| 摘要 |
PROBLEM TO BE SOLVED: To easily detect an abnormality in an ignition plug which is a cause of a malfunction of an internal combustion engine.SOLUTION: A failure in an ignition plug is detected by using a circuit for detecting an ionic current flowing through an electrode of the ignition plug during combustion. Concretely, the current flowing through the electrode of the ignition plug is repeatedly measured through the circuit in a period of time (from a time point tto a time point t) in which a primary coil of the ignition coil is energized previous to the spark ignition. In a period of time after the energization to the primary coil is started (the time point t) and before the energization to the primary coil is interrupted (the time point t), on condition that a current value based on the time series exceeds a threshold, it is determined that an abrupt discharge or electric leakage occurs in the ignition plug. |
