| 摘要 |
PROBLEM TO BE SOLVED: To further improve accuracy of abnormal combustion determination with reference to ion current.SOLUTION: An ion current signal measured via an ion current sensing circuit is divided in two by a reference timing to calculate an integration amount A of the ion current signal to the reference timing and an integration amount B of the ion current signal from the reference timing. Then, it is determined whether or not abnormal combustion takes place based on a magnitude of a ratio K(=B/A) of the integration amount B of the latter and the integration amount A of the former. The ratio K becomes smaller when the probability of abnormal combustion is high and becomes larger when the probability thereof is low. |
