Intake holes at the opposite ends are opened and closed by first intake valves. The middle intake hole is opened and closed by a second intake valve. A control device includes an intake variable valve device. First branch channels are connected to the intake holes and produce a normal tumble flow. A second branch channel is configured such that the flow rate of intake air passing through the middle intake hole is relatively greater on the side closer to the outer periphery of the combustion chamber. Where increasing the flow coefficient is given a higher priority, a three-valve drive mode is selected. Where the strength of the normal tumble flow is enhanced, a two-valve drive mode is selected. Where production of the normal tumble flow is reduced, a one-valve drive mode is selected.

An internal combustion engine comprises a fuel injector 31, a spark plug 16, a piston 14 having a cavity 91, a swirl control device 95, and a control system 70. The cavity is formed so as to change in distance from the fuel injector to a side wall surface of the cavity, in the circumferential direction. The system performs ignition assist control for successively performing injections of main fuel and ignition assist fuel, makes an air-fuel mixture formed by the ignition assist fuel burn by flame propagation by the spark plug, and makes the remaining fuel burn by pre-mix compression self-ignition. The system controls the swirl control device during the ignition assist control so that when the engine load is high, the fuel sprayed heads toward parts of the side wall surface which are short in distances from the fuel injector.

The present disclosure provides an engine structure for a vehicle. The engine structure includes: an intake port, a port plate provided in the single flow path of the intake port, and an injector. The port plate is longitudinally parallel to the flow path of the intake port so as to divide the flow path of the intake port into upper and lower flow paths, and the port plate includes an extension portion formed on part of a downstream end of the port plate such that the extension portion of the downstream end of the port plate extends longer than other portion of the downstream end of the port plate. In particular, the injector is provided in the intake port, and sprays fuel beyond the extension portion so as to inhibit the fuel from adhering to the port plate.

Provided is an internal combustion engine including a sparkplug disposed in the vicinity of the center portion of an upper wall surface of a combustion chamber. Tumble flow generated during lean burn operation is controlled such that the tumble flow shape changes according to the engine rotation speed between a first tumble shape (usual tumble shape) in which the flow direction of a gas around the sparkplug at the time of ignition is direction from an intake valve side toward an exhaust valve side in a latter half of a compression stroke, and a second tumble shape ( tumble shape) in which the flow direction of the gas is reversed in the latter half of the compression stroke from the direction from the intake valve side toward the exhaust valve side to the direction from the exhaust valve side toward the intake valve side.

An intake air control device includes: an intake air flow channel that includes an air flow pipe furcated into multiple branch flow channels that communicate with the same combustion chamber; an intake air valve provided to the air flow pipe to adjust an opening degree of the air flow pipe in accordance with a rotation angle thereof; a swirl valve provided to any one of the multiple branch flow channels to adjust an opening degree of the branch flow channel in accordance with a rotation angle thereof; and a cam plate that is rotatable and has a first cam slot. The intake air valve has a first protrusion inserted in the first cam slot. The first cam slot has a first rotation section within which the first protrusion slides and rotates about the rotational shaft of the intake air valve in response to rotation of the cam plate.

An intake air control device includes: an intake air flow channel that includes an air flow pipe furcated into multiple branch flow channels that communicate with the same combustion chamber; an intake air valve provided to the air flow pipe to adjust an opening degree of the air flow pipe in accordance with a rotation angle thereof; a swirl valve provided to any one of the multiple branch flow channels to adjust an opening degree of the branch flow channel in accordance with a rotation angle thereof; and a cam plate that is rotatable and has a first cam slot. The intake air valve has a first protrusion inserted in the first cam slot. The first cam slot has a first rotation section within which the first protrusion slides and rotates about the rotational shaft of the intake air valve in response to rotation of the cam plate.

An intake air control device includes: an intake air flow channel that includes an air flow pipe furcated into multiple branch flow channels that communicate with the same combustion chamber; an intake air valve provided to the air flow pipe to adjust an opening degree of the air flow pipe in accordance with a rotation angle thereof; a swirl valve provided to any one of the multiple branch flow channels to adjust an opening degree of the branch flow channel in accordance with a rotation angle thereof; and a cam plate that is rotatable and has a first cam slot. The intake air valve has a first protrusion inserted in the first cam slot. The first cam slot has a first rotation section within which the first protrusion slides and rotates about the rotational shaft of the intake air valve in response to rotation of the cam plate.

An intake air control device includes: an intake air flow channel that includes an air flow pipe furcated into multiple branch flow channels that communicate with the same combustion chamber; an intake air valve provided to the air flow pipe to adjust an opening degree of the air flow pipe in accordance with a rotation angle thereof; a swirl valve provided to any one of the multiple branch flow channels to adjust an opening degree of the branch flow channel in accordance with a rotation angle thereof; and a cam plate that is rotatable and has a first cam slot. The intake air valve has a first protrusion inserted in the first cam slot. The first cam slot has a first rotation section within which the first protrusion slides and rotates about the rotational shaft of the intake air valve in response to rotation of the cam plate.

A combustion system for use with one or more cylinder bores of an internal combustion engine includes at least one cylinder head defining first and second intake ports in fluid communication with the one or more cylinder bores. A flap is adjustably connected to the at least one cylinder head. The flap includes a first flap portion cooperating with the first intake port extending from an arm and a second flap portion cooperating with the second intake port extending from the arm and disposed adjacent the first flap portion. A controller in electrical communication with an actuator monitors the condition of the engine and actuates the flap to position the first and second flap portions between first and second positions to create a first combustion condition and a second combustion condition.

An intake device is provide for drawing in fresh gas and feeding the same to an internal combustion engine with internal combustion, wherein the intake device is suited for the formation of a fresh gas vortex in a combustion chamber of the internal combustion engine. The intake device includes a first manifold section, from which all first parts of fresh gas line groups branch off to a fresh gas outlet end, and a second manifold section, from which all second parts of the fresh gas line groups branch off to the fresh gas outlet end, which are fluidically separated from each other from the separation point to the fresh gas outlet end. A vortex throttle assembly is provided in a first manifold section and the amount throttle device is provided in the second manifold section.