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 prechamber assembly for a cylinder of a combustion engine is disclosed in which a plurality of ports placing a prechamber volume in fluid communication with the cylinder. A non-actuated, fixed orifice extends between the prechamber volume and a passageway formed in the prechamber assembly to permit combustion gases in the prechamber volume to enter the passageway. The passageway is configured to vent combustion gases therein out of the body. The orifice may reduce NOx emissions produced in the prechamber volume.

An internal combustion engine with a cylinder head and at least one piston-cylinder unit, in which, in a cylinder, a piston can be moved between a bottom and a top dead center position, where, in the cylinder, between the piston and the cylinder head a main combustion chamber is formed, which communicates with a prechamber which has a prechamber gas valve, and where the intake and outlet valves of the main combustion chamber are actuated by an actuator, where the prechamber gas valve is connected to a source for a gas-air mixture and the prechamber charge consists of a gas-air mixture with a lambda higher than 1.2, preferably higher than 1.5 and particularly preferably higher than 1.7, and the actuator is configured such that the intake valve closes before the piston reaches the bottom dead center position, where the piston is designed as a flat piston.

A method of remanufacturing a prechamber assembly includes determining a width W of an original circumferential weld bead that extends around and joins a proximal end of an outer peripheral wall of a prechamber housing and a distal end of an outer peripheral wall of a body assembly, cutting through the weld bead in order to separate the prechamber housing from the body assembly, and removing material from an outer peripheral portion of a distal end portion of the body assembly. The method includes removing the material in an axial direction parallel to the central axis of the prechamber assembly for a distance that is from 2.5-3 times the width W.

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 hole 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.

Disclosed is a pre-combustion chamber igniter, a methanol engine and a cold start control method thereof. The pre-combustion chamber igniter includes a housing, nozzles, a fuel injector, a spark plug and heating elements. The heating elements at outer surfaces of the nozzles can heat fuel spray sprayed to an inner wall of a pre-combustion chamber. According to the present disclosure, the pre-combustion chamber is heated using the heating elements during a cold start of the methanol engine, and an excess air coefficient of an interior of the pre-combustion chamber can be controlled between 0.8 and 1.0 to achieve ultra-lean combustion of the engine in a cold start state.

In one embodiment, a combustion system for an engine is disclosed. The system includes a cylinder block that defines a cylinder bore and opposing pre-chambers located along a circumference of the cylinder bore. The system also includes a fuel injector located equidistant from the circumference of the cylinder bore that injects fuel in a direction perpendicular to a diameter of the cylinder bore. The system further includes spark plugs located within the pre-chambers that ignite at least a portion of the fuel from the fuel injector to direct ignition flames into the cylinder bore.

A prechamber assembly for an internal combustion engine is disclosed. The prechamber assembly may have a prechamber housing with a first prechamber housing portion and a second prechamber housing portion. The first prechamber housing portion and the second prechamber housing portion may define a prechamber volume. The prechamber assembly may also have a cooling system. The cooling system may be configured to cool at least one of the first prechamber housing portion and the second prechamber housing portion based on a flow of a cooling fluid through the cooling system. The cooling system may have at least one cooling channel formed within the prechamber housing.

A pre-chamber is provided. In one embodiment, the pre-chamber is part of a two-stroke combustion engine having a cylinder head with a sparkplug receptacle that has a generally frustoconical shape, and the pre-chamber is coupled to the sparkplug receptacle. The pre-chamber may include a cooling jacket with a generally frustoconical shape and a combustion chamber having an upper zone and a lower zone, which may be narrower than the upper zone.

A nozzle for a prechamber assembly of an engine includes a nozzle body which is hollow and includes an outer surface, an inner surface, and an orifice surface. The outer surface defines an outer orifice opening, and the inner surface defines an interior chamber and an inner orifice opening. The orifice surface defines an orifice passage extending between, and in communication with, the outer orifice opening and the inner orifice opening. The orifice passage is in communication with the interior chamber via the inner orifice opening. The nozzle body includes a coolant surface which defines a coolant passage within the nozzle body. The coolant surface includes an orifice interface portion disposed adjacent the orifice surface such that the orifice surface and the orifice interface portion of the coolant surface are in heat-transferring relationship with each other.