FAILURE DIAGNOSIS METHOD AND FAILURE DIAGNOSIS SYSTEM

摘要

PROBLEM TO BE SOLVED: To provide a failure diagnosis method capable of detecting failure of an apparatus regarding combustion state detection of an internal combustion engine such as a fuel injection control device. SOLUTION: The failure of an ignition system of the internal combustion engine is diagnosed when time that a voltage signal S4 from which noise is removed by providing noise mask time NM2 with respect to a signal obtained from an ion current detecting means for detecting ion current generated in a monitor cylinder maintains a high state is longer than the prescribed time. The prescribed time is set shorter than the time obtained by subtracting the noise mask time NM2 and the maximum delay time from power supply stop with respect to the ignition member to monitor cylinder change from time D2 required from a last power supply stop period P4 to a present power supply stop period P5. COPYRIGHT: (C)2008,JPO&INPIT