Exhaust treatment system

Abstract

An exhaust treatment system for a power system is disclosed. The exhaust treatment system includes an exhaust conduit directing exhaust gas produced by the power system towards at least one exhaust treatment device. The exhaust treatment system may also include a substrate positioned within an enclosure of the at least one exhaust treatment device. The exhaust conduit may be configured to preheat the substrate with the exhaust gas prior to directing the exhaust gas into the enclosure.

1 . An exhaust treatment system for a power system, comprising:
 an exhaust conduit directing exhaust gas produced by the power system towards at least one exhaust treatment device; and   a substrate positioned within an enclosure of the at least one exhaust treatment device, wherein the exhaust conduit is configured to preheat the substrate with the exhaust gas prior to directing the exhaust gas into the enclosure.   
     
     
         2 . The exhaust treatment system of  claim 1 , wherein the exhaust conduit is configured to preheat the substrate such that a temperature of a surface of the substrate that contacts the exhaust gas is higher than a temperature of the exhaust gas within the enclosure. 
     
     
         3 . The exhaust treatment system of  claim 1 , wherein the exhaust conduit is configured to preheat the substrate such that a temperature of a surface of the substrate that contacts the exhaust gas is substantially the same as a temperature of the exhaust gas within the enclosure. 
     
     
         4 . The exhaust treatment system of  claim 1 , wherein the enclosure includes an inner chamber which encloses the substrate, and an outer chamber positioned around the inner chamber with an annular space defined therebetween, the exhaust conduit being configured to direct the exhaust gas through the annular space prior to directing the exhaust gas into the inner chamber. 
     
     
         5 . The exhaust treatment system of  claim 4 , further including a fluid flow passage that fluidly couples a downstream end of the annular space to an inlet positioned at an upstream end of the inner chamber. 
     
     
         6 . The exhaust treatment system of  claim 5 , wherein the inner chamber includes an outlet positioned at a downstream end. 
     
     
         7 . The exhaust treatment system of  claim 4 , wherein the enclosure includes features that are configured to increase a transfer of heat from the exhaust gas to substrate positioned within the inner chamber. 
     
     
         8 . The exhaust treatment system of  claim 1 , wherein the at least one exhaust treatment device includes a first exhaust treatment device positioned upstream of a second exhaust treatment device. 
     
     
         9 . The exhaust treatment system of  claim 8 , wherein said substrate is a first substrate of the first exhaust treatment device and the second exhaust treatment device includes a second substrate positioned within the enclosure and the exhaust conduit is configured to preheat both the first and the second substrate with the exhaust gas prior to directing the exhaust gas into the enclosure. 
     
     
         10 . A method of operating an exhaust treatment device of an engine, comprising:
 directing exhaust gas produced by the engine towards the exhaust treatment device, the exhaust treatment device including a substrate positioned within an enclosure;   heating the substrate to a temperature higher than a temperature of the exhaust gas prior to directing the exhaust gas past the substrate; and   directing the exhaust gas into the enclosure and past the substrate after the heating.   
     
     
         11 . The method of  claim 10 , wherein the heating includes heating the substrate using the exhaust gas prior to directing the exhaust gas into the enclosure. 
     
     
         12 . The method of  claim 11 , wherein heating the substrate includes passing the exhaust gas from the engine along an external surface of the enclosure. 
     
     
         13 . The method of  claim 12 , wherein directing the exhaust gas into the enclosure includes directing the exhaust gas into the enclosure after passing the exhaust gas along the external surface of the enclosure. 
     
     
         14 . The method of  claim 10 , wherein heating the substrate includes heating the substrate using an electric heater. 
     
     
         15 . The method of  claim 10 , further including directing the exhaust gas around the enclosure prior to directing the exhaust gas into the enclosure. 
     
     
         16 . A method of reducing phosphorous aging of an exhaust treatment device of an engine, comprising:
 directing exhaust gas produced by the engine into an enclosure of the exhaust treatment device, the exhaust treatment device including a substrate positioned within the enclosure;   transferring heat from the exhaust gas to the substrate prior to directing the exhaust gas into the enclosure; and   directing the exhaust gas in the enclosure past the substrate.   
     
     
         17 . The method of  claim 16 , wherein the transferring of heat includes directing the exhaust gas from the engine around an external surface of the enclosure prior to directing the exhaust gas into the enclosure. 
     
     
         18 . The method of  claim 16 , wherein the transferring of heat includes heating the substrate and cooling the exhaust gas such that a temperature of the exhaust gas within the enclosure is below a temperature of the substrate. 
     
     
         19 . The method of  claim 16 , wherein directing the exhaust gas past the substrate includes decreasing a deposition of phosphorous containing compounds in the exhaust gas on the substrate. 
     
     
         20 . The method of  claim 16 , wherein transferring heat from the exhaust gas to the substrate includes heating the substrate to reduce a temperature differential between the substrate and the exhaust gas in the enclosure.