PURPOSE: To reduce the transmission energy to an ignition plug, to stabilize the ignition of the dilute air-fuel mixture, and to improve the fuel consumption by boosting the battery voltage with a DC-DC converter and by storing the high voltage in high voltage condensers for individual cylinders so as feed it directly to an ignition plug at a preset time.
CONSTITUTION: The output voltage of a battery B is boosted to 1KV with a DC-DC converter and is fed to ignition circuits F1WF4. The input high voltage is charged in high voltage condensers C1WC4. When an ignition time designation signal (f) is fed into a circuit A, an ignition signal (a) is fed out at the preset time for the first cylinder, and a semiconductor switch S1 is made conductive. As a result, the potential of the output terminal Q of the condenser C1 is rapidly changed, and the change is fed to an auxiliary condenser C1', thereby a transient phenomenon occurs in the primary circuit, and a damped AC voltage at a frequency f1 is generated across the terminals of a coil Lp. This voltage is boosted by a step-up transformer to induce the high voltage across the secondary winiding, and the high voltage is applied to an ignition plug P1 to discharge it, then the high energy of the condenser C1 flows through the secondary winding and is fed into the ignition plug P1 in a short time.
SONE MASAZUMI
IMAI IWAO
ISHIKAWA YASUTAKE
