A pre-chamber spark plug for a combustion chamber of an internal combustion engine includes a pre-chamber which has a plurality of openings and which is fluidically connectable to the combustion chamber via the plurality of openings. A fuel/air mixture is introducible from the combustion chamber into the pre-chamber via the plurality of openings. Each of the plurality of openings has a respective flow cross section through which the fuel/air mixture is flowable. With respect to an imaginary plane running along an imaginary axis of the pre-chamber and dividing the pre-chamber into a first half and a second half of equal size, a sum of the flow cross sections of first openings disposed in the first half is greater than a sum of the flow cross-sections of second openings disposed in the second half.

A pre-chamber spark plug has a pre-chamber which has openings, where, with respect to a first plane running in the longitudinal direction of the pre-chamber and dividing the pre-chamber into two halves of equal size, first openings are disposed in a first of the halves and second openings are disposed in a second of the halves. The first openings are spaced apart from a second plane running in the longitudinal direction of the pre-chamber and extending perpendicular to the first plane by a first angle in the circumferential direction of the pre-chamber. The second openings are spaced apart from the second plane by a second angle in the circumferential direction of the pre-chamber. The mean value of the first angles is smaller than the mean value of the second angles.

An internal combustion engine may include a combustion chamber which is delimited by a cylinder; an injector with which fuel can be injected into the combustion chamber, whereby a mixture comprising fuel and air can be generated in the combustion chamber; a pre-chamber, which is fluidically separate from the combustion chamber with the exception of a passage opening and which is fluidically connected to the combustion chamber via the passage opening; a first spark plug with which an ignition spark can be produced in the pre-chamber; and a second spark plug with which an ignition spark can be produced in the combustion chamber and outside of the pre-chamber, wherein the pre-chamber, the injector, and the second spark plug are arranged, in this order, in a direction extending in a plane that is perpendicular to the axial direction of the cylinder.

Systems and methods for starting and operating a direct injection engine are described. In one example, the air and fuel are injected into a pre-chamber of a cylinder of an engine while the engine is not rotating. The air and fuel are combusted in the pre-chamber to improve ignition of an air and fuel mixture in the cylinder.

Systems, devices, and methods described herein provide one or more radical chemicals generators (RCGs) and/or mini-chambers (M-Cs) that can be used to provide enhanced radical ignition (ERI) in an internal combustion engine. RCGs as described herein can include quenching systems (QSs) that can be configured to quench a flame of combustion products to produce a jet of partial combustion products containing radical species (RS). The jet of partial combustion products can be injected to a main combustion chamber (MCC) of an engine to induce ERI. ERI can proceed under leaner fuel conditions and lower temperatures compared to those needed for conventional thermally induced, fuel oxidation chain initiation reaction processes.

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 engine system employs a pre-assembled and/or removable cartridge. In another aspect, an ignitor, a fuel injector and an air inlet valve are all accessible from a top of a cartridge even after assembly of the cartridge to an engine cylinder head. A further aspect positions centerlines of an ignitor, a fuel injector and an air inlet valve angularly offset from each other and also angularly offset from a vertical centerline of a cartridge to which they are mounted.

Method for operating a hydrogen fuelled combustion engine 1 comprising the steps of providing an internal combustion engine 1 having at least one cylinder 2 and a piston 3 supported at a crankshaft 5 for repeated reciprocal movement in the cylinder 2 so as to define a main combustion chamber 21, the internal combustion engine 1 further having an ignition device 4 arranged in said cylinder 2 with an igniter portion 42 and a hydrogen fuel injector 43 which are both arranged at a pre-chamber 41, wherein the pre-chamber 41 has a plurality of orifices 44 for providing fluid communication between said pre-chamber 41 and the main combustion chamber 21; and operating the engine in cycles comprising the following steps: introducing hydrogen fuel in the pre-chamber 41; introducing hydrogen fuel in the main combustion chamber 21; and igniting the introduced hydrogen fuel in the pre-chamber 41 for combusting the introduced hydrogen fuel in the main combustion chamber 21.

To meet both a request to improve the thermal efficiency in the medium load operation of an engine and a request to suppress knocking in the high load and high rotation operation of the engine, the engine includes a main combustion chamber including a cylinder block, a cylinder head, and a piston; a pre-chamber having a plurality of injection holes that are open into the main combustion chamber; and a spark plug that ignites an air-fuel mixture in the pre-chamber. A compression ratio of the main combustion chamber is not less than 14 and not more than 24. A second index that is a product between a volume of the pre-chamber and the compression ratio is not less than 1.03 cm.sup.3 and not more than 5.92 cm.sup.3.

A prechamber device includes an enclosure body and a cap forming an enclosed volume. The enclosure body has an orifice at one end. A precombustion chamber is defined within the enclosed volume and is in fluid communication with the orifice. A valve plug is movable along an axial axis of the enclosure body to adjust a valve opening at the orifice to a range of positions from a fully open position to a closed position. An actuator is coupled to the cap and the valve plug and is controllable to displace the valve plug along the axial axis of the enclosure body. The prechamber device is operable to generate turbulent jets that are directed into a main combustion chamber of an engine cylinder through the valve opening. During an engine cycle, the valve opening is controlled between the range of positions based on detected engine speed and engine load.