Fuel gas (G) to a pre-combustion chamber of an internal combustion engine. The pre-combustion chamber is formed inside a chamber body which is received in a cavity of the engine body, while the pipe is received in a passageway of the engine body which communicates with the cavity. A seal which may be made from an elastomer comprises a wall defining an interior space opening through the wall at first, second and third openings. A first portion of the wall defining the first and second openings is arranged in the cavity so that the chamber body can be inserted through the openings into the interior space of the seal, while a second portion of the wall comprising the third opening is received in the passageway so that the piped can be inserted into the interior space of the seal via the third opening. The pipe is sealed in fluid communication with the pre-combustion chamber via an inlet in the chamber body by sealing regions of the seal.

Disclosed herein is a BOG reliquefaction method for LNG ships. The BOG reliquefaction method for LNG ships includes: 1) compressing BOG; 2) cooling the BOG compressed in Step 1) through heat exchange between the compressed BOG and a refrigerant using a heat exchanger; 3) expanding the BOG cooled in Step 2); and 4) stably maintaining reliquefaction performance regardless of change in flow rate of the BOG compressed in Step 1) and supplied to the heat exchanger to be used as a reliquefaction target.

Disclosed herein is a BOG reliquefaction method for LNG ships. The BOG reliquefaction method for LNG ships includes: 1) compressing BOG; 2) cooling the BOG compressed in Step 1) through heat exchange between the compressed BOG and a refrigerant using a heat exchanger; 3) expanding the BOG cooled in Step 2); and 4) stably maintaining reliquefaction performance regardless of change in flow rate of the BOG compressed in Step 1) and supplied to the heat exchanger to be used as a reliquefaction target.

Various aspects of the present disclosure are directed to a cylinder head for an internal combustion engine. In one example embodiment, the cylinder head includes at least one spark plug having at least one earth electrode, a precombustion chamber accommodating the at least one spark plug, and a fuel channel which leads into the precombustion chamber. The fuel channel having a flow axis at an outlet that is oriented in the direction of the at least one earth electrode. An axis of rotation of the at least one spark plug has an offset with respect to the flow axis between 0 and 15% of the greatest precombustion chamber diameter.

A precombustion chamber gas engine includes a main-chamber forming portion forming a main combustion chamber, and a precombustion-chamber forming portion forming a precombustion chamber communicating with the main combustion chamber via a plurality of nozzle holes. The precombustion-chamber forming portion includes a cylindrical portion extending along an extension direction of a precombustion chamber central axis of the precombustion-chamber forming portion, and a tip portion closing a main-combustion-chamber-side end of the cylindrical portion and having the nozzle holes. The tip portion includes a thin region having a thickness T satisfying T<L where L is a length of each nozzle hole.

A pre-chamber arrangement (100) for a gas engine (1), including a pre-chamber body (20) accommodating a volume (30); and a supply device (50) for supplying a gaseous medium (52) into the pre-chamber volume (30); wherein the pre-chamber body (20) has a bottom portion (22) with channels (40) for allowing gas to flow between the pre-chamber volume (30) and a main combustion chamber (10) of the gas engine (1). Each channel (40) extends along a channel axis (C) from an inner opening (42) facing the pre-chamber volume (30) to an outer opening (44) configured to face the main combustion chamber (10). The bottom portion (22) has a curved outer surface (24). The channels (40) are obliquely arranged in relation to a radius (r) of the bottom portion (22). The bottom portion has flat surfaces (46) surrounding the outer openings of the channels.

A pre-chamber arrangement (100) for a gas engine (1), including a pre-chamber body (20) accommodating a volume (30); and a supply device (50) for supplying a gaseous medium (52) into the pre-chamber volume (30); wherein the pre-chamber body (20) has a bottom portion (22) with channels (40) for allowing gas to flow between the pre-chamber volume (30) and a main combustion chamber (10) of the gas engine (1). Each channel (40) extends along a channel axis (C) from an inner opening (42) facing the pre-chamber volume (30) to an outer opening (44) configured to face the main combustion chamber (10). The bottom portion (22) has a curved outer surface (24). The channels (40) are obliquely arranged in relation to a radius (r) of the bottom portion (22). The bottom portion has flat surfaces (46) surrounding the outer openings of the channels.

A method of injection of liquid or gaseous ammonia fuel into a reciprocating engine that includes at least two cylinders, each cylinder including a piston that moves reciprocally within that cylinder, each cylinder having a head location at one end located opposite to a compression end of the piston and defining a combustion chamber therebetween, the cylinder including at least one inlet valve through which combustion gases are fed into the combustion chamber and at least one exhaust valve through which spent combustion gases egress the combustion chamber, the piston moving the cylinder in a cycle between top dead center where the piston is located closest to the head location and bottom dead center where the piston is located furthest from the head location, and including at least one fuel injector located at or in the head location, and wherein the method comprises: injecting the ammonia fuel into the combustion chamber of each cylinder as at least one fuel jet with a timing of: after the at least one exhaust valve of the respective cylinder is substantially closed; and before the respective piston moves to at most 35 degrees, preferably at most 45 degrees, prior to top dead centre.

Various embodiments for a hydrogen zero emissions vehicle that utilizes hydride storage of hydrogen and buffering of hydrogen for high demand power are disclosed.

There are provided systems and methods for the use of rich limit extenders, and in particular pre-chamber assemblies, for increasing the ability of a spark-ignition engine to operate under fuel-rich conditions. In embodiments the pre-chamber assemblies are combined with spark-ignition engines as a reformer in a gas-to-liquid system for converting a combustible fuel source into synthesis gas. Embodiments of the reformers having pre-chambers provide a synthesis gas product having a H.sub.2/CO ratio, with increased H.sub.2 concentrations.