Abstract: ABSTRACT A solenoid valve is provided in a fuel injection pump fuel supply path. A communication path communicates with each other an armature chamber, which accommodates an armature, and a spill chamber, which accommodates a head of a valve body and is connected to a lower pressure side. When high pressure fuel is spilt to the low pressure side, an orifice in the communication path reduces a high frequency pressure wave propagated from the spill chamber to the armature chamber, thus reducing deformation or corrosion of the solenoid in over a long period of use.

Abstract: A prestroke control device for a fuel injection pump includes at least one control sleeve slidably fitted on at least one plunger, a control rod engaging the control sleeve, the control rod extending perpendicularly to the plunger and rotatable about an axis thereof for varying an axial position of the control sleeve relative to the plunger to thereby control the prestroke of the plunger, and an actuator for rotatively driving the control rod about its own axis. A counterweight is movable in unison with rotation of the control rod for cancelling a rotating force generated by axial movement of the control sleeve and acting upon the control rod.

Abstract: A unit fuel injector includes a body, the body having a fuel supply and return chamber, a fuel supply passage communicating with the chamber, and a drain passage communicating with the chamber. The body is provided with a pump mechanism, an injection nozzle mechanism for injecting high pressure fuel from the pump mechanism, and an electromagnetic valve mechanism for escaping the high fuel pressure from the pump mechanism. The electromagnetic valve mechanism include a poppet-type valve member. Immediately when a head of the valve member is disengaged from a valve seat facing the fuel supply and return chamber, the pressurized fuel within the pump mechanism is spilled or fed to the fuel supply and return chamber. The unit fuel injector further includes an auxiliary valve mechanism for opening and closing the drain passage. The auxiliary valve mechanism includes a valve port at one end of the drain passage, and when the head of the valve member abuts against a stop portion of the body, the valve port is closed.