Patent ID: 7251555
Filing Date: 2007-07-31
Classification: F02M

Abstract:
1. An abnormality diagnosis device of an exhaust gas recirculation system recirculating exhaust gas, which is discharged to an exhaust system of an internal combustion engine, into an intake system, wherein the exhaust gas recirculation system has an actuator for adjusting a quantity of the recirculated exhaust gas and a cooling device for cooling the recirculated exhaust gas, the abnormality diagnosis device comprising: a target value setting device that sets a target value of one of the quantity of the recirculated exhaust gas, a state quantity of fresh air suctioned from the intake system and a state quantity of the exhaust gas discharged to the exhaust system in accordance with each one of operation areas of the engine; a standard value storing device that stores a standard value of a manipulated variable of the actuator corresponding to the operation area of the engine and the target value; a measuring device that measures one of the quantity of the recirculated exhaust gas, the state quantity of the fresh air and the state quantity of the exhaust gas; a calculating device that calculates a deviation between a measurement value of the measuring device and the target value; and a diagnosing device that diagnoses existence or nonexistence of an abnormality in the cooling device based on comparison between the manipulated variable, which is provided when the actuator is manipulated such that the deviation is less than a predetermined threshold value, and the standard value corresponding to the operation area of the engine, in which the manipulation of the actuator is performed.