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.

A variable orifice fuel injector has an inward opening needle valve and an outward opening needle valve and has means to directly inject two types of fuels independently and collectively. Both needle valves are fully contained in a nozzle body, with a co-axial smaller needle valve at least partially being contained in a larger needle valve. The materials of the needle valves are individually chosen such that it provides good sealings for liquid and gas fuels.

An electromagnetic fuel injection valve includes a coupling between an armature and the valve member that allows limited relative movement of the valve member and armature in both the opening and closing directions of the valve member. An injector body includes a non-magnetic section to focus magnetic flux and attractive force through the armature and pole. A modular power group reduces the cost of assembly and includes a plastic encapsulated coil that is protected from environmental moisture and corrosion. A valve seat incorporates a valve seal which improves fuel flow past the valve member when the fuel injection valve is in the open position.

A gas metering valve for an internal combustion engine. The gas metering valve includes a housing in which a gas chamber is formed, which includes an inlet opening and an outlet opening. A movable valve element is situated in the gas chamber, which is movable by an electrical actuator against the force of a return spring and which cooperates with a valve seat for opening and closing the inlet opening. A blocking valve is situated between the valve element and the outlet opening, which opens in the flow direction to the outlet opening and blocks in the opposite flow direction.

An electromagnetic fuel injection valve includes a coupling between an armature and the valve member that allows limited relative movement of the valve member and armature in both the opening and closing directions of the valve member. An injector body includes a non-magnetic section to focus magnetic flux and attractive force through the armature and pole. A modular power group reduces the cost of assembly and includes a plastic encapsulated coil that is protected from environmental moisture and corrosion. A valve seat incorporates a valve seal which improves fuel flow past the valve member when the fuel injection valve is in the open position.

An improved body defining a restricted fluid flow passage in a fuel supply system for delivering a gaseous fuel to an internal combustion engine. The body is formed for installation between and fluidly connecting a gaseous fuel supply conduit and a gaseous fuel flow passage that defines a predetermined volume between the restricted fluid flow passage and a nozzle chamber of a fuel injector from which the gaseous fuel is injected into the internal combustion engine. The restricted fluid flow passage has the smallest effective flow area between the gaseous fuel supply conduit and the nozzle chamber. The restricted fluid flow passage is located a predetermined distance from an injection valve seal within the fuel injector. The predetermined distance is calculated as a function of the speed of sound in the gaseous fuel and an opened time of the fuel injector.

A large two-stroke turbocharged compression-ignited internal combustion crosshead engine with a plurality of cylinders has at least one pressure booster for each cylinder for boosting fuel pressure, two or more electronically controlled fuel valves for each cylinder with an inlet of the two or more electronically controlled fuel valves being connected to an outlet of the at least one pressure booster. An electronic control unit is connected to the at least one pressure booster and the two or more electronically controlled fuel valves. The electronic control unit is configured to determine a start time for a fuel injection event, activate the at least one pressure booster ahead of the determined start time and pen the two or more electronically controlled fuel valves at the determined start time.

A dual-fuel fuel injector, having: a first nozzle needle for discharge of liquid fuel via a first nozzle arrangement; and a multiplicity of second nozzle needles, arranged around the first nozzle needle and controlled in terms of axial stroke, for discharge of gaseous fuel via a second nozzle arrangement. Each of the second nozzle needles has for controlling the stroke thereof, a respective control chamber in the injector which can be charged with and relieved of pressure by a control fluid. The dual-fuel fuel injector has an annular duct which can be charged with and relieved of pressure by the control fluid. The dual-fuel fuel injector is designed such that, for controlling the stroke of the second nozzle needles, the control chambers for the second nozzle needles are charged with and relieved of pressure by the control fluid proceeding from the annular duct.

An apparatus and method for igniting a gaseous fuel directly introduced into a combustion chamber of an internal combustion engine comprises steps of heating a space near a fuel injector nozzle; introducing a pilot amount of the gaseous fuel in the combustion chamber during a first stage injection event; controlling residency of the pilot amount in the space such that a temperature of the pilot amount increases to an auto-ignition temperature of the gaseous fuel whereby ignition occurs; introducing a main amount of the gaseous fuel during a second stage injection event after the first stage injection event; and using heat from combustion of the pilot amount to ignite the main amount.

A method for activating an injector for injecting fuel into an internal combustion engine, in which a nozzle needle of the injector moves from a closed position in the direction of an open position as long as an activation signal is applied to the injector. The nozzle needle of the injector moves from the open position into the closed position when the activation signal is absent. The duration of the activation signal is selected in such a way that the nozzle needle does not reach its completely open position. In specific operating states, a second activation signal is applied to the injector before reaching the closed position of the injector, which has the result that the nozzle needle of the injector moves back in the direction of the open position.