A camshaft phaser includes an input member an output member defining an advance chamber and a retard chamber; a valve spool having a valve spool bore; a first recirculation check valve and a second recirculation check valve disposed within the valve spool bore; and a biasing member which biases the first recirculation check valve and the second recirculation check valve away from each other. The first recirculation check valve allows oil to pass from the advance chamber to the retard chamber and prevents oil from passing from the retard chamber to the advance chamber when the valve spool is in a retard position. The second recirculation check valve allows oil to pass from the retard chamber to the advance chamber and prevents oil from passing from the advance chamber to the retard chamber when the valve spool is in an advance position.

A rotor for a hydraulic camshaft adjuster. The rotor includes a first rotor element and a second rotor element. At least one of the rotor elements has oil channels separated from each other by radially arranged elevations. Each elevation of the first rotor element has a first joining profile and the second rotor element forms a complementary-shaped second joining profile corresponding to the position of each first joining profile, wherein the first and the second joining profile engage with each other in the assembled rotor. The first joining profile of the first rotor element has a notch and an elevation and the second joining profile of the second rotor element has a notch and an elevation formed in such a way that prior to the joining of the two rotor elements, a height of the elevation of the second joining profile, which engages in a notch of the first joining profile, is less than a height of the notch of the first joining profile, and a height of the elevation of the first joining profile, which engages in a notch-of the second joining profile, is less than a height of the notch of the second joining profile.

A camshaft phaser includes a stator having a plurality of lobes and a rotor coaxially disposed within the stator and having a plurality of vanes interspersed with the lobes defining a plurality of alternating advance chambers and retard chambers such that a phasing valve supplies and vents oil to and from the advance and retard chambers. A first check valve allows oil to flow from only one of the retard chambers to only one of the advance chambers when a first diverter valve permits communication between the one of the advance chambers and the first check valve and a second check valve allows oil to flow from the one of the advance chambers to the one of the retard chambers when a second diverter valve permits communication between the one of the retard chambers and the second check valve.

A hydraulic camshaft adjuster having: a stator with a radially inwardly opening working chamber a rotor arranged radially within the stator, wherein the rotor receives a vane dividing the working chamber into two part chambers, and rotatable relative to the stator about a rotational axis dependent on a hydraulic pressure set in the part chambers . A central valve controls the hydraulic pressure and is configured for selectively connecting individual hydraulic lines which open into the part chambers among one another and/or to a supply line.A check valve device is integrated per part chamber into a first hydraulic line configured in the vane, which check valve device is arranged to act in a permanently closing manner in a first hydraulic flow direction from the central valve into the respective part chamber and can be opened dependent on the hydraulic pressure in a second hydraulic flow direction which is opposed to the first hydraulic flow direction.

A valve timing control apparatus has a regulation member to fix a phase. The regulation member has a main regulation member and a sub regulation member. The main regulation member is inserted into a recess part to regulate the phase. The sub regulation member has an engagement part engageable with the main regulation member in an escape direction Y and disengageable from the main regulation member in an insertion direction X. Further, the sub regulation member has a pressure reception part that receives pressure in the escape direction Y from hydraulic fluid in an operation chamber. The main regulation member is urged in the insertion direction X by a main resilient member. Further, the sub regulation member is urged in the insertion direction X by a sub resilient member. The main regulation member moves in the escape direction Y only by hydraulic fluid, and moves in the insertion direction X only by the resilient member.

A camshaft phaser for variably adjusting the control times of gas exchange valves of an internal combustion engine, including: a stator and a rotor which can be rotated relative to the stator, wherein a plurality of hydraulic chambers are formed between the stator and the that are separated by radially inwardly projecting webs of the stator. Radially outwardly projecting vanes are formed on the rotor that divide each of the hydraulic chambers into first and second groups of working chambers with an opposing effective direction. A pressure medium pump is adapted to apply a pressure medium to the working chambers. A central valve controls the oil pressure in the working chambers. The pressure medium pump is directly connected to the working chambers in each ease via a pressure medium channel; the central valve is connected to the working chambers via discharge channels; and the central valve exclusively controls the pressure medium discharge from the working chambers.

An apparatus for camshaft timing adjustment, having a drive disc and a hub rotationally supported relative to each other and defining a common rotational axis wherein the hub is arranged within the drive disc or vice versa, a vane being accommodated in an adjusting chamber defined by the drive disc and the hub and separating the adjusting chamber into a first sub-chamber and a second sub-chamber, wherein the vane is attached to the hub or the drive disc, a hydraulic pump having a high pressure pump chamber, a low pressure pump chamber and a pump for pumping a hydraulic fluid from the low pressure pump chamber to the high pressure pump chamber, each pump chamber being fluidly connected to the first sub-chamber and the second sub-chamber.

A check valve for controlling the flow of a fluid into a variable camshaft timing phaser.

An oil pressure actuated or torsion assisted phaser with a lock pin that has a position which shuts off communication between the advance and retard chambers and the front cam bearing and/or oil control valve, effectively acting as a shutoff valve and preventing leakage of oil from the advance and retard chambers. The prevention of leakage maintains oil in the phaser after engine shutdown. Additionally, by shutting off communication between the advance and retard chambers and the oil supply, the side load on the lock pin from the oil pressure torque on the rotor vanes during unlocking of the lock pin can be reduced or eliminated.

There is provided a variable valve timing system including: a variable valve device; an oil control valve configured to control a hydraulic pressure with respect to the variable valve device; an external pipe connecting a main gallery and the oil control valve; and a hydraulic pressure sensor configured to detect a hydraulic pressure in an oil path formed at the crankcase. The oil control valve is disposed on one side surface of the engine in the vehicle width direction. One end portion of the external pipe is connected to one side of the main gallery in the vehicle width direction. In a bottom view of a vehicle, the one end portion of the external pipe overlaps with the crankcase, and the hydraulic pressure sensor overlaps with the crankcase on one side of the one end portion of the external pipe in the vehicle width direction.