Valve timing control apparatus

A valve timing control apparatus comprising:

• a drive-side rotor rotating in synchronization with a crankshaft of an internal combustion engine;
• a driven-side rotor arranged so as to have the same shaft center as the drive-side rotor, rotating in synchronization with a camshaft for opening and closing valves in the internal combustion engine;
• a fluid pressure chamber formed between the drive-side rotor and the driven-side rotor;
• a partitioning portion provided in at least one of the drive-side rotor and the driven-side rotor;
• a timing advance chamber and a timing delay chamber formed by partitioning the fluid pressure chamber by the partitioning portion;
• a lock mechanism including a lock member housed in any one of the drive-side rotor and the driven-side rotor and arranged so as to be ejected and retracted with respect to the other of the drive-side rotor and the driven-side rotor, and a concave portion formed in the other rotor so as to be fitted when the lock member is ejected, in which switching can be performed between a lock state where the lock member is ejected to be fitted to the concave portion to thereby allow a relative rotation phase of the driven-side rotor with respect to the drive-side rotor to be constrained to a given phase and a lock release state where the lock member is retracted from the concave portion to thereby release the constraint;
• a lock release flow path through which operating fluid supplied and discharged to and from the concave portion is circulated;
• a valve arranged in the middle of the lock release flow path, having a shutoff mode in which neither supply nor discharge of the operating fluid to and from the concave portion is performed;
• and
• a control unit controlling the operation of the valve,
• wherein the valve becomes in the shutoff mode just after the internal combustion engine is started to thereby shut off supply and discharge of the operating fluid to and from between the valve in the lock release flow path and the concave portion.