A gas injector for injecting a gaseous fuel. The gas injector includes a solenoid actuator having an armature, an internal pole and a coil; a closing element, which unblocks and seals a gas path at a valve seat, the armature being connected to the closing element; a sealed lubricant chamber, which is filled with a lubricant, and in which the armature is situated, the lubricant ensuring lubrication of the armature; and a flexible sealing element, which seals the lubricant chamber with respect to the gas path, a damping device being situated in the lubricant chamber.

A gas injector for injecting a gaseous fuel. The gas injector includes a solenoid actuator having an armature, an internal pole and a coil; a closing element, which unblocks and seals a gas path at a valve seat, the armature being connected to the closing element; a sealed lubricant chamber, which is filled with a lubricant, and in which the armature is situated, the lubricant ensuring lubrication of the armature; and a flexible sealing element, which seals the lubricant chamber with respect to the gas path, a damping device being situated in the lubricant chamber.

Gas admission valve assembly includes a housing, an elongated valve guide disposed within a central bore of the housing, a valve including a valve stem slidably disposed within the valve guide and a valve head selectively engagable with a valve seat of the housing to control flow between gas entry and exit openings into a housing entry chamber. First and second stem seals are disposed at opposite ends of the valve guide in sealing engagement with the valve stem between the valve stem and the central bore of the housing distally and the valve guide proximally.

A fuel injector includes a needle valve including a spring-retaining section and a guide section that is adjacent to the spring-retaining section. The spring-retaining section includes an elongated portion and a flange that are together configured to support a spring assembly. The guide section includes a plurality of constricted portions alternatingly arranged with a plurality of expanded portions to define an undulating shape of the guide section. Each of the plurality of expanded portions includes a plurality of indentations to permit fuel to travel therealong to exit an outlet of the fuel injector. The guide section has a length that is substantially equal to a length of the spring-retaining section.

An injection hole body has injection holes to inject fuel. A valve body forms a fuel passage with an inner surface of the injection hole body to communicate with inflow ports of the injection holes. The valve body opens and closes the fuel passage by being seated on and unseated from a seating surface of the injection hole body. An inflow port gap distance is a gap between the valve body and the inflow ports along a center axis of the valve body. An inter-injection hole distance is a distance between inflow ports, which are adjacent to each other, among the inflow ports placed around the center axis. The inter-injection hole distance is smaller than the inflow port gap distance in a state where the valve body is unseated from the seating surface and is at a farthest position in its movable range.

A method to prevent generation of impact noise caused by an armature contacting a stopper due to a return spring and damage of the armature and a stopper without adding a part. Excitation of an electromagnetic coil 4 causes an armature 9 at a standby position to move in a plunger 7 direction so as to move the plunger 7 inserted in a pressurizing chamber 3 in a tip end direction against a return spring 8 to a level such that fuel is not injected from an injection nozzle 2. Fuel supplied from a fuel tank to the pressurizing chamber 3 through a fuel intake pipe 10 and inlet check valve 11 is pressurized and vapor included in the fuel inside the pressurizing chamber 3 is discharged to a fuel return pipeline 14 through a spill valve 12 and return passage 13. Excitation of the electromagnetic coil 4 is stopped, and then the electromagnetic coil 4 is re-excited prior to the armature 9 and plunger 7 reaching the standby position due to the return spring 8, such that the return speed of the armature 9 is reduced and an impact when the armature 9 contacts a stopper 15 is mitigated.

In general, the subject matter described in this disclosure can be embodied in a fuel injector that includes an upper housing portion that defines an inlet passage adapted to receive fuel, and a lower housing portion that is attached to the upper housing portion and that defines an injector outlet adapted to dispense fuel. The fuel injector includes an electromagnetic coil assembly that is user removable while the upper housing portion remains attached to the lower housing portion. The fuel injector includes a movable pintle that is biased to a closed position that is adapted to prevent fuel from flowing through the injector outlet, and movable, responsive to magnetic force produced by energizing the electromagnetic coil assembly, to an open position that is adapted to permit fuel to flow through the injector outlet.

A nozzle needle for a fuel injector, the nozzle needle including an elongated nozzle needle main body which has, at one of its two long ends, a nozzle needle tip for selectively closing an injection opening of the fuel injector. The nozzle needle also including a plastic and/or ceramic sleeve for enclosing the nozzle needle main body peripherally along a longitudinal region of the nozzle needle, which longitudinal region is spaced apart from the nozzle needle tip.

A nozzle needle for a fuel injector, the nozzle needle including an elongated nozzle needle main body which has, at one of its two long ends, a nozzle needle tip for selectively closing an injection opening of the fuel injector. The nozzle needle also including a plastic and/or ceramic sleeve for enclosing the nozzle needle main body peripherally along a longitudinal region of the nozzle needle, which longitudinal region is spaced apart from the nozzle needle tip.

A fuel injector includes a needle valve including a spring-retaining section and a guide section that is adjacent to the spring-retaining section. The spring-retaining section includes an elongated portion and a flange that are together configured to support a spring assembly. The guide section includes a plurality of constricted portions alternatingly arranged with a plurality of expanded portions to define an undulating shape of the guide section. Each of the plurality of expanded portions includes a plurality of indentations to permit fuel to travel therealong to exit an outlet of the fuel injector. The guide section has a length that is substantially equal to a length of the spring-retaining section.