Controlling hydrocarbon injection for filter regeneration

Abstract

A method for providing hydrocarbons to an engine exhaust for regenerating a diesel particulate filter within an exhaust system of a diesel engine is provided. The diesel engine comprises an electronic control module, at least one cylinder, and at least one fuel injector in fluid communication with the at least one cylinder, and a diesel oxidation catalyst within the exhaust system. Temperature of a diesel oxidation catalyst output is monitored with an electronic control module. A total amount of hydrocarbons required for diesel particulate filter regeneration is calculated based upon the monitoring of the temperature of the diesel oxidation catalyst output. The total amount of hydrocarbons is injected into an exhaust system upstream of a diesel oxidation catalyst and at least one cylinder with a fuel injector as a post injection.

What is claimed is: 
     
         1 . A method of providing hydrocarbons to an engine exhaust for regenerating a diesel particulate filter within an exhaust system of a diesel engine, the diesel engine comprising an electronic control module, at least one cylinder, and at least one fuel injector in fluid communication with the at least one cylinder, and a diesel oxidation catalyst within the exhaust system, the method comprising:
 receiving a diesel particulate filter regeneration request from an electronic control module;   monitoring temperature of a diesel oxidation catalyst output with the electronic control module;   determining a total amount of hydrocarbons required for diesel particulate filter regeneration with the electronic control module;   determining a first percentage of the total amount of hydrocarbons required for diesel particulate filter regeneration for delivery as an injection directly into an exhaust system upstream of a diesel oxidation catalyst;   determining a second percentage of the total amount of hydrocarbons required for diesel particulate filter regeneration for delivery as an in-cylinder post injection with the electronic control module;   injecting the first percentage of the total amount of hydrocarbons required for diesel particulate filter regeneration into the exhaust system upstream of the diesel oxidation catalyst; and   injecting the second percentage of the total amount of hydrocarbons required for diesel particulate filter regeneration for delivery as an in-cylinder post injection based upon an output of the electronic control module.   
     
     
         2 . The method of  claim 1 , wherein the determining of the total amount of hydrocarbons required for diesel particulate filter regeneration of the engine is based upon inputs from a temperature sensor adjacent the diesel oxidation catalyst. 
     
     
         3 . The method of  claim 1 , wherein the determining a first percentage of the total amounts of hydrocarbons required for diesel particulate filter regeneration for delivery as an injection directly into an exhaust system is based upon inputs from a engine speed sensor disposed in communication with an electronic control module, an engine torque output estimator of the electronic control module, an input from a temperature sensor adjacent the diesel oxidation catalyst, and an input from an air intake flow sensor. 
     
     
         4 . The method of  claim 1 , wherein the determining the first percentage of the total amount of hydrocarbons required for diesel particulate filter regeneration for delivery as an injection directly into an exhaust system upstream of a diesel oxidation catalyst and the second percentage of the total amount of hydrocarbons required for diesel particulate filter regeneration is performed on a single processor. 
     
     
         5 . The method of  claim 1 , wherein the determining the first percentage of the total amount of hydrocarbons required for diesel particulate filter regeneration for delivery as an injection directly into an exhaust system upstream of a diesel oxidation catalyst will equal zero at an engine idle. 
     
     
         6 . The method of  claim 1 , wherein the injecting the first percentage of the total amount of hydrocarbons required for diesel particulate filter regeneration into the exhaust system upstream of the diesel oxidation catalyst and the second percentage of the total amount of hydrocarbons required for diesel particulate filter regeneration for delivery as an in-cylinder post injection occur generally simultaneously. 
     
     
         7 . The method of  claim 1 , wherein the injecting the first percentage of the total amount of hydrocarbons required for diesel particulate filter regeneration into the exhaust system upstream of the diesel oxidation catalyst is initiated following an initiation of injecting the second percentage of the total amount of hydrocarbons required for diesel particulate filter regeneration for delivery as an in-cylinder post injection 
     
     
         8 . The method of  claim 1 , further comprising transitioning an initial first percentage of the total amounts of hydrocarbons required for diesel particulate filter regeneration for delivery as an injection directly into an exhaust system is based upon inputs from a engine speed sensor disposed in communication with an electronic control module, an engine torque output estimator of the electronic control module, an input from a temperature sensor adjacent the diesel oxidation catalyst, and an input from an air intake flow sensor to a modified first percentage of the total amounts of hydrocarbons required for diesel particulate filter regeneration based upon changes in the inputs from the engine speed sensor, the engine torque output estimator, the temperature sensor adjacent the diesel oxidation catalyst, and the air intake flow sensor. 
     
     
         9 . The method of  claim 8 , wherein the transitioning from the initial first percentage of the total amounts of hydrocarbons required for diesel particulate filter regeneration to the modified of the total amounts of hydrocarbons required for diesel particulate filter regeneration is a filtered transition requiring changes in the inputs from the engine speed sensor, the engine torque output estimator, the temperature sensor adjacent the diesel oxidation catalyst, and the air intake flow sensor to exceed a predetermined amount for any transitioning to occur. 
     
     
         10 . A method for providing hydrocarbons to an engine exhaust for regenerating a diesel particulate filter within an exhaust system of a diesel engine, the diesel engine comprising an electronic control module, at least one cylinder, and at least one fuel injector in fluid communication with the at least one cylinder, and a diesel oxidation catalyst within the exhaust system, the method comprising:
 monitoring temperature of a diesel oxidation catalyst output with an electronic control module;   calculating a total amount of hydrocarbons required for diesel particulate filter regeneration based upon the monitoring of the temperature of the diesel oxidation catalyst output; and   injecting the total amount of hydrocarbons into an exhaust system upstream of a diesel oxidation catalyst and at least one cylinder with a fuel injector as a post injection.   
     
     
         11 . The method of  claim 10 , wherein a first percent of the total amount of hydrocarbons are injected into the exhaust system upstream of the diesel oxidation catalyst based upon monitoring engine intake air flow with an electronic control module. 
     
     
         12 . The method of  claim 10 , wherein a first percent of the total amount of hydrocarbons are injected into the exhaust system upstream of the diesel oxidation catalyst based upon monitoring engine speed with an electronic control module. 
     
     
         13 . The method of  claim 10 , wherein a first percent of the total amount of hydrocarbons are injected into the exhaust system upstream of the diesel oxidation catalyst based upon monitoring engine torque output with an electronic control module. 
     
     
         14 . The method of  claim 10 , wherein a first percent of the total amount of hydrocarbons are injected into the exhaust system upstream of the diesel oxidation catalyst, and a second percent of the total amount of hydrocarbons are injected into the at least one cylinder with a fuel injector as a post injection, the first percent and the second percent varying over time based upon changes in engine speed. 
     
     
         15 . The method of  claim 14 , wherein the first percent and the second percent varying over time require changes in engine speed to exceed a predefined amount. 
     
     
         16 . The method of  claim 10 , wherein a first percent of the total amount of hydrocarbons are injected into the exhaust system upstream of the diesel oxidation catalyst, and a second percent of the total amount of hydrocarbons are injected into the at least one cylinder with a fuel injector as a post injection, the first percent and the second percent varying over time based upon changes in engine torque output. 
     
     
         17 . A hydrocarbon injection system for an internal combustion engine having an exhaust system with a diesel particulate filter and a diesel oxidation catalyst, the hydrocarbon injection system comprising:
 an electronic control module having a memory and a processor;   an engine speed sensor disposed in communication with the electronic control module;   an engine torque output estimator disposed in communication with the electronic control module;   an exhaust system having a diesel oxidation catalyst, a diesel oxidation catalyst temperature sensor disposed adjacent the diesel oxidation catalyst and disposed in communication with the electronic control module, a diesel particulate filter disposed downstream of the diesel oxidation catalyst, and a exhaust system hydrocarbon injector disposed upstream of the diesel oxidation catalyst and disposed in communication with the electronic control module; and   at least one in-cylinder engine fuel injector disposed within a cylinder of the engine, the fuel injector disposed in communication with the electronic control module;   wherein the electronic control module determines a total amount of hydrocarbons required for diesel particulate filter regeneration based upon a diesel oxidation catalyst output temperature sensor, and the electronic control module generates a single hydrocarbon injection output causing at least one of the in-cylinder fuel injector and the exhaust system hydrocarbon injector to inject hydrocarbons when a diesel particulate filter regeneration is required.   
     
     
         18 . The hydrocarbon injection system of  claim 17 , wherein the electronic control module generates a single hydrocarbon injection output causing both the in-cylinder fuel injector and the exhaust system hydrocarbon injector to inject hydrocarbons when a diesel particulate filter regeneration is required. 
     
     
         19 . The hydrocarbon injection system of  claim 18 , wherein a first percentage of the total amount of hydrocarbons required for diesel particulate filter regeneration is injected with the exhaust system hydrocarbon injector and a second percentage of the total amount of hydrocarbons required for diesel particulate filter regeneration is injected with the in-cylinder fuel injector based upon outputs of the engine speed sensor received by the electronic control module. 
     
     
         20 . The hydrocarbon injection system of  claim 18 , wherein a first percentage of the total amount of hydrocarbons required for diesel particulate filter regeneration is injected with the exhaust system hydrocarbon injector and a second percentage of the total amount of hydrocarbons required for diesel particulate filter regeneration is injected with the in-cylinder fuel injector based upon outputs of the engine torque estimator received by the electronic control module.