Variable camshaft timing mechanism with a lock pin engaged by oil pressure

A variable cam timing mechanism for an internal combustion engine, the variable cam timing mechanism having a housing assembly with an outer circumference for accepting drive force and a rotor assembly for connection to a camshaft, having a plurality of vanes coaxially located within the housing assembly, wherein the housing assembly and the rotor assembly define at least one chamber separated by a vane of the plurality of vanes into an advance chamber with an advance wall and a retard chamber with a retard wall opposite the advance wall, a motion of the vane within the at least one chamber acting to shift a relative angular position of the housing assembly and the rotor assembly by fluid from a control valve and by cam torque, the variable cam timing mechanism comprising:

• an end lock pin slidably located in one of the rotor assembly or the housing assembly, the end lock pin being movable from an unlocked position in which an end portion of the end lock pin does not engage a recess in the other of the rotor assembly or the housing assembly, to a locked position in which the end portion of the end lock pin engages the recess, locking the relative angular position of the housing assembly and the rotor assembly, wherein the end lock pin is biased by a spring toward the unlocked position;
• and the locked position of the end lock pin is at an end position when the vane is in an advance end stop position;
• the control valve being movable into:
• a retard mode in which fluid is routed to the retard chamber and fluid is not routed to the end lock pin, such that the end lock pin is moved to the unlocked position by the spring;
• an advance mode in which fluid is routed to the advance chamber, and exhausted from the retard chamber;
• and
• an end stop lock mode in which fluid is routed to the advance chamber and the end lock pin is in the locked position.