| 摘要 |
PROBLEM TO BE SOLVED: To secure the accuracy of misfire detection even with valve opening timing of an intake valve retarded when using intake valve retard opening control in combination with misfire detection control.SOLUTION: An ECU 50 detects misfire of each cylinder based on a rotation fluctuation amount ΔNe of a crankshaft 18 detected in a predetermined misfire detection section. Further, the ECU 50 performs the intake valve retard opening control for retarding the valve opening timing (IVO) of the intake valve 34 as necessary. Furthermore, the ECU 50, when the IVO of another cylinder is situated near the boundary of the misfire detection section of either one cylinder, varies an ignition retard guard aopg of the one cylinder to the advance side and corrects ignition timing aop to the advance side. When the ignition timing is advanced, since the rotation fluctuation amount ΔNe in a normal combustion state becomes small and a misfire detection margin is improved, misfire can be detected stably even if the IVO of the other cylinder varies into and out of the misfire detection section. |
