An exhaust valve assembly for a two-stroke internal combustion engine has a housing adapted for connection to an engine block of the two-stroke internal combustion engine; an electric actuator having an electric motor, the electric motor being disposed in the housing; and at least one reciprocating exhaust valve operatively connected to the electric actuator. The at least one exhaust valve is linearly movable by the electric motor. A portion of the at least one exhaust valve is disposed in the housing.

In a variable valve control device, a variable valve control system and a method for controlling a variable valve mechanism according to the present invention, An ECM (201) transmits a phase detection value (RA1) computed based on a crank angle signal (CRANK) and a cam angle signal (CAM) to a VTC control unit (202) via a communication network (211), and VTC control unit (202) computes a phase detection value (RA2) based on a motor angle signal (MAS), controls a variable valve timing mechanism (114) based on phase detection value (RA2) in the transient state of an internal combustion engine, and controls variable valve timing mechanism (114) based on phase detection value (RA1) in the steady state of the internal combustion engine.

A method for verifying a CVVD location learning result may include performing a learning value verification control by confirming a position of a control shaft connected to a motor with a signal value of an auxiliary cam sensor for a rotation of a camshaft if a controller determines that a learning value acquired in a short duration and a long duration of a CVVD system is desired to be verified.

An electrically-actuated variable camshaft timing (VCT) assembly including an electric motor for controlling the VCT assembly having a rotor and a motor output shaft; a gearbox assembly having an input coupled to the motor output shaft and an output configured to be coupled with a camshaft of an internal combustion engine; and a torque-limiting assembly coupled to the motor output shaft that prevents angular displacement of the motor output shaft relative to the rotor and includes a spring that releasably engages the rotor to the motor output shaft to prevent angular displacement of the rotor relative to the motor output shaft at or below a torque limit and permits angular displacement of the rotor relative to the motor output shaft above the torque limit.

An electrically-actuated variable camshaft timing (VCT) assembly includes a gearbox assembly including an input; an electric motor having a rotor, a stator, and a motor shaft that is coupled with the input of the gearbox assembly, wherein the motor shaft includes etchings, on an outer surface of the motor shaft, that releasably couple the motor shaft to the rotor at a center aperture of the rotor when an amount of torque exerted on the motor shaft via the gearbox assembly is less than or equal to a predetermined torque value, and the etchings are further configured to decouple the motor shaft from the rotor when the amount of torque exerted on the motor shaft is greater than the predetermined torque value.

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.

Various embodiments include a method for detecting deviations occurring in the valve drive of an internal combustion engine comprising: measuring dynamic pressure oscillations of intake air in an air intake tract of respective internal combustion engine during operation; calculating an inlet valve stroke phase difference and/or an outlet valve stroke phase difference based on the measured dynamic pressure oscillation; calculating a valve stroke phase deviation value with respect to a valve stroke phase reference value based on the calculated phase difference; and calculating a first valve drive deviation value based on the valve stroke phase deviation value.

A valve timing adjusting device includes an intake variable valve mechanism and an exhaust variable valve mechanism. The exhaust variable valve mechanism includes an exhaust electric driving portion and an exhaust phase shifting portion including an input shaft. The exhaust phase shifting portion is disposed in a rotation transmission path between an exhaust camshaft and a crankshaft and configured to shift a rotation phase of the exhaust camshaft. The input shaft rotates in a rotational direction opposite to a rotational direction of the crankshaft when advancing the rotation phase. A phase of the exhaust phase shifting portion is configured to be shifted to a most advanced angle phase when the exhaust electric driving portion is de-energized or fails and when the exhaust phase shifting portion receives a torque in a forward rotational direction.

A method of continuously variable valve duration (CVVD) location learning may include when a controller determines necessity of position learning for short duration and long duration of a CVVD system, performing conditional application re-learning control in which the position learning is performed in a situation in which validity determination of system environment condition for CVVD hardware and validity determination of vehicle environment condition for engine operation information of an engine are satisfied.