Oxidation catalyst monitoring

Abstract

A control method for monitoring an oxidation catalyst of an exhaust system is provided. The control method includes determining an open loop factor based on an aging factor and an efficiency curve; controlling an injection of hydrocarbons into an exhaust stream based on the open loop factor; and monitoring the oxidation catalyst based on the injection of hydrocarbons.

What is claimed is: 
     
         1 . A control method for monitoring an oxidation catalyst of an exhaust system, comprising:
 determining an open loop factor based on an aging factor and an efficiency curve;   controlling an injection of hydrocarbons into an exhaust stream based on the open loop factor; and   monitoring the oxidation catalyst based on the injection of hydrocarbons.   
     
     
         2 . The control method of  claim 1 , wherein the aging factor is determined based on at least one of miles driven, and a time of operation. 
     
     
         3 . The control method of  claim 1 , wherein the efficiency curve is predefined based on physical characteristics of the oxidation catalyst. 
     
     
         4 . The control method of  claim 1 , wherein the efficiency curve is determined based on sensed parameters of the exhaust system. 
     
     
         5 . The control method of  claim 1 , wherein the monitoring the oxidation catalyst comprises monitoring a temperature of exhaust gas exiting the oxidation catalyst. 
     
     
         6 . The control method of  claim 5 , further comprising generating a message based on the monitoring. 
     
     
         7 . A control system for monitoring an oxidation catalyst of an exhaust system, comprising:
 a first module that determines an open loop factor based on an aging factor and an efficiency curve;   a second module that controls injection of hydrocarbons into an exhaust stream based on the open loop factor; and   a third module that monitors the oxidation catalyst based on the injection of hydrocarbons.   
     
     
         8 . The control system of  claim 7 , wherein the aging factor is determined based on at least one of miles driven, and a time of operation. 
     
     
         9 . The control system of  claim 7 , wherein the efficiency curve is predefined based on physical characteristics of the oxidation catalyst. 
     
     
         10 . The control system of  claim 7 , wherein the efficiency curve is determined based on sensed parameters of the exhaust system. 
     
     
         11 . The control system of  claim 7 , wherein the third module monitors the oxidation catalyst based on a temperature of exhaust gas exiting the oxidation catalyst. 
     
     
         12 . The control system of  claim 11 , wherein the third module generates a message based on the monitoring. 
     
     
         13 . An exhaust system of an engine, comprising:
 an oxidation catalyst; and   a control module that determines an open loop factor based on an aging factor and an efficiency curve, that injects hydrocarbons into an exhaust stream based on the open loop factor, and that monitors the oxidation catalyst based on the injection of hydrocarbons.   
     
     
         14 . The exhaust system of  claim 13 , wherein the aging factor is determined based on at least one of miles driven, and a time of operation. 
     
     
         15 . The exhaust system of  claim 13 , wherein the efficiency curve is predefined based on physical characteristics of the oxidation catalyst. 
     
     
         16 . The exhaust system of  claim 13 , wherein the efficiency curve is determined based on sensed parameters of the exhaust system. 
     
     
         17 . The exhaust system of  claim 13 , wherein the control module monitors the oxidation catalyst based on a temperature of exhaust gas exiting the oxidation catalyst.