A piston for a lean-burn gasoline engine comprising a cylinder, an air inlet and an exhaust outlet, wherein the air inlet and the exhaust outlet are arranged about a longitudinal axis of the cylinder. The piston comprises a central axis which is aligned with the longitudinal axis of the cylinder. The working surface (79) of the piston (454) comprises a central dished portion and an outer sloped portion surrounded by an outer sloped portion. A first pair of valve pockets (444a, 444b) are located in the outer sloped portion on a first side of the dished portion, and a second pair of valve pockets (445a, 445b) located in the outer sloped portion on the second side of the dished portion. The dished portion comprises a ramp protuberance located between the first pair of valve pockets. The dished portion is configured to promote tumble of air flow into the cylinder from the air inlet, in use during an intake stroke of the piston.

A cylinder structure of a diesel engine in which diesel fuel is ignited by a self-ignition manner includes a cylinder including a cylinder body in which a combustion chamber is formed and a cylinder head covering an upper portion of the cylinder body, at least one intake valve included in an intake port formed in the cylinder head, at least one exhaust valve included in an exhaust port formed in the cylinder head, and a diesel injector mounted at the center of the cylinder head and injecting diesel fuel. A lower surface of the cylinder head may be formed in a pent roof shape.

A combustion chamber structure for a spark-ignition internal combustion engine includes a combustion chamber, an ignition plug, and a guide portion. The combustion chamber is configured to produce tumble flow that swirls in an axial direction of a cylinder. The ignition plug is disposed in a central portion of an upper wall of the combustion chamber. The guide portion protrudes from the upper wall of the combustion chamber, and is configured to guide airflow passing through the central portion of the combustion chamber in an intake-exhaust direction of the combustion chamber while dispersing the airflow around the guide portion.

A fuel injection control device controls a spark-ignition engine of an intra-cylindrical direct fuel injection type. The engine includes a fuel injection valve configured to directly inject a fuel to an interior of a cylinder, and a spark plug configured to ignite, by a spark, an air-fuel mixture inside the cylinder. When the injected fuel collides with a portion in a predetermined low-temperature state, the fuel is injected while changing a fuel injection condition under predetermined operating conditions so as to restrain a fuel spray from keeping colliding with the same position continuously.

Diesel engines modified to be fuelled with gaseous fuels experience problems with knocking and pre-ignition, limiting the compression ratio and efficiency of the engine. A new combustion chamber for a gaseous fuelled internal combustion engine, in which the combustion chamber is defined by a cylinder head, a bore in a cylinder block and a piston reciprocating in the bore, comprises a piston portion of the combustion chamber defined by a recessed shape in a piston crown; and a head portion of the combustion chamber defined by a recessed surface in the cylinder head. A ratio between the piston portion of combustion chamber volume and the head portion of combustion chamber volume is in a range of 0.7 to 1.3.

A fuel injection control device controls a spark-ignition engine of an intra-cylindrical direct fuel injection type. The engine includes a fuel injection valve configured to directly inject a fuel to an interior of a cylinder, and a spark plug configured to ignite, by a spark, an air-fuel mixture inside the cylinder. When the injected fuel collides with a portion in a predetermined low-temperature state, the fuel is injected while changing a fuel injection condition under predetermined operating conditions so as to restrain a fuel spray from keeping colliding with the same position continuously.

A gasoline-diesel complex combustion engine may include a cylinder including a cylinder body in which a combustion chamber is formed to generate a driving power by combusting a gasoline fuel and a diesel fuel and a cylinder head formed to cover an upper portion of the cylinder body, a pair of intake ports formed in the cylinder head, a pair of exhaust ports formed in the cylinder head, a diesel injector disposed in a center of the cylinder head, a pair of spark plugs disposed on opposite sides of the diesel injector, a first intake pipe and a second intake pipe mounted in the intake ports, an exhaust pipe mounted in the exhaust ports, a pair of intake valves disposed in the first and second intake pipes, and a gasoline injector disposed in the first and second intake pipes to inject the gasoline fuel into the combustion chamber.

The present disclosure relates to an internal combustion engine comprising at least one cylinder, four charge-exchange points per cylinder, wherein a first and a second charge-exchange port are each an inlet port, and wherein a third and a fourth charge-exchange port are each an outlet port, also comprising one spark plug and one prechamber spark plug per each cylinder.