An electromagnetic valve used in a fuel system, in which at least a portion of a member constituting an magnetic circuit in an electromagnetic drive unit includes 0.15-0.45 mass % (inclusive) Ni, 0.65-1.0 mass % (inclusive) Al, 9.2-10.3 mass % (inclusive) Cr, and 0.90-1.6 mass % (inclusive) Mo, and the remainder comprises an alloy material comprising Fe and unavoidable impurities. The alloy material may further include 0.05-0.15 mass % (inclusive) Pb.

A fuel injection valve includes: a coil; a stationary core to generate a magnetic force; a movable structure including a moving core and a valve body and internally having a movable flow passage; and a body that internally accommodates the movable structure and internally has a part of the flow passage. The movable structure includes a throttle portion at which a passage area of the movable flow passage is partially throttled. The flow passage includes a throttle flow passage defined by the throttle portion and a separate flow passage between the movable structure and the body. A passage area of the separate flow passage is smaller than a passage area of the throttle flow passage. A position of the separate flow passage in a direction perpendicular to a moving direction of the movable structure is different from an outermost peripheral position of the moving core.

There is provided a hollow composite magnetic member obtained by partially reforming a hollow member which is formed of a ferromagnetic material containing Cr of 15 mass % or more and 18 mass % or less, in which the reformed portion includes an alloy containing Cr of 8 mass % or more and 18 mass % and Ni of 6.5 mass % or more and 50 mass % or less. Accordingly, a hollow composite magnetic member having a small width of the nonmagnetic portion and a fuel injection valve having the same can be provided.

A fuel injection valve includes: a coil that is configured to generate a magnetic flux when the coil is energized; a stationary core that is configured to become a passage of the magnetic flux; a movable core that is configured to be attracted to the stationary core when the movable core becomes a passage of the magnetic flux; and a magnetic-flux limiting portion that is displaced from the stationary core in an axial direction while a degree of magnetism of the magnetic-flux limiting portion is lower than a degree of magnetism of the stationary core. A boundary between the stationary core and the magnetic-flux limiting portion is defined as a limiting boundary, and an imaginary extension line, which is formed by extending the limiting boundary toward the movable core, is defined as a boundary extension line. The limiting boundary is tilted relative to the axial direction.

A movable core is driven by a magnetic attraction force with a fixed core to move a valve body to inject fuel. A yoke accommodates the fixed core. A coil is in a coil chamber between the fixed core and the yoke. The coil chamber is filled with a filling resin member being electrically insulative. The fixed core has a core facing surface facing the movable core and includes a protruding portion that protrudes radially outer side and is in contact with the yoke to conduct the magnetic flux. A resin molding flow channel is formed in the protruding portion to cause molten resin serving as the filling resin member to flow into the coil chamber. A length of the protruding portion along a cylinder center line is set to be shorter toward a radially outer side.

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 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.

Disclosed is a fuel injection valve in which a movable core and a fixed core are enclosed in a cylindrical body. The cylindrical body has an annular groove formed therein, on an outer circumferential side of a region in which the movable core and the fixed core are opposed to each other, to define a thin portion of small wall thickness. In a cross section taken along a center axis of the fuel injection valve, the thin portion has curved line sections on both end sides thereof in a direction along the center axis such that the curved line sections respectively connect a bottom of the annular groove to side edges of the annular groove by curved lines. The curved line sections are provided over a range of larger dimension, from the respective side edges in the direction along the center axis, than a depth dimension of the annular groove.

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.

Provided is a fuel injection device that sets an electromagnetic attraction force, which is generated in a magnetic gap between a magnetic core and a movable element, to more than or equal to a desired value. The fuel injection device includes a movable element that is attracted to the magnetic core and a housing provided opposite to the movable element in a direction orthogonal to an axial direction, wherein the movable element is configured so that an axial length of the movable element is 1.25 to 1.46 times as long as an axial length of the housing.