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 partial forced induction system is provided that has one or more combustion engine cylinders with each engine cylinder having a first and a second intake valve with individual ports. A source of forced induction in fluid communication with the one or more combustion engine cylinders and urging air into the one or more combustion engine cylinders. A naturally aspirated intake manifold path connecting to each of the first intake valves at each of said one or more engine cylinders. A forced induction intake manifold path connects the source of forced induction to each of said second intake valves at each of the one or more engine cylinders.

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.

A partial forced induction system is provided that has one or more combustion engine cylinders with each engine cylinder having a first and a second intake valve with individual ports. A source of forced induction in fluid communication with the one or more combustion engine cylinders and urging air into the one or more combustion engine cylinders. A naturally aspirated intake manifold path connecting to each of the first intake valves at each of said one or more engine cylinders. A forced induction intake manifold path connects the source of forced induction to each of said second intake valves at each of the one or more engine cylinders.

A water supply control apparatus is applied to an in-cylinder injection type internal combustion engine (1) which injects fuel from a central area (2a) in a cylinder (2). The water supply control apparatus comprises a condensed water supply mechanism (22) where a state of supplying condensed water (CW) into the cylinder (2) is changeable between a first supply state that the condensed water (CW) is supplied to a whole inside of the cylinder (2) and a second supply state that the condensed water (CW) is limitedly supplied to the central area (2a) of the cylinder (2). In the second supply state, the supply amount of condensed water supplied into the cylinder (2) in the second supply state is less than the supply amount of condensed water supplied into the cylinder (2) in the first supply state.

A condensed-water supply control apparatus is applied to an in-cylinder injection type internal combustion engine (1) where fuel is injected from a central area (2a) lying in a cylinder (2). The condensed-water supply control apparatus comprises: a storage tank (21) storing condensed water (CW) generated in the internal combustion engine (1); and a condensed-water supply mechanism (22) which is capable of supplying the condensed water stored in the storage tank (21) into the cylinder (2), and also controlling the supply amount of condensed water (CW) to a central area (2a) and the supply amount of condensed water (CW) to a peripheral area (2b), and in a low load state of the internal combustion engine (1), opens an adding water valve (27) and closes an adding water valve (26) so that the condensed water (CW) is supplied limitedly to the peripheral area (2b) of the cylinder (2).

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 method of reducing NO.sub.x in the exhaust of a diesel engine having at least one combustion chamber by introducing NH.sub.3 into the diesel engine prior to a combustion event, at least some of the NH.sub.3 injected reducing the amount of NO.sub.x in the exhaust of the diesel engine, whereby the exhaust will contain an amount of NO.sub.x that is less than if no injection of NH.sub.3 was used, and will also contain an amount of NH.sub.3 that is less than the amount injected into the diesel engine, the rest of the NH.sub.3 being consumed during the combustion event and the reduction of NH.sub.3.

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.