Abstract: A fuel injector includes a center tube which conducts fuel flow. A flat-seat poppet valve surrounds a lower portion of the center tube and controls the application of pressurized fuel to first and second check end passages to assist in check closure.

Abstract: A fuel injector includes a valve member disposed at the upper end of the injector case adjacent a valve recess. The valve member includes a bore and a counterbore, and a tube having a bore is slidably disposed within the counterbore. The valve member bore and the tube bore define a fuel flow passage substantially coincident with the central axis of the injector. The valve member is spring biased to an open position to communicate fuel at transfer pump pressure to the valve recess. At the initiation of the injection cycle, an actuator, preferably an electrical solenoid, closes the valve against the spring force so that fuel is communicated along the central passage to a nozzle.

Abstract: A fuel system for an internal combustion engine comprises a plurality of pump/injectors each of which comprises a housing within which is provided a plunger-type fuel pump, a spill valve, an injector and a non-return valve. The pump is arranged to supply fuel at high pressure to the injector and to a port of the spill valve. The other port of the spill valve is connected to a source of fuel through a non-return valve, and also to the spring chamber of the injector through the non-return valve. The spring chamber communicates through a restrictor with a common passage the pressure within which is controlled by a valve.

Abstract: A fuel pumping apparatus comprises a body defining a first bore within which a pumping plunger is reciprocable. The first bore communicates with a spill valve. A pilot piston is moveable within a pilot bore under the influence of the pressure within the first bore. A piston member is slidable within a blind drilling provided in the pilot piston such that upon movement of the pilot piston, fuel within the drilling is pressurised to a higher pressure than fuel within the first bore. Passage means connects the drilling with a fuel injection nozzle.

Abstract: A pump/injector includes a high pressure pump which delivers fuel to an inwardly opening fuel injection nozzle. Also provided is a spill valve which is connected to the pumping chamber of the pump and through which the pumping chamber is filled with fuel from a source by way of a first non-return valve. Connected intermediate the spill valve and the non-return valve is a branch passage to the spring chamber of the nozzle and the pressure in the spring chamber when the spill valve is opened to terminate delivery of fuel is controlled by a valve.

Abstract: A fluid connection between a pair of passages (12,15) which open onto surfaces (13,16) in respective body parts which are secured together. About one of the passages a sealing zone (21) is established in a respective surface and the zone is surrounded by a depression (20) which communicates with a drain passage.

Abstract: A unit injector for supplying fuel to an internal combustion engine has a bore (21) in which is mounted a pair of plungers (22) extending from the opposite ends of the bore. The plungers are actuated by cams (26) which are mounted on a pair of cam shafts of the engine.

Abstract: A fuel system for an internal combustion engine includes a pumping apparatus having a high pressure pump to which fuel is supplied by a low pressure pump. The low pressure pump draws fuel through a filter unit from a fuel tank. A reservoir chamber is provided above the apparatus and this in use is replenished with fuel through an inlet. The chamber has a restricted outlet communicating with the fuel inlet of the pumping apparatus. In the event that air is drawn into the system in sufficient quantity to stop the engine as for example if the fuel tank is drained of fuel, the fuel in the reservoir chamber flows through the restricted outlet to the fuel inlet of the apparatus to enable the engine to be restarted quickly.

Abstract: A liquid fuel injection pumping apparatus comprises a plunger reciprocable in a bore, an electrically operated spill valve to divert fuel pumped by the plunger to prevent it reaching an outlet. In an emergency the spill valve can be closed and valve means used to provide a restricted flow of fuel to the bore to allow continued fuel supply to an associated engine. The plunger defines a spill path which is opened at a predetermined position during the inward movement of the plunger and this terminates delivery of fuel from the bore to the outlet.