The present disclosure provides air intake ports and/or intake manifolds having an altered configuration to improve the efficiency of the air intake ports, intake manifolds, and by extension, the engine.

An intake duct structure of a motorcycle includes front forks disposed on both of right and left sides of a head pipe of a body frame and a main frame extending obliquely backward and downward from the head pipe, wherein the intake duct structure extends from a front end of the motorcycle toward the head pipe and is formed in such a manner that an interfered area where a rotational orbit of the front forks at a time of steering overlaps the intake duct structure is elastically deformable.

An intake device for an internal combustion engine configures a flow passage for intake air that is drawn into combustion chambers. The intake device includes an intake manifold configuring multiple runners that respectively distribute intake air to multiple cylinders, a surge tank including a cavity that is connected to the runners and defines a convergence portion, a throttle body incorporating a throttle valve, and a connection pipe connecting the surge tank and the throttle body and configuring a curved flow passage extending between the throttle body and the surge tank. The connection pipe includes a partition plate that divides the curved flow passage into a circumferentially inner flow passage and a circumferentially outer flow passage.

This air intake apparatus includes an air intake apparatus main body including a plurality of pieces bonded to each other along a split plane and an external gas passage formed inside the air intake apparatus main body by bonding the plurality of pieces to each other and including an external gas receiving port that directly receives external gas from a cylinder head and an external gas introduction port that introduces the external gas into a surge tank.

An air cleaner includes a housing and a filter element located within the housing. The housing includes a housing body and a fiber molding assembly. The housing body is formed by a plastic molding. The housing body has a wall located upstream of the filter element in an air flow direction and a recess, which is an inwardly recessed part of the wall. The fiber molding assembly is fixed to the wall, covers the recess from outside, and forms a part of a side wall of an inlet passage together with the recess. A communication hole for communication between the inlet passage and an interior of the housing body is formed in the recess.

A composite intake system and method of operating a rotary engine with variable intake manifold is provided. The system includes two switching valves in a secondary intake switching tube to change the intake method. When the rotary engine works under low speed conditions, it adopts the long intake manifold and the side-intake mode. When the rotary engine works under medium and high speed conditions, it uses the short intake manifold and the composite-intake mode. When the rotary engine works under ultra high speed conditions, it takes the short intake manifold and the peripheral-intake mode.

An intake manifold for an internal combustion engine includes a plurality of pieces joined with each other at a linearly extending joint. The pieces include a first piece and a second piece. The joint of the first piece and the second piece includes a first portion and a second portion excluding the first portion. The intake manifold is configured so that the first portion is opposed to a fuel system component of the internal combustion engine when the intake manifold is coupled to the internal combustion engine. A force required to separate the second piece from the first piece is referred to as a joining force. The joining force at the first portion is greater than the joining force at the second portion.

The present disclosure provides air intake ports and/or intake manifolds having an altered configuration to improve the efficiency of the air intake ports, intake manifolds, and by extension, the engine.

An engine intake air duct 1 has an intake portion 10 that extends along a first center line A, and a main duct portion 20 that extends along a second center line B. The main duct portion 20 has a merging portion 50, a discharge opening 21, and an extending portion 40 that extends from the merging portion 50 towards an opposite end to the discharge opening 20. A reflecting wall 41 is provided at an end face of the extending portion 40. The intake portion 10 merges with the main duct portion 20 in such a way that the first center line A is directed towards a downstream end of the main duct portion 20.

An air intake system for a commercial vehicle is disclosed. The air intake system includes a hood with at least one frontal intake opening through which air to be guided to an engine of the commercial vehicle can flow and with at least one plenum configured to receive air flowing through the intake opening. The air intake system further includes at least one air pipe having at least one air duct with at least one inlet opening through which the air flowing through the frontal intake opening can flow, the air duct arranged upstream of and fluidically connected with the plenum so as to guide the air to and into the plenum. The air intake system additionally includes at least one air filter and at least one silencer plate arranged upstream of the air filter, the silencer plate having a plurality of through openings through which the air can flow.