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.

An air intake structure for an outboard engine wherein air which is taken in from an air intake opening provided in an engine cover for covering the upper part of the outboard engine is supplied to and sucked into a throttle body. The engine cover has an air intake opening which is open at the front of the outboard engine in the forward movement direction and a lid member which can open and close the air intake opening. A space which connects the air intake opening and the throttle body is provided separated from an engine room.

A resonator structure of a saddle-ride vehicle includes a head box that includes a head pipe defining a handlebar steering axis and that forms an intake passage through which air is guided from a front of the vehicle into an inside of the vehicle when the vehicle is traveling, an air cleaner box that is connected to the head box and allows the air guided through the intake passage to be taken into a power unit of the vehicle, and a resonator that forms a resonator chamber configured to reduce an air intake noise. The resonator chamber is formed continuous to the intake passage inside the head box.

A supercharger (15) is provided with a bypass pathway (17). A backflow preventer (20) is provided to the air intake pathway (8) between an airflow meter (10) and the bypass pathway (17). The backflow preventer (20) has: a casing (41) formed by locally expanding the cross-sectional area of the air intake pathway; and an inner tube (42) substantially constructing a duct for the mainstream of air intake. The inner tube (42) is supported by a flange portion (50) and the downstream end (42a) opens within the casing (41). During backflow when the bypass pathway (17) opens, a portion of the intake air enters into an exit-side space section (55), and the flow is prevented by the flange portion (50). Consequently, reverse flow is suppressed.

An air intake assembly for a vehicle includes an air intake configured to intake ambient air and a heater box configured to be positioned adjacent a component of an exhaust assembly of the vehicle. The heater box is configured to intake ambient air and heat the air by heat absorption from the component of the exhaust assembly. The air intake assembly is configured to selectively permit passage of ambient air from the air intake and heated air from the heater box toward the engine assembly. The air intake assembly may selectively permit passage of ambient air and heated air by use of a valve in communication with the air intake and the heater box and further in connection with an engine assembly of the vehicle, the valve configured to selectively permit passage of ambient air from the air intake and heated air from the heater box toward the engine assembly.

In an air intake device for motorcycle, an air cleaner having a front end formed with a main intake port is disposed between a pair of left and right main frame pieces forming a main frame. An introducing passage is formed within the main frame for capturing an incoming wind. An intake air introducing port of the introducing passage is provided at a location rearwardly of the main intake port in the main frame piece. An intake air discharge port is defined in an intermediate portion of a front portion of the main frame with respect to a motorcycle widthwise direction so as to open rearwardly and to be fluid connected with the main intake port. A sub intake port is provided in communication with the main intake port so as to introduce an intake air into the main intake port.

An off-road vehicle includes a frame, a vehicle cover, a prime mover assembly, an intake manifold, and an electrical control unit. An intake seat for the intake manifold is positioned above one of the rear side plates of the vehicle cover. An air filter for the intake manifold is positioned behind a rear baffle of the vehicle cover, which in turn is positioned behind the seat(s). The rear baffle defines an air filter access port, allowing the filter element in the air filter to be accessed and changed from within the cabin. Covers of the air filter access port and the air filter allow changing of the filter element without requiring any tools.

The present disclosure provides an air intake system for a power machine that can use a hollow section of a frame of the power machine to form part of an air intake path. The air intake system can include an air inlet coupled to an exterior panel of the power machine, a filter assembly including a filter enclosure and a filter element, a first air conduit coupled between the inlet and an enclosed compartment of a frame of the power machine, and a second air conduit coupled between the enclosed compartment and the filter enclosure. To reach the filter enclosure, the air entering the filter enclosure can travel along an air intake path that includes the air inlet, the first air conduit, the enclosed compartment, and the second air conduit.

An intake system includes an air cleaner that is disposed above an engine main body mounted on a vehicle body frame and connected to cylinder heads of the engine main body and an air introducing unit for introducing air into an air inlet provided at a lateral part of the air cleaner on at least one side thereof in a vehicle width direction. The air introducing unit has an opened front end and is connected to the air cleaner so as to bend an intake direction from a vehicle front-rear direction to the vehicle width direction. In the air inlet, a plurality of ribs partition the air inlet into plural sections.

In a cowl stay structure for a vehicle which is mounted on a front end part of a body frame having a pair of main frames extending longitudinally to the left and right, and which supports a cowling, a cowl stay supporting the cowling has a front opening which serves as a duct with a hollow structure designed to guide the air taken in from a front side of a vehicle body to an air cleaner box. The cowl stay is mounted on a front surface of a head pipe arranged on the front end of the body frame for establishing a flow path of the front opening with said head pipe opening. A headlight configured to irradiate an area in front of a vehicle with light is placed inside the cowl stay. Such a cowl stay structure has reduced size and weight, and it supports multiple parts.