Dispensing System with Remotely Mounted Metering Device

Abstract

A system is disclosed for dispensing a reactant into an exhaust stream. The system dispenses a mixture of reactant and pressurized air into the exhaust stream. This system includes a mixing manifold that mounts to an exhaust pipe that carries the exhaust stream. The system also includes a metering device remotely mounted from the mixing manifold.

1 . A system for dispensing a reactant into an exhaust stream, the system comprising:
 a manifold defining a mixing chamber, an air passage that extends to the mixing chamber, a reactant passage that extends to the mixing chamber, and a cooling passage for circulating a liquid cooling fluid through the manifold;   a mixed air/reactant outlet in fluid communication with the mixing chamber; and   a metering device for controlling the flow of reactant to the reactant passage, the metering device being remotely mounted from the manifold and connected to the reactant passage by a reactant line.   
   
   
       2 . The system of  claim 1 , further comprising a check valve positioned at the reactant passage. 
   
   
       3 . The system of  claim 2 , wherein the check valve ensures that the reactant line remains full of reactant even when the metering device is not dispensing reactant. 
   
   
       4 . The system of  claim 1 , wherein the metering device includes a valve that is opened and closed based on input from an electronic control unit. 
   
   
       5 . The system of  claim 1 , wherein the metering device includes a fuel injector. 
   
   
       6 . The system of  claim 1 , wherein the metering device includes a spool valve. 
   
   
       7 . The system of  claim 1 , wherein the mixed air/reactant outlet includes a dispensing tube having an end that mounts within a mixed reactant/air passage of the manifold, and wherein the cooling passage is generally u-shaped and loops around the mixed reactant/air passage. 
   
   
       8 . The system of  claim 1 , further comprising a dispensing tube that projects outwardly from the manifold and defines the mixed air/reactant outlet. 
   
   
       9 . The system of  claim 8 , wherein the dispensing tube defines a dispensing orifice through a side wall of the dispensing tube. 
   
   
       10 . The system of  claim 9 , wherein the dispensing orifice has a diameter less than 0.11 inches. 
   
   
       11 . The system of  claim 10 , wherein the dispensing orifice has a diameter in the range of 0.04 to 0.06 inches. 
   
   
       12 . The system of  claim 9 , wherein the side wall includes an outer surface aligned at an oblique angle relative to a central axis of the dispensing tube. 
   
   
       13 . The system of  claim 12 , wherein the dispensing orifice defines a central axis that is generally perpendicular to the outer surface of the side wall. 
   
   
       14 . The system of  claim 7 , wherein the manifold includes a generally rectangular manifold block having a first side positioned opposite from a second side, and a third side that extends from the first side to the second side, wherein the dispensing tube projects outwardly from the first side of the manifold block, wherein a reactant inlet for accessing the reactant passage is located at the second side of the manifold block, wherein an air inlet for accessing the air passage is defined at the third side of the block, wherein a cooling fluid inlet for accessing the cooling passage is defined at the third side of the block, and wherein a cooling fluid outlet for accessing the cooling passage is defined at the third side. 
   
   
       15 . A system for dispensing a reactant into an exhaust stream, the system comprising:
 a manifold defining a mixing chamber, an air passage that extends to the mixing chamber, a reactant passage that extends to the mixing chamber;   a mixed air/reactant outlet in fluid communication with the mixing chamber;   a metering device for controlling the flow of reactant to the reactant passage, the metering device being remotely mounted from the manifold and connected to the reactant passage by a reactant line; and   a check valve positioned at the reactant passage, wherein the check valve ensures that the reactant line remains full of reactant even when the metering device is not dispensing reactant.