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.

Methods and systems are provided for controlling an airflow to an engine via a primary air induction pathway or a secondary air induction pathway, where the secondary air induction pathway routes the airflow to the engine via a deployable snorkel system. Thus, in one example, a method comprises routing the airflow to the engine solely via the primary air induction pathway by commanding open a first air inlet valve and commanding closed a second air inlet valve, and responsive to a request to switch the routing, commanding closed the first air inlet valve and commanding open the second air inlet valve. In this way, the snorkel system may selectively be used in response to requests from a vehicle operator.

Methods and systems are provided for controlling an airflow to an engine via a primary air induction pathway or a secondary air induction pathway, where the secondary air induction pathway routes the airflow to the engine via a deployable snorkel system. Thus, in one example, a method comprises routing the airflow to the engine solely via the primary air induction pathway by commanding open a first air inlet valve and commanding closed a second air inlet valve, and responsive to a request to switch the routing, commanding closed the first air inlet valve and commanding open the second air inlet valve. In this way, the snorkel system may selectively be used in response to requests from a vehicle operator.

A low emission submersible engine is part of a multipurpose aquatic device, such as an aquatic craft or an electrical generator. A propulsion system having a propeller is coupled to the submersible engine to produce a swimmer propulsion machine and a generator is attached to the engine to produce an electrical generator. The submersible engine receives air from a snorkel that extends up above a water line. The aquatic device has a fuel reservoir which may receive liquid fuel or may receive a fuel cylinder. Floatation chambers keep the aquatic device afloat with the engine submerged. The exhaust assembly and exhaust ports from the engine may also be submerged and the exhaust ports may provide additional thrust. A propulsion system housing integrates the drive shaft and propeller, clutch coupler, exhaust conduits and water flow conduits and is detachably attachable to the engine.

An ECU is covered by a fuel tank and an upper cover which are vehicle body trim parts along with the upper surface of an air cleaner box. A frame holding duct is connected to the air cleaner box, the frame holding duct extends vehicle forward from the air cleaner box, is connected to a body frame, and is arranged inside an upper cowl, the upper cowl covering the front portion of the body frame, a branching portion of the intake air is arranged in the frame holding duct, and a branching passage extending from the branching portion is disposed between the upper surface of the air cleaner box and the fuel tank and the upper cover and is positioned in front of the ECU.

In an air cleaner, an air cleaner case having an upper opening which opens upward is formed. The air cleaner case is formed of a front wall, a rear fender, and right and left side covers. The upper opening is closed by a seat. A sound absorbing member is bonded to a bottom plate of the seat and housed in an air cleaner space. The intake noise in the air cleaner is absorbed by the sound absorbing member.

An air intake structure of a saddle riding vehicle is disposed in the saddle riding vehicle in which a frame including a left and right pair of main frames and an air box are disposed, an intake passage is disposed between the main frames and an outer periphery of the head tube, and the intake passage includes: a front side intake duct that extends forward; and a rear side intake duct that couples the air box to the head tube. In the air intake structure of the saddle riding vehicle, the rear side intake duct is a separate body from the air box, the air box has a front surface on which an opening inserted through the rear side intake duct is provided, and the rear side intake duct is coupled to an intake passage from an inside of the air box through the opening.

This outboard machine has: a V-type engine (engine) in which a plurality of cylinders are arranged in a V-shape when viewed in a plan view; and a cover that covers the engine. The engine has a plurality of intake ports that form pairs in a V-shape inside the plurality of cylinders in a plan view and a concave space is formed between the plurality of intake ports. The cover has therein an intake path that guides air to the intake port, and is also provided with, at a position that is adjacent to the intake path and enters the concave space, a silencer that attenuates the sound during intake.

This outboard machine has: a V-type engine (engine) in which a plurality of cylinders are arranged in a V-shape when viewed in a plan view; and a cover that covers the engine. The engine has a plurality of intake ports that form pairs in a V-shape inside the plurality of cylinders in a plan view and a concave space is formed between the plurality of intake ports. The cover has therein an intake path that guides air to the intake port, and is also provided with, at a position that is adjacent to the intake path and enters the concave space, a silencer that attenuates the sound during intake.

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.