A fuel injector includes a housing extending along an injector axis. A pintle has an axially extending pintle shaft and a radially projecting annular collar with a collar surface, the pintle being axially moveable between an open position and a closed position. An armature is axially guided in the housing between a proximal position and a distal position, the armature having an axial through-hole in which the pintle shaft is guided and an armature surface which engages the collar surface, thereby moving the pintle into the open position when the armature moves to the proximal position. A first resilient member biases the pintle in the distal direction and a second resilient member biases the armature in the distal direction. The armature surface and the collar surface are slanted with respect to the injector axis and one of the armature surface and the collar surface is convex curved.

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.

Provided is a fuel injection valve capable of improving durability as compared with the conventional case and making the amount of fuel injected uniform as compared with the conventional case. Further, the present invention provides a fuel injection valve capable of injecting fuel with a high fuel pressure as compared with the conventional case and improving the reliability of the product as compared with the conventional case. For this reason, the configuration has a shape relationship in which φB>φC>φD>φE>φF is satisfied where φB represents a hole diameter of a valve body insertion hole 31 consisting of the through hole formed in the central axis of a movable core 30, φC represents an outer diameter of an intermediate portion 22, of a valve body 20, that slides on a valve body insertion hole (through hole) 31, φD represents a diameter of an inner peripheral face 121 of a front end member 12 having an injection hole 11 that slides on a front end side (downstream side) spherical portion 230 of the valve body 20, φE represents an outermost diameter (sphere diameter) of a front end side (downstream side) spherical portion 230 of the valve body 20, and φF represents an outer diameter of a neck 223, the smallest diameter portion, which is located toward the rear end (upstream) relative to the front end side (downstream side) spherical portion 230 of the valve body 20 and located at the intermediate portion 22 of the valve body 20, and a side face of the movable core 30 and the inner peripheral face of the nozzle body 10 are not in contact with each other.

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.

A fuel injection valve includes: a housing that includes an injection hole and a valve seat; a needle that includes a flange at a radially outer side of the needle and opens or closes the injection hole; a movable core that is installed on the valve seat side of the flange; a first spring that urges the needle toward the valve seat side; a second spring that urges the movable core toward an opposite side, which is opposite from the valve seat; and a limiting member that is installed on a radially outer side of the needle such that the limiting member enables movement of the movable core between the limiting member and the flange on the valve seat side of the flange. The limiting member includes an outside projection, which supports the second spring; and a tubular portion and an inside projection, which are contactable with the movable core.

A fuel injection valve including: an injection hole body formed of metal and having an injection hole configured to inject fuel; and a metal holder that has a cylindrical shape having an insertion port in which the injection hole body is inserted, and is fusion welded to a portion of the injection hole body located inside the insertion port. The injection hole body includes a body-side fused portion formed by fusion welding, a heat-affected portion which is located on a side of the insertion port with respect to the body-side fused portion, and of which a tissue structure is changed due to heat of the fusion welding, and a seal portion located on an opposite side of the heat-affected portion from the body-side fused portion and extending in an annular shape around a cylinder center line of the holder to come into close contact with the holder.

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.

A fuel injector is configured such that a non-magnetic member constituting a magnetic circuit is deformed by an axial force generated when the non-magnetic member is combined with a cover and a housing, thereby providing airtight contact. The fuel injector is a device that injects fuel into an engine by raising a needle. A magnetic field generated from a coil forms a magnetic circuit when the coil is magnetized, and the magnetic circuit raises the needle. The fuel injector includes a block ring disposed inside the coil, a cover disposed at an upper end of the block ring, and a housing disposed at a lower end of the block ring. The block ring is made of a non-magnetic material and configured to extend the magnetic circuit. When the cover and the housing are combined by being screwed together, the upper end and the lower end of the block ring are deformed to provide airtight contact with respect to the cover and the housing, respectively.

An injection valve may include: a valve needle moving from a closed position to an open position; a calibration spring biasing the needle towards the closed position; an armature moving toward the pole piece to take the valve needle towards the open position with respect to the valve needle; and a pole piece. Some valves include a magnetic ring moving between a first position, with a top side spaced apart from the pole piece and an underside in contact with the valve needle, and a second position where the top side is in contact with the pole piece. A second spring is in parallel to the calibration spring. An upper retaining element connected to a shaft extends in radial direction to limit movement of the armature relative to the valve needle so that the armature connects to the upper retaining element to displace the valve needle towards the open position.

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.