| 摘要 |
PURPOSE:To enable control of a period, in which the primary current of an ignition coil is increased to a given value, to a given period, by a method wherein setting of the maximum close factor of the ignition coil is varied by means of the operating state of an engine and a battery voltage. CONSTITUTION:A VTH generating circuit 20 inputs an output signal from an ignition timing signal generator 1, and an ignition period is computed to generate a threshold voltage VTH by means of which a voltage is increased to the number of revolutions through computation of function regarding the number of revolutions of an engine. A waveform shaping circuit 2 uses the VTH as a threshold level available when an input signal is increased, and the waveform of an output signal from the ignition timing signal generator 1 is shaped. As a result,in an output signal from the waveform shaping circuit 2, a ratio alpha% of a part H of a rectangular shape is decreased in contrast with an increase in a rotation speed, and a maximum close factor determined by the alpha% is increased in contrast with the number of revolutions. Thus, maximum close factor characteristics having low heat generation can be realized during middle speed running, and maximum close factor having high energy during high speed running.
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