Exhaust Gas Control Apparatus for Internal Combustion Engine

Abstract

An exhaust gas control apparatus ( 1 ) according to the invention is applied to a diesel engine ( 2 ) including a turbocharger ( 10 ). The exhaust gas control apparatus ( 1 ) includes an upstream side oxidation catalyst ( 13 ) which is provided down-stream of a turbine ( 10 b ) of the turbocharger ( 10 ); a downstream side oxidation catalyst ( 14 ) which is provided downstream of the upstream side oxidation catalyst ( 13 ); a particulate filter ( 15 ) which is provided downstream of the downstream side oxidation catalyst ( 13 ); and an injector ( 5 ) which supplies fuel required for a filter recovery process for oxidizing and removing particulate matter accumulated in the particulate filter ( 15 ). The capacity of the upstream side oxidation catalyst ( 13 ) is set such that a space velocity (SV) during idling of the internal combustion engine ( 2 ) is equal to or lower than 175,000 (l/h).

1 . An exhaust gas control apparatus applied to an internal combustion engine including a turbocharger, comprising: 
 an upstream side oxidation catalyst which is provided downstream of a turbine of the turbocharger;    a downstream side oxidation catalyst which is provided downstream of the upstream side oxidation catalyst;    a particulate filter which is provided downstream of the downstream side oxidation catalyst; and    fuel supply device which supplies fuel required for a filter recovery process for oxidizing and removing particulate matter accumulated in the particulate filter, wherein    a capacity of the upstream side oxidation catalyst is set such that a space velocity during idling of the internal combustion engine is equal to or lower than 175,000 (l/h).    
   
   
       2 . The exhaust gas control apparatus according to  claim 1 , wherein 
 the capacity of the upstream side oxidation catalyst is set such that the space velocity during idling of the internal combustion engine is equal to or higher than 58,000 (l/h).    
   
   
       3 . The exhaust gas control apparatus according to  claim 1 , wherein 
 the capacity of the upstream side oxidation catalyst is one-thirtieth to one-fifth of a capacity of the downstream side oxidation catalyst.    
   
   
       4 . The exhaust gas control apparatus according to  claim 2 , wherein 
 the capacity of the upstream side oxidation catalyst is one-thirtieth to one-fifth of a capacity of the downstream side oxidation catalyst.