A retention plate for a hydraulic lash adjuster of a valve train is provided. The retention plate includes a first surface. The retention plate includes a second surface mutually opposite the first surface. The second surface is adapted to contact with a cylinder head of an engine. The retention plate also includes a coupling mechanism defined on the retention plate. The coupling mechanism is adapted to couple the retention plate to the cylinder head. The coupling mechanism includes a through hole adapted to receive a mechanical fastener therethrough. The retention plate further includes a restriction mechanism defined on the retention plate. The restriction mechanism is adapted to restrict a movement of the hydraulic lash adjuster beyond the first surface towards the cylinder head. The restriction mechanism includes an aperture having an aperture size smaller than an outer diameter of the hydraulic lash adjuster.

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 compact, modular, lost motion variable valve actuation assembly includes a dry start hydraulic circuit to enable quick priming of a lost motion master-slave circuit from a dry start reservoir to the master piston chamber during engine start. Motion of the master piston on engine startup may draw in fluid from the dry start hydraulic circuit. The dry start components may be integrated into a compact modular rocker shaft pedestal package suitable for retrofit on existing engine head assemblies. The master piston may include a push tube interface that includes a deep push tube cavity and lubrication capabilities in the master piston that provides for improved wear, stability, easy installation and alignment. The slave piston may be provided with a valve catch to reduce valve closing velocity during cycles involving lost-motion.

The disclosure relates to a switching element comprising an external part and an internal part, which is axially displaceable in a bore of the external part. At least one radially displaceable locking element is disposed within at least one receptacle of the internal part and includes a flattened portion on a radially outwardly directed end. At least one recess of the external part can be acted upon by a control pressure and the at least one locking element can thereby be radially displaced from the locking position into a release position. At least in a respective locking position, a chamber delimited by the at least one locking element is spatially separated from the at least one recess of the external part by a respective locking section. At least one bypass is designed, which indirectly fluidly connects the at least one recess of the external part and a respective chamber.

A compact, modular, lost motion variable valve actuation assembly includes a dry start hydraulic circuit to enable quick priming of a lost motion master-slave circuit from a dry start reservoir to the master piston chamber during engine start. Motion of the master piston on engine startup may draw in fluid from the dry start hydraulic circuit. The dry start components may be integrated into a compact modular rocker shaft pedestal package suitable for retrofit on existing engine head assemblies. The master piston may include a push tube interface that includes a deep push tube cavity and lubrication capabilities in the master piston that provides for improved wear, stability, easy installation and alignment. The slave piston may be provided with a valve catch to reduce valve closing velocity during cycles involving lost-motion.

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 system and method of controlling a cylinder deactivation mechanism can comprise executing a valve lift event configured to lift a valve via a rocker arm. The rocker arm can be configured with a controllable latch in a latched condition, wherein the controllable latch is configured with an edge that is clamped in a recess in the rocker arm during the valve lift event, a clamp force supplied in part by pressure from the valve lift event. A deactivation signal can be sent to select the unlatched condition to collapse the controllable latch from the recess while the controllable latch is configured in the valve lift event with the edge clamped in the recess. A subsequent valve lift event can have actuation deactivated by collapsing the controllable latch from the recess once the valve lift event is complete and the clamp force is removed.

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 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 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.