| 摘要 |
PURPOSE:To reduce the deviation of ignition timing, by changing automatically, according to whether an engine is in high speed rotation range or in low rotation range, the time that is used as a reference on which the calculation of the timing of the operation of an igniter is based. CONSTITUTION:A rotational angle sensor 1 is composed of a rotor 2 on a crank shaft or in a distributor and a sensor of a photoelectric type, magnetic transducing type, etc. that comprises pickups A, B opposed to one projection P on the circumference of the rotor 2. As the rotor 2 rotates, the sensor 1 detects the time when it is positioned opposite to the pickups A, B every time when the projection P turns 180 deg., and the sensor 1 generates reference positional signals respectively. Based upon the signals, if the rotational frequency is in the high rotational range, the signal generated earlier than the other is used, and if the rotational frequency is in the low rotational range, the signal generated more later than the other is used as a reference signal. Thus, even in the low speed rotation range where fluctuation of rotation is high, the ignition timing is deviated hardly. |
