A combustion chamber structure in which an installation hole of the injector is improved to realize a rapid combustion and to reduce an unburned hydrocarbon. In the combustion chamber, a leading end of an injector is withdrawn from an upper end of an opening of an installation hole, and an additionally expanded surface area is formed on an upper inner surface of the installation hole from a portion to which the leading end of the injector is situated to an opening end of the installation hole. An angle between the additionally expanded surface area and a joint surface of a cylinder head is narrower than an angle between a center axis of the installation hole and the joint surface.

A combustion system includes a cylinder having a main chamber and a fuel injector positioned to inject fuel into the main chamber. A cylinder head is disposed at a top of the cylinder and forms an upper end of the main chamber. A prechamber adapter has a prechamber volume and a nozzle with a plurality of orifices for communication between the prechamber volume and an external environment. The prechamber adapter is threaded into a bore in the cylinder head and positioned to expose the nozzle to the main chamber. A spark plug is positioned within the prechamber adapter with a spark emitting end exposed to the prechamber volume. A piston movably disposed within the cylinder has a piston head forming a lower end of the main chamber. The piston head has a dome shape and a bowl formed in a top center of the dome shape.

An internal combustion engine has a cylinder head having a cylinder roof defining first and second intake ports. The cylinder head supports a spark plug positioned between a central axis of the cylinder roof and a fuel injector. A combustion pre-chamber is connected to and extends outwardly from the roof. The pre-chamber encapsulates the spark plug, and is offset from the central axis and positioned between the central axis and the first and second intake ports. The pre-chamber defines an inlet aperture and an outlet aperture positioned along a spray streamline of the fuel injector, and defines first and second side apertures. Each side aperture is positioned adjacent to a respective one of the first and second intake ports. A method of operating an engine having a pre-chamber is also provided.

An internal combustion engine has a cylinder head having a cylinder roof defining first and second intake ports. The cylinder head supports a spark plug positioned between a central axis of the cylinder roof and a fuel injector. A combustion pre-chamber is connected to and extends outwardly from the roof. The pre-chamber encapsulates the spark plug, and is offset from the central axis and positioned between the central axis and the first and second intake ports. The pre-chamber defines an inlet aperture and an outlet aperture positioned along a spray streamline of the fuel injector, and defines first and second side apertures. Each side aperture is positioned adjacent to a respective one of the first and second intake ports. A method of operating an engine having a pre-chamber is also provided.

The center injection engine is an engine equipped with the direct injector and an ignition apparatus at center of a ceiling part of the combustion chamber. The positive tumble flow flows from the intake port side to the exhaust port side on the ceiling part side of the combustion chamber, and also flows from the exhaust port side to the intake port side on the piston top part side. The ECU calculates the injection timing of the direct injector based on the engine load. In the first injection control, the higher the engine load becomes, the more the end crank angle is retarded.

An internal combustion engine for a motor vehicle has at least one cylinder for accommodating a piston and at least one pre-chamber spark plug allocated to the combustion chamber of the cylinder. The engine also has a pre-chamber, fluidically connected with the combustion chamber via several openings, in which at least one ignition spark is generable by the pre-chamber spark plug. At the induction stroke of the internal combustion engine, a rinsing of the pre-chamber with inlet gas including at least fuel and air occurs, so that, at the ignition point, an ignitable mixture of fuel and air is accommodated in the pre-chamber.

A combustion chamber structure for an internal combustion engine includes a recessed portion formed in a pent roof of a cylinder head on an upstream side of a tumble flow with respect to a spark plug.

In a spark-ignition internal combustion engine in which a protrusion including an intake-side inclined surface and an exhaust-side inclined surface is formed on a top surface of a piston, and a cavity is formed in the protrusion at a position associated with a spark plug, the intake-side inclined surface and the exhaust-side inclined surface are formed in such a way that a ratio of a length of the exhaust-side inclined surface with respect to a length of the intake-side inclined surface is 1.25 or larger in a cross section passing through a center axis of the piston and orthogonal to an axis direction of a crankshaft.

Methods and systems are provided for a fuel injector. In one example, a system may include a fuel injector having a half-annular venturi shaped outlet passage arranged between an outlet surface of the fuel injector and a half-cone shaped end portion of a nozzle. The nozzle may further comprise one or more air entraining features working in tandem with the half-annular venturi outlet passage to promote air-fuel mixing.

An internal combustion engine for a motor vehicle has at least one cylinder for accommodating a piston and at least one pre-chamber spark plug allocated to the combustion chamber of the cylinder. The engine also has a pre-chamber, fluidically connected with the combustion chamber via several openings, in which at least one ignition spark is generable by the pre-chamber spark plug. At the induction stroke of the internal combustion engine, a rinsing of the pre-chamber with inlet gas including at least fuel and air occurs, so that, at the ignition point, an ignitable mixture of fuel and air is accommodated in the pre-chamber.