An intake device of an engine includes an air cleaner and an air flow sensor. The air cleaner includes an air filter, a cleaner case which forms a primary side space above the air filter and a secondary side space below the air filter, an inlet duct, and an outlet duct. The air flow sensor is fixed to the outlet duct. The cleaner case has a first side wall on which the inlet duct is mounted, and a second side wall which opposedly faces the first side wall. The air filter has a folded shape like bellows, and is held in the cleaner case. The second side wall has a deflecting portion which deflects air introduced from the inlet duct into a flow directed in an obliquely upward direction.

A work machine with an internal combustion engine is provided with an air inlet for receiving combustion air, wherein an air pre-cleaner is mounted in the inlet, a radiator, a cooling air fan and a debris removal means, configured to remove debris from a flow of air produced by the cooling air fan through the radiator, the removal means comprising a screen for collecting the debris, and an aspirator for aspirating the debris away from the screen, and a venturi element mounted downstream of the aspirator, and having an inlet portion, a throat portion and an outlet portion, wherein a duct is mounted between the engine air pre-cleaner and the throat portion, so that particles removed by the pre-cleaner flow towards the throat portion, and out through the outlet portion of the venturi element, together with the aspirated debris.

An air intake system for a work vehicle may generally include an intake duct defining a passageway for directing air in a flow direction through the system. The duct may also include a pre-cleaner slot defined between inner and outer surfaces of the duct and a support ledge extending circumferentially around at least a portion of an inner perimeter of the duct. The system may also include a pre-cleaner configured to be installed within the intake duct by inserting the pre-cleaner through the pre-cleaner slot in a direction extending generally perpendicular to the flow direction. In addition, the air intake system may include a cover configured to be coupled to the intake duct such that the cover extends over the pre-cleaner slot when the pre-cleaner is installed within the intake duct.

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.

An insert type expansion pipe-integrated air cleaner may include an air cleaner body having a filter chamber in which air is introduced from an outside, the filter chamber having a chamber space provided with a filter, the chamber space being covered by an air cleaner cover, an expansion pipe chamber connected to the filter chamber such that the introduced air is discharged from the expansion pipe chamber to the outside, and a female passage boss through which the introduced air passes from the filter chamber to the expansion pipe chamber by having a cross-sectional area smaller than a cross-sectional area of the expansion pipe chamber while the female passage boss divides the filter chamber and the expansion pipe chamber.

An air intake system for a work vehicle may generally include an intake duct defining a passageway for directing air in a flow direction through the system. The duct may also include a pre-cleaner slot defined between inner and outer surfaces of the duct and a support ledge extending circumferentially around at least a portion of an inner perimeter of the duct. The system may also include a pre-cleaner configured to be installed within the intake duct by inserting the pre-cleaner through the pre-cleaner slot in a direction extending generally perpendicular to the flow direction. In addition, the air intake system may include a cover configured to be coupled to the intake duct such that the cover extends over the pre-cleaner slot when the pre-cleaner is installed within the intake duct.

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.

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 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.