An exhaust valve rocker arm assembly operable in an engine braking mode includes a rocker arm configured to rotate about a rocker shaft defining a pressurized fluid supply conduit, the rocker arm having a fluid supply passage defined therein. An engine brake capsule is disposed in the rocker arm and in fluid communication with the fluid supply passage. The engine brake capsule is configured to selectively move from a retracted position to an extended position where the engine brake capsule engages and partially opens an exhaust valve to perform a bleeder brake operation. A reset pin assembly is configured to selectively drain fluid from the engine brake capsule.

A valve actuation system comprises a valve actuation motion source configured to provide a main valve actuation motion and an auxiliary valve actuation motion for actuating at least one engine valve via a valve actuation load path. A lost motion subtracting mechanism is arranged in the valve actuation load path 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 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 in series 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 a main valve actuation motion and an auxiliary valve actuation motion for actuating at least one engine valve via a valve actuation load path. A lost motion subtracting mechanism is arranged in a pre-rocker arm valve train component 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 valve bridge 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 in series with the lost motion subtracting mechanism in the valve actuation load path.

A hydraulic tappet configured for a valve train of an internal combustion engine is provided. The tappet includes an outer housing, a socket plunger, and a hydraulic lash adjuster assembly. The socket plunger and the hydraulic lash adjuster assembly are disposed within the outer housing. The hydraulic lash adjuster assembly includes an outer casing, a piston, and a check valve assembly. The outer casing is configured with a spherical first end. The hydraulic lash adjuster assembly can include a swivel pad that engages the spherical first end. The piston is at least partially received by an opening in the outer casing. The piston and socket plunger define a first fluid chamber, while the piston and outer casing define a second fluid chamber. The check valve assembly is arranged to fluidly connect the first fluid chamber to the second fluid chamber.

It is described herein a hydraulic lifter for an internal combustion engine. The hydraulic lifter may comprise a lifter body, a self-contained hydraulic cartridge, a pushrod seat, and a retaining clip. The self-contained hydraulic cartridge may be disposed within a cartridge bore in the lifter body. The self-contained hydraulic cartridge may comprise a self-contained hydraulic system such that a lifter piston of the hydraulic system is not directly disposed within a bore in the lifter body.

An engine valve actuation system includes a rotatable camshaft having a cam lobe, and a lifter arm assembly having a lifter arm with a roller in contact with the cam lobe. A bushing is positioned in a pin bore of the lifter arm and journals the lifter arm upon the pin for reciprocation in response to rotation of the camshaft. An incoming oil passage extends to the pin bore, and an outgoing oil passage extends from the pin bore. The outgoing oil passage forms an oil spray port defining an oil spray path oriented to direct a spray of oil at the roller and/or the cam lobe. An oil feed groove is formed in at least one of the lifter arm or the bushing and fluidly connects the incoming oil passage to the outgoing oil passage.

A valve actuation system comprises a valve actuation motion source configured to provide a main valve actuation motion and an auxiliary valve actuation motion for actuating at least one engine valve via a valve actuation load path. A lost motion subtracting mechanism is arranged in the valve actuation load path 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 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 in series with the lost motion subtracting mechanism in the valve actuation load path at least during the second activated state.

A roller-lifter assembly for a cam-actuated engine, comprising a two-part roller lifter (10, 13, 16) comprising a pump actuator main body, a receiving portion extending from the main body (160, 161, 162, 163 164), and a cam follower comprising a roller assembly (31) or a flat tappet integrated to the main body and configured to follow a rotating cam of a cam-actuated (32) engine. A hydraulically-actuated capsule (200, 202, 203, 204, 205) is fitted to the receiving portion of the pump actuator, the capsule configured to rotate with respect to the pump actuator (100, 101, 102, 103, 104).

An exhaust valve rocker arm assembly operable in an engine braking mode includes a rocker arm configured to rotate about a rocker shaft defining a pressurized fluid supply conduit, the rocker arm having a fluid supply passage defined therein. An engine brake capsule is disposed in the rocker arm and in fluid communication with the fluid supply passage. The engine brake capsule is configured to selectively move from a retracted position to an extended position where the engine brake capsule engages and partially opens an exhaust valve to perform a bleeder brake operation. A reset pin assembly is configured to selectively drain fluid from the engine brake capsule.

A valvetrain assembly configured to selectively perform a bleeder brake operation includes a rocker arm configured to rotate about a rocker shaft, a camshaft having a lobe configured to impart motion to the rocker arm through a pushrod, and a valve bridge assembly operably associated with the rocker arm and configured to be selectively engaged by the rocker arm to open at least one of a first and second engine valve. An engine brake capsule is operably associated with the valve bridge assembly and configured to operate in a drive mode where the engine brake capsule does not cause the valve bridge assembly to open the first or second engine valves, and a brake mode where the engine brake capsule engages the valve bridge assembly to partially open the first engine valve to perform the bleeder brake operation.