| 摘要 |
PROBLEM TO BE SOLVED: To improve a control accuracy near the boundary of control ranges in a variable valve timing control device with a plurality of control ranges in which VCT phase control characteristics are different. SOLUTION: This variable valve timing control device has a plurality of control ranges in which VCT phase control characteristics are different (a spring present range in which a spring force in the spark-advancing direction acts and a spring absent range in which a spring force in the spark-advancing direction does not act). A predetermined area near the boundary of the control ranges is set as a gray zone (ambiguous range) in which the control range is difficult to be discriminated. When the target VCT phase comes out of the gray zone, a VCT control amount is calculated using a hold duty learned value for the control range in which the target VCT phase is present. When the target CVT phase is present in the gray zone, the hold duty learned value used for calculating the VCT control amount is changed to the hold duty learned value for the other control range and the VCT control amount is calculated when the deviation between the actual VCT phase and the target VCT phase is stable above a predetermined value. COPYRIGHT: (C)2011,JPO&INPIT
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