| 摘要 |
PROBLEM TO BE SOLVED: To further improve the accuracy of knocking determination referring to an ion current signal.SOLUTION: A current signal is sampled 51 by using a circuit for detecting an ion current passing through an electrode of an ignition plug during combustion, and predetermined frequency components overlapped in a time series of a sampling value are extracted. When the presence/absence of knocking is determined on the basis of the frequency components, the presence/absence of knocking is determined by comparing 56 a value obtained by subtracting 55 frequency components of a section which does not include signals generated due to knocking from frequency components in a section including signals generated due to the knocking, with a knocking determination value. Therefore, periodic noise mixing into an ion current signal due to the operation of an alternator can be removed. |
