| 摘要 |
PURPOSE:To enable a crank angle position to be detected through an AC signal derived from a magneto, by a method wherein the peak position and zero crossing point of an output signal of the magneto are detected and an ignition reference position signal is generated. CONSTITUTION:A peak detecting circuit 2 consisting of a voltage comparator 208 and the like detects the peak position and zero crossing point of the output signal of the magneto 1 which is rotated in response to the revolution of the engine, while a zero cross detecting circuit 3 has an operational amplifier 401 and the like. Outputs of the circuits 2, 3 are logically operated by a logic circuit 4 consisting of an OR circuit 401 to generate the ignition reference position signal. The logical sum of the output (d) of the amplifier 301 and the output (c) for the comparator 208 is obtained by the OR circuit 401, whereby a waveform (e) is obtained. The output of the waveform (e) is in the form of an output pulse train of which the pulse width is determined by a position substantially corresponding to the peak position of the output signal of the magneto 1 and a position corresponding to the zero crossing point. Accordingly, the ignition reference position signal is obtained for each cylinder of the engine. |
