow. In addition, blade members  1914  can have a width D that changes along a length thereof ( FIG. 58 ). In another alternative embodiment, a twist angle of blade members  1914  can change along a length thereof. Regardless, similar to the above-described embodiment, blade members  1914  are not configured to reverse the swirl generated by vanes  1306 . Rather, blade members  1914  are configured to reduce, stop, or arrest the swirl generated by vanes  1306 . In this manner, the velocity profiles of the exhaust gases can be more evenly distributed throughout the exhaust stream, which assists in conducting the selective catatytic reduction of NOx in the exhaust stream as it passes through the SCR substrate. Accordingly, the number of blade members  1914  used to reduce, stop, or arrest the swirl generated by vanes  1306  can be selected such that a reverse swirl is not generated by blade members  1914 . It should also be understood that individual blade members  1914  can be oriented or shaped to account for a greater or lesser degree of swirl arrest in comparison to the other blade members  1914  based on specific flow characteristics of a particular exhaust after-treatment system. 
       FIG. 59  illustrates a variation of exhaust treatment component  800 . Specifically, exhaust treatment component  800  in  FIG. 59  includes an exhaust mixing device  1900   a  that includes at least one of the swirl arrester devices  1910  described above. Swirl arrester devices  1910  may be positioned within and fixed to decomposition tube  84  to arrest swirling of the exhaust as it enters decomposition tube  84 . In another configuration, swirl arrester device  1910  may be positioned downstream from flow reversing device  740  to arrest swirling of the exhaust as it exits reversing device  740 . In this regard, cylindrical ring  1912  may be fixed to shell  758 . In yet another configuration, swirl arrester device  1910  may be fixed within inner sleeve  818  to arrest swirling of the exhaust before it exits exhaust treatment component  800 . As noted above, component  800  includes at least one of the swirl arrester devices  1910 . Preferably, component  800  includes at least two of the swirl arrester devices  1910 . Most preferably, component  800  includes each of the three swirl arrester devices  1910 . Although not illustrated, a swirl arrester device  1910  may be fixed (e.g., welded or monolithically formed) to central bulge  112  (see  FIGS. 7-9 ) of flow reversing device  740 . 
     Now referring to  FIGS. 60-61 , another exhaust treatment system  2000  will be described. Exhaust system  2000  is similar to exhaust treatment system  1000  illustrated in  FIG. 34  in that exhaust system  2000  includes exhaust treatment components  18  and  20 , where exhaust treatment component  18  may include a DOC  52  and/or a DPF  56  positioned within a housing  44  and exhaust treatment component  20  may include an SCR  70  and/or an ammonia slip catalyst  72  within a housing  64 . A common hood  1002  fluidly and mechanically connects exhaust treatment components  18  and  20 . 
     Exhaust treatment system  2000  includes a mixing assembly  2100  positioned upstream from SCR  70  that assists in intermixing the exhaust gases and reagent exhaust treatment fluid. As illustrated in  FIG. 60 , mixing assembly  2100  extends between hood  1002  and exhaust treatment component  20 . As best shown in  FIG. 61 , mixing assembly  2100  includes decomposition tube  82  with radially expanded portion  88 . It should be understood, however, that decomposition tube  82  can be entirely cylindrical or include a radially narrowed portion like mixing assembly  900  illustrated in  FIG. 33 . First end portion  84  of decomposition tube  82  may include a flared edge  1102 . Flared edge  1102  increases the diameter of first end  84  of decomposition tube  82 , and is designed to increase the ease with which the exhaust gases may enter mixing assembly  2100 . By increasing the ease with which the exhaust gases may enter mixing assembly  2100 , backpressures within exhaust treatment system  2000  may also be reduced. It should be understood that although  FIG. 60  illustrates first end  84  of decomposition tube  82  as being devoid of perforations  96 , the present disclosure contemplates the use of perforations  96  in first end  84  as illustrated in  FIG. 36 . 
     As in previously described embodiments, perforations  96  can vary in size around the circumference of first end  84 , and assist in creating turbulence and increasing velocity of the exhaust stream as it enters decomposition tube  82 . Moreover, although not illustrated in  FIG. 61 , it should be understood that mixing assemblies  2100  may also include a perforated collar  98  like that shown in  FIG. 9  without departing from the scope of the present disclosure. Similar to previously described embodiments, mixing assembly  2100  includes a flow reversing device  106  at second end  86 . Any of the flow reversing devices  106  such as those illustrated in  FIGS. 7 ,  11 ,  15 ,  19 ,  21 ,  41 ,  44 , and  52  may be used. 
     Although exhaust treatment system  2000  has been described above as including a mixing assembly  2100  spaced apart from end plate  1012 , it should be understood that the present disclosure should not be limited thereto. Specifically, as best shown in  FIG. 37 , it can be seen that hood  1002  can include an aperture  1026  for receipt of first end portion  84  of decomposition tube  82  such that decomposition tube  82  can be directly attached to end plate  1012  of hood  1002 . To mount dosing module (not shown) relative to end plate  1012  and decomposition tube  82 , a mounting ring  1028  can be secured to first end portion  84  such that dosing module can dose the reagent exhaust treatment fluid directly into decomposition tube  82 . 
     Mixing assembly  2100  may additionally include a static mixer  2104  positioned within decomposition tube  82  at a location upstream from flow reversing device  106 . Static mixer  2104  may include a plurality of mixing blades  2106  secured within a mounting ring  2108  that is secured by an interference fit or welding to an interior surface  2110  of decomposition tube  82 . Preferably, static mixer  2104  is positioned between first end  84  and second end  86  at radially expanded portion  88 . Mixing blades  2106  may be slightly twisted to swirl the mixture of exhaust gas and reagent exhaust treatment fluid as the mixture passes through decomposition tube  82 . 
     Injector  28  in exhaust treatment system  2000  is configured to dose the exhaust stream with a urea exhaust treatment fluid. Specifically, the injector  28  includes an orifice (not shown) that forms a plurality of spray paths of the urea exhaust treatment fluid. As best shown in  FIG. 60 , injector  28  is configured to form three (or four, five, six, etc.) conical spray paths  2111  of the urea exhaust treatment fluid when the injector  28  is actuated. With the number of spray paths  2111  in mind, static mixer  2104  can be configured to include a number of mixing blades  2106  that is equal to the number of spray paths  2111 . For example, in the exemplary embodiment illustrated in  FIG. 61 , static mixer  2104  includes three mixing blades  2106  that is equal to the number of spray paths  2111  illustrated in  FIG. 60 . 
     Further, mixing blades  2106  can be aligned with spray paths  2111  such that each spray path will impinge on a respective mixing blade  2106  and assist in breaking up large droplets of the urea exhaust treatment fluid. To align each of the spray paths  2111  and the mixing blades  2106 , injector  28  is first aligned relative to common hood  1002 . In this regard, injector  28  may include an alignment feature (not shown) that may align with an alignment feature (not shown) formed on common hood  1002 . Once injector  28  is properly aligned, mixing blades  2106  can be aligned with spray paths  2111 . 
     When mixing blades  2106  are aligned with spray paths  2111 , mixing blades  2106  may include a plurality of through-holes  2113  for allowing any collected urea exhaust treatment fluid to pass through mixing blades  2106 . In this manner, the formation of urea deposits can be prevented, or at least substantially minimized. It should be understood that the number and/or size of through-holes  2113  can be varied according to system requirements. In addition, it should be understood that through-holes  2113  can be configured to include a louver (not shown) that generates swirl in the exhaust. In an alternative configuration, mixing blades  2106  can be aligned such that spray paths  2111  do not impinge on mixing blades  2106 . In such a configuration, it is desirable that flow reversing device  106  include through holes  1202  like those illustrated in  FIG. 41  to allow any collected urea exhaust treatment fluid to pass through mixing assembly  2100 , if needed. In yet another embodiment illustrated in  FIG. 60A , it can be seen that decomposition tube  82  includes a plurality of ultrasonic transducers  1406  that are arranged to correspond to each of the conical flow paths  2111  emitted by injector  28 . By clocking the ultrasonic transducers  1406  with the conical flow paths  2111 , the break-up and atomization of the reagent exhaust treatment fluid can be enhanced. In such a configuration, it should be understood that static mixer  2104  is not necessarily present. 
     Static mixer  2104  can include a support rod  2112  that axially extends from mixing blades  2106  in a direction toward flow reversing device  106 . Support rod  2112  provides an attachment point for flow reversing device  106  such that flow reversing device  106  may be secured to support rod  2112  by welding, brazing, or the like. The use of support rod  2112  to secure flow reversing device  106  relative to decomposition tube  82  removes the need for a separate support baffle (now shown) that secures flow reversing device  106  to an interior surface of housing  64 . It should be understood, however, that static mixer  2104  is not required to include support rod  2112 . 
     Although static mixer  2104  is described above as having a plurality of mixing blades  2106 , it should be understood that other types of static mixers can be used as is known in the art. For example, plate mixer or a perforated mixer can be used without departing from the scope of the present disclosure. In addition, a mesh screen can be used without departing from the scope of the present application. More particularly, as best shown in  FIG. 62 , a static mixer  2104   a  is illustrated including an outer cylindrical mounting ring  2108   a  and an inner cylindrical mounting ring  2108   b . A plurality of mesh screens  2150  connect outer mounting ring  2108   a  to inner mounting ring  2108   b . Mesh screens  2150  may be round, oval-shaped, or any other shape desired by one skilled in the art so long as each mesh screen  2150  is aligned with a conical spray path  2111  emitted by injector  28 . Accordingly, the number of mesh screens  2150  is preferably equal to the number of conical spray paths  2111  emitted by injector  28 . In addition, it should be understood that mesh screens  2150  can be shaped like blade members  2106  (e.g., twisted) without departing from the scope of the present disclosure. Similar to static mixer  2104 , mixer  2104   a  is configured to be mounted within decomposition tube  82 . 
       FIGS. 63 and 64  illustrate alternative configurations for the decomposition tubes  82  described in the above-noted exemplary configurations. In this regard, the decomposition tubes  82   a  and  82   b  illustrated in  FIGS. 63 and 64 , respectively, can be used in the configurations illustrated in each of  FIGS. 6 ,  7 ,  10 ,  14 ,  17 ,  20 ,  23 ,  29 ,  32 - 38 ,  41 ,  43 ,  45 - 49 ,  55 ,  57 , and  59 - 61  without departing from the scope of the present disclosure. In  FIG. 63 , decomposition tube  82   a  includes a first end portion  84   a  and a second end portion  86   a . Decomposition tube  82   a  may be substantially cylindrical, with a radially expanded portion  88   a  positioned between the first and second end portions  84   a  and  86   a . Radially expanded portion  88   a  includes a conically-expanding portion  90   a  that expands the decomposition tube  82   a , a cylindrical portion  92   a  downstream from the conically-expanding portion  90   a  having a diameter that is greater than that of first and second end portions  84   a  and  86   a , and a conically-narrowing portion  94   a  that narrows decomposition tube  82   a . It should be understood that first and second end portions  84   a  and  86   a  may have different diameters, without departing from the scope of the present disclosure. It should also be understood that the present disclosure does not require conically-narrowing portion  94   a . That is, radially expanded portion  88   a  may extend over the entire length of second end portion  86   a.    
     First end portion  84   a  includes a plurality of louvered panels  85   a . Louvered panels  85   a  may each include a length L3 that extends substantially along an entire length of first end portion  84   a . Louvered panels  85   a  may be stamped from first end portion  84   a , and may be tilted either radially outward or radially inward such that a plurality of elongate slots  87   a  are formed in first end portion  84   a  that allow the exhaust gas to enter first end portion  84   a . An angle of inclination may be varied for each louvered panel  85   a  such that each louvered panel  85   a  is tilted the same amount, or each louvered panel  85   a  is tilted a different amount. Louvered panels  85   a  assist in creating a high-velocity swirl within the first end portion  84   a  such that the mixture of exhaust treatment fluid and the exhaust gases will prevent or substantially prevent impinging of the mixture on an inner surface of the decomposition tube  82   a . While first end portion  84   a  of decomposition tube  82   a  is illustrated as being cylindrical, it should be understood that first end portion  84   a  can be cone-shaped without departing from the scope of the present disclosure. Although louvered panels  85   a  and elongate slots  87   a  are illustrated as extending axially along a length of the first end portion  84   a , it should be understood that louvered panels  85   a  and elongate slots  87   a  may be angled around a circumference of first end portion  84   a . A size and shape of louvered panels  85   a  and elongate slots  87   a  may also be variable. 
     In  FIG. 64 , decomposition tube  82   b  includes a first end portion  84   b  and a second end portion  86   b . Decomposition tube  82   b  may be substantially cylindrical, with a radially expanded portion  88   b  positioned between the first and second end portions  84   b  and  86   b . Radially expanded portion  88   b  includes a conically-expanding portion  90   b  that expands the decomposition tube  82   b , a cylindrical portion  92   b  downstream from the conically-expanding portion  90   b  having a diameter that is greater than that of first and second end portions  84   b  and  86   b , and a conically-narrowing portion  94   b  that narrows decomposition tube  82   b . It should be understood that first and second end portions  84   b  and  86   b  may have different diameters, without departing from the scope of the present disclosure. It should also be understood that the present disclosure does not require conically-narrowing portion  94   b . That is, radially expanded portion  88   b  may extend over the entire length of second end portion  86   b.    
     First end portion  84   b  includes a plurality of louvered panels  85   b . Louvered panels  85   b  may each include a length L4 that extends substantially along a half to three-quarters a length of first end portion  84   b . Louvered panels  85   b  may be stamped from first end portion  84   b , and may be tilted either radially outward or radially inward such that a plurality of elongate slots  87   b  are formed in first end portion  84   b  that allow the exhaust gas to enter first end portion  84   b . An angle of inclination may be varied for each louvered panel  85   b  such that each louvered panel  85   b  is tilted the same amount, or each louvered panel  85   b  is tilted a different amount. Louvered panels  85   b  assist in creating a high-velocity swirl within the first end portion  84   b  such that the mixture of exhaust treatment fluid and the exhaust gases will prevent or substantially prevent impinging of the mixture on an inner surface of the decomposition tube  82   b . While first end portion  84   b  of decomposition tube  82   b  is illustrated as being cylindrical, it should be understood that first end portion  84   b  can be cone-shaped without departing from the scope of the present disclosure. Although louvered panels  85   b  and elongate slots  87   b  are illustrated as extending axially along a length of the first end portion  84   b , it should be understood that louvered panels  85   b  and elongate slots  87   b  may be angled around a circumference of first end portion  84   b . A size and shape of louvered panels  85   b  and elongate slots  87   b  may also be variable. 
     Decomposition tube  82   b  may also include perforations  96   b  that can vary in size around the circumference of first end portion  84   b , and assist in creating turbulence and increasing a velocity of the exhaust stream as it enters decomposition tube  82   b . Although perforations  96   b  are illustrated as being positioned in a pair of rows around a circumference of first portion  84   b , it should be understood that perforations  96   b  can be staggered without departing from the scope of the present disclosure. 
     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.