A fuel injection valve includes a fixed core and a movable core. The fixed core includes a fixed-side high rigidity portion having high rigidity and a fixed-side low rigidity portion having rigidity lower than that of the fixed-side high rigidity portion. The movable core includes a movable-side high rigidity portion having high rigidity and a movable-side low rigidity portion having rigidity lower than that of the movable-side high rigidity portion. Current fed to a coil generates a magnetic attractive force to cause the movable core to move toward the fixed core together with a needle and to cause the movable-side high rigidity portion to abut on the fixed-side high rigidity portion.

Various embodiments may include a method for actuating a fuel injector with a solenoid drive and a nozzle needle. The solenoid drive has a solenoid and a movable armature. The fuel injector has an idle stroke between the armature and the nozzle needle. An example method includes: applying a precharging current to the solenoid drive during a precharging phase to move the movable armature into mechanical contact with the nozzle needle; and applying a voltage pulse to the solenoid drive during a boost phase until the current intensity of the current flowing through the solenoid reaches a predetermined peak value.

Provided is a fuel injection valve capable of stroking a valve body in two stages of large and small strokes and improving responsiveness of a valve opening operation. Therefore, a first mover 201 is attracted to a magnetic core 107. A second mover 202 is formed separately from the first mover 201, and is attracted to the magnetic core 107 on an inner diameter side of the first mover 201. A valve body 101 has a flange portion 101a on an upstream side of the second mover 202. A spacer 213 forms a gap (void g1) in an axial direction between the flange portion 101a and the second mover 202 in a valve closed state.

A nozzle body has an injection hole configured to inject fuel and a fuel passage connecting to the injection hole. A needle is configured to open and close the fuel passage to switch between fuel injection from the injection hole and stop of the fuel injection. An injection hole axis is an imaginary line extending along a center of the injection hole. An injection hole perpendicular cross section is a cross section of the injection hole perpendicular to the injection hole axis. The injection hole perpendicular cross section has a flat shape. The injection hole perpendicular cross section has an area that gradually expands from an inlet of the injection hole to an outlet of the injection hole while maintaining a similar shape.

A sealing structure includes an O-ring and a back-up ring. An outer diameter of the back-up ring is smaller than an inner diameter of a mounting portion of a delivery pipe. An inner diameter of the back-up ring is gradually increased from a pressure-receiving surface toward a seating surface, and is greater than an outer diameter of a fuel introducing portion of a fuel injection valve. In a section of the back-up ring, an edge angle defined between the pressure-receiving surface and an inner circumferential surface is smaller than a gap angle defined between the pressure-receiving surface and a tapered outer surface of a tapered portion in the fuel introducing portion. A dimension of the seating surface in the back-up ring is shorter than a dimension in an end surface.

Provided is a fuel injection valve capable of correcting an eccentricity of a valve body. For this reason, a fuel injection valve 100 includes a valve body 101; a mover 201 that drives the valve body 101; a fixed core 107 (magnetic core) that attracts the mover 201; and a flow path 107D-133F (magnetic core downstream flow path) representing a flow path that is formed on a downstream side of the fixed core 107. The mover 201 includes an upstream flow path 201C (mover upstream flow path) representing a flow path that is connected to the flow path 107D-133F to allow fuel to flow downstream. The radial lengths (L21 and L22) of an overlap between a downstream opening surface of the flow path 107D-133F and an upstream opening surface of the upstream flow path 201C are smaller than the radial lengths (L11 and L12) of the flow path 107D-133F.

A diagnostic system for a fuel injector includes a plurality of sensors to sense vehicle data. A controller includes a fuel injector diagnostic module configured to receive the vehicle data during operation of the vehicle and to selectively identify at least one of a fuel injector with a stuck armature and a fuel injector with pintle fatigue.

A diagnostic system for a fuel injector includes a plurality of sensors to sense vehicle data. A controller includes a fuel injector diagnostic module configured to receive the vehicle data during operation of the vehicle and to selectively identify at least one of a fuel injector with a stuck armature and a fuel injector with pintle fatigue.

A drive device capable of detecting individual variations of an injection quantity of a fuel injection device of each cylinder and adjusting a current waveform provided to an injection pulse width and a solenoid such that the individual variations of the fuel injection devices are reduced. The fuel injection device in the present invention includes a valve body that close a fuel passage by coming into contact with a valve seat and opens the fuel passage by separating from the valve seat and a magnetic circuit constructed of a solenoid, a fixed core, a nozzle holder a housing and a needle and when a current is supplied to the solenoid a magnetic suction force acts on the needle and the needle has a function to open the valve body by colliding against the valve body after performing a free running operation and changes of acceleration of the needle due to collision of the needle against the valve body are detected by a current flowing through the solenoid.

A fuel injector for an internal combustion engine of a motor vehicle. The fuel injector including the following: (a) a pole piece, (b) an armature which can be moved along a movement axis, (c) a coil and (d) a permanent magnet, wherein the movable armature has at least one electrically insulating element which is designed to reduce eddy currents in the armature, and wherein the permanent magnet is fitted such that it generates a magnetic field which produces a force which acts on the armature in the direction of the pole piece. The invention also describes a method for ascertaining a position of a movable armature in a fuel injector and also an engine controller.