Particulate regeneration and engine control system

Abstract

A particulate regeneration system for an engine is disclosed. The particulate regeneration system may have a particulate filter configured to remove particulate matter from a flow of engine exhaust, and a diesel oxidation catalyst located upstream of the particulate filter to facilitate oxidation of the trapped particulate matter. The particulate regeneration system may further have a regeneration device located upstream of the diesel oxidation catalyst and configured to selectively heat the exhaust above an oxidation temperature of the trapped particulate matter, and a selective catalytic reduction device located downstream of the particulate filter to remove NOx from the engine exhaust. The particulate regeneration system may also have a controller in communication with the regeneration device and the engine. The controller may be configured to modify engine operation in response to initiation of a regeneration event.

1 . A particulate regeneration system for an engine, comprising:
 a particulate filter configured to remove particulate matter from a flow of engine exhaust;   a diesel oxidation catalyst located upstream of the particulate filter to facilitate oxidation of the trapped particulate matter;   a regeneration device located upstream of the diesel oxidation catalyst and configured to selectively heat the exhaust above an oxidation temperature of the trapped particulate matter;   a selective catalytic reduction device located downstream of the particulate filter to remove NOx from the engine exhaust; and   a controller in communication with the regeneration device and the engine, the controller being configured to modify engine operation in response to initiation of a regeneration event.   
   
   
       2 . The particulate regeneration system of  claim 1 , wherein changing engine operation results in improved fuel efficiency of the engine. 
   
   
       3 . The particulate regeneration system of  claim 2 , wherein changing engine operation also results in increased NOx production. 
   
   
       4 . The particulate regeneration system of  claim 3 , wherein the effectiveness of the selective catalytic reduction device increases at the oxidation temperature to accommodate the increased NOx production. 
   
   
       5 . The particulate regeneration system of  claim 2 , wherein changing engine operation includes changing a fuel injection characteristic. 
   
   
       6 . The particulate regeneration system of  claim 1 , wherein the oxidation temperature is about 400° C. 
   
   
       7 . The particulate regeneration system of  claim 6 , wherein the diesel oxidation catalyst converts NO to NO 2 . 
   
   
       8 . The particulate regeneration system of  claim 1 , wherein the diesel oxidation catalyst includes a coating applied to an upstream portion of the particulate filter. 
   
   
       9 . A method of improving fuel efficiency of an engine, comprising:
 combusting fuel to generate a flow of exhaust;   converting a constituent in the exhaust to an oxidation facilitating constituent;   removing particulate matter from the exhaust flow;   heating the removed particulate matter above an oxidation threshold temperature;   changing engine operation in response to a temperature of the particulate matter exceeding the oxidation threshold temperature; and   removing NOx from the exhaust flow.   
   
   
       10 . The method of  claim 9 , wherein changing engine operation results in improved fuel efficiency of the engine. 
   
   
       11 . The method of  claim 10 , wherein changing engine operation also results in increased NOx production. 
   
   
       12 . The method of  claim 11 , wherein a NOx removal effectiveness increases at the oxidation threshold temperature to accommodate the increased NOx production. 
   
   
       13 . The method of  claim 10 , wherein changing engine operation includes changing a fuel injection characteristic. 
   
   
       14 . The method of  claim 9 , wherein the oxidation threshold temperature is about 400° C. 
   
   
       15 . The method of  claim 14 , wherein the converting includes converting NO to NO2. 
   
   
       16 . A power system, comprising:
 an internal combustion engine configured to combust fuel and generate a flow of exhaust;   a particulate filter configured to remove particulate matter from the flow of exhaust;   a diesel oxidation catalyst located upstream of the particulate filter and configured to convert NO to NO2 to facilitate oxidation of the trapped particulate matter;   a regeneration device located upstream of the diesel oxidation catalyst and configured to selectively heat the exhaust to about 400° C. to initiate combustion of the removed particulate matter;   a selective catalytic reduction device located downstream of the particulate filter to remove NOx from the engine exhaust; and   a controller in communication with the regeneration device and the engine, the controller being configured to change a fuel injection characteristic in response to initiation of a regeneration event.   
   
   
       17 . The power system of  claim 16 , wherein changing a fuel injection characteristic results in improved fuel efficiency of the engine. 
   
   
       18 . The power system of  claim 17 , wherein changing fuel injection characteristics also results in increased NOx production. 
   
   
       19 . The power system of  claim 18 , wherein the effectiveness of the selective catalytic reduction device increases at about 400° C. to accommodate the increased NOx production. 
   
   
       20 . The power system of  claim 16 , wherein the diesel oxidation catalyst includes a coating applied to an upstream portion of the particulate filter.