TROUBLESMOOTING METHOD FOR INTERNAL COMBUSTION ENGINE VALVE TIMING CHANGE-OVER CONTROL DEVICE

摘要

PURPOSE:To make a troubleshooting with low cost and precision by comparing a change-over signal to be outputted to a valve timing change-over mechanism according to an engine operating condition with a detected suction air amount signal for the failure detection of a valve timing change-over mechanism. CONSTITUTION:A valve timing change-over control device operates a connection change-over mechanism when a valve opening command signal is outputted from ECU5 to an electromagnetic valve 22 so as to mutually connect respective rocker arms cooperating with a cam for low speed and a cam for high speed and to change over an engine valve from low speed valve timing to high speed valve timing for opening and closing. When a prescribed time has passed after the instruction of the valve timing had been changed over to the high speed valve timing, it is judged whether or not the actual suction air amount by a suction air amount sensor 9 is beyond the permissible range of suction air amount while the change-over mechanism is operating properly. When YES is judged, it is judged as valve timing failure, so as to generate an alarm.