| 摘要 |
PURPOSE:To prevent a spark plug from smoking in an effective manner, by detecting size of a coil inducing signal during a period of energizing an ignition coil or an oscillating component included in the former, while setting it down to a smoking detecting signal, and operating a smoking preventer for control. CONSTITUTION:When an ignition signal is outputted out of a central processing unit 12, a power transistor 3 is set in motion via a driving circuit 11 and primary winding of an ignition coil 1 is energized with a continuous rating current, high voltage is induced in its secondary winding. At this time, if smoking occurs in a spark plug 2, a secondary current value of the ignition coil 1 increases with reduction in leak resistance, therefore an oscillating component to be superposed on the secondary current value and a secondary voltage value also decreases to some extent. Accordingly, a variation in this oscillating component is detected via a filter circuit 13, a one-shot multivibrator circuit 14, a masking circuit and an integrator 16, comparing it with the setting value with a comparator 17. And, according to output of this comparator 17, the spark plug 2 is made to be multiplicately discharged, thereby removing the smoking. |
