Fuel injection pumps for combustion engines

Claim 1

In a fuel injection pump of the type comprising a rotary distributor and a supply pump which are mounted within a casing and both driven by the combustion engine in which the injectors are to be supplied from the said injection pump, the said rotary distributor being pierced by an axial duct which communicates respectively with a high-pressure radial distributor passage which opens successively into the outgoing lines to the injectors, with radial admission passages adapted to communicate periodically with stationary supply ducts which are continuously connected to the discharge and of the supply pump, with radial bores containing plungers operated by the cams of a nonrotating external cam ring, and with means for metering the fuel flow to the injectors by discharging a fraction of the fuel which is delivered by the plungers, the fact that the metering means consist of a nonrotating metering ring which is slidably mounted on the rotary distributor in leak-tight manner and has a discharge orifice which is capable of communicating in a variable manner with radial discharge passages formed in the rotary distributor and extending from the axial duct of the said distributor in order that the fuel should be discharged in a variable manner both in time-duration and in flow rate according to the axial position taken up by the said metering ring on the said distributor and according to the relative angular position of the said passages, the said ring being on the one hand thrust back elastically by oppositely acting springs towards a position corresponding to zero discharge and on the other hand thrust back axially in the discharge position by all-speed regulating means comprising a bellcrank lever actuated hydraulically by a push-rod plunger in dependence on the supply pressure which exists periodically between two successive injections within the axial duct of the distributor, the movement of the said lever under the action of the said plunger being limited by an adjustable stop and controlled in dependence on a manually adjustable elastic push-rod, the said metering ring being also controlled in the discharge position by means which are responsive to the speed of rotation of the engine and to the controlling action of the accelerator.