| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent combustion from being unstable since the degree of overlap is excessive during idle operation or low load operation and to prevent occurrence of engine stall in such a case that a variable valve timing mechanism falls in trouble so as to be inoperative. SOLUTION: An ECU 70 controls the drive of VVTs 29L, 29R, and determines whether or not the phase anglesθ01,θ02, of actual valve timings of the VVTs 29L, 29R fall in a phase angle range based upon desired valve timing anglesθT1,θT2 calculated from an engine rotational speed NE, a water cooling temperature THW and the like, and whether or not such a condition is successively determined by a number of repetitions greater than 5. If it is determined by a number of repetitions greater than 5 that the phase angles are out of the phase angle range, the ECU 70 determines that the VVTs 29L, 29R are erroneously operated, and forces the desired valve timing of the VVTs 29L, 29R which are not erroneously operated, to be fixed to a valve timing which has the minimum degree of overlap.</p> |
