| 摘要 |
PROBLEM TO BE SOLVED: To provide a discharge-type ignition device for an internal combustion engine which can realize a low cost and a reduced size, which can be installed in a narrow mounting space and which can maintain supply of overlapping current necessary for and sufficient to a stable discharge.SOLUTION: An overlapping discharging function added to an ignition device for an internal combustion engine which produces a discharge breakdown in the discharge gap g of an ignition plug 2 and forces a discharge current to flow by means of an ignition coil 1 operated on the basis of an ignition signal, is configured by overlapping direct-current high voltage obtained by supplying alternative current for overlapping voltage generation to a multistage voltage-doubling rectifier circuit 4 in the same polarity of an induction voltage of a secondary coil 1b through the operation of a DC-AC booster circuit 3 by an overlap time control circuit 6. The charge voltage to a discharge electrode is detected by an overlapping current detection/comparison circuit 8, and compared with an overlapping current set value. If the detected value for the overlapping current is lower than the set value, the value for the wave height of the alternating current from the DC-AC booster circuit 3 for generating the overlapping voltage is raised. If the detected value is higher than the set value, the value for the wave height of the alternating current from the DC-AC booster circuit 3 for generating the charge voltage is lowered. Thus, the detected value for the overlapping current is brought closer to the set value. |
