| 摘要 |
PURPOSE:To always detect right ignition timing by obtaining the ignition timing from a rotating part, which is not changed by advance and delay timing values, in the case of each intake and exhaust cam shaft made with its advance or delay timing value independently possible. CONSTITUTION:In a control circuit 82, from a signal theta1 of a crank angle sensor and a rotational angle signal theta2 of a cam shaft, any of the transistor units 88 is turned on prior to ignition timing of the first and fourth cylinders and off in the ignition timing. At the time of this off-operation, high voltage is induced in one coil of a coil unit 90, and spark ignition is generated in spark plugs 92a, 92d of a simultaneous ignition cylinder connected to a secondary side of the coil. While, when the other transistor of the unit 88 is turned off, a spark is generated in spark plugs 92b, 92c of the other simultaneous ignition cylinder. Thus because a rotary angle of cam shafts 16, 18 is detected from an external cam unit 36A in a part integrally rotated with a crankshaft of timing selecting mechanisms 24, 26, in no relation to their operative condition, the ignition timing can be detected to a fixed position for the crankshaft. |
