A method for adding fluid to an hydraulic lash adjuster (HLA) comprises the steps of placing the HLA in to a centrifuge, the centrifuge having a fluid container, placing a sufficient amount of a first fluid in the fluid container to fluidly communicate with at least one fluid port of the HLA, and spinning the HLA at a first speed sufficient to move the first fluid in to at least the second of two fluid chambers in the HLA.

A system for variable actuation of an engine valve of an internal-combustion engine includes a master piston and a slave piston, driven by the master piston. A control valve controls a communication of a volume of a pressurized fluid with a lower pressure environment, which is connected to a fluid accumulator, and an electronic control unit controls the electrically operated control valve. A device for dampening pressure oscillations is connected to the volume of pressurized fluid and includes an additional volume adapted for receiving fluid from the volume of pressurized fluid only when, following upon oscillations of the pressure in the volume of pressurized fluid, the pressure exceeds a maximum threshold value, which is higher than a mean pressure value that is set up in the volume of pressurized fluid when the master piston drives the slave piston in normal operating conditions.

A system for variable actuation of an engine valve of an internal-combustion engine includes a master piston and a slave piston, driven by the master piston. A control valve controls a communication of a volume of a pressurized fluid with a lower pressure environment, which is connected to a fluid accumulator, and an electronic control unit controls the electrically operated control valve. A device for dampening pressure oscillations is connected to the volume of pressurized fluid and includes an additional volume adapted for receiving fluid from the volume of pressurized fluid only when, following upon oscillations of the pressure in the volume of pressurized fluid, the pressure exceeds a maximum threshold value, which is higher than a mean pressure value that is set up in the volume of pressurized fluid when the master piston drives the slave piston in normal operating conditions.

An internal-combustion engine has a plurality of cylinders each with two intake valves driven by respective pumping pistons operatively associated to cams of a camshaft, by respective hydraulic circuits. The hydraulic has its pressure chamber communicating with hydraulic actuators of the two intake valves, so that the two intake valves of each cylinder are controlled, via two different hydraulic circuits, by cams associated to two different cylinders. Each cam is configured to give rise to a cycle of opening and closing of each of the intake valves in an angular range of rotation of the crankshaft less than 180 such that, in each operating cycle of a cylinder, only the first intake valve initially opens and closes while the second intake valve remains closed, and then the second intake valve opens and closes while the first intake valve remains closed.

An internal-combustion engine has a plurality of cylinders each with two intake valves driven by respective pumping pistons operatively associated to cams of a camshaft, by respective hydraulic circuits. The hydraulic has its pressure chamber communicating with hydraulic actuators of the two intake valves, so that the two intake valves of each cylinder are controlled, via two different hydraulic circuits, by cams associated to two different cylinders. Each cam is configured to give rise to a cycle of opening and closing of each of the intake valves in an angular range of rotation of the crankshaft less than 180 such that, in each operating cycle of a cylinder, only the first intake valve initially opens and closes while the second intake valve remains closed, and then the second intake valve opens and closes while the first intake valve remains closed.

A valve train assembly includes a valve bridge assembly. The valve bridge assembly includes: a valve bridge; a first cavity formed towards a first end portion of the valve bridge; and a hydraulic lash adjuster (HLA) disposed within the first cavity, the HLA for engaging a first valve stem. The valve train assembly further includes: a pivotally mounted first rocker arm for engaging the valve bridge and to pivot in response to a rotating first cam to cause a first valve lift event in an engine cycle. The first rocker arm includes: a rocker arm cavity formed within an end portion thereof; and a control capsule disposed within the rocker arm cavity, wherein the control capsule is configurable in an ON configuration and an OFF configuration.

A valve bridge assembly includes a valve bridge; a first cavity formed towards a first end portion of the valve bridge; and a hydraulic lash adjuster (HLA) disposed within the first cavity for engaging a first valve stem. The HLA includes a first contact surface for engaging the first valve stem. The first contact surface is curved.

A variable valve lift apparatus may include an outer body, an inner body inserted in the outer body to move up and down in the outer body, a valve cylinder inserted in the outer body on a lower side of the inner body to have one side coupled to the inner body and the other side coupled to the valve, a latching member provided either to the outer body or to the inner body to be operated by a hydraulic pressure for coupling to the outer body and the inner body selectively, a hydraulic chamber formed between the outer body and the inner body, a latching flow passage formed in the outer body to supply the hydraulic pressure to the latching member, and an oil removal valve provided to drain a fluid.