Abstract: A pump-injector assembly comprises a plunger slidable in a bore. The plunger has a first or upper position in which fuel is admitted into the lower part of the injector bore through an inlet port, and a second or lower position in which a tapered lower end of the plunger obturates fuel spray nozzles provided through the bottom of the bore. A recess is provided in the plunger wall and communicates with the bottom of the bore through a longitudinal passageway of the plunger. A ramp inclined to the plunger axis is formed by the upper edge of the recess and co-operates with a fuel outlet port located on the wall of the injector bore to control the beginning of the injection. Rotation of the plunger relative to this outlet port permits adjustment of the amount of injected fuel charge.

Abstract: This device comprises a body provided with a bore in which a plunger is slidably mounted, this plunger is movable between a lower position in which it obturates injection nozzles provided through the bottom of the bore, and an upper position where it is spaced from the bottom. Metering means comprise a feed groove provided in the piston wall and opening on the tapered end thereof, this groove having an upper edge inclined to the piston axis. This upper edge co-operates with a fuel inlet port. A similar groove is provided in the piston wall, this groove having an inclined upper edge co-operating with a fuel discharge port. Fuel metering is achieved by rotation of the plunger about its axis.