The disclosure relates to a hydraulic camshaft adjuster having a stator, which is synchronously rotatable with a crankshaft of the internal combustion engine, a rotor rotatably arranged relative to the stator and synchronously rotatable with a camshaft, two groups of working chambers that can each be loaded with a pressure medium in a pressure medium circuit, and a central locking device for locking the rotor in a defined position relative to the stator. The stator is delimited on a first front end by a multi-part locking cover. The multi-part locking cover has a first locking cover and a second locking cover. A first stage of a mechanical ratchet is formed on the first locking cover, and at least one further stage of the mechanical ratchet is formed on the second locking cover.

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.

An ECU (101) causes lock pin-release hydraulic pressure to be applied to an advance-side lock pin-release oil passage (5a) to disengage an advance-side lock pin (6) from an advance-side engagement groove (9), thereby making a rotor (1) rotatable in an advance direction, and forming a clearance communicating with a retard-side lock pin-release oil passage (5c), between the advance-side engagement groove (9) and the advance-side lock pin (6). Next, the ECU (101) causes hydraulic pressure to be applied to advancing hydraulic chambers (16) to rotate the rotor (1), and causes the lock pin-release hydraulic pressure to be applied through the clearance and through the retard-side lock pin-release oil passage (5c) to a retard-side engagement groove (10) to disengage a retard-side lock pin (7).

The present disclosure provides a locking structure of a valve timing adjustment apparatus for an internal combustion engine, using torque from a camshaft and the pressure of working fluid. The locking structure includes an anti-rotation mechanism for inhibiting or preventing a position change between a rotor and a housing by preventing relative rotation of the rotor to the housing. The anti-rotation mechanism further includes: a plurality of locking grooves which are formed on the ratchet plate with different depths and connected to each other; and a locking pin member. In particular, the locking pin member has: a hollow outer pin elastically disposed in a fitting hole formed in vanes, an inner pin elastically disposed inside the outer pin, and a lifter ring coupled to the upper portion of the outer pin to slide on the inner side of the fitting hole.

The present disclosure provides a valve timing adjustment apparatus for an internal combustion engine. The apparatus includes an anti-rotation mechanism for inhibiting a position change between a rotor and a housing by inhibiting or preventing relative rotation of the rotor to the housing. The anti-rotation mechanism includes: a plurality of locking grooves formed on the ratchet plate with different depths and connected to each other; and a locking pin member having an outer pin elastically disposed in a fitting hole formed in one of the vanes, and an inner pin elastically disposed inside the outer pin. In particular, the inner pin locks the rotor to the housing when the outer pin and the inner pin are sequentially fitted in the locking grooves by torque from the camshaft.

A hydraulic camshaft adjuster adjusts the control time of gas exchange of an internal combustion engine. A reservoir for storing pressure medium is formed on a cover of the hydraulic camshaft adjuster. An overflow opening of the cover is dimensioned such that a volume of pressure medium remains in the reservoir when the hydraulic camshaft adjuster is stationary. This ensures that pressure medium is supplied to the return valve of a central locking mechanism when the engine is running.

A phase setter for adjusting the rotational angular position of a cam shaft relative to a crankshaft of an internal combustion engine. The phase setter includes a stator; a rotor which together with the stator forms a first and second pressure chambers; a control valve featuring a pressure port, and first and second working ports; a feed for the inflow of pressure fluid to the pressure port, a first connecting channel connecting the first pressure chamber to the first working port, and a second connecting channel connecting the second pressure chamber to the second working port; and a reflux valve device acts in the feed and includes a valve structure extending annularly around the rotational axis and has one or more spring tongues or can be axially moved to restrict backflow of pressure fluid through the feed more significantly than the inflow of pressure fluid to the pressure port.

The disclosure relates to a hydraulic camshaft adjuster having a stator, which is synchronously rotatable with a crankshaft of the internal combustion engine, a rotor rotatably arranged relative to the stator and synchronously rotatable with a camshaft, two groups of working chambers that can each be loaded with a pressure medium in a pressure medium circuit, and a central locking device for locking the rotor in a defined position relative to the stator. The stator is delimited on a first front end by a multi-part locking cover. The multi-part locking cover has a first locking cover and a second locking cover. A first stage of a mechanical ratchet is formed on the first locking cover, and at least one further stage of the mechanical ratchet is formed on the second locking cover.

A camshaft adjuster, comprising a drive element and an output element, wherein the drive element can be rotated in relation to the output element within an angular range between an early and a late position. The camshaft adjuster also includes a spring configured to brace the drive element with the output element, wherein the spring is configured to rotate the drive element in relation to the output element into a desired position within the angular range and is further configured to angularly adjust from both an early position and a late position into a direction of the desired position.

A variable valve timing control device includes a phase detecting portion; a phase control portion driving an electromagnetic solenoid while obtaining a detection signal detected by the phase detecting portion to set a spool to one of a phase control region and a lock region; and a boundary memory portion memorizing a boundary electric current value for referring a boundary between the phase control region and the lock region when the phase control portion operates a phase control; and a characteristic calculation portion obtaining the boundary electric current value by calculation, the boundary electric current value supporting the boundary between the phase control region and the lock region based on solenoid characteristic information of the electromagnetic solenoid and valve characteristic information of an electromagnetic control valve, the characteristic calculation portion memorizing the boundary electric current value to the boundary memory portion.