A compression ignited combustion engine has at least one cylinder and first and second gas intake ports in a cylinder head restricting a combustion chamber. One gas intake passage leads to the two ports and is widened in a Y-shaped end influencing gas entering each port into a tangential flow in opposite direction with respect to the flow into the other port. The first intake port is designed to allow gas entering this port to continue said tangential flow so as to enter the combustion chamber in a swirl in a first rotation direction, whereas the second intake port is designed to guide gas entering this port to also enter the combustion chamber in a swirl in said first rotation direction.

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.

An apparatus that controls a swirl ratio in a diesel engine for a motor vehicle includes a first intake port that directs a first airflow into a combustion chamber, and a second intake port that directs a second airflow into the combustion chamber. The first and second intake ports are arranged to direct the first airflow and the second airflow such that a desired swirl ratio is achieved in the combustion chamber.

An engine structure configured to a control swirl in a diesel engine combustion chamber and a diesel engine assembly including the engine structure defines first and second intake ports and a connecting passage connecting the first and second intake ports. The first intake port is in fluid communication with the combustion chamber and configured to direct a first intake airflow into the combustion chamber, and the second intake port is in fluid communication with the combustion chamber and configured to direct a second intake airflow into the combustion chamber. The connecting passage connects the first intake port to the second intake port and is defined by the engine structure outside of the combustion chamber.

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.

A compression ignited combustion engine has at least one cylinder and first and second gas intake ports in a cylinder head restricting a combustion chamber. One gas intake passage leads to the two ports and is widened in a Y-shaped end influencing gas entering each port into a tangential flow in opposite direction with respect to the flow into the other port. The first intake port is designed to allow gas entering this port to continue said tangential flow so as to enter the combustion chamber in a swirl in a first rotation direction, whereas the second intake port is designed to guide gas entering this port to also enter the combustion chamber in a swirl in said first rotation direction.

An air intake port (10) for a lean-burn gasoline engine (110) comprises an air inlet (14), two air outlets (15a, 15b), and an air channel connecting the air inlet (14) to the two air outlets (15a, 15b) and comprising an upstream common duct (11) and two downstream port legs (12a, 12b), the two downstream port legs (12a, 12b) branching off from the common duct (11) at a bifurcation point (13). A total cross section of the air intake port (10) gradually decreases between the air inlet (14) and the two air outlets (15a, 15b). A gradient of decrease of the total cross section is locally reduced in a region adjacent the bifurcation point (13).

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 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 air intake device includes: an air intake valve provided so as to change intake air by rotation of a rotation shaft; an actuator which is a driving source for rotating and driving the rotation shaft of the air intake valve; a first link member rotatable by a predetermined operation angle about the rotation shaft; a second link member rotatably connected to the first link member; a connection member which connects the first link member and the second link member so as to be rotatable to each other; and a biasing member whose one side end is engaged to the first link member and whose other side end is engaged to the second link member or the connection member to bias the first link member and the second link member or the connection member so that rattling between the first link member and the second link member is suppressed.