Exhaust mixer with backward flow

Abstract

An exhaust gas mixer configured to turn exhaust gas including a reluctant into a backward flow is provided. The mixer is further configured to turn the backward flow into a forward flow and direct the exhaust gas into an SCR.

1 . A mixer for mixing exhaust gas components comprising:
 a structure configured to receive an entering flow of exhaust gas and turn the entering exhaust flow into a backward flow within the structure wherein the backward flow is at an angle greater than 90 degrees to the entering flow.   
   
   
       2 . The mixer of  claim 1  wherein the structure is further configured to direct the backward flow into a selective catalytic reduction (SCR) device. 
   
   
       3 . The mixer of  claim 1  wherein the structure is further configured to turn the backward flow into a forward flow within the structure, wherein the forward flow is at an angle greater than 90 degrees to the backward flow. 
   
   
       4 . The mixer of  claim 3  wherein the structure is further configured to direct the forward flow into a selective catalytic reduction (SCR) device. 
   
   
       5 . The mixer of  claim 4  wherein the entering flow includes a reductant. 
   
   
       6 . The mixer of  claim 3  wherein the structure further includes:
 an internal baffle configured to create the backward and forward flows.   
   
   
       7 . The mixer of  claim 6  wherein the baffle further includes:
 a front wall configured to direct the entering flow into the backward flow;   a side wall extending from the periphery of the front wall; and   an opening in the side wall.   
   
   
       8 . The mixer of  claim 1  wherein at least a portion of the backward flow overlaps at least a portion of the entering flow. 
   
   
       9 . The mixer of  claim 2  wherein at least a portion of the forward flow overlaps at least a portion of the entering flow and overlaps at least a portion of the backward flow. 
   
   
       10 . A mixer for mixing exhaust gas components comprising:
 a housing configured to receive an exhaust stream in a entering direction; and   a baffle inside the housing including a front wall located in the path of the exhaust stream entering direction and configured to turn the exhaust stream into a backward direction.   
   
   
       11 . The mixer of  claim 10  wherein the baffle further includes:
 a side wall extending from the periphery of the front wall; and   an opening in the side wall.   
   
   
       12 . The mixer of  claim 11  wherein baffle is configured to pass the exhaust stream through the opening and turn the exhaust stream into a forward direction. 
   
   
       13 . The mixer of  claim 11  wherein the backward direction is at an angle greater than 90 degrees to the entering direction and the forward direction is at an angle greater than 90 degrees to the backward direction. 
   
   
       14 . A method of mixing exhaust gas components comprising:
 receiving an exhaust stream traveling in a entering direction; and   turning the exhaust stream traveling in the entering direction to travel in a backward direction, wherein the backward direction is at an angle greater than 90 degrees to the entering direction.   
   
   
       15 . The method of  claim 14  wherein the backward direction is substantially parallel to the entering direction. 
   
   
       16 . The method of  claim 14  further including:
 turning the exhaust stream traveling in the backward direction to travel in a forward direction wherein the forward direction is at an angle greater than 90 degrees to the backward direction.   
   
   
       17 . The method of  claim 16  wherein at least a portion of the forward flow overlaps at least a portion of the entering flow and overlaps at least a portion of the backward flow. 
   
   
       18 . The method of  claim 16  further including:
 directing the exhaust stream traveling into a selective catalytic reduction (SCR) device.   
   
   
       19 . The method of  claim 16  wherein the forward direction is substantially parallel to the backward direction and the entering direction. 
   
   
       20 . The method of  claim 19  wherein the exhaust stream flows through the SCR in a direction that is substantially the same as the entering direction.