A gas injector for injecting a gaseous fuel, in particular directly into a combustion chamber of an internal combustion engine, including: a valve closing element for opening or closing a pass-through opening, a valve body, and a sealing seat between the valve body and the valve closing element, in the case of a maximum lift of the valve closing element a flow cross section between the valve body and the valve closing element being smaller in the flow direction upstream from the sealing seat than a flow cross section between the valve closing element and the sealing seat and being smaller than a flow cross section in the flow direction downstream from the sealing seat.

The invention relates to a fuel injection valve comprising a housing (1) in which pressure is applied to a nozzle needle (8), in a control chamber (28), at least indirectly with a closing force in the direction of a valve seat (10). The pressure in the control chamber (28) can be adjusted using a control valve (40) as said control chamber (28) is able to be connected to a low pressure chamber (46) via an outlet restrictor (31) and be filled with fuel at high pressure via an inlet restrictor (30). A longitudinally-displaceable control piston (29) is arranged in the control chamber (28) and divides said chamber (28) into a first control sub-chamber and a second control sub-chamber (228), the first control sub-chamber (128) being able to be connected to the low pressure chamber (46) by means of said outlet restrictor (31). A sealing surface (38) is formed on the control piston (29) and interacts with a sealing seat (39) in the control chamber (28) such that the inlet restrictor (30) is hydraulically disconnected from the second control sub-chamber (228) when the sealing surface (38) comes to rest against the sealing seat (39). Said first control sub-chamber (128) and second control sub-chamber (228) are constantly hydraulically interconnected by means of a restrictor connection (34).

An object of the present invention is to provide a fuel injector which can promote convergence of a motion of a valve body while a valve is opened and promote stabilization of an injection amount. In the present invention, a fuel injector includes a movable iron core 404, a fixed iron core 401, a first spring member 405, a second spring member 406, contact portions 102c and 404b′, and a gap g1. The movable iron core 404 is provided relatively displaceable to a valve body 102. The fixed iron core 401 is opposed to the movable iron core 404. The first spring member 405 energizes the valve body 102 in a valve closing direction. The second spring member 406 energizes the movable iron core 404 in a valve closing direction. The contact portions 102c and 404b′ are in contact with each other in a case where the movable iron core 404 displaces in a valve opening direction with respect to the valve body 102. The gap g1 is formed between the contact portions 102c and 404b′ in a valve closing state. In a state in which the movable iron core 404 and the valve body 102 move in different directions after the movable iron core 404 collides with the fixed iron core 401 while a valve is opened, a spring force is not applied between the movable iron core 404 and the valve body 102.

A fuel injector includes fixed metal components, in particular an injector body, a solenoid actuator equipped with a retaining spring that holds a control valve stem, a control valve body including a seat for the control valve stem, a spacer between the body of the control valve and an injection nozzle, a control chamber, and an injection needle seat. The fuel injector also includes movable metal components, in particular the control valve stem and an armature thereof and an injection needle. Surfaces of the metal components that are in contact with one another are contact surfaces. Resistive surface coatings are arranged on a number of the contact surfaces. The overall electrical resistivity of the injector between the body of the solenoid actuator and the body of the injector varies by at least three distinct ohm values intermittently according to the kinetics of the injection needle of the injector.

A fuel injector includes fixed metal components, in particular an injector body, a solenoid actuator equipped with a retaining spring that holds a control valve stem, a control valve body including a seat for the control valve stem, a spacer between the body of the control valve and an injection nozzle, a control chamber, and an injection needle seat. The fuel injector also includes movable metal components, in particular the control valve stem and an armature thereof and an injection needle. Surfaces of the metal components that are in contact with one another are contact surfaces. Resistive surface coatings are arranged on a number of the contact surfaces. The overall electrical resistivity of the injector between the body of the solenoid actuator and the body of the injector varies by at least three distinct ohm values intermittently according to the kinetics of the injection needle of the injector.

A valve assembly for a fluid injector is disclosed. The valve assembly includes a valve body having a longitudinal axis, an armature, a valve needle having a needle tip and a damping element. The armature and the damping element include penetrating first openings in which the valve needle is arranged. The damping element is fixed to the valve needle and arranged between the armature and the needle tip with respect to the longitudinal axis to attenuate a movement of the valve needle relative to the valve body during the operation of the valve assembly.

A valve assembly for a fluid injector is disclosed. The valve assembly includes a valve body having a longitudinal axis, an armature, a valve needle having a needle tip and a damping element. The armature and the damping element include penetrating first openings in which the valve needle is arranged. The damping element is fixed to the valve needle and arranged between the armature and the needle tip with respect to the longitudinal axis to attenuate a movement of the valve needle relative to the valve body during the operation of the valve assembly.

An injector for injecting fluid with a valve assembly including a valve body and a valve needle, the needle including an armature retainer and being operable to prevent and to enable injection of fluid, and with an electromagnetic actuator assembly, operable to exert a force for influencing a position of the valve needle, including a pole piece and an armature. The pole piece is positionally fixed with the valve body. The armature is operable to be axially displaced relative to the pole piece and to take along the armature retainer when being displaced towards the pole piece. A fluid channel is defined by the armature retainer constriction surface and the pole piece constriction surface. A hydraulic diameter of the fluid channel is at least twice at large when the valve needle is in a closing position compared to the hydraulic diameter at a maximum displacement away from the closing position.

An injector for injecting fluid with a valve assembly including a valve body and a valve needle, the needle including an armature retainer and being operable to prevent and to enable injection of fluid, and with an electromagnetic actuator assembly, operable to exert a force for influencing a position of the valve needle, including a pole piece and an armature. The pole piece is positionally fixed with the valve body. The armature is operable to be axially displaced relative to the pole piece and to take along the armature retainer when being displaced towards the pole piece. A fluid channel is defined by the armature retainer constriction surface and the pole piece constriction surface. A hydraulic diameter of the fluid channel is at least twice at large when the valve needle is in a closing position compared to the hydraulic diameter at a maximum displacement away from the closing position.

The disclosure relates to a fuel injection valve that includes a valve needle, a closing spring applying a spring force to the valve needle, which spring force loads the valve needle in the direction of a closing position, and an actuator assembly. A coil of the actuator assembly produces a magnetic force on a magnet armature of the actuator assembly such that, as the magnet armature travels toward a pole piece of the actuator assembly,. the magnet armature covers an idle stroke to a stop element of the valve needle and then carries the valve needle toward the pole piece. A spring constant of the closing spring and the magnetic force are matched such that the magnitude of the resultant force of the spring force and the magnetic force decreases with increasing distance of the valve needle from the closing positionand remains the same with increasing the distance.