A fuel injection apparatus includes a valve element provided with a flow passage allowing a fuel to flow therethrough, a valve seat which the valve element will contact with or separate from, and a casing accommodating therein the valve element and the valve seat. During valve opening in which the valve element is separated from the valve seat, the fuel flowing through the flow passage is discharged through a gap between the valve element and the valve seat. A direction in which the valve seat is placed relative to the valve element is the same as a direction of the fuel flowing in the flow passage. The fuel injection apparatus further includes a discharge-side flow passage in which the fuel to be discharged during valve opening is allowed flow. The discharge-side flow passage is formed outside an outer peripheral portion of the valve seat.

A fuel injection apparatus includes a valve element provided with a flow passage allowing a fuel to flow therethrough, a valve seat which the valve element will contact with or separate from, and a casing accommodating therein the valve element and the valve seat. During valve opening in which the valve element is separated from the valve seat, the fuel flowing through the flow passage is discharged through a gap between the valve element and the valve seat. A direction in which the valve seat is placed relative to the valve element is the same as a direction of the fuel flowing in the flow passage. The fuel injection apparatus further includes a discharge-side flow passage in which the fuel to be discharged during valve opening is allowed flow. The discharge-side flow passage is formed outside an outer peripheral portion of the valve seat.

A fuel injector includes a collar, which may be formed of a porous, sintered material, the collar being located around the needle and allowing a restricted fluid pathway, such as orifices through the collar, between first and second volumes of fuel, the collar being located in a section of the nozzle body which has a greater cross-sectional area than the rest of the bore.

A fuel injector includes a collar, which may be formed of a porous, sintered material, the collar being located around the needle and allowing a restricted fluid pathway, such as orifices through the collar, between first and second volumes of fuel, the collar being located in a section of the nozzle body which has a greater cross-sectional area than the rest of the bore.

A needle for a jet device includes a needle body and a tapered part arranged at the end of the needle body, in which the needle body is circumferentially provided with supporting bodies, so that when the needle is assembled in a nozzle of the jet device, the outer surfaces of the supporting bodies are coordinated with an inner chamber of the nozzle to limit the position of the needle body and form fluid channels among the supporting bodies, thereby to effectively prevent the needle from deviating from the spout of the nozzle or from radially swinging.

A needle for a jet device includes a needle body and a tapered part arranged at the end of the needle body, in which the needle body is circumferentially provided with supporting bodies, so that when the needle is assembled in a nozzle of the jet device, the outer surfaces of the supporting bodies are coordinated with an inner chamber of the nozzle to limit the position of the needle body and form fluid channels among the supporting bodies, thereby to effectively prevent the needle from deviating from the spout of the nozzle or from radially swinging.

An injector has an injector body including an injector cavity defining an inner wall and a longitudinal axis, an injector orifice and a plunger slidably disposed within the injector cavity. The plunger has an outer portion and an inner portion at different locations longitudinally along the plunger. The inner portion has a plurality of surface portions including a guiding portion configured to substantially mate with the inner wall of the injector cavity, guide the plunger to slidably move in a direction along the longitudinal axis and substantially prevent the plunger from laterally translating within the injector cavity. The plurality of surface portions also includes a restriction portion configured to form a restrictive cavity between an exterior surface of the inner portion and the inner wall of the injector cavity axially along a length of the inner portion.

An injector has an injector body including an injector cavity defining an inner wall and a longitudinal axis, an injector orifice and a plunger slidably disposed within the injector cavity. The plunger has an outer portion and an inner portion at different locations longitudinally along the plunger. The inner portion has a plurality of surface portions including a guiding portion configured to substantially mate with the inner wall of the injector cavity, guide the plunger to slidably move in a direction along the longitudinal axis and substantially prevent the plunger from laterally translating within the injector cavity. The plurality of surface portions also includes a restriction portion configured to form a restrictive cavity between an exterior surface of the inner portion and the inner wall of the injector cavity axially along a length of the inner portion.

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.

A nozzle needle for an injector for injecting fuel includes at least one guiding section with a recess and a guiding surface configured to rest against an inner surface of a nozzle body of the injector, the recess at least partially delimiting the guiding surface and being configured to allow a flow of fuel along the guiding section, and the guiding surface being guided about the longitudinal axis of the nozzle needle in a helical manner.