Urea pump assembly for an exhaust gas treatment system

Abstract

Exemplary embodiments of the present invention are directed towards improved systems and methods for the delivery of urea to an exhaust gas treatment system. In one exemplary embodiment, a urea pump assembly for an exhaust treatment system is provided. The pump assembly includes a housing comprising: a housing chamber, a first fluid inlet and a first fluid outlet, the first fluid inlet being in fluid communication with the first fluid outlet through a first conduit. The housing also comprises a second fluid inlet and a second fluid outlet, the second fluid inlet being in fluid communication with the second fluid outlet through a second flexible conduit. The second flexible conduit is located within a portion of the housing chamber and in thermal communication with the first conduit. The pump assembly also includes a pump located within the housing chamber, the pump being engaged with the second conduit and configured to move fluid between the second fluid inlet and the second fluid outlet.

1 . A urea pump assembly for an exhaust treatment system, comprising:
 a housing comprising:
 a housing chamber, 
 a first fluid inlet and a first fluid outlet, the first fluid inlet being in fluid communication with the first fluid outlet through a first conduit, 
 a second fluid inlet and a second fluid outlet, the second fluid inlet being in fluid communication with the second fluid outlet through a second flexible conduit, the second flexible conduit being located within a portion of the housing chamber and in thermal communication with the first conduit; and 
   a pump located within the housing chamber, the pump being engaged with the second conduit and configured to move fluid between the second fluid inlet and the second fluid outlet.   
   
   
       2 . The urea pump assembly of  claim 1 , further comprising a first valve for metering fluid through the first fluid inlet and a second valve for metering fluid through the first fluid outlet. 
   
   
       3 . The urea pump assembly of  claim 2 , wherein the first valve is mounted to the housing through a first connector and the second valve is mounted to the housing through a second connector. 
   
   
       4 . The urea pump assembly of  claim 1 , further comprising an electric heater located proximate to the second fluid inlet, the second fluid outlet or both. 
   
   
       5 . The urea pump assembly of  claim 4 , further comprising a temperature sensor in thermal communication with the heater. 
   
   
       6 . The urea pump assembly of  claim 1 , wherein the pump includes a projecting member rotatable about an axis of the pump, the projecting member configured to compress the flexible member and thereby move a fluid in the flexible member from the second fluid inlet to the second fluid outlet during rotation of the projecting member. 
   
   
       7 . The urea pump assembly of  claim 6 , wherein the flexible member of the second conduit comprises a flexible tube, wherein the second conduit is arcuate about the axis of the pump. 
   
   
       8 . The urea pump assembly of  claim 7 , wherein the pump comprises a positive displacement pump and the projecting member is rotatable about the axis at a variable speed and is reversible, the variable speed of the pump controlling a mass flow rate of the fluid flowing through the second conduit. 
   
   
       9 . The urea pump assembly of  claim 1 , further comprising a third fluid inlet in fluid communication with the second conduit, the third fluid inlet configured to supply air to the second conduit. 
   
   
       10 . An exhaust treatment system, comprising:
 an exhaust gas conduit extending between an internal combustion engine and an exhaust gas treatment device, the exhaust gas conduit being configured to guide an exhaust gas stream from the internal combustion engine to the exhaust gas treatment device for treatment of the exhaust gas stream;   a urea pump assembly for providing urea to the exhaust gas stream, the urea pump assembly comprising:
 a housing having a first conduit for receiving and guiding a first fluid from the internal combustion engine through a first internal portion of the housing and a second conduit in thermal communication with the first conduit and the first fluid, the second conduit receiving and guiding urea solution through a second internal portion of the housing, 
 a pump located in the second internal portion of the housing, the pump causing movement of the urea solution along the second conduit; and 
   a fluid outlet in fluid communication with the second conduit and the exhaust gas conduit or exhaust gas treatment device, wherein the pump causes dispensing of the urea solution into the exhaust gas stream through the fluid outlet.   
   
   
       11 . The exhaust treatment system of  claim 10 , wherein the urea pump assembly includes an electrical heater located along a portion of the second conduit for heating the urea solution. 
   
   
       12 . The exhaust treatment system of  claim 10 , wherein the pump comprises a positive displacement pump that is variable in speed and reversible, the pump being configured to control a mass flow rate of the urea solution through the second conduit. 
   
   
       13 . The exhaust treatment system of  claim 12 , wherein at least a portion of the second conduit comprises a flexible member and wherein the pump includes a projecting member rotatable about an axis of the pump, the projecting member configured to compress the flexible member to move urea solution along the second conduit and towards the fluid outlet. 
   
   
       14 . The exhaust treatment system of  claim 10 , further comprising a control module in power or signal communication with a heater, a temperature sensor, a pump motor, a valve or a combination thereof. 
   
   
       15 . A method of heating a urea solution for delivery to an exhaust treatment system, comprising:
 fluidly coupling a urea pump assembly to a first fluid system of an engine to provide a first fluid flow through the urea pump assembly;   fluidly coupling the urea pump assembly to a urea solution supply to provide a urea solution to the urea pump assembly; and   activating a motor to cause movement of the urea solution through the urea pump assembly and to cause discharge of the urea solution into an exhaust gas stream,   wherein during movement of the urea solution through the urea pump assembly the urea solution is heated by the first fluid.   
   
   
       16 . The method of  claim 15 , wherein the urea pump assembly includes an electric heater for heating the urea solution. 
   
   
       17 . The method of  claim 16 , wherein the urea pump assembly includes a temperature sensor for sensing the temperature of the urea solution. 
   
   
       18 . The method of  claim 15 , wherein the motor includes a positive displacement pump that is variable in speed and reversible, the variable speed of the pump controlling a mass flow rate of urea solution through the urea pump assembly. 
   
   
       19 . The method of  claim 18 , wherein the positive displacement pump comprises a length of flexible conduit for guiding the urea solution through the urea pump assembly, and wherein the pump includes a projecting member rotatable about an axis of the pump, the projecting member being configured to compress the flexible member along its length to cause movement of the urea solution through the urea pump assembly. 
   
   
       20 . The method of  claim 15 , further comprising controlling the urea pump assembly using a control module in power or signal communication with a heater, a temperature sensor, a pump motor, a valve or a combination thereof.