Systems and methods for mixing exhaust gas and reductant

Abstract

A mixing assembly for an exhaust aftertreatment system includes: a mixing body including upstream and downstream mixing body openings, the upstream mixing body opening configured to receive exhaust gas; an upstream plate coupled to the mixing body, the upstream plate including a plurality of upstream plate openings, each of the plurality of upstream plate openings configured to receive a flow percentage that is less than 50% of a total flow of the exhaust gas; a downstream plate coupled to the mixing body downstream from the upstream plate in a direction of exhaust gas flow, the downstream plate including a downstream plate opening; and a swirl plate positioned between the upstream plate and the downstream plate and defining a swirl collection region and a swirl concentration region, the swirl collection region positioned over the plurality of upstream plate openings and the swirl collection region positioned over the downstream plate opening.

What is claimed is: 
     
         1 . A mixing assembly for an exhaust aftertreatment system, the mixing assembly comprising:
 a mixing body comprising an upstream mixing body opening and a downstream mixing body opening, the upstream mixing body opening configured to receive exhaust gas;   an upstream plate coupled to the mixing body, the upstream plate comprising a plurality of upstream plate openings, each of the plurality of upstream plate openings configured to receive a flow percentage that is less than 50% of a total flow of the exhaust gas;   a downstream plate coupled to the mixing body downstream from the upstream plate in a direction of exhaust gas flow, the downstream plate comprising a downstream plate opening; and   a swirl plate positioned between the upstream plate and the downstream plate and defining a swirl collection region and a swirl concentration region contiguous with the swirl collection region, the swirl collection region positioned over the plurality of upstream plate openings and the swirl collection region positioned over the downstream plate opening.   
     
     
         2 . The mixing assembly of  claim 1 , wherein the plurality of upstream plate openings comprises a first upstream plate opening that is configured to receive a first flow percentage that is less than 40% of the total flow of the exhaust gas. 
     
     
         3 . The mixing assembly of  claim 2 , wherein the plurality of upstream plate openings further comprises a second upstream plate opening that is configured to receive a second flow percentage that is less than 10% of the total flow of the exhaust gas. 
     
     
         4 . The mixing assembly of  claim 1 , further comprising a splash plate positioned between the upstream plate and the downstream plate and located in the swirl collection region, the splash plate comprising a plurality of splash plate openings. 
     
     
         5 . The mixing assembly of  claim 4 , further comprising an injector mount coupled to the mixing body and configured to be coupled to an injector such that an injector center axis of the injector extends into the swirl collection region;
 wherein the splash plate is coupled to the upstream plate and the downstream plate.   
     
     
         6 . The mixing assembly of  claim 5 , wherein the injector center axis intersects the splash plate. 
     
     
         7 . The mixing assembly of  claim 1 , wherein:
 the plurality of upstream plate openings comprises:
 a first upstream plate opening that is configured to receive a first flow percentage that is between 20% and 40%, inclusive of the total flow of the exhaust gas; and 
 a second upstream plate opening that is configured to receive a second flow percentage that is between 20% and 40%, inclusive of the total flow of the exhaust gas; and 
   the second flow percentage is less than the first flow percentage.   
     
     
         8 . The mixing assembly of  claim 7 , wherein:
 the plurality of upstream plate openings further comprises:
 a third upstream plate opening that is configured to receive a third flow percentage that is between 4% and 20%, inclusive of the total flow of the exhaust gas; and 
 a fourth upstream plate opening that is configured to receive a fourth flow percentage that is between 4% and 15%, inclusive of the total flow of the exhaust gas; 
   the third flow percentage is less than the second flow percentage; and   the fourth flow percentage is less than the third flow percentage.   
     
     
         9 . The mixing assembly of  claim 8 , wherein:
 the plurality of upstream plate openings further comprises a fifth upstream plate opening that is configured to receive a fifth flow percentage that is between 1% and 5%, inclusive, of the total flow of the exhaust gas; and   the fifth flow percentage is less than the fourth flow percentage.   
     
     
         10 . The mixing assembly of  claim 1 , further comprising an injector mount coupled to the mixing body and configured to be coupled to an injector such that an injector center axis of the injector extends into the swirl collection region;
 wherein the injector center axis does not intersect the swirl plate.   
     
     
         11 . The mixing assembly of  claim 10 , wherein:
 the mixing body is centered on a mixing body center axis; and   the injector mount is configured such that the injector center axis is orthogonal to the mixing body center axis.   
     
     
         12 . A mixing assembly comprising:
 a mixing body comprising an upstream mixing body opening and a downstream mixing body opening, the upstream mixing body opening configured to receive exhaust gas;   an upstream plate coupled to the mixing body, the upstream plate comprising a first upstream plate opening that is configured to receive a first flow percentage that is between 20% and 40%, inclusive of a total flow of the exhaust gas; and   an injector mount coupled to the mixing body and configured to be coupled to an injector, the injector mount defined by an injector center axis that does not extend across the first upstream plate opening.   
     
     
         13 . The mixing assembly of  claim 12 , wherein:
 the upstream plate further comprises a second upstream plate opening that is configured to receive a second flow percentage that is between 0.28% and 12%, inclusive of the total flow of the exhaust gas;   the second upstream plate opening is formed between the mixing body and the upstream plate; and   the injector center axis extends between the first upstream plate opening and the second upstream plate opening.   
     
     
         14 . The mixing assembly of  claim 12 , further comprising:
 a downstream plate coupled to the mixing body downstream from the upstream plate in a direction of exhaust gas flow, the downstream plate comprising a downstream plate opening; and   a swirl plate positioned between the upstream plate and the downstream plate and defining a swirl collection region and a swirl concentration region contiguous with the swirl collection region, the swirl collection region extending across the first upstream plate opening and the swirl collection region extending across the downstream plate opening.   
     
     
         15 . The mixing assembly of  claim 14 , wherein:
 the mixing body is centered on a mixing body center axis; and   the swirl plate extends between the mixing body center axis and the first upstream plate opening.   
     
     
         16 . The mixing assembly of  claim 15 , further comprising a splash plate coupled to the upstream plate and located in the swirl collection region, the splash plate comprising:
 a plurality of splash members; and   a plurality of splash plate openings, each of the plurality of splash plate openings contiguous with one of the plurality of splash members;   wherein the swirl plate extends between the mixing body center axis and the splash plate.   
     
     
         17 . A mixing assembly comprising:
 a mixing body comprising an upstream mixing body opening and a downstream mixing body opening, the upstream mixing body opening configured to receive exhaust gas;   an upstream plate coupled to the mixing body, the upstream plate comprising an upstream plate opening that is configured to receive a first flow percentage that is between 20% and 40%, inclusive of a total flow of the exhaust gas; and   a swirl plate coupled to the upstream plate and defining a swirl collection region and a swirl concentration region contiguous with the swirl collection region, the swirl collection region extending across the upstream plate opening and the swirl collection region separated from the upstream plate opening by the swirl plate.   
     
     
         18 . The mixing assembly of  claim 17 , further comprising:
 a first splash plate coupled to the upstream plate and located in the swirl collection region, the first splash plate comprising:
 a plurality of first splash members; and 
 a plurality of first splash plate openings, each of the plurality of first splash plate openings contiguous with one of the plurality of first splash members; and 
   a second splash plate coupled to the upstream plate and located in the swirl collection region, the second splash plate comprising:
 a plurality of second splash members; and 
 a plurality of second splash plate openings, each of the plurality of second splash plate openings contiguous with one of the plurality of second splash members. 
   
     
     
         19 . The mixing assembly of  claim 18 , wherein:
 the mixing body is centered on a mixing body center axis;   the swirl plate extends between the mixing body center axis and the first splash plate; and   the swirl plate extends between the mixing body center axis and the second splash plate.   
     
     
         20 . The mixing assembly of  claim 19 , wherein:
 the upstream plate is disposed along a plane; and   
       the mixing body center axis is orthogonal to the plane.