Patent ID: 8490610

Claim:
A control device for an internal combustion engine, the engine including an EGR device having an EGR passage for introducing exhaust gas from an exhaust passage into an intake passage and an EGR valve arranged in the EGR passage and which varies the amount of the exhaust gas introduced into the intake passage, the control device comprising: a fuel cutoff control section that performs fuel cutoff control by which fuel supply to the engine is blocked, and suspends the fuel cutoff control in a condition in which engine speed becomes lower than or equal to a predetermined resumption engine speed when the fuel cutoff control is being carried out; a diagnosis section that forcibly opens and closes the EGR valve when the fuel cutoff control section is performing the fuel cutoff control, and diagnoses whether an abnormality has occurred in the EGR device based on extent of pressure change in the intake passage caused by opening and closing the EGR valve; and a forcible suspension section that, when the diagnosis section is performing the diagnosis, suspends the diagnosis in a condition in which the engine speed becomes lower than or equal to a predetermined forcible suspension engine speed equal to or greater than the resumption engine speed, wherein the forcible suspension section sets a smaller value as the forcible suspension engine speed when the EGR valve is not in a forcibly opened state than when the EGR valve is in the forcibly opened state.