Ring Reductant Mixer

Abstract

An engine exhaust aftertreatment system including a ring disposed in an exhaust conduit. The ring assists in the introduction and conversion of a reductant introduced by an injector.

1 . An engine exhaust aftertreatment system comprising:
 an injector configured to introduce a reductant into an exhaust conduit of   a engine and a ring disposed in the exhaust conduit.   
     
     
         2 . The engine exhaust aftertreatment system of  claim 1  wherein the ring is disposed downstream of the injector and upstream of a selective catalytic reduction catalyst. 
     
     
         3 . The engine exhaust aftertreatment system of  claim 1  wherein the ring is planar. 
     
     
         4 . The engine exhaust aftertreatment system of  claim 1  wherein the ring is toroidal. 
     
     
         5 . The engine exhaust aftertreatment system of  claim 4  wherein the ring has a rectangular cross-section. 
     
     
         6 . The engine exhaust aftertreatment system of  claim 1  wherein the ring defines a central opening with an area along a traverse plane of the exhaust conduit that is between 50% and 70% the area of the traverse plane within the exhaust conduit. 
     
     
         7 . The engine exhaust aftertreatment system of  claim 1  wherein the ring defines a central opening with an area along a traverse plane of the exhaust conduit that is between 20% and 90% the area of the traverse plane within the exhaust conduit. 
     
     
         8 . The engine exhaust aftertreatment system of  claim 1  wherein the ring has a width that is between 2% and 25% of a width of the exhaust conduit. 
     
     
         9 . The engine exhaust aftertreatment system of  claim 1  wherein the ring defines a gap between an outer surface of the ring and an inner wall of the exhaust conduit. 
     
     
         10 . The engine exhaust aftertreatment system of  claim 9  wherein the gap extends around a perimeter of the ring. 
     
     
         11 . The engine exhaust aftertreatment system of  claim 10  wherein the gap is formed by spacers mounting the ring to the exhaust conduit. 
     
     
         12 . The engine exhaust aftertreatment system of  claim 9  wherein the gap has a width that is between 1/16 and ½ of an inch. 
     
     
         13 . The engine exhaust aftertreatment system of  claim 9  wherein the gap has an area along a traverse plane of the exhaust conduit that is between 0.5% and 5% the area of the traverse plane within the exhaust conduit. 
     
     
         14 . The engine exhaust aftertreatment system of  claim 1  wherein the injector directs a spray of reductant through a central opening in the ring. 
     
     
         15 . The engine exhaust aftertreatment system of  claim 14  wherein the ring is located at a distance from the injector so that the spray of reductant is not larger than the central opening when the spray reaches the ring. 
     
     
         16 . The engine exhaust aftertreatment system of  claim 1  wherein the exhaust conduit divides into 2 or more legs downstream of the ring. 
     
     
         17 . The engine exhaust aftertreatment system of  claim 16  wherein the exhaust conduit divides at a distance from the ring that is greater than a width of the exhaust conduit. 
     
     
         18 . The engine exhaust aftertreatment system of  claim 16  wherein  2  or more legs combine into the exhaust conduit upstream of the injector. 
     
     
         19 . The engine exhaust aftertreatment system of  claim 1  wherein the ring includes a plurality of openings. 
     
     
         20 . The engine exhaust aftertreatment system of  claim 1  wherein the ring includes a plurality of deflectors and central structures that extend into a central opening in the ring.