Exhaust treatment system having a reductant supply system

Abstract

An exhaust treatment device is disclosed. The exhaust treatment device includes a supply of reductant at a first pressure and an exhaust passage. The device further includes a venturi located within the exhaust passage and configured to facilitate reductant entry into the exhaust passage by reducing a pressure of exhaust flowing through the exhaust passage to a second pressure that is less than the first pressure.

1 . An exhaust treatment system comprising:
 a supply of reductant at a first pressure;   an exhaust passage; and   a venturi located within the exhaust passage and configured to facilitate reductant entry into the exhaust passage by reducing a pressure of exhaust flowing though the exhaust passage to a second pressure that is less than the first pressure.   
   
   
       2 . The exhaust treatment system of  claim 1 , further including at least one orifice located at a throat of the venturi. 
   
   
       3 . The exhaust treatment system of  claim 2 , wherein the supply of reductant enters the exhaust passage through the at least one orifice. 
   
   
       4 . The exhaust treatment system of  claim 1 , further including a temperature controlled valve. 
   
   
       5 . The exhaust treatment system of  claim 4 , wherein the temperature controlled valve is located upstream of the venturi and is configured to control a flow of exhaust through the venturi. 
   
   
       6 . The exhaust treatment system of  claim 1 , wherein the reductant is urea. 
   
   
       7 . The exhaust treatment system of  claim 1 , further including a catalyst that is at least one of an alumina, elite, aluminophosphate, hexaluminate, aluminosilicate, zirconate, titanosilicate, or titanate. 
   
   
       8 . The exhaust treatment system of  claim 1 , wherein the exhaust passage is a first exhaust passage and the system further includes a second exhaust passage in parallel with the first exhaust passage. 
   
   
       9 . The exhaust treatment system of  claim 8 , wherein the second exhaust passage includes an inlet upstream of the venturi and an outlet downstream of the venturi. 
   
   
       10 . A method of operating an exhaust treatment system comprising:
 controlling a flow of exhaust through exhaust passage as a function of temperature; and   injecting a reductant into the exhaust passage based on a flow rate of exhaust through the exhaust passage.   
   
   
       11 . The method of  claim 10 , wherein the injecting a reductant includes passively injecting the reductant based on a pressure difference between a reductant supply and the exhaust passage. 
   
   
       12 . The method of  claim 10 , wherein the injecting a reductant includes injecting a reductant into a venturi of the exhaust passage. 
   
   
       13 . The method of  claim 10 , wherein the controlling a flow of exhaust includes controlling a temperature controlled valve in the exhaust passage. 
   
   
       14 . The method of  claim 13 , wherein the controlling a flow of exhaust includes diverting flow around a portion of the exhaust passage. 
   
   
       15 . An exhaust passage comprising:
 a venturi configured to receive a reductant and provide an atomized flow of the reductant to the exhaust passage.   
   
   
       16 . The exhaust passage of  claim 15 , further including at least one orifice located at a throat of the venturi configured to atomize the reductant. 
   
   
       17 . The exhaust passage of  claim 15 , further including a valve configured to control a flow of exhaust to the venturi. 
   
   
       18 . The exhaust passage of  claim 17 , wherein the valve is configured to control the flow of exhaust as a function of a temperature of the exhaust. 
   
   
       19 . The exhaust passage of  claim 15 , wherein an amount of flow of the reductant is a function of a pressure of an exhaust flow through the venturi. 
   
   
       20 . The exhaust passage of  claim 15 , wherein an amount of flow of the reductant is a function of temperature of an exhaust flow.