A combustion engine of a motorcycle has an engine rotary shaft extending in a vehicle widthwise direction. Incoming wind taken in from a front of a steering handle that is positioned in front of the combustion engine, is introduced through an air intake duct to the combustion engine. The air intake duct extends from the front of the steering handle to a rearward of a cylinder block so as to pass above a radiator and pass laterally of one side of the cylinder block.

An air intake duct, of a saddle-riding type vehicle, in which a flow velocity of an intake air is less likely to be reduced to enable prevention of reduction of an efficiency of a supercharger, is provided. The air intake duct of a motorcycle serves to supply incoming wind as the intake air to the supercharger for a combustion engine. The air intake duct has a passage area that is gradually reduced from an air intake port at a front portion toward a downstream portion connected to the supercharger at a rear portion.

Systems are disclosed to restrain movement of engine components in the event of a collision. A system may comprise an upper intake manifold; a cam cover; a shear catch located between the upper intake manifold and the cam cover; an upper component of the shear catch is arranged on the upper intake manifold; a lower component of the shear catch is arranged on the cam cover; and the upper component and the lower component are arranged opposite each other such that they engage when the upper intake manifold is subjected to shear forces. Variations to the size, arrangement, and shape of a shear catch are disclosed herein.

An air intake duct of a motorcycle forms an air intake passage for supplying an intake air to a supercharger. The air intake duct forms a curve portion and is connected to the supercharger. The air intake passage has a transverse cross-section which is shaped such that a dimension in an orthogonal direction that is orthogonal to a radial direction of the curve portion is gradually reduced from the center of the curve portion toward an outer side, in the radial direction, of the curve portion.

Methods and systems are provided for modifying intake flow for internal combustion engines. The turning vanes have inlet ends positioned substantially coplanar and spaced from respective runner openings and have surfaces that converge from the inlet ends toward outlet ends to be increasingly less obstructive to air moving across the plenum as measured in a direction away from the inlet end and toward the respective runner openings. The outlet ends being positioned within each respective runner opening.

An intake manifold for an internal combustion engine having: at least one runner having a front side and a back side defining a hollow interior space, and a port for receiving air into the hollow interior space, the back side having a plurality of cylinder holes aligning with cylinder head openings of the internal combustion engine and a plurality of bolt holes configured for receiving a plurality of bolts, each bolt having a bolt head and a bolt thread, the front side having a plurality of access holes aligning with the plurality of bolt holes, the access holes being configured to allow a user to access and secure the bolt head using a bolt-securing tool, the access holes being further configured to receive a seal, such that the intake manifold can be secured to the internal combustion engine with no portion of the bolt thread lying within the hollow interior space of the intake manifold thus preventing obstruction of air circulation through the hollow interior space.

The intake structure for an internal combustion engine includes: a collision surface configured to face an inlet of a carburetor; a deflecting surface configured to deflect a blowback flow, which is to diffuse after colliding against the collision surface, in one direction along the collision surface; a receiving surface configured to receive the blowback flow deflected by the deflecting surface; and a fuel-accumulating surface formed below the collision surface. A first clearance between an air-guiding direction distal end of the deflecting surface and the receiving surface is brought into communication to a downstream side of a filter of an air cleaner in a fresh-air intake direction so as to act as a main intake passage for fresh air.

The present invention provides an admission pipe structure for automobile air admission, wherein internal part in pipe body of admission pipe includes channel, admission hole and exit hole formed on two sides of the channel are installed with first sleeve connection part and second sleeve connection part, and first sleeve connection part and second sleeve connection part are respectively sleeved onto exit connector and admission connector of the admission manifold pipe such that buckling component can be set up in penetration into two through-grooves installed in outer surface of second sleeve connection part thereby using buckling component to block at ring-shaped groove for fixedly positioning. When compressed air coming from the central cooler enters into admission pipe, compressed air can be smoothly guided by arc-shaped channel in pipe body, and aluminum alloy materials in admission pipe itself can prevent damages caused by the high-speed airflow of the compressed air.

Disclosed is an intake manifold for a vehicle with a unified flow path. The intake manifold has a plurality of branch pipes connected to intake ports of cylinders of an automotive engine, and a surge tank unit connected to the branch pipes and having an external air inlet formed at a side to receive external air, in which the surge tank unit has a unified gas inlet formed at the external air inlet so that blow-by gas an fuel evaporation gas both flows inside. Accordingly, flow resistance when external air flows inside is reduced and freezing at the blow-by gas inlet is prevented in winter. Therefore, the amount of air mixture to be supplied into the cylinders is increased, whereby the volume efficiency of the cylinders is improved and engine torque is increased.

A valve body unit (11) in which a plurality of valve bodies (17) which open and close intake passages (10) are attached on a rotational shaft (16) is inserted into inner sides of housing passages (28) of a housing (12) and, thereafter, a holder (13) is mounted in the housing (12) to rotatably support the valve body unit (11). A flange (14) is fixed onto an upper surface of the housing (12) on the holder (13) by means of a vibration welding and the holder (13) is retained with this flange (14) and the housing (12).