| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem of an apparatus for detecting malfunction being needed in an idling speed control system which changes the opening degree of a control valve by a stepping motor. SOLUTION: This control device for an internal combustion engine is provided with an idling speed control system for controlling the flow rate of an intake air which flows into an auxiliary air passage which bypasses a throttle valve at idling operation of the engine, and further is provided with a fuel supply control means for starting fuel cut, when an engine revolution exceeds a first prescribed revolution in an idling operation condition and for restoring the fuel cut, when the engine revolution dips from a second prescribed revolution set up lower than the first, and an abnormality detection means for detecting the abnormality of the idling speed control system, when the value changing according to time interval from restoration of the fuel cut to the restart thereof satisfies a prescribed condition. |
