IGNITION DEVICE FOR INTERNAL COMBUSTION ENGINE

PROBLEM TO BE SOLVED: To provide an ignition device for an internal combustion engine, designed to accurately grasp a combustion sate by certainly operating an ion detection circuit. SOLUTION: The ignition device for the internal combustion engine mainly includes: an ignition coil CL composed of a primary coil L1 and a secondary coil L2; a switching element Q switched on/off based on an ignition signal SG received from a control device ECU; an ignition plug PG discharging electricity by receiving inductive voltage of the secondary coil L2; and an ion current detection circuit ION. The secondary coil L2 is dividedly composed of a first winding L2a and a second winding L2b which are wound in the same direction. At timing when high voltage for ignition/electric discharge is supplied to the ignition plug PG, a capacitor C1 for a power supply is charged with voltage of the secondary winding L2a, and bias voltage of the ion current detection circuit is developed. After that, when the voltage of the ignition plug PG drops, ion current flows via the ignition plug PG by the bias voltage of the capacitor C1 for the power supply. COPYRIGHT: (C)2010,JPO&INPIT