Control system and method for improved efficiency of particulate matter filter regeneration

Abstract

An engine control system includes an injection determination module and an injection distribution module. The injection determination module determines a desired amount of hydrocarbons (HC) to inject into exhaust gas produced by an engine for regeneration of a particulate matter (PM) filter. The injection distribution module controls a ratio of auxiliary injection to post-combustion injection based on engine load, engine speed, and the desired amount of HC injection, wherein auxiliary injection includes injecting HC into the exhaust gas, and wherein post-combustion injection includes injecting HC into cylinders of the engine during a period after combustion.

1 . An engine control system, comprising:
 an injection determination module that determines a desired amount of hydrocarbons (HC) to inject into exhaust gas produced by an engine for regeneration of a particulate matter (PM) filter; and   an injection distribution module that controls a ratio of auxiliary injection to post-combustion injection based on engine load, engine speed, and the desired amount of HC injection, wherein auxiliary injection includes injecting HC into the exhaust gas, and wherein post-combustion injection includes injecting HC into cylinders of the engine during a period after combustion.   
     
     
         2 . The engine control system of  claim 1 , wherein the injection distribution module determines amounts of auxiliary injection and post-combustion injection based on the engine load, the engine speed, and the desired amount of HC injection. 
     
     
         3 . The engine control system of  claim 2 , further comprising:
 a regeneration control module that generates control signals for an auxiliary HC injector and fuel injectors based on the amounts of auxiliary injection and post-combustion injection, respectively.   
     
     
         4 . The engine control system of  claim 3 , wherein the auxiliary HC injector is located upstream from an oxidation catalyst (OC) in an exhaust treatment system, and wherein the fuel injectors correspond to cylinders of the engine. 
     
     
         5 . The engine control system of  claim 4 , wherein the regeneration control module generates control signals for fuel injectors corresponding to one bank of cylinders of the engine. 
     
     
         6 . The engine control system of  claim 2 , wherein the injection distribution module determines a factor using a lookup table that includes a plurality of factors relating to engine load and engine speed. 
     
     
         7 . The engine control system of  claim 6 , wherein the injection distribution module determines the amount of auxiliary injection based on a product of the factor and the desired amount of HC injection, and wherein the injection distribution module determines the amount of post-combustion injection based on a difference between the desired amount of HC injection and the determined amount of auxiliary injection. 
     
     
         8 . The engine control system of  claim 1 , wherein the injection determination module determines the desired amount of HC injection based on a temperature of the exhaust gas at an inlet of the PM filter. 
     
     
         9 . The engine control system of  claim 8 , wherein the injection determination module determines the desired amount of HC to inject into the exhaust gas based on at least one of exhaust gas flow and vehicle speed. 
     
     
         10 . The engine control system of  claim 9 , wherein the injection determination module performs proportional-integral-derivative (PID) control of the desired amount of HC to inject into the exhaust gas. 
     
     
         11 . A method, comprising:
 determining a desired amount of hydrocarbons (HC) to inject into exhaust gas produced by an engine for regeneration of a particulate matter (PM) filter; and   controlling a ratio of auxiliary injection to post-combustion injection based on engine load, engine speed, and the desired amount of HC injection, wherein auxiliary injection includes injecting HC into the exhaust gas, and wherein post-combustion injection includes injecting HC into cylinders of the engine during a period after combustion.   
     
     
         12 . The method of  claim 11 , further comprising:
 determining amounts of auxiliary injection and post-combustion injection based on the engine load, the engine speed, and the desired amount of HC injection.   
     
     
         13 . The method of  claim 12 , further comprising:
 generating control signals for an auxiliary HC injector and fuel injectors based on the amounts of auxiliary injection and post-combustion injection, respectively.   
     
     
         14 . The method of  claim 13 , wherein the auxiliary HC injector is located upstream from an oxidation catalyst (OC) in an exhaust treatment system, and wherein the fuel injectors correspond to cylinders of the engine. 
     
     
         15 . The method of  claim 14 , further comprising:
 generating control signals for fuel injectors corresponding to one bank of cylinders of the engine.   
     
     
         16 . The method of  claim 12 , further comprising:
 determining a factor using a lookup table that includes a plurality of factors relating to engine load and engine speed.   
     
     
         17 . The method of  claim 16 , further comprising:
 determining the amount of auxiliary injection based on a product of the factor and the desired amount of HC injection; and   determining the amount of post-combustion injection based on a difference between the desired amount of HC injection and the determined amount of auxiliary injection.   
     
     
         18 . The method of  claim 11 , further comprising:
 determining the desired amount of HC injection based on a temperature of the exhaust gas at an inlet of the PM filter.   
     
     
         19 . The method of  claim 18 , further comprising:
 determining the desired amount of HC to inject into the exhaust gas based on at least one of exhaust gas flow and vehicle speed.   
     
     
         20 . The method of  claim 19 , further comprising:
 performing proportional-integral-derivative (PID) control of the desired amount of HC to inject into the exhaust gas.