Back to results
US 5,050,376 AGranted
Control system for diesel particulate trap regeneration system
AssigneeAllied-Signal Inc.
InventorsPaul M. Stiglic, Brian C. Gabelman, James A. Hardy
Life of this patent
Estimating the term…
Loading patent…
Loading patent…
AssigneeAllied-Signal Inc.
InventorsPaul M. Stiglic, Brian C. Gabelman, James A. Hardy
Estimating the term…
A control system for regenerating a particulate trap in the exhaust system of a diesel engine includes control logic which controls the air/fuel ratio of the engine by operating a backpressure valve in the engine exhaust system to provide a proper amount of excess oxygen to permit efficient combustion of the particulate content of the trap, but to avoid rapid and damaging combustion rates. Actual engine air/fuel ratio is compared to a commanded air/fuel ratio, and the position of the backpressure valve is adjusted accordingly. The commanded air/fuel ratio is ratcheted upwardly or downwardly once in a predetermined time period in response to a temperature error signal between exhaust gas temperature sensed in the engine exhaust manifold and a predetermined commanded temperature. An override is provided to permit the vehicle operator to override regeneration when power is required from the engine, and a low power cut-off is provided to suspend regeneration when the engine is operated for a period of time at low power conditions where regeneration is inefficient.
Method of regenerating an exhaust gas particulate trap in an exhaust system for an internal combustion engine, comprising the steps of measuring the air/fuel ratio of said internal combustion engine, generating a signal representing a commanded value of the air/fuel signal corresponding to an air/fuel ratio with sufficient excess air to burn the particles stored in the trap, generating an error signal representing the difference between the measured air/fuel ratio and the commanded value of the air/fuel ratio, and controlling the air/fuel ratio of said engine as a function of said error signal, said exhaust system including a valve for regulating exhaust gas flow through said system to thereby vary the backpressure on said engine, said step of controlling the air/fuel ratio of the engine including the step of operating said backpressure valve in response to said error signal to thereby control said air/fuel ratio by controlling the backpressure on said engine.
Method of regenerating an exhaust gas particulate trap as claimed in claim, 5, wherein said method includes the steps of increasing said commanded value of the air/fuel ratio by a predetermined magnitude if the temperature signal exceeds a predetermined level and decreasing the commanded value of the air/fuel ratio by a predetermined magnitude if the temperature signal is less than a predetermined value.
Method of regulating an exhaust gas particulate trap in an exhaust system for an internal combustion engine, said exhaust system including a backpressure valve for regulating flow of exhaust gas through the exhaust system whereby backpressure on the engine may be regulated by operation of the valve, comprising the steps of determining a commanded value of the air/fuel ratio of said engine providing sufficient excess oxygen to effect regeneration of the trap, modifying the commanded value of the air/fuel ratio as a function of exhaust gas temperatures, and operating said backpressure valve to vary backpressure on said engine to achieve the commanded air/fuel ratio.
Dependencies are inferred from the claim text.