Fehlzündungserkennungseinrichtung für eine innere Brennkraftmaschine

摘要

In a misfire detector device for use in internal combustion engine, an electrical interrupter circuit on-off actuates a primary current flowing through a primary circuit of an ignition coil to induce a sparkplug voltage which is applied to a multi-electrode type spark plug. A check diode or a series gap is provided in a secondary circuit of the ignition coil to prevent a current flowing back to the ignition coil. A sparkplug voltage detector circuit detects an attenuation time length of a sparkplug voltage waveform presented subsequent to a time period predetermined after an end of a spark action of the spark plug. On the basis of the attenuation time length, a distinction circuit determines whether a misfire occurs in a cylinder of an internal combustion engine.