| 摘要 |
PROBLEM TO BE SOLVED: To perform proper fail-safe, by accurately diagnosing failure of a sensor used for feedback control of a variable valve system capable of varying a valve lift. SOLUTION: When detecting results of two sensors do not coincide, preliminary fail-safe is performed for fixing the valve lift to an intermediate value. When a noncoincident state of the detecting result continues for a predetermined time or more, sensor failure is determined, and the fail-safe is transferred to fail-safe for sensor abnormality. In the fail-safe for the sensor abnormality, a valve lift quantity is fixed to a minimum value, and at this time, the sensor of detecting a minimum valve lift quantity is specified as a normal sensor, and the feedback control is resumed by using the normal sensor. COPYRIGHT: (C)2005,JPO&NCIPI
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