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 combustion chamber injection nozzle (12) having a plurality of injection channels (37) for a main fuel gas, a pre-combustion chamber, and a plurality of torch channels (52) for hot combustion gas connected to the pre-combustion chamber (15), the injection channels (37) and the torch channels (52) communicating with peripheral openings arranged next to one another so as to alternate in a circumferential direction.

An engine is provided. In one embodiment, the engine includes a precombustion chamber having a body, a secondary combustion chamber disposed at least partially in the body, and a plurality of passages configured to place the precombustion chamber in fluid communication with a main combustion chamber.

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 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.

Generally, embodiments of a pre-chamber unit having a pre-combustion chamber including one or more induction ports in a configuration which achieves flow fields and flow field forces inside the pre-combustion chamber which act to direct flame growth away quenching surface of the pre-combustion chamber.

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.

An engine is provided. In one embodiment, the engine includes a precombustion chamber having a body, a secondary combustion chamber disposed at least partially in the body, and a plurality of passages configured to place the precombustion chamber in fluid communication with a main combustion chamber.

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 pre-chamber body for an internal combustion engine is disclosed. The pre-chamber body may have a pre-chamber. The pre-chamber body may also have a flow transfer passage, which may fluidly connect the pre-chamber and an exterior of the pre-chamber body. In addition, the pre-chamber body may have at least one backflow channel, which may fluidly connect the pre-chamber and the flow transfer passage.