Liquid cooled reductant delivery unit for automotive selective catalytic reduction systems

Abstract

A reductant delivery unit having active cooling which is constructed to have sufficient structural robustness, and to improve corrosion resistance of the assembly, where an attack on the base injector is conceivable with the use of incorrect coolant media. The reductant delivery unit has an upper shield, a lower shield connected to the upper shield, and an inner sleeve. The reductant delivery unit also includes a lower sleeve connected to the inner sleeve and the lower shield. A liquid cooling cavity is formed by the connection between the inner sleeve and the lower shield, the lower sleeve and the lower shield, and the lower sleeve and the inner sleeve. Coolant flows into the liquid cooling cavity to provide a cooling function to an injector partially located within the inner sleeve, and a corrugated portion of the lower sleeve transfers heat away from at least a portion of the injector.

What is claimed is: 
     
         1 . An apparatus, comprising:
 a reductant delivery unit, comprising:
 a liquid cooling cavity; 
 a lower sleeve, a portion of the lower sleeve forming part of the liquid cooling cavity; and 
 an injector substantially surrounded by the liquid cooling cavity; 
 wherein coolant is circulated into and out of the liquid cooling cavity to control the temperature of the injector. 
   
     
     
         2 . The apparatus of  claim 1 , further comprising:
 an inner sleeve connected to the lower sleeve; and   a lower shield connected to the inner sleeve and the lower sleeve, the lower shield, inner sleeve, and lower sleeve forming the liquid cooling cavity.   
     
     
         3 . The apparatus of  claim 2 , further comprising:
 an outer surface formed as part of the inner sleeve;   an inner surface formed as part of the lower shield, the inner surface of the lower shield connected to the outer surface of the inner sleeve; and   an outer surface formed as part of the lower sleeve;   wherein a portion of the outer surface of the lower sleeve is connected to the inner surface of the inner sleeve, and another portion of the outer surface of the lower sleeve is connected to outer surface of the lower shield.   
     
     
         4 . The apparatus of  claim 3 , further comprising:
 a first connection point formed by the connection between the outer surface of the inner sleeve and the inner surface of the lower shield;   a second connection point formed by a portion of the outer surface of the lower sleeve connected to an inner surface of the inner sleeve; and   a third connection point formed by an area of the outer surface of the lower sleeve is connected to the outer surface of the lower shield.   
     
     
         5 . The apparatus of  claim 4 , further comprising:
 an upwardly extending flange formed as part of the lower sleeve; and   a downwardly extending flange formed as part of the inner sleeve connected to the upwardly extending flange;   wherein the connection between the upwardly extending flange and the downwardly extending flange forms at least part of the second connection point.   
     
     
         6 . The apparatus of  claim 4 , further comprising:
 an inwardly extending flange formed as part of the lower shield; and   an outwardly extending flange formed as part of the lower sleeve connected to the inwardly extending flange;   wherein the connection between the inwardly extending flange and the outwardly extending flange forms at least part of the third connection point.   
     
     
         7 . The apparatus of  claim 1 , the lower sleeve further comprising corrugated portion for transferring heat away from the injector as fluid is circulated through the liquid cooling cavity. 
     
     
         8 . The apparatus of  claim 7 , the injector further comprising:
 a valve portion; and   a lower valve body being part of the valve portion;   wherein a portion of the lower valve body press-fit into the corrugated portion of the lower sleeve.   
     
     
         9 . A reductant delivery unit, comprising:
 a lower shield;   an inner sleeve connected to the lower shield;   a lower sleeve connected to the inner sleeve and the lower shield;   a corrugated portion formed as part of the lower sleeve;   an injector at least partially surrounded by the inner sleeve, and at least partially disposed within the corrugated portion; and   a liquid cooling cavity formed by the connection between the inner sleeve and the lower shield, the connection between the lower sleeve and the lower shield, and the connection between the lower sleeve and the inner sleeve, the liquid cooling cavity for receiving and circulating coolant;   wherein coolant flows into and out of the liquid cooling cavity, and coolant circulates through the liquid cooling cavity, allowing the corrugated portion to transfer heat away from the injector.   
     
     
         10 . The reductant delivery unit of  claim 9 , the injector further comprising:
 a solenoid portion;   a valve portion controlled by the solenoid portion; and   a lower valve body, the lower valve body being part of the valve portion;   wherein the lower valve body is at least partially disposed within the lower sleeve such that at least part of the lower valve body is disposed within and in contact with the corrugated portion.   
     
     
         11 . The reductant delivery unit of  claim 9 , wherein a portion of the lower valve body is press-fit into the corrugated portion. 
     
     
         12 . The reductant delivery unit of  claim 9 , further comprising:
 an outer surface formed as part of the inner sleeve;   an inner surface formed as part of the lower shield, the inner surface of the lower shield connected to the outer surface of the inner sleeve; and   an outer surface formed as part of the lower sleeve;   wherein a portion of the outer surface of the lower sleeve is connected to the inner surface of the inner sleeve, and another portion of the outer surface of the lower sleeve is connected to outer surface of the lower shield.   
     
     
         13 . The reductant delivery unit of  claim 12 , further comprising:
 a first connection point formed by the connection between the outer surface of the inner sleeve and the inner surface of the lower shield;   a second connection point formed by a portion of the outer surface of the lower sleeve connected to an inner surface of the inner sleeve; and   a third connection point formed by an area of the outer surface of the lower sleeve connected to the outer surface of the lower shield.   
     
     
         14 . A reductant delivery unit having active cooling, comprising:
 an upper shield;   a lower shield connected to the upper shield;   an inner sleeve, an outer surface of the inner sleeve connected to an inner surface of the upper shield, and an inner surface of the lower shield;   a lower sleeve having an outer surface, a portion of the outer surface of the lower sleeve connected to the inner surface of the inner sleeve, and another portion of the outer surface of the lower sleeve connected to outer surface of the lower shield;   a corrugated portion formed as part of the lower sleeve;   an injector partially located within the inner sleeve, and partially located within the lower sleeve; and   a liquid cooling cavity formed by the connection between the inner sleeve and the lower shield, the lower sleeve and the lower shield, and the lower sleeve and the inner sleeve;   wherein coolant flows into the liquid cooling cavity to provide a cooling function to the injector, and the corrugated portion of the lower sleeve transfers heat away from at least a portion of the injector.   
     
     
         15 . The reductant delivery unit having active cooling of  claim 14 , further comprising:
 a first connection point formed by the connection between the outer surface of the inner sleeve and the inner surface of the lower shield;   a second connection point formed by a portion of the outer surface of the lower sleeve is connected to an inner surface of the inner sleeve; and   a third connection point formed by an area of the outer surface of the lower sleeve is connected to the outer surface of the lower shield.   
     
     
         16 . The reductant delivery unit having active cooling of  claim 14 , the injector further comprising a lower valve body, wherein a portion of the lower valve body is press-fit into the corrugated portion of the lower sleeve.