A fuel valve includes a housing, a nozzle with nozzle holes opening to a volume inside the nozzle at the front end of the housing, a gaseous fuel inlet port in the housing connected to high pressure gaseous fuel, an axially displaceable valve needle received in a longitudinal bore in the housing, and rests on a valve seat in a closed position and has lift from the valve seat in an open position, the valve seat placed between a fuel chamber and an outlet port, the fuel chamber connected to the fuel inlet port, the outlet port connected to the volume in the nozzle, an actuator system for moving the needle between the closed and open positions, an ignition liquid inlet port connected to high pressure ignition liquid, and conduit connecting the ignition liquid inlet port to the fuel chamber, the conduit including a fixed flow restriction.

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 comprising a cylinder block, a cylinder head, and a piston; a pre-chamber having a plurality of injection holes that 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 first index, which is the product between a total cross-sectional area of the plurality of injection holes and the compression ratio, is not less than 0.1496 cm.sup.2 and not more than 0.8449 cm.sup.2.

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.

Methods and systems are provided for reducing emissions during an engine cold start. In one example, a method may include, during emission control device heating, initiating combustion in a cylinder via a spark plug directly coupled to the cylinder and providing secondary air via a turbulent jet ignition system. In this way, an amount of hydrocarbons in feedgas provided to the emission control device prior to the emission control device reaching its light-off temperature may be reduced.

A method for operating a spark ignited gaseous fuel internal combustion engine is disclosed. The engine may have at least one main combustion chamber and at least one ignition device configured to initiate an ignition event within an ignition region. The method may include supplying pressurized fuel to the ignition region at times between about 30° to about 0° crank angle before the ignition event is initiated by the ignition device for enriching the ignition region with fuel. The method may also include initiating an ignition event in the ignition region for combusting an enriched air/fuel mixture within the ignition region.

Systems and methods for stopping and starting a direct injection engine are described. In one example, the air is injected into one or more pre-chambers of engine cylinders to adjust engine pumping torque during an engine stop so that the engine may stop at a crankshaft position that facilitates direct engine starting.

A dual fuel engine is provided. The dual fuel engine includes an engine cylinder and a piston disposed within the engine cylinder. The dual fuel engine includes a cylinder head coupled to the engine cylinder and a fuel injector coupled to the cylinder head. The fuel injector is adapted to supply a first fuel to the engine cylinder. The dual fuel engine further includes a pre-combustion chamber coupled to the cylinder head at a predetermined distance from the fuel injector. The pre-combustion chamber is in fluid communication with the engine cylinder via at least one conduit and the pre-combustion chamber is adapted to receive a second fuel and an air mixture. The second fuel is different from the first fuel. The dual fuel engine further includes a spark plug structured and arranged within the pre-combustion chamber and the spark plug is adapted to ignite the second fuel within the pre-combustion chamber.

An igniter system for a reciprocating piston internal combustion engine having one or more cylinders including at least one igniter per cylinder is disclosed. The igniter system can comprise: a combustion chamber connected to a main cylinder of the engine by a restricted diameter bore, wherein a lean burn fuel mixture is introduced into the combustion chamber by the normal compression stroke of the engine; a hydrogen valve that injects a hydrogen rich gas into the combustion chamber forming a mixture of hydrogen and air having a hydrogen concentration above the stoichiometric ratio for hydrogen and air in the combustion chamber; and a spark ignition source that injects hot unburned hydrogen into the main cylinder, thereby initiating ignition.

A nozzle for a prechamber assembly of an engine includes a nozzle body. The nozzle body is hollow and includes an outer surface and an inner surface. The outer surface defines an outer opening, and the inner surface defines an interior chamber and an inner opening. The nozzle body includes an orifice surface which defines an orifice passage extending between, and in communication with, the outer and inner openings. The orifice passage is in communication with the interior chamber via the inner opening. The orifice surface is continuously curved. The inner surface of the nozzle body can include a groove surface that is contiguous with the orifice surface. The groove surface defines an orifice groove in communication with the interior chamber and with the orifice passage.

A pre-chamber arrangement (100) for a gas engine (1), including a pre-chamber body (20) accommodating a volume (30); and an inlet passage (40) with an inlet port (42), for supplying a gaseous medium (50) into the pre-chamber volume (30); the pre-chamber volume (30) extends in a longitudinal direction (1) between a top end (32) and a bottom end (34); the pre-chamber volume (30) is configured to accommodate an end of a spark plug (60) at the top end (32) and at the bottom end (34), the pre-chamber body (20) has openings (26) for allowing gas to flow between the pre-chamber volume (30) and a main combustion chamber (10) of the gas engine (1); the inlet port (42) is positioned, at a distance (D) from the top end (32) of the pre-chamber volume (30), in the longitudinal direction (L), such that a volume of residual gases is trapped at the top end of the pre-chamber volume when the gaseous medium is supplied into the pre-chamber volume during an intake stroke.