A three valve cylinder head assembly includes a cylinder head mountable to an internal combustion engine. The cylinder head has a combustion chamber which has a sloped roof such that the combustion chamber has a wedge shape. Additionally, the cylinder head has an exhaust port and a pair of intake ports. An exhaust valve is movably integrated into the cylinder head for opening and closing the exhaust port. A pair of intake valves is each movably integrated into the cylinder head for opening and closing a respective one of the intake ports. A cam shaft is rotatably disposed on the cylinder head and the cam shaft engages the exhaust valve and each of the intake valves. The cam shaft sequentially opens the exhaust valve and each of the intake valves as the cam shaft rotates for supporting operation of the internal combustion engine.

A variable cam timing system in an engine is provided. The variable cam timing system includes a camshaft receiving rotational input from a crankshaft. The camshaft includes a valve cam rotationally actuating a valve coupled to a cylinder and a null cam actuating a null follower including a null spring exerting a return force on the null cam during interaction between the null cam and the null follower, where the null follower is independent from the cylinder.

A variable cam timing system in an engine is provided. The variable cam timing system includes a camshaft receiving rotational input from a crankshaft. The camshaft includes a valve cam rotationally actuating a valve coupled to a cylinder and a null cam actuating a null follower including a null spring exerting a return force on the null cam during interaction between the null cam and the null follower, where the null follower is independent from the cylinder.

A camshaft phaser arrangement configured for a concentric camshaft assembly having an inner camshaft and an outer camshaft is provided. The camshaft phaser arrangement can facilitate independent phasing of intake and exhaust valves. The camshaft phaser arrangement includes a first driven wheel and a second driven wheel, both configured to be driven by a driving wheel. A first camshaft phaser is connected to the first driven wheel and configured to be connected to either the inner or outer camshaft. A second camshaft phaser is connected to the second driven wheel and configured to be connected to either the inner or outer camshaft which is not connected to the first driven wheel. A motion transfer assembly can connect the second camshaft phaser to the concentric camshaft assembly. One or both of the camshaft phasers can be an electric camshaft phaser or a hydraulic camshaft phaser.

Check valve assembly for a tensioner with a U-shaped retainer defining a cavity and having at least one retainer opening and axially extending flanges; a moveable member received within the cavity; a check valve spring received within the cavity and between the moveable member and the retainer; a valve seat having axially extending flanges and defining a seat opening nesting within the cavity of the retainer, and a check valve vent washer. The check valve vent washer has an outer circumference with a plurality of spaced apart legs and openings; and an inner circumference in fluid communication with the outer circumference through the openings, the inner circumference has a concentric interior well connecting the plurality of openings to a vent reservoir, a central ring defining a central hole in communication with the internal reservoir, the central ring comprising a vent groove connecting the vent reservoir to the central hole.

There is provided a pulley system for a crankshaft, the pulley system including: a crankshaft rotatably supported by a cylinder block; a crank pulley connected to one end of the crankshaft, and having an accessory belt wrapped the crank pulley; a crank timing pulley connected to one end of the crankshaft, and having a timing belt wrapped around the crank timing pulley; a timing belt cover mounted on a front wall of the cylinder block, and having an opening through which a portion of the crank pulley passes; and a stopper structure restricting the accessory belt from moving into an inner space of the timing belt cover. In particular, the timing belt and the crank timing pulley are placed in the inner space of the timing belt cover, and the crank pulley is placed in an outer space of the timing belt cover.

A housing is rotatable synchronously with a crankshaft of an engine. A plurality of external teeth arrangements is respectively shaped into a ring form and is formed integrally with the housing in one piece and is configured to mesh with a plurality of chains, respectively, each of which is wound around the crankshaft or a sprocket that is rotatable. A cam plate is connected to a camshaft of the engine and is rotatable relative to the housing. A plurality of stoppers is formed integrally with the housing in one piece while the stoppers are configured to limit relative rotation between the housing and the cam plate within a predetermined range when the stoppers contact the cam plate. Each stopper is placed at a position, at which the stopper does not overlap with any of the external teeth arrangements in a view taken in an axial direction of the housing.

A rotor for a hydraulic camshaft adjuster. The rotor includes a first rotor element and a second rotor element. At least one of the rotor elements has oil channels separated from each other by radially arranged elevations. Each elevation of the first rotor element has a first joining profile and the second rotor element forms a complementary-shaped second joining profile corresponding to the position of each first joining profile, wherein the first and the second joining profile engage with each other in the assembled rotor. The first joining profile of the first rotor element has a notch and an elevation and the second joining profile of the second rotor element has a notch and an elevation formed in such a way that prior to the joining of the two rotor elements, a height of the elevation of the second joining profile, which engages in a notch of the first joining profile, is less than a height of the notch of the first joining profile, and a height of the elevation of the first joining profile, which engages in a notch-of the second joining profile, is less than a height of the notch of the second joining profile.

The present utility model discloses a portable four-stroke engine, comprising: an engine body, a flywheel and an oil storage tank, wherein an air valve distribution chamber and a crank shaft chamber are arranged in the engine; a crank shaft is arranged in the crank shaft chamber, and is connected to the flywheel; the oil storage tank is arranged on the engine body, located above the flywheel, and configured to store lubricating oil; a cam and a rocker arm mechanism are arranged in the air valve distribution chamber; and the cam is configured to drive the rocker arm mechanism. The portable four-stroke engine provided by the present utility model has a small volume and therefore has better operation performance.

Provided is a belt cover of an internal combustion engine having ease of attachment and detachment and sealability.

A belt cover structure for an internal combustion engine includes an oil pump case OP and a lower cover 9 that cover a timing belt TB, and a side mount bracket 8 that is adjacent to an upper side of the lower cover 9 and is held by a cylinder block CB. Mating surfaces 96c and 86c that are aligned with each other are respectively formed on the lower cover 9 and the side mount bracket 8. A lower seal member 41 is disposed on the mating surface 96c, and the mating surface 86c is configured to cover the mating surface 96c from the outside. The lower cover 9 and the side mount bracket 8 are fixed in a state where the mating surface 86c of the side mount bracket 8 is pressed against the mating surface 96c of the lower cover 9 via the seal member 41.