A rotary engine including at least two pilot subchambers each in parallel fluid communication with the internal cavity, so that each pilot subchamber is in fluid communication with the combustion chambers as the rotor rotates. Each of the at least two pilot subchambers in fluid communication with a corresponding pilot fuel injector. At least one ignition source is configured for igniting fuel in the pilot subchambers. A compound engine assembly and a method of combusting fuel in a rotary engine are also discussed.

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.

An internal combustion engine having a prechamber with first and second sub-chambers. The first sub-chamber has a prechamber gas valve and an igniter. The second sub-chamber has a plurality of first orifices to couple with a main combustion chamber. The second sub-chamber is coupled to the first sub-chamber via a direct connection or an indirection connection. The direct connection includes at least one second orifice, such as a plurality of second orifices. The indirect connection includes a third sub-chamber, wherein the third sub-chamber is coupled to the first sub-chamber by at least one third orifice (e.g., a plurality of third orifices), and the third sub-chamber is coupled to the second sub-chamber by at least one second orifice (e.g., a plurality of second orifices).

A precombustion-chamber engine includes a cylinder, a cylinder head disposed on a top of the cylinder, and a piston reciprocably disposed within the cylinder. A main combustion chamber is defined between the piston and the cylinder head. The cylinder head includes a precombustion-chamber forming part which defines a precombustion chamber communicating with the main combustion chamber through a nozzle. The precombustion chamber includes a cylindrical first passage part extending upwardly from the nozzle, a second passage part extending upwardly from the first passage part and having an upwardly-increasing cross-sectional area, and a cylindrical space part which extends upwardly from the second passage part and in which a spark plug is disposed. Center O of a cross-section, orthogonal to straight line L, of the second passage part is eccentric with respect to straight line L composed of an axis of the first passage part and an extended line of the axis.

A rotary engine including at least two pilot subchambers each in parallel fluid communication with the internal cavity, so that each pilot subchamber is in fluid communication with the combustion chambers as the rotor rotates. Each of the at least two pilot subchambers in fluid communication with a corresponding pilot fuel injector. At least one ignition source is configured for igniting fuel in the pilot subchambers. A compound engine assembly and a method of combusting fuel in a rotary engine are also discussed.

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.

The present disclosure includes systems and methods for monitoring a prechamber of an engine. In one embodiment, a system includes a combustion engine having a combustion chamber and a prechamber, where the prechamber is configured to direct a flame toward the combustion chamber, a fuel supply valve configured to adjust a flow of a fuel toward the prechamber, a prechamber valve configured to receive the fuel into the prechamber, a knock sensor coupled to the combustion engine, and a controller. The controller is configured to control operations of the combustion engine, to receive a signal from the knock sensor, to determine a combustion parameter based at least on the signal, to determine a condition of one or both of the prechamber and the prechamber valve based at least on the combustion parameter, and to adjust the fuel supply valve based at least on the condition.

A precombustion-chamber engine includes a cylinder, a cylinder head disposed on a top of the cylinder, and a piston reciprocably disposed within the cylinder. A main combustion chamber is defined between the piston and the cylinder head. The cylinder head includes a precombustion-chamber forming part which defines a precombustion chamber communicating with the main combustion chamber through a nozzle. The precombustion chamber includes a cylindrical first passage part extending upwardly from the nozzle, a second passage part extending upwardly from the first passage part and having an upwardly-increasing cross-sectional area, and a cylindrical space part which extends upwardly from the second passage part and in which a spark plug is disposed. Center O of a cross-section, orthogonal to straight line L, of the second passage part is eccentric with respect to straight line L composed of an axis of the first passage part and an extended line of the axis.

An engine has an ignition source in a combustion chamber of the engine. An inner housing is provided that includes one or more jet apertures and defines an inner chamber containing the ignition source. An outer housing (or pre-chamber) is provided that includes one or more jet apertures in communication with the main combustion chamber and defines an outer chamber containing the inner housing.

In a laser ignition device which is mounted in an internal combustion engine and at least includes a laser spark plug equipped with an optical window which protects an optical device from high temperature and high pressure generated in a combustion chamber and a prechamber cap equipped with a cylindrical prechamber, a prechamber throat portion that is a bottomed cylinder with a sectional area smaller than that of the prechamber, and a plurality of prechamber spray holes which communicate with a combustion chamber on a side of a closed end of the prechamber throat portion, the prechamber cap is arranged between the optical window and the combustion chamber. A converging point FP is located inside the prechamber to ignite an air-fuel mixture delivered into the prechamber, thereby jetting combustion flames from the prechamber into the combustion chamber to fire the internal combustion engine. The center axis AX.sub.F of the prechamber is oriented horizontally eccentrically from the center axis AX.sub.S of the prechamber throat portion.