A valve assembly for an engine includes a gas exchange valve, a valve guide, and a seal. The gas exchange valve includes a valve stem. The valve guide includes an outer surface having a stem seal retention surface disposed at a seal end thereof. The valve stem extends through the valve guide such that the valve is reciprocally movable over a range of travel along the longitudinal axis with respect thereto. The seal is mounted to the stem seal retention surface of the valve guide such that the seal is in running, sealing engagement with the valve stem. The stem seal retention surface includes a shoulder surface to help retain the seal.

The disclosure relates to a cylinder head for covering a combustion chamber of an internal combustion engine. The cylinder head comprises at least one material recess for heat isolation, which is formed in a main body of the cylinder head and is arranged between a fluid-guide channel and a cooling channel. The material recess can be produced e.g. directly during the shaping (e.g. casting or pressing) of the cylinder head and/or thereafter. For example, in the event that exhaust gas is guided through the fluid-guide channel, a significantly lower heat input occurs from the hot exhaust gas into the cooling fluid. In addition, the thermal decoupling via the material recess leads to the hot exhaust gas cooling to a lesser degree in the fluid-guide channel.

A valve assembly for an engine includes a gas exchange valve, a valve guide, and a seal. The gas exchange valve includes a valve stem. The valve guide includes an outer surface having a stem seal retention surface disposed at a seal end thereof. The valve stem extends through the valve guide such that the valve is reciprocally movable over a range of travel along the longitudinal axis with respect thereto. The seal is mounted to the stem seal retention surface of the valve guide such that the seal is in running, sealing engagement with the valve stem. The stem seal retention surface includes a shoulder surface to help retain the seal.

The disclosure relates to a cylinder head for covering a combustion chamber of an internal combustion engine. The cylinder head comprises at least one material recess for heat isolation, which is formed in a main body of the cylinder head and is arranged between a fluid-guide channel and a cooling channel. The material recess can be produced e.g. directly during the shaping (e.g. casting or pressing) of the cylinder head and/or thereafter. For example, in the event that exhaust gas is guided through the fluid-guide channel, a significantly lower heat input occurs from the hot exhaust gas into the cooling fluid. In addition, the thermal decoupling via the material recess leads to the hot exhaust gas cooling to a lesser degree in the fluid-guide channel.

An apparatus includes a valve and an actuator. The valve has a portion movably disposed within a valve pocket defined by a cylinder head of an engine. The valve is configured to move relative to the cylinder head a distance between a closed position and an opened position. The portion of the valve defines a flow opening that is in fluid communication with a cylinder of an engine when the valve is in the opened position. The actuator is configured to selectively vary the distance between the closed position and the opened position.

The cylinder head includes an intake port communicating with a cylinder of a cylinder block, a cylinder head main body having an exhaust port communicating with the cylinder, and a rocker housing integrally formed on the cylinder head main body and an inner side of which is defined as a valve-system accommodating space. The rocker housing includes a lateral wall having a lateral wall main body and a base end portion which extends along a lower end of the lateral wall main body, connects the lateral wall main body to the cylinder head main body, and has a thickness thicker than that of the lateral wall body. A flow path which extends in an extending direction of the base end portion and through which a fluid flow is formed in the base end portion.

An internal combustion engine has a cylinder head defining an exhaust valve guide bore with a side wall and an end wall, and an exhaust valve stem passage extending between an exhaust port and the end wall of the bore. A diameter of the passage is less than a diameter of the bore. An exhaust gas valve guide is positioned in the bore and spaced apart from the end wall to form an air gap therebetween.

A valve bridge system comprises a valve bridge configured to extend between at least two engine valves of an internal combustion engine. In one embodiment, a valve bridge guide is operatively connected to the valve bridge and configured to extend between at least two valve springs respectively corresponding to the at least two engine valves, the valve bridge guide defining a surface conforming to a valve spring of the at least two valve springs. In another embodiment, the valve bridge guide may comprise at least a first member maintained in a first fixed position relative to and at a predetermined distance from the valve bridge. In both embodiments, the valve bridge guide is configured to avoid contact with the valve bridge in a controlled state, but to permit contact with valve bridge to resist uncontrolled movement of the valve bridge.

A thermally compensated bore guide system for a shaft, the shaft configured to translate along a longitudinal axis, is provided. The thermally compensated bore guide system includes an inner bore defined within a component. The inner bore is configured to circumferentially surround at least a portion of the shaft, wherein the inner bore is non-linear in response to the thermally compensated bore guide system being at a first thermal condition and wherein the inner bore is configured to be linear and to define a bore axis substantially aligned with the longitudinal axis in response to the thermally compensated bore guide system being at a second thermal condition.

A cam carrier includes a pair of longitudinal frames provided parallel to an axial direction of a camshaft and a plurality of transversal frames connected to the pair of longitudinal frames to be spaced from each other and supporting the camshaft via cam bearings. A flexible structure suppressing amounts of change in a relative position and an inclined angle of the cam bearings relative to the camshaft due to a thermal expansion is provided on at least one of wall surfaces of the longitudinal frames, the wall surfaces being located between adjacent transversal frames.