A recess hole is connected to a radially outer side of an oil passage portion and forms an oil supply passage. A check valve part has: a valve seat portion provided in the oil passage portion to form a valve seat; a sleeve having one end connected to the valve seat portion; a lateral hole to communicate an internal space of the sleeve with outside of the sleeve; and a valve body provided in the sleeve so as to be separated from the valve seat or in contact with the valve seat. The lateral hole has an opening exposed to outside of the sleeve, and a range of the opening overlaps with a range of the recess hole in an axial direction of the sleeve.

In a valve timing adjustment device, a first arm projection portion that is caught by a terminal hook portion of a spiral spring and urged toward a lock phase side by the spiral spring is installed on a face opposite to the front surface of a plate in a first arm in a case where a rotational phase of a second rotating body with respect to a first rotating body is on a first rotational phase side, and a second arm projection portion that abuts on an outermost peripheral portion of the spiral spring is installed on a face opposite to the front surface of the plate in a second arm in a case where the rotational phase is on the first rotational phase side.

A hydraulically-actuated variable camshaft timing (VCT) system comprises a spool valve including a sleeve and a spool, having a plurality of radially-outwardly extending lands, received within the sleeve; a first fluid supply port in the sleeve configured to receive fluid from a fluid supply; a second fluid supply port in the sleeve configured to receive fluid from the fluid supply; an advancing port in the sleeve in fluid communication with an advancing chamber of a hydraulically-actuated camshaft phaser; a retarding port in the sleeve in fluid communication with a retarding chamber of the hydraulically-actuated camshaft phaser; and an exhaust port axially positioned in the sleeve in between the first fluid supply port and the second fluid supply port or in between the advancing port and the retarding port, wherein the exhaust port is configured to selectively receive fluid from either the advancing chamber or the retarding chamber depending on an axial position of the spool relative to the sleeve.

An oil control valve for a cam phaser of an internal combustion engine, the oil control valve including a valve housing, including a first operating connection, a second operating connection, a supply connection, and a tank drain connection configured to drain a hydraulic fluid; a piston assembly, including a piston, a hollow check valve tube, a first check valve and a second check valve configured to provide cam torque recirculation, wherein the piston assembly is arranged in the housing axially displaceable by an actuator, wherein a control chamber is arranged within the piston between the first check valve and the second check valve and wherein a check valve compression spring which closes the first check valve and the second check valve is arranged within the piston between the first check valve and the second check valve.

An oil control valve for a cam phaser of an internal combustion engine, the oil control valve including a valve housing, including a first operating connection, a second operating connection, a supply connection, and a tank drain connection configured to drain a hydraulic fluid; a piston assembly, including a piston, a hollow check valve tube, a first check valve and a second check valve configured to provide cam torque recirculation, wherein the piston assembly is arranged in the housing axially displaceable by an actuator, wherein a control chamber is arranged within the piston between the first check valve and the second check valve and wherein a check valve compression spring which closes the first check valve and the second check valve is arranged within the piston between the first check valve and the second check valve.

A phaser which has three camshaft start positions at start-up during cranking before the engine can fire. By having three possible start positions of the phaser, there is an increase in flexibility of the cam position at startup during cranking. The three start positions can also be achieved in open loop, reducing the complexity of the control system needed at cranking.

A press-fit member having a cylindrical shape is press-fit into a through hole formed in a vane. An advance-side lock pin and a retard-side lock pin are provided coaxially with each other inside the press-fit member. In the outer circumferential surface of the press-fit member, an advance-side lock pin-release oil passage for applying lock pin-release hydraulic pressure to an advance-side engagement groove and a retard-side lock pin-release oil passage for applying the lock pin-release hydraulic pressure, applied to the advance-side engagement groove, to a retard-side engagement groove are formed.

A press-fit member having a cylindrical shape is press-fit into a through hole formed in a vane. An advance-side lock pin and a retard-side lock pin are provided coaxially with each other inside the press-fit member. In the outer circumferential surface of the press-fit member, an advance-side lock pin-release oil passage for applying lock pin-release hydraulic pressure to an advance-side engagement groove and a retard-side lock pin-release oil passage for applying the lock pin-release hydraulic pressure, applied to the advance-side engagement groove, to a retard-side engagement groove are formed.

A vane phaser with an unlocking and relocking mechanism attached to the lock pin, which through the use of a solenoid, distinct from the solenoid used for the oil control valve, which can lock and unlock the vane phaser. When the solenoid is energized and during rotation of the camshaft, the solenoid makes contact with a lever or gear wheel attached to the lock pin, causing the lock pin to rotate. A helical feature on the lock pin itself or on the lever causes the lock pin to move axially, unlocking the vane phaser.

A hydraulically operated camshaft phasing mechanism has two lock pins. One of the lock pins engages at an intermediate position and an end lock pin engages near one of the stops at the end of the phaser range of authority. At least one of the locking pins, preferably the end lock pin, when the vane is at an end stop position, is engaged by oil pressure and spring loaded to release when the oil pressure side of the end lock pin is vented.