A cover covering an engine and an intake duct for introducing fresh air outside an engine room into a combustion chamber of the engine are provided in the engine room. The cover includes a top face cover portion covering the engine from above, and a side face cover portion covering the engine from the lateral side. The intake duct is disposed so as to be continuous to a side edge of the side face cover portion such that the intake duct covers the engine from the lateral side together with the side face cover portion.

An apparatus and a method are provided for a multiple inlet air box to communicate an airstream through an air filter to an air intake duct of an internal combustion engine of a vehicle. The multiple inlet air box is comprised of a housing that supports the air filter within an interior of the housing. A mount portion within the housing fixedly receives a base of the air filter. Multiple air inlets couple with corresponding air inlet ports of the vehicle to direct the airstream into the multiple inlet air box. A duct directs the airstream from the multiple air inlets to the interior of the housing. A conduit communicates the airstream from an interior of the air filter to the air intake duct of the internal combustion engine.

An air intake structure for introducing an intake air into an engine includes: a first air intake passage fluidly connected with an air outlet; a second air intake passage branched off from the first air intake passage and having a passage length greater than that of the first air intake passage; and an open-close valve provided in the first air intake passage. The second air intake passage has a portion thereof bent to allow the flow of intake air in one direction reverse to that of the air flowing a different portion thereof. The first air intake passage, the second air intake passage and the open-close valve are provided within an air cleaner.

An assembly for a snowmobile includes an airbox having a plenum for coupling to a throttle body of an engine and two branches defining openings for air intake. A storage box is mounted between the two branches and defines area for receiving a console. The airbox is part of a hood of the vehicle and includes an opening over a storage box. The disclosure also includes a ribbed bumper mount with a latch assembly for securing the hood.

An apparatus and a method are provided for a multiple inlet air box to communicate an airstream through an air filter to an air intake duct of an internal combustion engine of a vehicle. The multiple inlet air box is comprised of a housing that supports the air filter within an interior of the housing. A mount portion within the housing fixedly receives a base of the air filter. Multiple air inlets couple with corresponding air inlet ports of the vehicle to direct the airstream into the multiple inlet air box. A duct directs the airstream from the multiple air inlets to the interior of the housing. A conduit communicates the airstream from an interior of the air filter to the air intake duct of the internal combustion engine.

A precleaner for engine air filtration includes a housing, separator tubes for inducing cyclonic airflow, and channel arrangements in airflow communication with the separator tubes to channel airflow and particulates toward a dust outlet arrangement.

A method for manufacturing a waterproof felt duct may include (a) laminating a waterproof film on one side of a first nonwoven fabric and laminating a second nonwoven fabric on the waterproof film laminated on the first nonwoven fabric to form a laminated body; (b) forming a waterproof felt base material by thermally adhering the laminated body; (c) cutting the waterproof felt base material into a desired shape; (d) molding a duct while surrounding the waterproof felt base material cut into the desired shape around the external surface of a molding jig having a worm gear shape; (e) heat-treating the molded duct; (f) cooling the heat-treated duct; and (g) ejecting the cooled duct from the molding jig.

A spin tube assembly for an engine air cleaner is provided. The spin tube assembly includes a housing, a spin tube panel, a plurality of spin tubes and at least one constrictor. The plurality of spin tubes are supported on the spin tube panel in parallel relation to one another. Each spin tube of the plurality of spin tubes includes a helical element causing air entering the spin tube to rotate such that particles within the air are moved by centrifugal action outwardly against a wall of the spin tube. At least one spin tube of the plurality of spin tubes has a constrictor upstream from the helical element thereof. The constrictor causes a localized restriction of air entering the at least one spin tube compared to the spin tubes without constrictors. Methods of use and configuration are also provided.

An intake apparatus for an internal combustion engine may include: an air duct coupled to a front of an engine compartment, and having a first inlet and a second inlet formed on an outer side of the air duct and a passage space defined therein; and an integrated valve coupled to the air duct to selectively open and close the first inlet or the second inlet.

Examples of the present disclosure describe systems and methods for determining an estimated ambient air temperature in an environment in which a vehicle is operating. The estimated ambient air temperature may be compared to an ambient temperature sensor value. The comparison may be used to determine whether an ambient air temperature sensor of the vehicle is functioning properly or if an error notification or fault code should be triggered.