Intake ports include a second port configured such that a flow rate of flowing gas is adjusted via a swirl control valve. When a surge tank is viewed in a cylinder axis direction, first and second branched passages are connected with a space being interposed therebetween in a cylinder array direction, and are connected to the surge tank on extension lines, each of which extends from an upstream end portion of an independent passage connected to the second port to an opposite side of each cylinder.

Provided is a thermally insulated insert member and an engine having the thermally insulated insert member. Thermally insulated insert member is disposed in an intake port of a cylinder head of the engine. The thermally insulated insert member includes a guide member that guides a flow of intake air flowing in t he intake port; and a thermally insulative support member with a shape that can be fitted within the intake port. The guide member is formed of a metal and is supported in the intake port via the thermally insulative support member.

Provided is a thermally insulated insert member and an engine having the thermally insulated insert member. Thermally insulated insert member is disposed in an intake port of a cylinder head of the engine. The thermally insulated insert member includes a guide member that guides a flow of intake air flowing in t he intake port; and a thermally insulative support member with a shape that can be fitted within the intake port. The guide member is formed of a metal and is supported in the intake port via the thermally insulative support member.

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.

An intake device of an internal combustion engine includes a partition, a gap, and a projecting part. The partition divides an interior of an intake pipe into a first passage and a second passage. The gap exists at a boundary between an inner face of the intake pipe and the partition or in the partition, and couples the first passage and the second passage. The projecting part is disposed near the gap on a face of the partition or the inner face of the intake pipe that forms an inner face of the first passage, or on a face of the partition or the inner face of the intake pipe that forms an inner face of the second passage.

Methods and systems are provided for operating a split exhaust engine system that provides blowthrough air and exhaust gas recirculation to an intake passage via a first exhaust manifold and exhaust gas to an exhaust passage via a second exhaust manifold. In one example, in response to flowing the exhaust gas recirculation and blowthrough air from the first exhaust manifold to the intake passage via a first set of exhaust valves, a first set of swirl valves coupled upstream of a first set of intake valves may be adjusted to at least partially block intake air flow to the first set of intake valves. Each engine cylinder may include two intake valves including one of the first set of intake valves and two exhaust valves.

The internal combustion engine comprises a swirl control valve able to change a strength of a swirl generated in a combustion chamber; a load sensor for detecting an engine load; and a control device for controlling the swirl control valve. The control device controls the swirl control valve, when the engine load detected by the load sensor is lower than a predetermined load, so that the swirl ratio is higher when a suction intake gas amount is increasing, compared to when it is decreasing.

An internal combustion engine includes a crankcase including a crankshaft and at least one cylinder coupled to the crankcase. The at least one cylinder has an intake port and defines an internal combustion chamber. The engine further includes a throttle body assembly with a throttle valve coupled to the intake port of the at least one cylinder and a throttle plate. Additionally, the engine includes a supplementary air inlet fluidly coupled to the intake port and spaced apart from the throttle valve. The supplementary air inlet is configured to receive a flow of air from a location downstream of the throttle plate when the throttle plate is in a fully closed position and the flow of air is directed into the combustion chamber through the intake port for combustion therein.

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 internal combustion engine comprises a swirl control valve able to change a strength of a swirl generated in a combustion chamber; a load sensor for detecting an engine load; and a control device for controlling the swirl control valve. The control device controls the swirl control valve, when the engine load detected by the load sensor is lower than a predetermined load, so that the swirl ratio is higher when a suction intake gas amount is increasing, compared to when it is decreasing.