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.

An engine with a rotating valve assembly is disclosed. The valve assembly including a housing having an internal cavity, an open top, and an open bottom, the open top and open bottom being in fluid communication with the internal cavity; a valve barrel positioned in the internal cavity and adapted for rotation therein, the valve barrel having an annular peripheral surface and an aperture extending transversely therethrough communicating with the peripheral surface on opposite sides; a first seal assembly positioned in the open top and a second seal assembly positioned in the open bottom, the first and second seal assemblies each include a seal having a sealing surface in mating engagement with the peripheral surface and an aperture extending therethrough.

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.

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.

A manufacturing method for an engine includes: preparing, as a preparing step, a cylinder head having a surface on which a ceiling surface of a combustion chamber is formed; forming, as a film formation step, a thermal insulation film on the ceiling surface; measuring, as a measurement step, a volume of the thermal insulation film; and selecting, as a selection step, a rank for an engine valve to be used in combination with the ceiling surface so as to correspond to an amount of difference of a measured volume of the thermal insulation film from a designed value of a volume of the thermal insulation film, the rank being selected from a plurality of ranks set in correspondence with thicknesses of umbrella portions of engine valves.

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.

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.

In a saddle-ride type vehicle in which a cylinder head of a single-cylinder engine main unit has a front wall and a rear wall, an exhaust system being connected to the front wall and an intake system being connected to the rear wall, a joining surface of the cylinder head to a head cover is formed on a plane crossing a cylinder axis, the plane being inclined downward toward a front. Rotation axes of camshafts are arranged on the plane. An axis of a valve stem of a throttle valve is arranged on the plane. A curve cover curved so as to cover driven sprockets fixed to the camshafts is formed on one side in a vehicle width direction of the head cover. A drum housing box housing a throttle drum fixed to one end of the valve stem is arranged close to the curve cover.

An internal combustion engine including: a cylinder block in which a plurality of cylinders are formed; and a cylinder head formed in conjunction with the cylinder block into one body to form a plurality of combustion chambers, wherein an upper surface of the cylinder head is divided, along a direction in which the plurality of cylinders are arranged, into first regions that are regions that overlap the combustion chambers as viewed from an axial direction of the cylinders and a second region that is a region located between two of the first regions adjacent to each other, and at least either an intake-side cam journal or an exhaust-side cam journal is disposed in the second region.

A gaseous fuel engine includes an engine housing having a cylinder block with a combustion cylinder therein, and an engine head including an intake port, an exhaust port, a fuel port, and an igniter bore, each extending to a fire deck. The gaseous fuel engine includes a fuel admission valve movable to close and open the fuel port. A non-axisymmetric clearance is defined between an inner port surface and the fuel admission valve and directionally biases a flow of gaseous fuel from the fuel port. Related methodology is also disclosed.