Abstract: An ECU stores and holds in a memory unit NOx information which is information concerning NOx in an exhaust gas flowing through an exhaust system of an onboard engine of a vehicle or NOx purification by a catalyst placed in the exhaust system. The ECU includes a parameter acquisition unit that acquires an NOx parameter, which is an outflow quantity of NOx flowing out to a downstream side of the catalyst or a correlation value correlating to the outflow quantity of NOx, according to a working state of the engine, an integrated value computation unit that computes a parameter integrated value by integrating NOx parameters acquired by the parameter acquisition unit, and a storage processing unit that stores in the memory unit the parameter integrated value as the NOx information.

Abstract: An ECU stores and holds in a memory unit NOx information which is information concerning NOx in an exhaust gas flowing through an exhaust system of an onboard engine of a vehicle or NOx purification by a catalyst placed in the exhaust system. The ECU includes a parameter acquisition unit that acquires an NOx parameter, which is an outflow quantity of NOx flowing out to a downstream side of the catalyst or a correlation value correlating to the outflow quantity of NOx, according to a working state of the engine, an integrated value computation unit that computes a parameter integrated value by integrating NOx parameters acquired by the parameter acquisition unit, and a storage processing unit that stores in the memory unit the parameter integrated value as the NOx information.

Abstract: A failure diagnosis apparatus for an exhaust gas recirculation system eliminates the influence of various disturbance factors that vary the suction air pressure, diagnoses a failure of the exhaust gas recirculation system on the basis of the suction air pressure, and prevents incorrect diagnosis. The system includes a fresh air pressure unit for determining an estimated fresh air pressure inside a suction pipe from the operating condition of an internal combustion engine and an actual exhaust gas recirculation pressure estimating unit for determining an EGR gas pressure on the basis of a measured suction pipe pressure detected by a suction pipe pressure detecting unit and estimated fresh air pressure. A failure is judged on the basis of the estimated EGR gas pressure and the detected operating condition.

Abstract: To provide a failure diagnosis apparatus for an exhaust gas recirculation system which is capable of eliminating the influence of various disturbance factors that vary the suction air pressure, diagnosing a failure of the exhaust gas recirculation system on the basis of the suction air pressure, and preventing wrong diagnosis. A failure diagnosis apparatus for an exhaust gas recirculation system consists of a fresh air pressure estimating means 2911 for calculating an estimated fresh air pressure inside a suction pipe from the operating condition of an internal combustion engine, an actual EGR (exhaust gas recirculation) gas pressure estimating means 2914 for estimating an EGR gas pressure on the basis of a measured suction pipe pressure detected by a suction pipe pressure detecting means 2911 and an estimated fresh air pressure calculated above, and a failure judging means 2910 for judging the failure on the basis of the estimated EGR gas pressure and the detected operating condition.

Abstract: To provide a failure diagnosis apparatus for an exhaust gas recirculation system which is capable of eliminating the influence of various disturbance factors that vary the suction air pressure, diagnosing a failure of the exhaust gas recirculation system on the basis of the suction air pressure, and preventing wrong diagnosis. A failure diagnosis apparatus for an exhaust gas recirculation system consists of a fresh air pressure estimating means 2911 for calculating an estimated fresh air pressure inside a suction pipe from the operating condition of an internal combustion engine, an actual EGR (exhaust gas recirculation) gas pressure estimating means 2914 for estimating an EGR gas pressure on the basis of a measured suction pipe pressure detected by a suction pipe pressure detecting means 2911 and an estimated fresh air pressure calculated above, and a failure judging means 2910 for judging the failure on the basis of the estimated EGR gas pressure and the detected operating condition.

Abstract: To provide a failure diagnosis apparatus for an exhaust gas recirculation system which is capable of eliminating the influence of various disturbance factors that vary the suction air pressure, diagnosing a failure of the exhaust gas recirculation system on the basis of the suction air pressure, and preventing wrong diagnosis. A failure diagnosis apparatus for an exhaust gas recirculation system consists of a fresh air pressure estimating means 2911 for calculating an estimated fresh air pressure inside a suction pipe from the operating condition of an internal combustion engine, an actual EGR (exhaust gas recirculation) gas pressure estimating means 2914 for estimating an EGR gas pressure on the basis of a measured suction pipe pressure detected by a suction pipe pressure detecting means 2911 and an estimated fresh air pressure calculated above, and a failure judging means 2910 for judging the failure on the basis of the estimated EGR gas pressure and the detected operating condition.

Abstract: To provide a failure diagnosis apparatus for an exhaust gas recirculation system which is capable of eliminating the influence of various disturbance factors that vary the suction air pressure, diagnosing a failure of the exhaust gas recirculation system on the basis of the suction air pressure, and preventing wrong diagnosis. A failure diagnosis apparatus for an exhaust gas recirculation system consists of a fresh air pressure estimating device 2911 for calculating an estimated fresh air pressure inside a suction pipe from the operating condition of an internal combustion engine, an actual EGR (exhaust gas recirculation) gas pressure estimating device 2914 for estimating an EGR gas pressure on the basis of a measured suction pipe pressure detected by a suction pipe pressure detecting device 2911 and an estimated fresh air pressure calculated above, and a failure judging device 2910 for judging the failure on the basis of the estimated EGR gas pressure and the detected operating condition.

Abstract: To provide a failure diagnosis apparatus for an exhaust gas recirculation system which is capable of eliminating the influence of various disturbance factors that vary the suction air pressure, diagnosing a failure of the exhaust gas recirculation system on the basis of the suction air pressure, and preventing wrong diagnosis. A failure diagnosis apparatus for an exhaust gas recirculation system consists of a fresh air pressure estimating means 2911 for calculating an estimated fresh air pressure inside a suction pipe from the operating condition of an internal combustion engine, an actual EGR (exhaust gas recirculation) gas pressure estimating means 2914 for estimating an EGR gas pressure on the basis of a measured suction pipe pressure detected by a suction pipe pressure detecting means 2911 and an estimated fresh air pressure calculated above, and a failure judging means 2910 for judging the failure on the basis of the estimated EGR gas pressure and the detected operating condition.