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.

A hydraulic camshaft adjuster (1), in which the locking system (7, 8) includes a first and a second control element (7, 8). In order to approach the middle position easily, the first control element (7) has a first and a second switching position, wherein in the first switching position a fluidic connection between the hydraulic pump (P) and a first of the two sub-chambers (B) and a fluidic connection between the other, second sub-chamber (A) and the tank (T) can be established, and in the second switching position a fluidic connection between the hydraulic pump (P) and the second of the two sub-chambers (A) and a fluidic connection between the other, first sub-chamber (B) and the tank (T) can be established, and the second control element (8) is free from different switching positions and has no influence on the flow of hydraulic fluid.

A hydraulic fluid control valve (HFCV) configured to recirculate an exiting hydraulic fluid from a first hydraulic actuation chamber to a second hydraulic actuation chamber is provided. The HFCV includes a spring well that combines a hydraulic fluid received from a hydraulic fluid pressure source with a recirculated hydraulic fluid from the first hydraulic actuation chamber and delivers the combination to the second hydraulic actuation chamber.

A friction member is clamped between a driven shaft of an internal combustion engine and a vane rotor and includes an oil passage hole. The oil passage hole communicates between a first oil passage of the driven shaft a second oil passage of the vane rotor. Each of positioning arrangements includes a primary engaging portion of the vane rotor and a secondary engaging portion of the friction member. The positioning arrangements are configured to limit relative rotation between the vane rotor and the friction member in a communicating state where the first oil passage and the second oil passage are communicated with each other through the oil passage hole.

A camshaft phaser routes pressurized fluid from a set of chambers that are decreasing in volume to a reservoir. Oscillations of the rotor with respect to the stator create intervals in which the pressure in the reservoir exceeds the pressure in the set of chambers which are increasing in volume. During these intervals, fluid flows from the reservoir, through one-way valves, into the chambers which are increasing in volume. Pressurization of the reservoir increases the volume of flow through the one-way valves, decreasing the pump flow requirement for the camshaft phaser.

A self-resetting single-valve hydraulic drive device and method based on primary and secondary pistons for a push rod engine is provided. A primary driving piston and a secondary driving piston are respectively provided on a rocker arm body and a valve bridge body. The secondary driving piston is connected to an exhaust valve. A driving oil passage connects the primary driving piston, the secondary driving piston and a drive control valve. When the drive control valve opens the driving oil passage, the primary driving piston and the secondary driving piston realize a hydraulic linkage. During a drive lift, the rocker arm body and the valve bridge body do not move, and the secondary driving piston opens the exhaust valve. In the beginning of a positive-power lift, a primary piston body oil passage and a secondary piston oil passage are closed, and the secondary driving piston is automatically reset.

A device for controlling a camshaft phaser includes a hydraulic element with a body, a slide assembly having a slide body, and a valve assembly with a first valve, a second valve, and a third valve. The device also includes an actuator which moves along a longitudinal axis between 1) a first position in which the first valve opens or closes a first fluid communication, 2) a second position in which the second valve and the tray open or close a second fluid communication, and 3) a third position in which the third valve and the slide body open or close a third fluid communication between a retard port and a retard chamber.

Methods and systems are provided for a valve system for actuating two cylinder valves in an engine. In one example, the valve system may include a single pump and a solenoid valve capable of non-concurrently actuating the two cylinder valves coupled to separate cylinders.

A variable cam timing phaser includes a housing disposed about an axis and having an inner housing surface defining a housing interior. The variable cam timing phaser includes a rotor moveable between an advance position and a retard position. The rotor includes a hub and a vane, with the rotor and the housing defining a chamber. The vane further defines the chamber into an advance chamber and a retard chamber. The variable cam timing phaser also includes a control valve assembly including a valve housing and a control piston. The variable cam timing phaser also includes a chamber biasing assembly disposed in one of the advance and the retard chambers and configured to bias the rotor into a predetermined position between the advance and the retard positions. The chamber biasing assembly includes a chamber piston, a chamber biasing member, and a chamber check valve.

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.