A variable valve lift apparatus includes an outer body for selectively performing a first lever motion depending on a rotation of a high cam, the outer body further forming an inside space, an inner body disposed in the inside space of the outer body so as to selectively perform a second lever motion depending on a rotation of the high cam by being selectively locked to the outer body, the selective performing of the second lever motion depending on a rotation of a low cam being released from the outer body, and the inner body being configured so that a valve is connected with one end of the inner body, a connecting shaft rotatably connecting the outer body with the inner body, and a lost motion spring wound around the connecting shaft so as to return the outer body after being relatively rotated with respect to the inner body when the outer body is released from the inner body, wherein a roller rolling-contacting with the low cam is disposed at the inner body, and the connecting shaft is disposed between a pivot axis for a lever motion of the inner body and the roller.

A camshaft has a decompression device for an internal combustion engine, wherein a valve lifter is rotatably supported in a base circle of a cam, which can be brought into operative connection with a gas exchange valve via rotation. The valve lifter is operatively connected to a centrifugal fly weight, which is arranged coaxially to the camshaft and which is rotatably supported, in such a way that the valve lifter forms a contour of the base circle in the region of action with the gas exchange valve from a certain rotational speed of the camshaft. The camshaft has a cavity in the region of the centrifugal fly weight, to which cavity lubricant pressure can be applied. A radial first bore from the cavity to the centrifugal fly weight is arranged in the camshaft. A slideable element that can be displaced by the lubricant pressure is arranged in the first bore. By way of the design of the camshaft, an unstable centrifugal fly weight is stabilized and thus acoustics are improved.

An engine includes a cylinder head including a first oil path and a second oil path. The cylinder head includes a valve gear including a first support and a second support that support a rocker shaft. The first support includes, on its outer surface, a first constriction located at an inlet of a connection-switching third oil path and connected to the first oil path, and a second constriction connected to the second oil path. The second support includes, on its outer surface, a third constriction connected to the first oil path, and a fourth constriction located at an inlet of a lubrication fourth oil path and connected to the second oil path.

Systems and methods for intermittent supply of lubricating oil to a tip of a rocker arm assembly. In one embodiment, a lubricating oil may be selectively to a tip of a rocker arm via oil channels aligned only during opening of a valve coupled to the tip.

There is provided a lubricating structure for a power transmission mechanism in which a crankshaft is coupled to a piston disposed in a cylinder bore and in which power is transmitted from the crankshaft to a camshaft. The lubricating structure includes: an idler gear that is configured to transmit power from the crankshaft to the camshaft; and an idler gear shaft that supports the idler gear via a bearing. One end portion of the idler gear shaft protrudes into the cylinder bore, and an oil passage configured to guide oil from the cylinder bore to the bearing is formed in the idler gear shaft.

A continuous variable valve duration apparatus may include a camshaft, a first and second cam portions, first and inside brackets transmitting rotation of the camshaft to the first and second cam portions respectively, a slider housing of which the first and second inside brackets are rotatably inserted thereto, cam caps of which each cam cap engaging portion is rotatably connected thereto, a connecting bracket connecting the cam caps and of which a guide opening for the guide protruded portion to be inserted thereto for guiding movement of the slider housing is formed thereto, a slider pin rotatably inserted into the first sliding opening and slidably inserted into the camshaft, a cam pin of which a cam opening for the cam to be slidably inserted thereto is formed and rotatably inserted into the second sliding opening and a controller selectively changing a position of the slider housing.

An engine variable valve train includes a cam changeover mechanism for axially shifting a cylindrical cam carrier fitted on and around a camshaft for changing over cam lobes on the cam carrier to cause one of the cam lobes to selectively act on an engine valve for engine operation. The cam changeover mechanism includes changeover pins adapted to be advanced and retracted for engagement with or disengagement from a lead groove formed around the cam carrier, and with a changeover driving shaft constituting a linear motion cam mechanism for causing the changeover pins to selectively advance to engage with the lead groove. The cam carrier, while rotating with the cam shaft, is axially shifted by the action of the lead groove having the changeover pins selectively engaged therewith, so that the cam lobes are changed over and one of the cam lobe is made to act on the engine valve.

A rocker arm assembly for an engine is configured to fit about a pivot shaft that extends along a central axis. The assembly includes an intermediate shaft configured to be rotatably disposed about the pivot shaft. A cam-side arm is pivotable about the central axis and is configured to be driven by a cam. A valve-side arm is pivotable about the central axis and relative to the cam-side arm, and is configured to convert rotation of the rocker arm assembly about the central axis into operation of an engine valve. An annular compressible fluid chamber is disposed between the intermediate shaft and the valve-side arm. When the cam-side arm and the intermediate shaft are engaged, pivoting of the cam-side arm compresses fluid within the chamber, causing corresponding pivoting of the valve-side arm and operation of the valve. The fluid provides hydraulic lash adjustment.

A cylinder head assembly for an internal combustion engine includes: a cylinder head defining a combustion chamber and having at least one opening communicating therewith; at least one port; at least one rotatable valve element disposed between the at least one opening and the at least one port; and at least one seal assembly disposed between the at least one rotatable valve element and the cylinder head, the seal assembly comprising a seal having a concave sealing face which conforms to a peripheral surface of the at least one valve element, a labyrinth seal disposed opposite the sealing face, and a resilient secondary seal disposed between the seal and the cylinder head.

A shaft assembly for a powertrain includes a shaft having a cavity extending at least partially from a first axial end to a second axial end of the shaft and opening at at least one of the first axial end and the second axial end. For example, the shaft may be a balance shaft, a camshaft, or a transmission shaft. A first core plug is disposed in the cavity. The shaft and the core plug may be the same material, or may be different materials. The shaft may have a first density, first cross-sectional area, or first area modulus, and the core plug may have a different second density, second cross sectional area, or second area modulus which may be less than the first density, the first cross-sectional area, or the first area modulus.