Reductant Insulating System

Abstract

A reductant insulating system configured to prevent a flow of reductant used by an engine's selective catalytic reduction (SCR) device from overheating.

1 . A reductant insulating system comprising:
 an insulating line thermally associated with a flow of reductant used by a selective catalytic reduction device associated with an engine wherein the insulating line is configured to maintain the reductant below a temperature limit.   
   
   
       2 . The insulating system of  claim 1  wherein a flow of coolant passes through the insulating line. 
   
   
       3 . The insulating system of  claim 2  located at least partially inside an engine compartment. 
   
   
       4 . The insulating system of  claim 3  wherein the temperature of the coolant exceeds the temperature of the reductant flow at steady state operation of the engine. 
   
   
       5 . The insulating system of  claim 4  wherein the temperature inside the engine compartment exceeds the temperature of the coolant at steady state operation of the engine. 
   
   
       6 . The coolant system of  claim 5  wherein the flow of reductant originates from a source outside the engine compartment. 
   
   
       7 . The insulating system of  claim 6  wherein the flow of coolant is supplied from a radiator used to cool the engine. 
   
   
       8 . The insulating system of  claim 1  wherein the insulating line is thermally associated with a valve used to control the flow of reductant. 
   
   
       9 . The insulating system of  claim 2  wherein the insulating line is thermally associated with a reductant line used to transport the reductant from a reductant source to the exhaust of the engine. 
   
   
       10 . The insulating system of  claim 9  wherein the insulating line includes an outer pipe configured to allow the flow of coolant to pass through the outer pipe and around the reductant line. 
   
   
       11 . The insulating system of  claim 9  wherein the insulating line includes a contact pipe configured to be in contact with the reductant line. 
   
   
       12 . The insulating system of  claim 9  wherein the insulating line includes a conduit pipe surrounding the reductant line and configured to allow the flow of coolant to pass through. 
   
   
       13 . A method for maintaining a flow of reductant used by a selective catalytic reduction device below a temperature limit comprising:
 passing the flow of reductant through an insulating line thermally associated with the flow of reductant; and   passing a coolant through the insulating line wherein the coolant is hotter than the flow of reductant.   
   
   
       14 . The method of  claim 13  wherein the coolant is cooler than the space containing the insulating line. 
   
   
       15 . The method of  claim 13  further including:
 supplying the flow of coolant from a radiator used to cool the engine.   
   
   
       16 . The method of  claim 13  further including:
 passing the flow of reductant through a reductant line to transport the reductant from a reductant source to the exhaust of the engine.   
   
   
       17 . The method of  claim 14  wherein the space containing the insulating line is the space inside an engine compartment. 
   
   
       18 . The method of  claim 17  further including:
 locating a source of reductant outside the engine compartment.   
   
   
       19 . A power system including:
 an engine contained inside an engine compartment;   a selective catalytic reduction device in the exhaust of the engine;   a reductant system configured to supply a reductant to the exhaust for use in the selective catalytic reduction device;   a reductant insulating system configured to maintain the reductant below a temperature limit.   
   
   
       20 . The power system of  claim 19  wherein a flow of coolant passes through the reductant insulating system and the coolant is hotter than the reductant and cooler than the temperature inside the engine compartment.