Methods and systems are provided for purging a pre-chamber. In one example, a system is provided with a combustion chamber formed by a cylinder head coupled to a cylinder block and a pre-chamber in fluidic communication with the combustion chamber. The system is also provided with a purge port coupled to the pre-chamber and structured to flow purge air into the pre-chamber, where the flow of the purge air is driven by operation a purge pump and a piston disposed within the combustion chamber.

An inlet manifold includes a main inlet oriented along a first direction and a pilot inlet oriented along a second direction perpendicular to the first direction. A wye passage includes an inlet branch in fluid communication with the main inlet. The inlet manifold also includes a first main passage in fluid communication with a first outlet branch of the wye passage and a second main passage in fluid communication with a second outlet branch of the wye passage. The first main passage extends generally along the first direction between the wye passage and a first main outlet. The second main passage extends generally along the first direction between the wye passage and a second main outlet. The inlet manifold also includes a pilot passage in fluid communication with the pilot inlet. The pilot passage extends generally along the first direction between the pilot inlet and a pilot outlet.

A method of operating an internal combustion engine having pilot subchambers communicating with main combustion chambers, the internal combustion engine configured in use to deliver a main fuel injection of a maximum quantity of fuel to the main combustion chambers when the internal combustion engine is operated at maximum load. The method includes delivering a pilot fuel injection of at most 10% of the maximum quantity to the pilot subchambers, igniting the pilot fuel injection within the pilot subchambers, directing the ignited fuel from the pilot subchambers to the main combustion chambers, and delivering a main fuel injection of a main quantity of fuel to at least one of the main combustion chambers receiving the ignited fuel, with the main quantity being at most 10% of the maximum quantity.

In certain embodiments, a two-stage precombustion chamber may be used to reduce engine NOx levels, with fueled precombustion chambers, while maintaining comparable engine power output and thermal efficiency. One or more fuel admission points may be located in either the first prechamber stage or the second prechamber stage. A more efficient overall combustion characterized by low levels of NOx formation may be achieved by a two-stage precombustion chamber system while generating very high energy flame jets emerging from the second prechamber stage into the main combustion chamber. A first prechamber stage may be substantially smaller than a second prechamber stage. The volumes and aspect ratios of the two prechamber stages, along with the location of the electrodes within the first stage prechamber, the holes patterns, angles and the separate fueling, may be selected to create a distribution of fuel concentration that is substantially higher in the first stage prechamber compared to the second prechamber stage.

A gas engine includes: a main combustion chamber; and a precombustion chamber including an ignition plug disposed in a precombustion-chamber upper section and a throat formed in a precombustion-chamber lower section, the throat including a nozzle hole, configured such that mixed gas flows into the throat of the precombustion chamber via the nozzle hole from the main combustion chamber in a compression stroke. The nozzle hole has an opening edge portion on a throat side, the opening edge portion including a curved surface portion formed along a peripheral edge of the opening edge portion. The throat extends linearly along a center axis of the precombustion chamber. A ratio of a length of the throat to an inner diameter of the throat is not smaller than 1.6 and not greater than 2.6, and a value obtained by multiplying a ratio of the inner diameter of the throat to a radius of the curved surface portion by a ratio of the inner diameter of the throat to a precombustion chamber upper portion diameter is not smaller than 18.

A cylinder head comprising a cavity for receiving a pre-chamber gas valve, wherein an opening extending substantially or completely around the pre-chamber gas valve forms an annular passage with a wall of the cavity, that surrounds the pre-chamber gas valve, wherein the annular passage is connected to at least one gas feed passage for supplying the pre-chamber gas valve with combustion gas, wherein the annular passage with at least one inclined gas passage is connected with the lower cavity of the pre-chamber gas valve.

An internal combustion engine includes a piston reciprocally moving in at least one cylinder. An intake valve controls the supply of fresh air into a power chamber defined within the cylinder by the moving piston. An ancillary chamber is fluidly connected with the power chamber via a flow-through valve. An auxiliary piston is reciprocally movable in the ancillary chamber and determines the volume of the ancillary chamber. A fuel supply valve introduces fuel into the ancillary chamber. The flow-through valve, the fuel supply valve and the auxiliary piston are moved such that no fresh air from the power chamber goes into the ancillary chamber and such that fuel is expelled from the ancillary chamber into the power chamber via the flow-through valve for combustion with fresh air compressed in the power chamber.

An internal combustion engine including an igniter disposed at least partially within an aperture defined in a housing of the engine, the igniter having a body including a tip supporting portion and having a tip extending from the tip supporting portion. A cooling sleeve is disposed around the tip supporting portion, and the cooling sleeve defines a path of heat transfer between the tip supporting portion and the housing. The engine may be a rotary engine. A method for cooling an igniter of an internal combustion engine is also discussed.

The invention relates to an engine having prechamber ignition, in particular a gas engine, that comprises a main combustion space in a cylinder of the engine for combusting an air-fuel mixture and a prechamber having an ignition device arranged therein and a fuel injector arranged therein, wherein the prechamber has at least one transfer port that fluidically connects the prechamber to the main combustion space. The engine is characterized in that the fuel injector arranged in the prechamber is the only fuel injector via which fuel can be introduced into the associated main combustion space.

An ignition system for a vehicle internal combustion engine (12) has a capsule defining a pre-chamber (136), an ignition fuel supply system (500) configured to inject an ignition fuel to the pre-chamber to create an ignition fuel-air mix in the pre-chamber, an ignition surface (137) within the pre-chamber, the ignition surface being defined by an interior surface of the capsule and configured to be contacted by the ignition fuel in the pre-chamber to thereby ignite the ignition fuel by hot surface ignition, and at least one jet nozzle (152). The ignition fuel is characterised by having a carbon content by mass less than 65%, a hot surface ignition temperature less than 500 deg C., and a volumetric energy density (LHV) greater than 18 MJ/L. The at least one jet nozzle is configured such that ignition of the ignition fuel by contact with the ignition surface causes at least one of hot gases, partially combusted fuel and flames to leave the pre-chamber through the at least one jet nozzle.