| 摘要 |
<P>PROBLEM TO BE SOLVED: To solve a problems wherein, when an increasing rate is calculated from the increasing amount of ion current and the width of a predetermined crank angle and it is determined based on the increasing rate whether a combustion state is normal combustion, knocking or preignition, the preignition is not detected until the increasing rate advances to the predetermined crank angle, and as a result, start of control for suppressing the preignition is delayed, and a drop in combustion efficiency during a period when the sign of the preignition occurs is left as it is. <P>SOLUTION: The maximum value of the increasing rate is calculated from an ion current waveform detected by an ion current detection circuit. A crank angle sensor detects the angle of a crank at a position where the increasing rate of the ion current waveform is at an maximum. When the increasing rate of the ion current waveform detected by the ion current detection circuit is an increasing rate threshold or higher and the crank angle detected by the crank angle sensor advances in comparison with a crank angle threshold, it is determined that the sign of the preignition or the preignition occurs. <P>COPYRIGHT: (C)2013,JPO&INPIT |
