Patent ID: 7198014

Claim:
A valve timing control apparatus for an engine, comprising: a drive rotational member synchronously rotated with a crankshaft; a driven rotational member provided coaxially with the drive rotational member and rotated with a camshaft; a fluid pressure chamber provided in one of the drive rotational member and the driven rotational member; a vane dividing the fluid pressure chamber into an advanced angle chamber and a retarded angle chamber; a relative rotational phase-controlling mechanism for supplying or discharging a working fluid to or from one or both of the advanced angle chamber and the retarded angle chamber, for changing a relative position of the vane to the fluid pressure chamber, and for controlling a relative rotational phase between the drive rotational member and the driven rotational member within a range from a most retarded angle phase at which a volume of the retarded angle chamber becomes maximum to a most advanced angle phase at which a volume of the advanced angle chamber becomes maximum; a locking mechanism for restraining the relative rotational phase at an intermediate phase between the most advanced angle phase and the most retarded angle phase; and a biasing mechanism for applying a torque to the drive rotational member relative to the driven rotational member so that the relative rotational phase advances toward the most advanced angle phase, wherein a larger one of a first torque which is a minimum torque required for changing the relative rotational phase from the most retarded angle phase to the intermediate phase in a case where a fluid pressure is discharged from both of the advanced angle chamber and the retarded angle chamber and cranking is performed at a first temperature before warming up of the engine and a second torque which is a minimum torque required for changing the relative rotational phase from the most retarded angle phase to the intermediate phase in a case where hydraulic pressure remains in the advanced angle chamber and the retarded angle chamber and cranking is performed at a second temperature which is a minimum temperature at which the relative rotational phase is controlled by the relative rotational phase-controlling mechanism is selected as a minimum set torque for the biasing mechanism.