Utilizing a GPF Downstream of a Hydrocarbon Trap

Abstract

An exhaust system for an internal combustion engine, and methods of using, the system comprising a hydrocarbon trap; and a gasoline particulate filter, located downstream from the hydrocarbon trap.

1 . An exhaust system for an internal combustion engine, the system comprising:
 a. a hydrocarbon trap; and   b. a gasoline particulate filter, located downstream from the hydrocarbon trap.   
     
     
         2 . The exhaust system of  claim 1 , wherein the system does not include a three-way-catalyst. 
     
     
         3 . The exhaust system of  claim 1 , wherein the system does not include a three-way-catalyst downstream of the hydrocarbon trap. 
     
     
         4 . The exhaust system of  claim 1 , wherein the system includes a three-way-catalyst upstream of the hydrocarbon trap in a close-coupled position. 
     
     
         5 . The exhaust system of  claim 1 , wherein the hydrocarbon trap is formulated to adsorb a portion of hydrocarbon contained in an exhaust gas at temperatures up to about 350° C. 
     
     
         6 . The exhaust system of  claim 5 , wherein the hydrocarbon trap is also formulated to desorb hydrocarbons at a temperature of about 350° C. or greater. 
     
     
         7 . The exhaust system of  claim 1 , wherein the gasoline particulate filter is formulated to oxidize the hydrocarbon contained in an exhaust gas. 
     
     
         8 . The exhaust system of  claim 1 , wherein the hydrocarbon trap and the gasoline particulate filter comprise separate substrates. 
     
     
         9 . A method of treating an exhaust gas from an internal combustion engine, comprising contacting the exhaust gas with:
 a. a hydrocarbon trap; and   b. a gasoline particulate filter, located downstream from the hydrocarbon trap.   
     
     
         10 . The method of  claim 9 , wherein the hydrocarbon trap adsorbs a portion of hydrocarbon contained in the exhaust gas at temperatures up to about 350° C. 
     
     
         11 . The method of  claim 9 , wherein the hydrocarbon trap desorbs a portion of hydrocarbon contained in the exhaust gas at temperatures of about 350° C. or greater. 
     
     
         12 . The method of  claim 9 , wherein the gasoline particulate filter oxidizes the hydrocarbon contained in an exhaust gas. 
     
     
         13 . The method of  claim 9 , wherein the exhaust gas does not contact a three-way-catalyst. 
     
     
         14 . The method of  claim 9 , wherein the exhaust gas does not contact a three-way-catalyst downstream of the hydrocarbon trap. 
     
     
         15 . The method of  claim 9 , wherein the exhaust gas contacts a three-way-catalyst which is in a close-coupled position upstream of the hydrocarbon trap.