A fuel injection valve configured to inject fuel from an injection hole includes: a coil that is configured to generate a magnetic flux when the coil is energized; a stationary core that forms a portion of a flow passage, which is configured to conduct the fuel to the injection hole, wherein the stationary core is configured to become a passage of the magnetic flux; a movable core that is configured to be attracted toward the stationary core when the movable core becomes a passage of the magnetic flux; a passage forming portion that is placed on a downstream side of the stationary core and forms a portion of the flow passage; and a covering portion that covers a stationary boundary, which is a boundary between the passage forming portion and the stationary core, from a flow passage side of the stationary boundary where the flow passage is located.

A fuel injection valve includes a valve body, a fixed core, a movable core, a spring, and a cup. The spring is elastically deformed according to valve opening operation of the valve body, and exerts a valve closing elastic force for closing the valve body. The cup contacts a valve closing contact surface of the valve body, and transmits the valve closing elastic force to the valve body. At a start of predetermined-distance movement of the movable core together with the cup, the cup is in contact with the valve closing contact surface, and the valve body or the cup has a supply flow channel through which fuel is supplied to the valve body closing contact surface which is in a state contacting the cup.

An electromagnetic fuel injection valve includes: a valve body having a rod connected to a valve part; a movable core fitted onto the rod slidably between valve-open side and valve-closed side stoppers; a fixed core having an attracting face opposing the movable core; a valve spring urging the valve body in a valve-closing direction; and an auxiliary spring exhibiting a spring force that urges the movable core to separate from the valve-open side stopper and abut against the valve-closed side stopper when a coil is unenergized. A first curved face part is protruded from a surface, opposing the movable core, of the fixed core, and a second curved face part is provided in an outer peripheral part of a surface, opposing the movable core, of the valve-open side stopper, the first and second curved face parts each having an arcuate cross-section and being capable of abutting against the movable core.

An injector component of an injector for introducing a fluid is described as including a base body, a coating on at least one first end face of the base body, the coating having a maximum, which lies on an outer half of the base body, and an outer lateral surface of the base body does not have any coating.

An electromagnetic fuel injection valve includes: a valve body having a rod connected to a valve part; a movable core fitted onto the rod slidably between valve-open side and valve-closed side stoppers; a fixed core having an attracting face opposing the movable core; a valve spring urging the valve body in a valve-closing direction; and an auxiliary spring exhibiting a spring force making the movable core abut against the valve-closed side stopper when a coil is unenergized. A surface, opposing the movable core, of the valve-closed side stopper includes: an annular first curved face part curved convexly toward the movable core and capable of abutting thereagainst; and first and second taper faces continuous respectively to inner and outer peripheral sides of the first curved face part and gradually separated from the movable core in going radially inward and outward, respectively, from the first curved face part.

Provided is a technique for identifying a variation in an injection amount by estimating a valve opening start timing in an extremely small injection region of a half lift region. Therefore, a fuel injection control device according to the present invention estimates a valve opening start timing of a fuel injection valve by referring to a characteristic of a reference fuel injection valve acquired in advance.

An injector component of an injector for introducing a fluid is described as including a base body, a coating on at least one first end face of the base body, the coating having a maximum, which lies on an outer half of the base body, and an outer lateral surface of the base body does not have any coating.

A fixed core generates a magnetic attraction force with energization of a coil. A movable core has an attracted surface facing an attracting surface of the fixed core is attracted to the fixed core to cause the valve body to open a nozzle hole. A stopper member abuts against the movable core to restrict movement of the movable core. The movable core has an abutment portion that abuts against the stopper member, and a core body portion in which the attracted surface is formed. The attracting surface and the attracted surface extend annularly around an axis line of the fixed core, are formed so as to be separated from each other in an axis line direction in a state where the abutment portion abuts against the stopper member, and a separation distance from each other increases toward a radially outer side.

A fuel injection control device includes an additional energization unit. Concerning an undershoot state caused by a first energization for fuel injection, a return period is an estimated period required for a movable core to return to an initial position from a first energization. An injection interval ranges from the first energization to a second energization that is for a next fuel injection. An allowable period is obtained by subtracting a rise period estimated for the second energization from the return period. The additional energization unit adds an additional energization between the first energization and the second energization when the injection interval is longer than or equal to the allowable period and is shorter than or equal to the return period.

In a fuel injection device, a driving unit structure has a magnetic aperture, in which an inner diameter is gradually enlarged toward the mover side, provided in an inner peripheral surface of the magnetic core. It is possible to reduce magnetic delay time upon valve opening from the supply of the electric current to the coil to the rise of magnetic flux and magnetic delay time upon valve closing from the stoppage of the electric current to the coil to reduction of magnetic flux, by providing a magnetic aperture in the inner peripheral surface of the magnetic core. Thus it is possible to improve the dynamic responsiveness upon valve opening and valve closing.