An engine system is provided, which includes a cylinder block, a cylinder head, a piston, a main combustion chamber, a subchamber, an injector that injects fuel into the main combustion chamber, a main spark plug that ignites a mixture gas inside the main combustion chamber, a subspark plug that ignites the mixture gas inside the subchamber, and a controller electrically connected to the injector, the main spark plug and the subspark plug. When an engine load is above a given reference load, the controller controls, in a low-speed range below a given reference engine speed, the ignition devices so that the subignition is performed after the main ignition, and the controller controls, in a high-speed range exceeding the reference engine speed, the ignition devices so that only the subignition is performed, or so that the main ignition is performed at the same timing as or after the subignition.

An engine system is provided, which includes a cylinder block, a cylinder head, a piston, a main combustion chamber, a subchamber, an injector that injects fuel into the main combustion chamber, a main spark plug that ignites a mixture gas inside the main combustion chamber, a subspark plug that ignites the mixture gas inside the subchamber, and a controller electrically connected to the injector, the main spark plug and the subspark plug. When an engine load is above a given reference load, the controller controls, in a low-speed range below a given reference engine speed, the ignition devices so that the subignition is performed after the main ignition, and the controller controls, in a high-speed range exceeding the reference engine speed, the ignition devices so that only the subignition is performed, or so that the main ignition is performed at the same timing as or after the subignition.

Systems are provided for cooling combustion chamber gasses and increasing an amount of air entrained in an injected fuel spray. In one example, a cooling passage may be included in an internal combustion engine, the cooling passage positioned exterior to a cylinder bore of the engine and coupled to the cylinder bore at a first opening and a second opening. The cooling passage may receive gasses from the cylinder bore via the first opening, and may cool the gasses as they travel through the cooling passage before returning the gasses to the cylinder bore via the second opening.

An internal combustion engine is provided with a pre-chamber provided inside a main combustion chamber. The pre-chamber includes an ignition plug, and a casing provided to a ceiling part to cover the ignition plug, the casing isolating an internal space formed therein from the main combustion chamber. A tumble flow of a mixture gas is formed inside the main combustion chamber. A plurality of communicating holes are formed in the casing, and include a first communicating hole opening to an intake port side and a second communicating hole opening to an exhaust port side. The tumble flow flowing into the pre-chamber through the first communicating hole forms in the pre-chamber a vortex flowing in the opposite direction from the tumble flow. The main combustion chamber is provided with a structure configured to suppress a flow opposing the vortex flowing into the pre-chamber through the second communicating hole.

An internal combustion engine is provided with a pre-chamber provided inside a main combustion chamber. The pre-chamber includes an ignition plug, and a casing provided to a ceiling part to cover the ignition plug, the casing isolating an internal space formed therein from the main combustion chamber. A tumble flow of a mixture gas is formed inside the main combustion chamber. A plurality of communicating holes are formed in the casing, and include a first communicating hole opening to an intake port side and a second communicating hole opening to an exhaust port side. The tumble flow flowing into the pre-chamber through the first communicating hole forms in the pre-chamber a vortex flowing in the opposite direction from the tumble flow. The main combustion chamber is provided with a structure configured to suppress a flow opposing the vortex flowing into the pre-chamber through the second communicating hole.

An ignition device configured to ignite a fuel included in an air-fuel mixture supplied to a main combustion chamber of an internal combustion engine. The ignition device includes a partition member that forms a precombustion chamber that encloses an ignition point of a fuel. The partition member has a plurality of communicating holes communicating between the main combustion chamber and the precombustion chamber. The ignition device further includes a first interference member that protrudes inward from an inner surface of the partition member.

Methods and systems are provided for a pre-chamber. In one example, a pre-chamber comprises a plurality of venturi passages fluidly coupling it to a primary combustion chamber. The plurality of venturi passages may be configured to assist in drawing out residual gases from a previous combustion event during a current combustion event.

Systems are provided for cooling combustion chamber gasses and increasing an amount of air entrained in an injected fuel spray. In one example, a cooling passage may be included in an internal combustion engine, the cooling passage positioned exterior to a cylinder bore of the engine and coupled to the cylinder bore at a first opening and a second opening. The cooling passage may receive gasses from the cylinder bore via the first opening, and may cool the gasses as they travel through the cooling passage before returning the gasses to the cylinder bore via the second opening.

An ignition device configured to ignite a fuel included in an air-fuel mixture supplied to a main combustion chamber of an internal combustion engine. The ignition device includes a partition member that forms a precombustion chamber that encloses an ignition point of a fuel. The partition member has a plurality of communicating holes communicating between the main combustion chamber and the precombustion chamber. The ignition device further includes a first interference member that protrudes inward from an inner surface of the partition member.

Systems are provided for cooling combustion chamber gasses and increasing an amount of air entrained in an injected fuel spray. In one example, a cooling passage may be included in an internal combustion engine, the cooling passage positioned exterior to a cylinder bore of the engine and coupled to the cylinder bore at a first opening and a second opening. The cooling passage may receive gasses from the cylinder bore via the first opening, and may cool the gasses as they travel through the cooling passage before returning the gasses to the cylinder bore via the second opening.