Systems and methods are provided for operating an internal combustion engine in a two-stroke mode or a four-stroke mode to achieve greater fuel efficiency and minimize emissions. The system comprises a mode-adaptable valve; a valve rocker arm to actuate opening and closing of the mode adaptable valve; a cam follower of a first cam for carrying out a two-stroke mode; a cam follower of a second cam for carrying out a four-stroke mode; and a pin to mechanically couple the valve rocker arm to the cam follower of the first cam or the cam follower of the second cam. Coupling the valve rocker arm to the cam follower of the first cam enables a two-stroke mode and coupling the valve rocker arm to the cam follower of the second cam enables a four-stroke mode.

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.

Internal combustion engine having cam actuated valves that can be controlled to facilitate the use of different air charge levels in different cylinders or sets of cylinders are described. In one aspect a first set of cylinders is operated in a skip fire manner in which the corresponding cylinders are deactivated during skipped working cycles. Cam actuated intake valves associated with a second set of cylinders are operated differently so that the air charge in the cylinders in the second set is different than the air charge in fired cylinders subject to the skip fire control. According to another aspect, an engine having cam actuated intake valves is operated in a dynamic firing level modulation mode. During the dynamic firing level modulation operation, the cam actuated intake valves are controlled in at least two different manners to such that different cylinder working cycles have different air charges.

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 method of controlling an operation of an inlet valve system arranged in connection with each cylinder of an internal combustion piston engine, includes monitoring at least one parameter relating to engine load conditions, controlling using a primary control procedure an opening and closing timing of an inlet valve in response to the at least one parameter, and feeding charge air into the cylinder when the inlet valve is open. In a secondary control procedure a parameter relating to engine load conditions is measured and the closing timing of the inlet valve of the inlet valve system is controlled in response to the at least parameter independently from and with higher priority than the primary control procedure.

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.

The disclosure relates to a valve train for an internal combustion engine and to an internal combustion engine. The valve train has an inlet valve actuation mechanism for the periodic actuation of an inlet valve of the internal combustion engine. The valve train also has a delay element, which is in contact with the inlet valve actuation mechanism and which has a hydraulic chamber for delaying a closing movement of the inlet valve by means of a hydraulic medium. The valve train has a hydraulic feed for feeding the hydraulic medium into the hydraulic chamber, the hydraulic feed having a control shaft, and the control shaft being mechanically driven by the internal combustion engine. The control shaft has an axially extended cavity for the hydraulic medium, and at least one opening for intermittently feeding the hydraulic medium from the cavity to the hydraulic chamber.

A tubular structure comprises a first end and a second end, a cylindrical outer structure, and at least one inner cavity defined by the cylindrical outer structure and the first and second ends. The first and second ends each include a recess and a cap press fit within the recess. The caps provide a connection point for the ends of the tubular structure. Each end includes a vent in fluid communication with the inner cavity during manufacturing of the tubular structure, prior to insertion of the caps. An isotropic internal support structure extends longitudinally between the ends within the cylindrical outer structure and defines an oil flow channel extending through the tubular structure, each cap includes a cap orifice aligned with the oil flow channel, and the cylindrical outer structure, the first and second ends, and the internal support structure are continuously and unitarily formed.

A system and method for mechanically timed cylinder deactivation includes an inner passage in the camshaft that supplies fluid for deactivating one or more valve opening mechanisms associated with the cylinders of an internal combustion engine.

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.