METHOD AND DEVICE FOR ON-BOARD MONITORING THE PERFORMANCE OF AN OXIDATION CATALYST

摘要

An engine exhaust treatment system fluidly coupled to an internal combustion engine (12) having a combustion cylinder, comprising: an oxidation catalyst (14) disposed in an engine exhaust stream; a hydrocarbon injector (38) disposed upstream of the oxidation catalyst (14); a temperature sensor (22) disposed in the exhaust stream upstream of the oxidation catalyst (14); a temperature sensor (24) disposed in the exhaust stream downstream of the oxidation catalyst (14); and a controller (30) in communication with the temperature sensor (22) located in the exhaust gas stream upstream of the oxidation catalyst (14), with the temperature sensor (24) located in the exhaust gas stream downstream of the oxidation catalyst (14), and with the A hydrocarbon injector (38), wherein the controller (30) is configured to: inject hydrocarbon fuel into the exhaust stream upstream of the oxidation catalyst (14); and measure a temperature of the exhaust gas stream on the upstream and downstream sides of the oxidation catalyst (14); characterized in that the hydrocarbon injector is disposed in the combustion cylinder and the controller (30) is configured to schedule fuel injection to inject fuel into the Modify the combustion cylinder during a combustion cylinder exhaust stroke in addition to an injection of fuel into the cylinder for combustion, calculate a difference in exhaust gas flow temperature between the upstream and downstream sides of the oxidation catalyst (14), and convert the NO to NO by the oxidation catalyst (14) from the Determine the difference in exhaust gas flow temperature based on a predetermined correlation profile between the temperatures on the upstream and downstream sides of the oxidation catalyst (14) and the conversion of NO to NO, wherein the predetermined correlation profile between the temperatures on the upstream and downstream sides of the oxidation catalyst (14) and the conversion from NO to NO is a predetermined correlation profile based on several factors having the difference in temperatures between the upstream and downstream sides of the oxidation catalyst (14), and wherein the factors further include the age of the oxidation catalyst, the exhaust gas flow and the amount of post fuel injection.