Abstract: In a fuel injection valve, a nozzle body having a valve seat, and mounted through an electrically conductive spacer on a nozzle holder, a needle valve and an insulating layer constitute an ON-OFF switch for producing signals indicating the beginning and completion of injection, and an electrical insulation member provided between the rear end surface of the needle valve and the spacer to maintain the insulated state between the needle valve and the nozzle body during the fuel injection operation.

Abstract: A source of high pressure fuel supply is hydraulically connected with a fuel tank or reservoir through a low pressure supply pump. Pressurized fuel from the high pressure fuel supply source is communicated to an injector which comprises a body having an axial bore therein and a plunger axially slidably received in the bore of the injector body. The injector body has a fuel induction passageway to which the pressurized fuel is communicated from the supply source while the plunger has a passageway means therein which is communicated with or communicable with the fuel injection passageway at one end thereof. Upon a reciprocal movement of the plunger, the passageway means at the other end is brought into or out of communication with a nozzle hole formed in the injector body by a controllable amount and duration thereby starting or terminating a controlled rate of injection of the pressurized fuel into an engine.

Abstract: A fuel injection apparatus for internal combustion engines, which includes a servo piston having a large size portion and a small size portion. The large size portion defines a servo-pressure chamber and a counter-servo-pressure chamber, and the small size portion a pump working chamber, respectively. Operating fluid is supplied from an exclusive pressure feed means to the servo-pressure chamber and the counter-servo-pressure chamber alternately through the action of a solenoid controlled selector valve, while fuel is supplied to the pump working chamber from another pressure feed means provided separately from the firstmentioned pressure feed means. The large size portion of the servo piston has its outer peripheral surface formed with an oblique-base notch opening in its end face facing the servo-pressure chamber. The piston housing has its peripheral wall formed with a spill port which is located for engagement with the oblique-base notch.