| 摘要 |
PROBLEM TO BE SOLVED: To realize a positive and proper fail safe in an internal combustion engine controlling a suction air quantity by using an variable valve mechanism changing opening and closing characteristics of an intake valve. SOLUTION: Various sensors are diagnosed for anomalies (level 1 diagnosis), and engine power control and constant vehicular speed travel control are diagnosed for operational anomalies (level 2 diagnosis). When an anomaly is determined in the level 1 and 2 diagnoses, a process of limiting engine power by limiting a lift amount and cutting fuel is demanded as a level 1 fail safe process. A CPU of a control unit is diagnosed (level 3 diagnosis), and an ultimate level 2 fail safe process of selecting a fail safe demand from many on the basis of the level 1-3 diagnoses is carried out. In the level 2 fail safe process, a process of stopping the engine is carried out in an anomaly of the CPU, and a limp home operation is carried out in, for example, an undetectable state of the opening and closing characteristics.
|
