System and Method of LIquid Injection into a Gas Stream

Abstract

A system for use in injection of a liquid reductant into an exhaust gas ( 20 ) and for evaporating the liquid reductant includes an exhaust pipe ( 12 ) having an interior area ( 15 ). Exhaust gas ( 20 ) flows through the interior area ( 15 ) of the exhaust pipe ( 12 ), the flow of exhaust gas being at an elevated temperature from the ambient. A deflection plate ( 118 ) has a non-planar shape and is disposed within the interior area ( 15 ) of the exhaust pipe ( 12 ). An injector ( 14 ) injects the liquid reductant into the exhaust pipe ( 12 ) and directs the liquid reductant at the deflection plate ( 118 ).

1 . A method for injection of a liquid reductant into an exhaust gas and for evaporating the liquid reductant, the method comprising:
 providing an exhaust pipe having an interior area;   providing a flow of exhaust gas through the interior area of the exhaust pipe, the flow of exhaust gas having an elevated temperature compared to an ambient;   disposing a deflection plate having a non-planar shape within the interior area of the exhaust pipe and disposed generally transversely to the direction of exhaust gas flow; and   injecting the liquid reductant into the exhaust pipe and directing the injected liquid reductant at the deflection plate.   
   
   
       2 . The method of  claim 1  wherein the liquid reductant is injected upstream of the deflection plate. 
   
   
       3 . The method of  claim 1  wherein the injected liquid reductant is deflected off of the deflection plate and has a path that is generally parallel to the exhaust pipe. 
   
   
       4 . The method of  claim 1  wherein the deflection plate has a generally concave shape with respect to the flow of exhaust gas. 
   
   
       5 . The method of  claim 1  wherein the deflection plate has a generally parabolic shape. 
   
   
       6 . The method of  claim 1  wherein the exhaust gas is an exhaust gas from combustion of a diesel engine. 
   
   
       7 . The method of  claim 1  wherein the deflection plate is disposed upstream of a catalyst. 
   
   
       8 . A system for use in injection of a liquid reductant into an exhaust gas and for evaporating the liquid reductant, the system comprising:
 an exhaust pipe having an interior area;   a flow of exhaust gas through the interior area of the exhaust pipe, the flow of exhaust gas having an elevated temperature compared to an ambient;   a deflection plate having a non-planar shape disposed within the interior area of the exhaust pipe and disposed generally transversely to the direction of exhaust gas flow; and   an injector for injecting the liquid reductant into the exhaust pipe and directing the liquid reductant at the deflection plate.   
   
   
       9 . The system of  claim 8  wherein the liquid reductant is injected upstream of the deflection plate. 
   
   
       10 . The system of  claim 8  wherein the injected liquid reductant is deflected off of the deflection plate and has a path that is generally parallel to the exhaust pipe. 
   
   
       11 . The system of  claim 8  wherein the deflection plate has a generally concave shape with respect to the flow of exhaust gas. 
   
   
       12 . The system of  claim 8  wherein the deflection plate has a generally parabolic shape. 
   
   
       13 . The system of  claim 8  wherein the exhaust gas is an exhaust gas from combustion of a diesel engine. 
   
   
       14 . The system of  claim 8  wherein the deflection plate is disposed upstream of a catalyst. 
   
   
       15 . A system for use in injection of a liquid reductant into an exhaust gas and for evaporating the liquid reductant, the system comprising:
 an exhaust pipe having an interior area;   a flow of exhaust gas through the interior area of the exhaust pipe, the flow of exhaust gas having an elevated temperature from an ambient;   a deflection plate having a parabolic shape disposed within the interior area of the exhaust pipe; and   an injector for injecting the liquid reductant into the exhaust pipe and directing the liquid reductant at the deflection plate.   
   
   
       16 . The system of  claim 15  wherein the exhaust pipe is generally cylindrical. 
   
   
       17 . The system of  claim 16  wherein the deflection plate is generally concentrically mounted in the exhaust pipe. 
   
   
       18 . The system of  claim 15  wherein the deflection plate deflects a reflected liquid reductant spray generally parallel to the exhaust pipe. 
   
   
       19 . The system of  claim 18  wherein the reflected liquid reductant spray does not contact interior surfaces of the exhaust pipe. 
   
   
       20 . The system of  claim 18  wherein the deflection plate is made of a corrosion-resistant material.