An intake port structure has a sleeve disposed along an inner peripheral surface of an intake port of a cylinder head and made of a material having a thermal conductivity lower than a material of the cylinder head. When a cross-sectional area of an intake passage on an upstream side in an vicinity of a mating surface between the cylinder head and the intake passage toward the cylinder head is defined as a mating surface upstream area, and an intake port cross-sectional area of the intake port, which excludes the sleeve, on a downstream side in the vicinity is defined as a mating surface downstream area, the mating surface downstream area is greater than the mating surface upstream area, and the intake port cross-sectional area at a place where the sleeve is disposed in the intake port is gradually reduced from the mating surface toward a combustion chamber side.

An air cleaner of a vehicle for filtering particulate matter from air supplied through an intake includes a case with an outlet. The case surrounds the air cleaner, which further includes two connecting tubes each having a first end attached to the throttle body of the vehicle and a second end disposed in the outlet in the case of the air cleaner. A funnel is inserted into the second end of each of the connecting tubes. Clean air from the air cleaner is proved to the engine through the connecting tubes.

An air cleaner of a vehicle for filtering particulate matter from air supplied through an intake includes a case with an outlet. The case surrounds the air cleaner, which further includes two connecting tubes each having a first end disposed through the outlet and a second end located in the case. A funnel is clamped to the second end of each of the connecting tubes. A bracket is attached to each of the funnels for rigidly mounting the funnels inside the case of the air cleaner. The first end of each of the connecting tubes is further connected to the throttle body of the vehicle to provide clean air from the air cleaner to the engine.

An exhaust manifold comprises a plurality of exhaust intake conduits structured to be fluidly coupled to an engine and receive exhaust gas from a corresponding cylinder of the engine. At least one exhaust intake conduit provides a reduction in an exhaust intake conduit cross-sectional area from an inlet to an outlet. A plurality of bends are each defined by a respective one of the exhaust intake conduit outlets. An exhaust intake manifold is fluidly coupled to the exhaust intake manifold and defines an exhaust intake manifold flow axis. Each of the plurality of bends is shaped so as to define an angle of approach of exhaust gas flowing therethrough. A first angle of approach of the first bend relative to the exhaust intake manifold flow axis is smaller than a second angle of approach of an inner second bend.

Disclosed herein is an actuator for an intake manifold, wherein the actuator may include: a housing having a negative pressure space; an operating unit operated by the pressure of air introduced into and discharged from the negative pressure space, and rotating the variable valve; an exhaust flow path connected to an external negative pressure supply source; an intake flow path receiving external air which raises the pressure of the negative pressure space; a spool hole formed in the housing so as to communicate with the exhaust flow path and the intake flow path; an air entry and exit flow path formed in the housing so as to communicate with the negative pressure space and the spool hole; a valve body selectively opening/closing the exhaust flow path and the intake flow path; and a solenoid unit operating the valve body.

A throttle body adapter connects a throttle body and an air intake manifold spaced from the throttle body in a marine engine. The throttle body adapter has an air passage having an inlet and an outlet of different shapes. The throttle body adapter has threaded openings which allow a fuse box, an electronic control module, a hose fitting and a mounting bracket for a beauty cover to be mounted to the throttle body adapter with threaded fasteners. The throttle body adapter further comprises a threaded opening adapted to receive an air inlet temperature sensor.

To provide a compact intake manifold which can easily and reliably hold the flame arrester (25) to the base member, the base member (21) having the flame arrester (25) incorporated therein has the recessed body portion (31) and the annular fitting holding portion (32) for fitting the flame arrester (25) in the axial direction. The fitting holding portion (32) includes an abutment surface (32a) and a fitting inner wall peripheral surface (32b). The flame arrester (25) includes a flame suppressing structure (26), an outer cylinder body (27) surrounding the flame suppression structure (26), and an elastic holder member (51) which covers the outer peripheral surface and both end faces of the outer cylindrical body (27). The elastic holder member (51) has an outer peripheral fitting portion (52) fitted to the fitting holding portion (32) while being held in close contact with the outer cylindrical body (27).

To provide an intake manifold which can reliably prevent the step from being formed in the inner wall surface of the intake passage (15) while having provided therein the fitting holding portion (32) for fitting and holding the flame arrester (25) in the axial direction, the intake manifold (10) includes a base member (21), a cover member (22) and a flame arrester (25) having a flame suppression structure. Between the flame arrester (25) and the radical stepped surface (31b) of the recessed body portion (31) is provided a retaining rectifying member (23) that prevents the flame arrester (25) from coming off with respect to the fitting holding portion (32) and forms a third inner peripheral surface (23a) continuous without a step from an opening portion on the other end side (25b) of the flame arrester (25) to the base side second inner wall surface (31c).

A two-wheeled vehicle includes a frame assembly having a front end and a rear end extending along a longitudinally-extending centerline, a front ground-engaging member operably coupled to the front end of the frame assembly at a front rotational axis, and a rear ground-engaging member operably coupled to the rear end of the frame assembly at a rear rotational axis. The vehicle further includes an engine supported by the frame assembly and operably coupled to the front and rear ground-engaging members, and the engine includes a throttle body assembly. Additionally, the vehicle includes an air intake assembly fluidly coupled to the engine and including an airbox and a mounting plate having a first channel and a second channel. The first and second channels are configured to align with the throttle body assembly. The mounting plate is configured to couple the airbox to the throttle body assembly.

A volumetric expander for increasing the air intake between a throttle body and an intake manifold includes a throttle body neck, a manifold adapter, and a throttle body adapter. The manifold adapter and the throttle body adapter are positioned opposite each other along a intake tube of the throttle body neck, wherein a first air channel traversing along the intake tube is aligned with a first intake opening of both the manifold adapter and the throttle body adapter. Additionally, a second air channel is aligned with a second intake opening of both the manifold adapter and the throttle body adapter. A manifold gasket is positioned into the manifold adapter and creates an air tight seal between the manifold adapter and the intake manifold, while a throttle body gasket is positioned into the throttle body adapter and creates an air tight seal between the throttle body adapter and the throttle body.