Reductant spray injector boss

Abstract

A mounting boss ( 36 ) for mounting a spray injector ( 16 ) on an exhaust pipe ( 32 ) of a vehicle exhaust system ( 12 ) includes a first wall ( 38 ) and a second wall ( 44 ). The first wall ( 38 ) extends at an obtuse angle to an outer surface ( 40 ) of the exhaust pipe ( 32 ) and defines a first interior surface ( 42 ). The second wall ( 44 ) extends at an obtuse angle with the outer surface ( 40 ) of the exhaust pipe ( 32 ) and defines a second interior surface ( 46 ). The first interior surface ( 42 ) and the second interior surface ( 46 ) define a recirculation area ( 48 ) that is in fluid communication with the exhaust pipe ( 32 ). The recirculation area ( 48 ) has a decreasing cross-sectional area in the direction of the flow of exhaust gas in the exhaust pipe ( 12 ). An aperture ( 50 ) is disposes in the first wall ( 38 ) for receiving the spray injector ( 16 ).

1 . A mounting boss for mounting a spray injector on an exhaust pipe of a vehicle exhaust system, comprising:
 a first wall that extends at an obtuse angle to an outer surface of the exhaust pipe, the first wall defining a first interior surface;   a second wall that extends at an obtuse angle with the outer surface of the exhaust pipe, the second wall defining a second interior surface, wherein the first interior surface and the second interior surface define a recirculation area in fluid communication with the exhaust pipe, the recirculation area having a decreasing cross-sectional area in the direction of the flow of exhaust gas in the exhaust pipe; and   an aperture disposed in the first wall for receiving the spray injector.   
     
     
         2 . The mounting boss of  claim 1  wherein the obtuse angle of the first wall is about 120 to 140-degrees from the outer surface of the exhaust pipe. 
     
     
         3 . The mounting boss of  claim 1  wherein the obtuse angle of the second wall is about 155 to 175-degrees from the outer surface of the exhaust pipe. 
     
     
         4 . The mounting boss of  claim 1  wherein the second interior surface has a generally concave shape. 
     
     
         5 . The mounting boss of  claim 1  wherein the aperture has an axis that is about 30 to 50-degrees from an axis of the exhaust pipe. 
     
     
         6 . The mounting boss of  claim 1  further comprising a lip extending from the first wall and having a flat surface. 
     
     
         7 . The mounting boss of  claim 1  wherein the mounting boss has a length to height ratio of about 7:1, wherein the length is measured from a center of the aperture to a junction of the second wall with a surface of the exhaust pipe, and wherein the height is measured from the surface of the pipe to the center of the aperture. 
     
     
         8 . A mounting boss for mounting a spray injector on an exhaust pipe of a vehicle exhaust system, the exhaust pipe having a pipe axis, the mounting boss comprising:
 a first wall defining an aperture for receiving a spray injector, the aperture having an axis that is about 30 to 50-degrees from the pipe axis;   a second wall extending from the first wall to an outer surface of the exhaust pipe, the second wall defining a second interior surface having a generally concave shape, and   a recirculation area defined by the first interior surface and the second interior surface and in fluid communication with the exhaust pipe.   
     
     
         9 . The mounting boss of  claim 8  wherein the axis of the aperture is about 40-degrees from the pipe axis. 
     
     
         10 . The mounting boss of  claim 8  wherein the first wall is about 130-degrees from the outer surface of the exhaust pipe. 
     
     
         11 . The mounting boss of  claim 8  further comprising a lip extending from the first wall and having a flat surface. 
     
     
         12 . The mounting boss of  claim 8  wherein the recirculation area has a decreasing cross-sectional area in the direction of the flow of exhaust gas in the exhaust pipe. 
     
     
         13 . The mounting boss of  claim 8  wherein the mounting boss has a length to height ratio of about 7:1, wherein the length is measured from a center of the aperture to a junction of the second wall with a surface of the exhaust pipe, and wherein the height is measured from the surface of the pipe to the center of the aperture. 
     
     
         14 . A method of spraying reductant into an exhaust gas passageway formed by at least one exhaust pipe for emitting exhaust gases from an engine to the ambient, the method comprising:
 positioning a reductant spray injector in fluid communication with the exhaust gas passageway for spraying reductant into the exhaust gas passageway;   locating a mounting boss in fluid communication with the exhaust pipe, the mounting boss comprising a first wall extending at an obtuse angle to an outer surface of the exhaust pipe, a second wall extending at an obtuse angle with the outer surface of the exhaust pipe, and an aperture disposed in the first wall for receiving the reductant spray injector; and   spraying the reductant from the reductant spray injector into the exhaust pipe at an angle of about 30 to 50-degrees with respect to an axis of the exhaust pipe.   
     
     
         15 . The method of  claim 14  further comprising forming a recirculation area within the mounting boss and in fluid communication with the exhaust pipe. 
     
     
         16 . The method of  claim 14  further comprising integrally forming the mounting boss with the exhaust pipe. 
     
     
         17 . The method of  claim 14  wherein the obtuse angle of the first wall is about 120 to 140-degrees from the outer surface of the exhaust pipe. 
     
     
         18 . The method of  claim 14  wherein the obtuse angle of the second wall is about 155 to 175-degrees from the outer surface of the exhaust pipe. 
     
     
         19 . The method of  claim 14  further comprising introducing the spray injector into an aperture in the first wall of the mounting boss. 
     
     
         20 . The method of  claim 19  wherein the mounting boss has a length to height ratio of about 7:1, wherein the length is measured from a center of the aperture to a junction of the second wall with a surface of the exhaust pipe, and wherein the height is measured from the surface of the pipe to the center of the aperture.