An air intake circuit for a heat engine is intended to be positioned between an air compression element and at least an upper portion of a hollow combustion chamber in a cylinder head of the engine. The air intake circuit includes the cylinder head, an air intake manifold, and at least one air intake duct. The circuit also includes at least one concave receptacle turned towards the outside of the engine, housed in a cavity of the cylinder head, and connected to a tubular element pushed into the at least one air intake duct.

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.

In this air intake apparatus for an internal combustion engine, an external gas passage includes external gas introduction nozzles that introduce external gas into air intake pipes, and a length of each of the external gas introduction nozzles in a direction in which the external gas introduction nozzles extend is larger than an equivalent diameter of an exit of each of the external gas introduction nozzles.

An intake system of a vehicle includes: an intake manifold having a plurality of runners for supplying intake gas to a multiple-cylinder engine; a surge tank cover coupled to the intake manifold to define a surge tank communicating with the plurality of runners via the intake manifold; an intake air inlet formed on the intake manifold as a passage through which intake air flows into the surge tank; an intake outlet formed on the intake manifold as a passage through which intake air sequentially passing through the intake air inlet, the surge tank, and the plurality of runners, and is discharged to the engine as the intake gas; a gas inlet which is a passage formed on the intake manifold and selectively receiving recirculation exhaust gas; and a gas chamber formed on the intake manifold so that the recirculation exhaust gas flows in through the gas inlet.

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 elastic connecting support for arrangement between a combustion engine and an air filter of a handheld work apparatus is disclosed. The connecting support has a first channel for largely fuel-free air and a second channel for a fuel/air mixture. The connecting support is realized as a single piece, and has, on a first side, an engine connecting flange, at which the first and second channel end, for connection to the combustion engine. The first channel has a first peripheral wall and the second channel has a second peripheral wall. The first peripheral wall and the second peripheral wall are arranged at a distance in relation to each other in a longitudinal section of the connecting support. The channels extend from the first side to a second side of the connecting support. On the second side, the first channel and the second channel end at a common connecting flange.

An intake port may include a short port and a long port. The short port may include a main extension portion extending from an intake air inlet; a main inclined portion inclined at a predetermined angle from the main extension portion toward a center of a cylinder; a main vertical portion which bends downward toward the cylinder from the main inclined portion; and a main intake air outlet formed at an end portion of the main vertical portion. The long port may include an auxiliary extension portion extending from the main extension portion; an auxiliary vertical portion bending downward toward the cylinder from the auxiliary extension portion; and a partition wall portion between the auxiliary extension portion and the auxiliary vertical portion, which allows the intake air to flow in a direction opposite to a direction in which the intake air introduced into the cylinder through the short port flows.

A first downstream part of an intake manifold has a first downstream passage configured to communicate with an intake port of a first cylinder head. A second downstream part of the intake manifold has a second downstream passage configured to communicate with an intake port of a second cylinder head. An upstream part is coupled to the first downstream part and the second downstream part. The upstream part is arranged upstream from the first and second downstream parts in the flow direction of intake air and has a first upstream passage and a second upstream passage. The material of the first downstream part and the material of the second downstream part both have higher rigidity than the material of the upstream part.

There is provided an internal combustion engine in which respective combustion states of cylinders can be uniformized with a simple configuration. A central axis (CL1) of a connecting part (7) of one of air supply ports (5) inclines with a predetermined inclination angle in a direction away from an air supply inlet (3) with respect to a y direction orthogonal to an x direction in which an air supply manifold 1 extends, and an inclination angle of the connecting part (7) of the one of the air supply ports (5) is larger than an inclination angle of the connecting part (7) of other air supply ports (5) located on a side closer to the air supply inlet (3) than the one of the air supply ports (5).