A helical torsion valve spring assembly includes one or more helical torsion springs mounted within a frame and are held in a statically loaded state so that installation of a valve spring retainer can be easily performed. The entire helical torsion valve spring assembly is installed as a single part onto a cylinder head of an engine valvetrain. The helical torsion springs are mounted around a shaft to accurately locate the helical torsion springs so that the forces acting on the retainer and valve are precisely controlled. The assembly minimizes the size of the retainer, and applies only one bending mode to the helical torsion springs, which provides maximum utilization of the spring material and minimizes coil vibration. The assembly allows spring coils to be strategically packaged in the engine valvetrain to create space in critical areas.

A switching oil gallery de-aeration arrangement for a switchable valve arrangement is provided, including a switching control valve that activates or deactivates the switchable valve arrangement. The switching control valve is movable from a first position, in which pressurized hydraulic fluid from a hydraulic lash adjuster fluid gallery flows to a passage on the hydraulic lash adjuster and through a switching hydraulic fluid gallery to a check valve such that pressurized hydraulic fluid from the hydraulic lash adjuster fluid gallery pressurizes the switching hydraulic fluid gallery and is released through the check valve, and a second position, in which pressurized hydraulic fluid having a higher pressure sufficient for carrying out a switching function of the switchable valve arrangement is delivered by the switching hydraulic fluid gallery via the second intersection to the second port.

A variable valve lift system may include a roller finger follower having an end connected with a valve and a roller mounted thereto. A hydraulic lash adjuster supports another end of the roller finger follower and has operating modes which are changed to a high lift mode or a low lift mode according to supplied hydraulic pressure to change a height of the hydraulic lash adjuster. A hydraulic pressure supplying portion supplies the hydraulic pressure to the hydraulic lash adjuster. A cam is mounted to a camshaft and contacts the roller of the roller finger follower. The cam has a first ramp and a second ramp formed thereon.

A rocker arm includes a roller, a support shaft coaxially mounted in the roller and having a first end portion and a second end portion, walls including at least a first wall and a second wall arranged along the rotation axis and opposite each other with having the roller therebetween, the first wall having a first through hole through which the first end portion is inserted and the second wall having a second through hole through which the second end portion is inserted, and plate portions including at least a first plate portion and a second plate portion arranged opposite each other with having the first wall, the second wall and the support shaft therebetween. The first plate portion is in contact with a first end surface of the first end portion and the second plate portion is in contact with a second end surface of the second end portion.

A rocker arm includes a pair of sidewalk disposed along a heightwise direction so as to be opposed to each other. The sidewalk define a space to house a roller and have opposed portions extending in the heightwise direction relative to adjacent portions which are adjacent to the opposed portions. The opposed portions have thinner portions having smaller thicknesses than the adjacent portions.

A variable valve gear for an internal combustion engine includes: a cam base portion integrally or separately provided in a camshaft, and immovably fixed to the camshaft; a cam lobe portion connected to the cam base portion so as to swing and shift between a first state where the cam lobe portion is positioned to project from an outer circumference of the base portion and a second state where the cam lobe portion is positioned to be lower than the cam base portion in the first state; a lock mechanism locking the cam lobe portion in the first and second state; and a biasing member biasing the cam lobe portion to be shifted to the first state, to such an extent that the cam lobe portion is shifted to the second state by reaction force from a cam follower when the locking mechanism is unlocked.

A valvetrain includes a rocker arm assembly having an electromagnetic latch housed in a chamber formed by a rocker arm. The chamber may be a retrofit hydraulic chamber. A flux shifting bi-stable latch provides a sufficiently compact design. Isolation of the magnetic elements within the rocker arm chamber may provide protection from metal particles carried by oil in an operating environment for the rocker arm assembly. Wiring connections to the rocker arms may be made through spring posts on the rocker arms. Connection to the rocker arms may be made with springs that can endure the rapid motion induced by the rocker arms. A wiring harness for the rocker arms may attach to hydraulic lash adjusters of the rocker arm assemblies. The rocker arm assemblies and their wiring may be formed into a unitary module that facilitates installation.

The present invention provides a variable valve mechanism of an internal combustion engine, which includes a rocker arm that includes a roller arm including a roller that rotatably abuts against a cam and a side arm provided at a side of the roller arm and that drives a valve, and a switching device that includes a switching pin and a hydraulic chamber provided inside the rocker arm and that switches a drive state of the valve by displacing the switching pin between a coupling position at which the switching pin extends between the roller arm and the side arm and a non-coupling position at which the switching pin does not extend between the roller arm and the side arm based on variations in hydraulic pressure in the hydraulic chamber. The switching pin is provided on an axis of the roller, and the hydraulic chamber is provided inside the roller arm.

Air is restrained from flowing into a high pressure chamber while the number of parts is reduced. A plunger is slidably fitted into a body; a reservoir is formed in the plunger with a communication hole formed in a head section thereof to allow communication between an inside and an outside; a high pressure chamber is formed in the body between the body and the plunger bottom section; an oil supply hole is formed in a plunger circumferential wall section; a return spring is interposed between the body and the plunger; a valve mechanism is disposed on the plunger bottom section; the reservoir is set such that a space continuously extends; and the oil supply hole is oriented outward in the radial direction as compared to an axis of the plunger.

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.