CONTROL DEVICE FOR VANE TYPE VARIABLE VALVE TIMING ADJUSTMENT MECHANISM

PROBLEM TO BE SOLVED: To improve the responsiveness of variable valve timing control without causing the problem of overshoot, in a vane type variable valve timing adjustment mechanism (VCT). SOLUTION: Check valves 30 and 31 are provided in an oil pressure supply oil passage 28 of an advance chamber 18 and an oil pressure supply oil passage 29 of a delay chamber 19, respectively, and drain oil passages 32 and 33 bypassing the check valves 30 and 31, respectively are provided in parallel in the oil pressure supply oil passages 28 and 29 of each chamber 18, 19, and drain selector valves 34 and 34 are provided in the drain oil passages 32 and 33, respectively. When the deviation between a target displacement angle and an actual displacement angle is a predetermined value or more, the drain selector valve on the oil pressure chamber side from which oil is discharged is opened to execute "highest speed control" for driving the VCT in the direction of the target displacement angle at the highest speed, and when the deviation between the target displacement angle and the actual displacement angle is reduced, the drain selector valve on the oil pressure chamber from which oil is discharged is closed to switch the control to "retention control " for stopping the variable operation of the VCT or reducing the speed thereof. COPYRIGHT: (C)2008,JPO&INPIT