A needle includes a first seal portion, which is formed at an end portion of the needle located on a side where an injection hole is placed, and a second seal portion, which is formed on a side of the first seal portion where a stationary core is placed. When a boundary between a first outer wall of the first seal portion and a second outer wall of the second seal portion is lifted away from or is seated against an inner wall, the injection hole is opened or closed. Thereby, a seat diameter of the boundary and the inner wall is stabilized, and a change in a fuel injection quantity caused by aging can be reduced. Furthermore, the first outer wall of the first seal portion is shaped into a form of a spherical surface.

A fuel injection valve includes a valve body, a fixed core, a movable core, a spring, a cup, and a guide. The cup contacts the spring and the valve body to transmit a valve closing elastic force to the valve body, and includes a cylindrical portion having a cylindrical shape. The guide has a sliding surface on which an outer peripheral surface of the cylindrical portion slides so as to guide the movement of the cylindrical portion in an axial direction while restricting the movement of the cylindrical portion in a radial direction. The guide has a recessed surface connected to the sliding surface and recessed to increase a gap between the recessed surface and the cup in the radial direction.

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 current control unit in a fuel injection device controls a magnitude of a current flowing through a coil during single energization. A current Ip1 flows once a signal input to the current control unit is turned ON at time t11. As a result, a movable core and a needle abut against each other with a lift amount increased at time t12, and then the needle is separated from a valve seat and pre-injection is performed. At time t13, which follows the pre-injection, the needle and movable core lift amount becomes a lift amount D1 at a time when the needle and the valve seat abut against each other, and temporary valve closing occurs. At time t14, which follows time t13, currents Ix1 and Im1 larger than the current Ip1 are caused to flow through the coil, and then main injection is performed with the needle and movable core lift amount turned into a lift amount D2 larger than the lift amount D1. Therefore, fuel injection can be performed twice during the single energization.

A combined assembly for filtering and calibrating a fuel injector arranged in an internal combustion engine, the combined filtration and calibration assembly extending along a longitudinal axis and comprising a calibration sleeve provided with a longitudinal bore and defining a multitude of filtration holes. The combined filtration and calibration assembly has a calibrated opening in the bore.

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.

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.

A fuel injection valve includes: a circular plate portion that is abuttable against an end surface of a needle opposite from a valve seat while the needle being provided to open and close an injection hole upon lifting and seating of the needle relative to the valve seat; and a tubular portion that extends from the circular plate portion toward the valve seat and has an end part, which is opposite from the circular plate portion and is abuttable against a movable core second contact surface of a movable core opposite from the valve seat. In a state where the circular plate portion abuts against the needle, and the tubular portion abuts against the movable core, a gap is formed between a flange member end surface of a flange of the needle and a movable core first contact surface of the movable core opposite from the valve seat.

A fuel injector includes a fuel valve with a valve seat and a movable valve needle, a calibration spring and an electromagnetic actuator with a solenoid and a movable armature. The calibration spring exerts a pressing force on the valve needle for pressing the valve needle in a closing direction towards the valve seat. When the solenoid is electrically energized, the electromagnetic actuator is operable to transfer a lifting force to the valve needle by engagement with the armature for lifting the valve needle from the valve seat to a fully open position against the pressing force of the calibration spring. The calibration spring and the electromagnetic actuator are configured such that the lifting force equals the pressing force in the fully open position.