| 摘要 |
PURPOSE:To improve transition responsiveness of an energizing timing control and prevent any mis-fire, by giving the minimum closing rate at the time for starting a calculation of an ignition coil energizing start time begins when the closing rate is large. CONSTITUTION:Control for an ignition coil energizing start timing is divided into the case wherein a closing rate is large and an output signal from a waveform shaping circuit 2 at the start timing is within an L region and them case wherein a closing rate is small and an output signal from a waveform shaping circuit 2 at the start timing is within an H region. When a borrow signal from a second counter 10 is within the L region of an output signal of the waveform shaping circuit 2, an input condition is in a G mode and a logic circuit 15 outputs a rectangular wave to secure a prescribed energizing time. With such an arrangement, when the closing rate is greater than the H region of the rectangular wave, the logic circuit 15 sets the minimum closing rate. Therefore, a period during which primary current to the ignition coil is at a prescribed value can be controlled to a prescribed ratio of an igniting cycle of an engine and then even if an igniting cycle is shortened abruptly, ignition coil shut off current is not reduced greatly, whereby mis-fire is prevented.
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