A fuel injector for operation with combustible gas, having a gas nozzle assembly having at least one gas nozzle opening, and at least one gas nozzle needle associated with the gas nozzle assembly and accommodated in an axial holder so that the stroke of the gas nozzle needle can be controlled. Each gas nozzle opening leads out of the holder having a radial direction component at the nozzle end. The fuel injector has, in the holder, a needle seat upstream of the particular nozzle opening, which needle seat is provided for selectively blocking a combustible-gas flow path to the associated gas nozzle opening in interaction with the gas nozzle needle. The gas nozzle openings are distributed over part of the circumference in the circumferential direction of the gas nozzle needle. The holder, adjoining the needle seat and extending away therefrom axially in the upstream direction, is asymmetric with respect to an axial center axis through the gas nozzle needle. The asymmetry results from a cross-section expansion of the holder on a side of the holder that lies radially opposite the gas nozzle opening, such that a greater mass flow rate of combustible gas can be conducted in the holder by the crosssection expansion than on the gas nozzle opening side opposite thereto. The holder is also shaped to apply a flow direction oriented toward the radially opposite gas nozzle opening, already upstream of the needle seat and via the cross-section expansion, to a combustible-gas flow guided to the needle seat by the cross-section expansion.

In a combustion cycle in which fuel for forming a homogenized air-fuel mixture in the combustion chamber is injected from the first fuel injector, ignition-use fuel for forming an ignition-use air-fuel mixture in the vicinity of the electrode part is injected from the second fuel injector, and lean combustion is performed by an excess air rate of 2.0 or more, the ignition-use fuel is injected by at least an injection rate of 1.0 mm.sup.3/ms or more for a duration of 250 μs or more in an interval from a crank angle advanced by exactly 20 degrees from an ignition timing of the spark plug to the ignition timing, and the quantity of the ignition-use fuel is 2.0 mm.sup.3/st or less.

In a gas engine provided with a gas supply pipe (35) branching into a supercharger-side gas supply pipe (33) and a cylinder-side gas supply pipe (37), a supercharger-side gas adjusting valve (43) and a cylinder-side gas adjusting valve (45) for controlling flow rates of passages, when the gas concentration of the fuel gas changes, the cylinder-side gas adjusting valve is controlled first to keep the output of the gas engine constant and then the supercharger-side gas adjusting valve is controlled to achieve the fuel gas flow rate Q1 based on the constant flow ratio by means of a gas supply controller (63), while maintaining the flow rate ratio Q1/Q2 at a constant value where Q1 is a fuel gas flow rate in the supercharger-side gas supply pipe and Q2 is a fuel gas flow rate in the cylinder-side gas supply pipe.

The present invention relates to liquefied gas treatment system and method, and the liquefied gas treatment system includes: a liquefied gas supply line connected from a liquefied gas storing tank to a source of demand; a heat exchanger provided on the liquefied gas supply line between the source of demand and the liquefied gas storing tank, and configured to heat exchange liquefied gas supplied from the liquefied gas storing tank with heat transfer media; a media heater configured to heat the heat transfer media; a media circulation line connected from the media heater to the heat exchanger; a media state detecting sensor provided on the media circulation line, and configured to measure a state of the heat transfer media; and a controller configured to set a coagulation prevention reference value for preventing the heat transfer media from being coagulated, and change a flow rate of the heat transfer media flowing into the media heater or calories supplied to the heat transfer media by the media heater on the basis of a state value of the heat transfer media by the media state detecting sensor and the coagulation prevention reference value.

A fuel supply controlling device includes: an auxiliary chamber fuel supply valve that supplies a gaseous fuel to an auxiliary chamber; a non-return valve between the auxiliary chamber fuel supply valve and the auxiliary chamber, the non-return valve blocking a reverse flow from the auxiliary chamber; a valve state detector that detects an operating state of the non-return valve; a rotation angle detector that detects a rotation angle within an engine cycle; and a controller that determines an operation command value of the auxiliary chamber fuel supply valve. The controller measures an actual operating state of the non-return valve based on signals from the valve state detector and the rotation angle detector in association with the detected rotation angle, and corrects the operation command value of the auxiliary chamber fuel supply valve such that the measured actual operating state is brought close to a target operating state.

A uniflow-scavenging-type two-cycle engine includes: a cylinder; a piston that slides in the cylinder; an exhaust port that is provided at a first end of the cylinder; an exhaust valve that opens and closes the exhaust port; a scavenging port that is provided in an inner circumferential surface of a second end of the cylinder in the stroke direction of the piston and inhales an active gas into a combustion chamber in accordance with a sliding movement of the piston; a plurality of fuel injection valves that inject a fuel gas to the active gas, which has been drawn in from the scavenging port to the combustion chamber, to thereby generate a premixed gas; and a fuel injection control unit that varies injection directions of fuel gas injected from a part or all of the fuel injection valves.

A gas control system of a non-road gas engine and a gas control method thereof are disclosed by the present disclosure. The gas control system includes a mixer, the mixer is provided with an air inlet, a gas inlet and a mixed gas outlet respectively, the air inlet is provided with a first pressure sensor, the gas inlet is provided with a second pressure sensor and a pressure regulating valve that are spaced apart, and the mixed gas outlet is provided with a third pressure sensor; the first pressure sensor, the second pressure sensor, the pressure regulating valve and the third pressure sensor are respectively electrically connected to a controller, and the controller controls an opening degree of the pressure regulating valve according to pressure information fed back by the first pressure sensor, the second pressure sensor and the third pressure sensor so as to adjust an air-gas ratio of the mixed gas. The system has a simple structure. By disposing a pressure regulating valve at the gas inlet, the pressure of the gas entering the mixer is controlled, and the air-gas ratios required under various working conditions are controlled, which realizes a closed-loop control so that a control range of the air-gas ratio is smaller, the accuracy is higher, and a transient response speed of the engine is improved.

The invention relates to a fuel injector (1) for operating with combustible gas. The fuel injector has a plurality of combustible-gas nozzle valve elements (9), and the stroke of each of the combustible-gas nozzle valve elements can be controlled by means of a paired hydraulic piston control assembly (55) of the fuel injector, wherein each piston control assembly is formed by two control chambers (59, 61) and a piston section (63) on the combustible-gas nozzle valve element paired with the piston control assembly, said piston section separating the control chambers in such a way that their volumes can be varied, and the fuel injector is designed to control the stroke of the combustible-gas nozzle valve elements in tandem using a 3/2-way valve (67), by means of which the hydraulic pressure in one of the two control chambers of the piston control assemblies is controlled.

The invention relates to a fuel injector (1) for operating with combustible gas. The fuel injector has a plurality of combustible-gas nozzle valve elements (9), and the stroke of each of the combustible-gas nozzle valve elements can be controlled by means of a paired hydraulic piston control assembly (55) of the fuel injector, wherein each piston control assembly is formed by two control chambers (59, 61) and a piston section (63) on the combustible-gas nozzle valve element paired with the piston control assembly, said piston section separating the control chambers in such a way that their volumes can be varied, and the fuel injector is designed to control the stroke of the combustible-gas nozzle valve elements in tandem using a 3/2-way valve (67), by means of which the hydraulic pressure in one of the two control chambers of the piston control assemblies is controlled.

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.