Method and apparatus for exhaust aftertreatment of an internal combustion engine

Abstract

An exhaust gas aftertreatment device includes a single intake path for an exhaust gas feedstream from an internal combustion engine and a coated substrate including a first substrate portion fluidly in parallel with a second substrate portion. A flow modification device selectively restricts flow of the exhaust gas feedstream exclusively to the first substrate portion, exclusively to the second substrate portion, and concurrently to the first substrate portion and the second substrate portion in controllably variable proportions.

1 . An exhaust gas aftertreatment device, comprising:
 a single intake path for an exhaust gas feedstream from an internal combustion engine;   a coated substrate including a first substrate portion fluidly in parallel with a second substrate portion; and   a flow modification device configured to selectively restrict flow of the exhaust gas feedstream exclusively to the first substrate portion, exclusively to the second substrate portion, and concurrently to the first substrate portion and the second substrate portion in controllably variable proportions.   
     
     
         2 . The exhaust gas aftertreatment device of  claim 1 , further comprising the first substrate portion including a washcoat configured to process a stoichiometric exhaust gas feedstream and the second substrate portion including a washcoat configured to process a lean exhaust gas feedstream. 
     
     
         3 . The exhaust gas aftertreatment device of  claim 1 , wherein the first substrate portion is annular to the second substrate portion. 
     
     
         4 . The exhaust gas aftertreatment device of  claim 1 , wherein the flow modification device is controllable to a plurality of positions including one of a first position to effect flow of the exhaust gas feedstream exclusively to the first substrate portion, a second position to effect flow of the exhaust gas feedstream exclusively to the first substrate portion, and a third position intermediate the first and second positions to effect flow of the exhaust gas feedstream concurrently to the first substrate portion and the second substrate portion in proportions corresponding to the third position. 
     
     
         5 . The exhaust gas aftertreatment device of  claim 4 , wherein the first position permits exhaust gas flow exclusively through the first substrate portion. 
     
     
         6 . The exhaust gas aftertreatment device of  claim 4 , wherein the second position permits exhaust gas flow exclusively through the second substrate portion. 
     
     
         7 . The exhaust gas aftertreatment device of  claim 4 , wherein the third position permits exhaust gas flow concurrently through both the first and second substrate portions. 
     
     
         8 . The exhaust gas aftertreatment device of  claim 1 , wherein the first substrate portion is contiguous to the second substrate portion. 
     
     
         9 . The exhaust gas aftertreatment device of  claim 1 , wherein the flow modification device is positioned upstream of the coated substrate relative to exhaust gas flow. 
     
     
         10 . The exhaust gas aftertreatment device of  claim 1 , wherein the flow modification device is positioned downstream of the coated substrate relative to exhaust gas flow. 
     
     
         11 . The exhaust gas aftertreatment device of  claim 1 , wherein the first substrate portion is configured to process an oxygen-rich exhaust gas. 
     
     
         12 . Method for managing an exhaust gas feedstream with an exhaust gas aftertreatment device, the method comprising:
 equipping the exhaust gas aftertreatment device with a single intake path, a substrate including a first portion configured fluidly in parallel with a second portion, and a flow modification device configured to control flow of the exhaust gas feedstream through one of the first portion exclusively, the second portion exclusively, and the first portion and the second portion concurrently;   monitoring engine operation; and   controlling the flow modification device based upon the engine operation.   
     
     
         13 . The method of  claim 12 , further comprising:
 controlling the flow modification device to a first position when the engine operates at a stoichiometric air/fuel ratio.   
     
     
         14 . The method of  claim 13 , further comprising:
 controlling the flow modification device to a second position when the engine operates at a lean air/fuel ratio.   
     
     
         15 . The method of  claim 14 , further comprising:
 controlling the flow modification device to a third position when the engine operates at a rich air/fuel ratio.   
     
     
         16 . The method of  claim 12 , further comprising:
 monitoring temperature of the exhaust gas feedstream; and   controlling the flow modification device based upon the temperature.   
     
     
         17 . The method of  claim 16 , further comprising:
 controlling the flow modification device to direct the exhaust gas feedstream to one of the first portion exclusively and second portion exclusively based upon the temperature of the exhaust gas feedstream.