An engine includes a combustion chamber, a cylinder head, an intake valve, a partition wall plate, and a tumble valve. The cylinder head includes an intake port that communicates with the combustion chamber. The intake valve includes a head configured to open and close an open end of the intake port. The partition wall plate partitions the intake port into first and second passages. The tumble valve is configured to open and close either one of the first passage and the second passage. A cross sectional shape of the partition wall plate is defined on a basis of a shape of a gap that is surrounded by a contour of the head and a contour of the open end, as viewed in a reference direction. The reference direction is a direction from a reference point in the intake port to a gap between the open end and the head.

Methods and systems are provided for introducing a charge motion to a cylinder via a protrusion system coupled to an intake port of an engine. In one example, a system may include positioning a tongue from inside a spring-loaded casing to extend into air intake runner, generating desired tumble and swirl along an intake port proximate to an engine cylinder.

The present disclosure provides an apparatus for improving engine air flow including: a combination recess which is formed at an intake port of a cylinder head and is extended toward a combustion chamber along an air flow path at a position combined with an intake manifold; a fixing body which is fit-inserted to and combined to the combination recess; and a plate an end of which is combined to the fixing body on the flow path of the intake port and which guides the air flow flowing into the intake port.

A cylinder head for an internal-combustion engine includes, for each cylinder of the engine, at least one intake duct extending from an inlet located at a lateral face of the head down to an outlet cylindrical mouth and an intake valve associated with each intake duct. The surface of the intake duct has a longitudinal projection for deflecting the flow of air that flows through the intake duct. The projection is configured to provide a deflection of the air flow towards the two sides of the valve stem, so as to substantially reduce the quantity of air that hits the valve stem directly. The projection extends down to the outlet cylindrical mouth, so as to hinder a flow of air through an angular sector of the cross-sectional area of the outlet mouth which angular sector faces towards the lateral face of the cylinder head.

An air intake structure for a vehicle engine includes: a variable flap rotatably provided in an intake air passage so as to control a cross-sectional area of intake air flow; a port plate provided to a downstream of the variable flap, and generating displacement in cooperation with the variable flap; a driving unit supplying a driving force for generating displacement of both the variable flap and the port plate; and a controller determining a rotation angle of the variable flap in accordance with an operating range of an engine, and controlling the rotation angle of the variable flap by driving the driving unit.

An engine includes a combustion chamber, a cylinder head, an intake valve, a partition wall plate, and a tumble valve. The cylinder head includes an intake port that communicates with the combustion chamber. The intake valve includes a head configured to open and close an open end of the intake port. The partition wall plate partitions the intake port into first and second passages. The tumble valve is configured to open and close either one of the first passage and the second passage. A cross sectional shape of the partition wall plate is defined on a basis of a shape of a gap that is surrounded by a contour of the head and a contour of the open end, as viewed in a reference direction. The reference direction is a direction from a reference point in the intake port to a gap between the open end and the head.

A purge system includes a prechamber in fluid communication with a main chamber of an engine cylinder, and a port divider having a dividing wall that creates a plurality of passages within an intake port of the main chamber. The purge system further includes an outer tube fixed between a first passage of the port divider and the prechamber, and an inner tube rotatable within the outer tube. The outer tube includes apertures along a wall of the outer tube that fluidly connect the outer tube with the first passage of the port divider and with the prechamber. The inner tube includes slots along a wall of the inner tube that to fluidly connect the first passage of the port divider and the prechamber when the slots align with the apertures.

A cylinder head (1) disclosed herein includes a cylinder head main body (10) having an intake port (3) communicating with a combustion chamber (2) of an engine; and an insulation member (20) being arranged at an inner side of the intake port (3), made of resin, and formed into an annular shape. A step part (14) is formed at a downstream side of the insulation member (20) in a flow direction of intake air in the intake port (3) such that the intake port (3) has a cross section perpendicular to the flow direction at the downstream side smaller than a cross section perpendicular to the flow direction at an upstream side of the flow direction; and an annular seal member (21) that seals a space between the insulation member (20) and the step part (14) is arranged between the insulation member (20) and the step part (14).

A cylinder head (1) disclosed herein includes a cylinder head main body (10) having an intake port (3) communicating with a combustion chamber (2) of an engine; and an insulation member (20) being arranged at an inner side of the intake port (3), made of resin, and formed into an annular shape. A step part (14) is formed at a downstream side of the insulation member (20) in a flow direction of intake air in the intake port (3) such that the intake port (3) has a cross section perpendicular to the flow direction at the downstream side smaller than a cross section perpendicular to the flow direction at an upstream side of the flow direction; and an annular seal member (21) that seals a space between the insulation member (20) and the step part (14) is arranged between the insulation member (20) and the step part (14).

An intake device of an internal combustion engine includes a partition, a control valve, and a third passage. The partition divides an interior of an intake pipe that couples with a combustion chamber into a first passage and a second passage. The control valve is capable of opening and closing the first passage. The third passage opens at or near a coupling site between the partition and the intake pipe on an inner face of the second passage. The third passage is configured to be capable of sucking in at least a part of a boundary layer produced at or near the coupling site by a vapor flowing through the second passage in a state in which the control valve is working in a direction of closing the first passage.