Sparkplug voltage detecting probe device for use in internal combustion engine

摘要

In a sparkplug voltage detecting probe device for use in internal combustion engine comprising, a sensor is provided to form a static capacity between the sensor and an ignition coil which is connected to a spark plug. A sparkplug voltage divider circuit has a capacitor connected between the sensor and the ground. A release circuit has a resistor connected in parallel with the capacitor so as to provide a time constant of a RC path. A short circuit is provided to instantaneously release an electrical charge from the capacitor either immediately before establishing a spark voltage for the spark plug or immediately after initiating the spark action of the spark plug. A sparkplug voltage waveform detecting circuit detects a sparkplug voltage waveform divided by the sparkplug voltage divider circuit.