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.

The invention provides a friction-welded structure assembly, comprising a first workpiece (10B), a second workpiece (10C) and a friction welding connecting part (10A). The lower side of the friction welding connecting part (10A) has a first friction welding junction interface (10H) which is in contact with a surface of the first workpiece (10B) and a second friction welding junction interface (11H) which is in contact with a surface of the second workpiece (10C). The friction welding connecting part (10A) is tightly pressed on both the first workpiece (10B) and the second workpiece (10C) which are positioned to be relatively corresponding and fixed to each other, while being moved under a pressure, so as to heat said first friction welding junction interface (10H) and said second friction welding junction interface (11H), then said friction welding connecting part (10A) is stopped under the pressure, and said first friction welding junction interface (10H) and said second friction welding junction interface (11H) become cool, thereby said first workpiece (10B) and said second workpiece (10C) are welded together to form the friction-welded structure assembly via said friction welding connecting part (10A). Also, The invention relates to a water-cooled internal combustion engine cylinder head using the friction-welded structure assembly described above.

An apparatus for intake and exhaust of an engine includes: an outer tube including an outer-tube close end, an outer-tube open end, and a first outer-tube aperture set including a first aperture and a first outer-tube aperture group, an inner tube positioned in the outer tube about a concentric line, including an inner-tube close end, an inner-tube open end, and a first inner-tube aperture set including a second aperture and a first inner-tube aperture group, in which the inner-tube close end is proximate to the outer-tube close end, and a shaft connected to the inner-tube open end for rotating the inner tube in the outer tube about the concentric line, in which when the inner tube rotates, the second aperture sweeps across a portion of the first aperture and the first inner-tube aperture group sweeps across a portion of the first outer-tube aperture group.

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.

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.

Provided herein, is a valve stem seal assembly having an elastomeric sealing element, a symmetrical retainer and a valve guide. The retainer has first portion, a second portion, a continuous stop formed between the first portion and the second portion, an inner surface and an outer surface. The valve guide has a top surface in contact with the elastomeric sealing element and a side surface in contact with the inner surface of the second portion of the retainer. The stop of the retainer projects radially inward and the retainer is symmetrical.

Provided herein, is a valve stem seal assembly having an elastomeric sealing element, a symmetrical retainer and a valve guide. The retainer has first portion, a second portion, a continuous stop formed between the first portion and the second portion, an inner surface and an outer surface. The valve guide has a top surface in contact with the elastomeric sealing element and a side surface in contact with the inner surface of the second portion of the retainer. The stop of the retainer projects radially inward and the retainer is symmetrical.

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 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.

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.