MULTIPLE-IGNITION DEVICE FOR INTERNAL COMBUSTION ENGINE

PROBLEM TO BE SOLVED: To solve the problem in a change in an air current or, a change of air-fuel ratio caused by fuel injection nozzle deterioration due to aging and adhesion of carbon in an intake/exhaust port wherein ignition is hardly achieved, ignition energy enough for completely burning air-fuel mixture is not applied to deteriorate combustion, and the rotational frequency becomes unstable so that normal ignition is not performed. SOLUTION: The amount of time of angle where an ion current continues is measured, the fluctuation rate of the measured time or angle is computed, the operating state of an internal combustion engine in computing the fluctuation rate is detected, and the multi-ignition frequency is controlled so that the fluctuation rate obtained in the detected operating state reaches a target fluctuation rate preset according to the operating state of the internal combustion engine.