The systems and methods described herein provide an approach for cam phase angle control where an axial or rotational position of an actuator of a cam phaser has a direct relationship to the phase angle of the cam shaft, allowing for accurate cam phasing without the need for cam shaft or crank shaft position sensors. Providing phase angle adjustability without the need for crank shaft or cam shaft position sensors enables control of phase angle solely by sensing the axial or rotational position of the actuator of the cam phaser.

A fully variable electro-hydraulic valve system having a buffering function, comprising: a camshaft (101), a valve assembly (106), a sliding sleeve (103), a spiral shaft (102), a piston (105), and a position restoring spring (104); the sliding sleeve (103) is fixed relative to an engine; the piston (105) abuts against the valve assembly (106); the spiral shaft (102) is controlled by a cam surface of the camshaft (101) in the axial direction; a spiral surface (102E) is provided at a first end of the spiral shaft (102), and a control gear (102A) is provided at a second end thereof; the sliding sleeve (103) is provided with a buffering oil hole (123) that communicates with a buffering cavity (R), and the buffering oil hole (123) communicates with a low-pressure oil circuit of the engine by means of a throttling device (124). When a valve is going to be seated, the piston (105) firstly collides with a buffering ring (121); due to the effect of the throttling device (124), engine oil within the buffering cavity (R) has a damping effect on the movement of the buffering ring (121), such that the valve is slowly seated, thus reducing the impact damage caused to the valve and a sealing surface of a valve seat, thereby effectively prolonging the service life of a valve system.

A fully variable electro-hydraulic valve system having a buffering function, comprising: a camshaft (101), a valve assembly (106), a sliding sleeve (103), a spiral shaft (102), a piston (105), and a position restoring spring (104); the sliding sleeve (103) is fixed relative to an engine; the piston (105) abuts against the valve assembly (106); the spiral shaft (102) is controlled by a cam surface of the camshaft (101) in the axial direction; a spiral surface (102E) is provided at a first end of the spiral shaft (102), and a control gear (102A) is provided at a second end thereof; the sliding sleeve (103) is provided with a buffering oil hole (123) that communicates with a buffering cavity (R), and the buffering oil hole (123) communicates with a low-pressure oil circuit of the engine by means of a throttling device (124). When a valve is going to be seated, the piston (105) firstly collides with a buffering ring (121); due to the effect of the throttling device (124), engine oil within the buffering cavity (R) has a damping effect on the movement of the buffering ring (121), such that the valve is slowly seated, thus reducing the impact damage caused to the valve and a sealing surface of a valve seat, thereby effectively prolonging the service life of a valve system.

A compression-release engine brake system operating an exhaust valve of an engine during a compression-release engine braking operation. The compression-release brake system comprises an exhaust rocker arm and a brake reset device disposed in a reset bore formed in the exhaust rocker arm. The brake reset device comprises a reset check valve, a slider-piston slidably disposed in the reset bore and an external slider bias spring biasing the piston foot away from the brake reset device. The external slider bias spring is disposed outside the reset bore and around the piston-slider. The brake reset device permits pressurized hydraulic fluid to flow from a supply conduit to a reset conduit to supply a brake actuation piston when the reset check valve is open. The actuation piston extends and engages the exhaust valve toward the end of a compression stroke of the internal combustion engine, and the brake reset device resets.

A compression-release engine brake system operating an exhaust valve of an engine during a compression-release engine braking operation. The compression-release brake system comprises an exhaust rocker arm and a brake reset device disposed in a reset bore formed in the exhaust rocker arm. The brake reset device comprises a reset check valve, a slider-piston slidably disposed in the reset bore and an external slider bias spring biasing the piston foot away from the brake reset device. The external slider bias spring is disposed outside the reset bore and around the piston-slider. The brake reset device permits pressurized hydraulic fluid to flow from a supply conduit to a reset conduit to supply a brake actuation piston when the reset check valve is open. The actuation piston extends and engages the exhaust valve toward the end of a compression stroke of the internal combustion engine, and the brake reset device resets.

A valve actuation system comprises a valve actuation motion source configured to provide main and auxiliary valve actuation motions for actuating at least one engine valve via a valve actuation load path. A lost motion subtracting mechanism is arranged in a valve bridge and configured, in a first default operating state, to convey at least the main valve actuation motion and configured, in a first activated state, to lose the main valve actuation motion and the auxiliary valve actuation motion. Additionally, a lost motion adding mechanism is arranged in a rocker arm and configured, in a second default operating state, to lose the auxiliary valve actuation motion and configured, in a second activated state, to convey the auxiliary valve actuation motion, wherein the lost motion adding mechanism is parallel with the lost motion subtracting mechanism in the valve actuation load path at least during the second activated state.

A valve actuation system comprises a valve actuation motion source configured to provide main and auxiliary valve actuation motions for actuating at least one engine valve via a valve actuation load path. A lost motion subtracting mechanism is arranged in a valve bridge and configured, in a first default operating state, to convey at least the main valve actuation motion and configured, in a first activated state, to lose the main valve actuation motion and the auxiliary valve actuation motion. Additionally, a lost motion adding mechanism is arranged in a rocker arm and configured, in a second default operating state, to lose the auxiliary valve actuation motion and configured, in a second activated state, to convey the auxiliary valve actuation motion, wherein the lost motion adding mechanism is parallel with the lost motion subtracting mechanism in the valve actuation load path at least during the second activated state.

An internal combustion engine includes an electro-hydraulic system for variable actuation of intake valves where each cylinder has two intake valves, associated with two intake conduits. A first conduit is generates within the cylinder a tumble motion of airflow introduced therein, when the intake valve associated thereto is at least partially opened. The second intake conduit generates within the cylinder a swirl motion of airflow introduced therein when the second intake valve is at least partially opened. A controller of controls one or more control valves to open only one of the intake valves of each cylinder in a condition of reduced engine operation, below a predetermined load and/or a predetermined speed of the engine, and to always open both intake valves in the remaining conditions of engine operation. The first intake valve is the only valve to be opened in the reduced engine operation condition.

An internal combustion engine includes an electro-hydraulic system for variable actuation of intake valves where each cylinder has two intake valves, associated with two intake conduits. A first conduit is generates within the cylinder a tumble motion of airflow introduced therein, when the intake valve associated thereto is at least partially opened. The second intake conduit generates within the cylinder a swirl motion of airflow introduced therein when the second intake valve is at least partially opened. A controller of controls one or more control valves to open only one of the intake valves of each cylinder in a condition of reduced engine operation, below a predetermined load and/or a predetermined speed of the engine, and to always open both intake valves in the remaining conditions of engine operation. The first intake valve is the only valve to be opened in the reduced engine operation condition.

The present disclosure relates to a camless engine in which a camless system is configured for controlling one or more engine valves of an internal combustion engine is disclosed. The system comprises a pneumatic accumulator configured to store compressed air, and at least one pneumatic actuator having a piston rod. The pneumatic actuator is configured for abutment with the engine valves of the internal combustion engine. The system further comprises at least one pneumatic control valve fluidly connected between the pneumatic accumulator and the pneumatic actuator, a sensor configured to sense an engine parameter and to transmit a signal to actuate the pneumatic control valves and an electronic control unit configured to control the pneumatic valves based on the signal received from the sensor.