Patent ID: 7913674

Claim:
An abnormality determination device for determining abnormality of an EGR device that recirculates part of exhaust gases exhausted from a combustion chamber of an internal combustion engine to an intake system of the engine, comprising: a throttle valve that is provided in the intake system; fresh air amount-detecting means for detecting an amount of fresh air drawn into the combustion chamber of the engine; fresh air amount control means for feedback-controlling the amount of fresh air such that the detected amount of fresh air converges to a predetermined target fresh air amount, by controlling an opening of said throttle valve during execution of an operation by the EGR device for recirculating exhaust gases; decreasing degree parameter-obtaining means for obtaining a decreasing degree parameter indicative of a degree of decrease in the amount of fresh air caused by the feedback control; and abnormality determination means for determining abnormality of the EGR device based on the obtained decreasing degree parameter, wherein the parameter-obtaining means detects an opening of the throttle valve, detects an upstream-downstream differential pressure across the throttle valve, or estimates an insufficient amount of exhaust gas recirculation for an amount of exhaust gas recirculation to be obtained when the EGR device is normal, as the decreasing parameter.