| 摘要 |
PROBLEM TO BE SOLVED: To provide an abnormality diagnostic device for an exhaust gas recirculating device capable of easily and surely performing an abnormality diagnosis of the exhaust gas recirculating device, suppressing deterioration of exhaust emission and deterioration of drivability. SOLUTION: An exhaust passage 7 of a diesel engine 1 and the downstream side of a throttle valve 4 of an intake passage 2 are communicated by an exhaust gas recirculating passage 8. By controlling opening of an EGR control valve 9 provided in the exhaust gas recirculating passage 8, exhaust gas recirculated amount recirculated from an exhaust system to an intake system is regulated. When a prescribed abnormality diagnostic condition is formed, an ECU 19 performs a control to gradually change the opening of the EGR control valve 9, detects changed amount of air intake amount for a prescribed period and diagnoses the exhaust gas recirculating device having an abnormality when the detected value does not exceed a prescribed decision value. |
