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.

An actuation transmission apparatus for actuating a component of a switchable valve train device of an internal combustion engine includes: a shaft rotatable by an actuation source; a contacting element for contacting the component of the switchable valve train device; and a biasing device for biasing the contacting element rotationally with respect to the shaft; wherein, in use, the biasing device becomes biased by the shaft when the actuation source rotates the shaft when the actuation source attempts to actuate the component of the switchable valve train device, via the contacting element, when the component of the switchable valve train device is not able to be actuated, whereby the biasing device is configured to cause the contacting element to actuate the component of the switchable valve train device when the component of the switchable valve train device becomes actuatable again.

A valve mechanism includes a valve, a camshaft, an intermediate swing arm located between a cam and the valve, a lift regulating mechanism and a roller assembly. The cam drives the valve to move by means of the intermediate swing arm. The roller assembly is supported by the cam, an eccentric wheel of the lift regulating mechanism and an intermediate swing arm roller. A peripheral surface of the eccentric wheel includes a lift regulating section having a start point and an end point, a maximum lift point of the lift regulating section is located between the start point and the end point, and the lift regulating section is divided into a first section which is convex and a second section having at least a part thereof concave.

A valve mechanism includes a valve, a camshaft, an intermediate swing arm located between a cam and the valve, a lift regulating mechanism and a roller assembly. The cam drives the valve to move by means of the intermediate swing arm. The roller assembly is supported by the cam, an eccentric wheel of the lift regulating mechanism and an intermediate swing arm roller. A peripheral surface of the eccentric wheel includes a lift regulating section having a start point and an end point, a maximum lift point of the lift regulating section is located between the start point and the end point, and the lift regulating section is divided into a first section which is convex and a second section having at least a part thereof concave.

A valve train includes a camshaft which has a cam group having a firing cam and a braking cam. A first cam follower is assigned to the firing cam with the first cam follower being provided in a firing mode for actuating a gas exchange valve. A second cam follower is assigned to the braking cam which is provided in a braking mode for actuating the gas exchange valve. A changeover device is provided to changeover between the firing mode and the braking mode. The camshaft has a separate switching cam which, in at least one operating mode, is provided to act directly on a switching element of the changeover device and which is provided for a direct changeover between the firing mode and the braking mode.

A valve train includes a camshaft which has a cam group having a firing cam and a braking cam. A first cam follower is assigned to the firing cam with the first cam follower being provided in a firing mode for actuating a gas exchange valve. A second cam follower is assigned to the braking cam which is provided in a braking mode for actuating the gas exchange valve. A changeover device is provided to changeover between the firing mode and the braking mode. The camshaft has a separate switching cam which, in at least one operating mode, is provided to act directly on a switching element of the changeover device and which is provided for a direct changeover between the firing mode and the braking mode.

A method of using a through axle switching rocker arm according to one example of the present disclosure is provided. The switching rocker arm comprises an outer and inner arm and a roller axle. The inner arm is pivotally coupled to the outer arm about a pivot axle and has an inner bushing that supports an inner roller. The inner bushing defines an inner diameter. The roller axle extends through the inner bushing and defines an outer diameter. The inner diameter of the inner bushing engages the outer diameter of the roller axle thereby inhibiting further pivoting of the inner arm relative to the outer arm defining a rocker arm travel constraint. The method includes designing first and second cam profiles based on the through axle switching rocker arm such that a difference in lift between the first and second cam profiles is held within the rocker arm travel constraint.

A variable valve driving mechanism of an engine, and the engine. The variable valve driving mechanism comprises a rocker arm (1) configured to control open and close of a valve (7) and a servo rocker arm (2) arranged in parallel to the rocker arm (1). A swing end of the servo rocker arm (2) extends to the top of the swing end of the rocker arm (1). A valve adjustment gap (1-2) provided in the swing direction of the servo rocker arm (2) and the rocker arm (1) is formed between the servo rocker arm (2) and the rocker arm (1). A gap compensating device telescopically filling the valve adjustment gap (1-2) and configured to adjust the valve (7) to be delayed to close or open in advance when extending to the valve adjustment gap (1-2) is provided between the servo rocker arm (2) and the rocker arm (1). When the valve (7) is open or closed normally, the gap compensating device is contracted, and the rocker arm (1) is not in contact with the servo rocker arm (2) in the swing process by means of the valve adjustment gap (1-2). When it is required to control the valve (7) to be delayed to close or open in advance, the gap compensating device extends into the valve adjustment gap (1-2) to eliminate the gap, and the open/close time of the valve (7) is adjusted to avoid the problem that the valve is not properly closed caused by a plurality of oil control paths.