A work machine, such as a skid steer loader or a compact track loader, includes a directional air intake assembly with a directional cap positioned on an intake pipe for selectively drawing ambient air into an internal combustion engine. A cooling vent ejects air heated by a rear-mounted engine upwardly into the atmosphere. Extending higher than and adjacent to the cooling vent, the directional cap has an elongated head that blocks ingress to the intake pipe other than through an opening at a face of the cap. Selectively positioning and angling the opening between a side of the loader and an edge of the cooling vent avoids taking in debris from near the wheels or tracks, avoids taking in heated air from the cooling vent, and takes advantage of negative pressure caused by the updraft from the cooling vent to remove particulates, resulting in cleaner air for the engine at close to ambient temperature.

A watercraft propulsion system includes a propulsion unit to be driven by an engine. The engine includes a cylinder block, an air intake channel, an exhaust channel, a supercharging device, and a fuel injector. The watercraft propulsion system includes the engine, the propulsion unit to be driven by the engine, a rotation speed sensor to detect a rotation speed of the engine, an air intake pressure sensor to detect an air intake pressure of the engine, and a controller. The controller is configured or programmed to compute a command fuel injection amount so that the engine performs a combustion operation at an air/fuel ratio in a lean-burn range (lean-combustion range) according to the rotation speed detected by the rotation speed sensor and the air intake pressure detected by the air intake pressure sensor, and to drive the fuel injector based on the computed command fuel injection amount.

An air intake system for a vehicle has a conduit having an internal wall forming an air passage. A deflector is disposed within the air passage. A restricting structure is disposed within the air passage between the deflector and a conduit outlet. The restricting structure defines at least in part an opening substantially laterally aligned with the deflector. The restricting structure has a lateral wall disposed downstream of the deflector and extending within the air passage. The lateral wall has a front surface generally facing a conduit inlet, and a plurality of surface-increasing features provided on the front surface. Each of the surface-increasing features has a length of at least 1 mm measured from the front surface in a direction normal thereto. An air intake system having a collector connected to the deflector and positioned to collect at least some moisture from air flowing past the deflector is also described.

An intake plenum is for a marine engine, the marine engine having first and second throttle devices for controlling flow of intake air to the marine engine. The intake plenum has an airbox providing an expansion volume, first and second inlets that convey the intake air in parallel to the expansion volume, first and second outlets that convey the intake air in parallel from the expansion volume to the first and second throttle devices, and first and second Helmholtz-style attenuator devices located at the first and second outlets, respectively. Together the first and second inlets, expansion volume, and first and second Helmholtz-style attenuator devices are configured to attenuate different frequencies of sound emanating from the marine engine via the first and second outlets.

An intake system of an engine is provided, including a first passage provided to an engine bay, for leading fresh air to the engine, a second passage branched from a branching part at an intermediate location of the first passage, and extending toward a cabin, and an intake noise increasing device provided to the second passage, and configured to increase intake pressure in response to an intake air pressure wave. The intake noise increasing device has a cylindrical bellows part configured to expand and contract in a cylindrical axis direction, and a vibrating membrane formed integrally with the bellows part to close a first opening of the bellows part. The second passage has an introducing passage section connected to a second opening of the bellows part, and extending toward the branching part, and the introducing passage section is disposed so as to be lowered while separating from the bellows part.

A snow bike intake, snow bike conversion kit, and/or air intake pod snow bike conversion kit, having: a throttle body coupling; an elbow-shaped intake duct coupled to the throttle body, a pre-filter body cage coupled at a rear thereof to the duct, and a textile cover fitting about the cage. The duct has an interior angle between 40 and 60 degrees. There are a plurality of flat (interior and exterior surface) sensor mounts disposed about and through the duct, including an octagonal ring of sensor mounts circumscribing the duct body. The cage has a flat front opposite the rear that has a larger diameter than a diameter of the rear. The duct has an aspect ratio of exterior angle length to diameter no greater than 3.5:1 and the duct and prefilter combined has an aspect ratio of exterior angle length to diameter no greater than 4.5:1.

A V-type multi-cylinder engine including a pair of banks, includes: an intake member forming an intake passage through which air is guided from outside; a pair of throttles each configured to regulate an amount of the air sucked into each of the pair of banks through the intake passage; and one single temperature sensor configured to detect a temperature of the air in the intake passage. The intake member includes a pair of openings downstream in a flowing direction of the air. Each the pair of throttles is connected to each of the pair of openings. The temperature sensor is disposed between the pair of openings.

There is provided an air cleaner configured to be disposed inside a vehicle body frame, the air cleaner including: an air cleaner case in which an intake chamber is formed; an air filter disposed in the intake chamber; an inlet tube configured to take in air to the intake chamber; and an outlet tube configured to send out the air from the intake chamber. The inlet tube extends in a front-rear direction. The inlet tube has a bottom wall curved downward in a side view to form a concave curved portion below a discharge port of the inlet tube. The concave curved portion is formed with a drain hole.

A vessel propulsion apparatus includes an engine and a propulsion unit to be driven by the engine. The engine includes a cylinder head including a combustion chamber and a pair of intake openings to communicate with the combustion chamber. The engine further includes a pair of intake ports respectively including a pair of downstream portions respectively connected to the pair of intake openings. A distance between the pair of downstream portions decreases toward the pair of intake openings.

Combustion air intake ports are provided on left and right side faces of an upper part of an engine cover. An outer louver is disposed to confront the combustion air intake port, and an inner louver is disposed inward of the outer louver at a predetermined interval to face the outer louver. The combustion air received from the combustion air intake port passes through the outer louver and the inner louver and is guided to the engine unit from the guide hole. In this case, a splash of water is dispersed in the outer louver, and a large-sized water droplet falls down due to its self-weight before the combustion air reaches the inner louver, so that a small-sized water droplet can be collected and removed using inertial impaction at the inner louver. Therefore, it is possible to effectively separate water.