Plunger type fuel injection pump

Claim 1

A fuel injection pump of the plunger type for an automotive type internal combustion engine, the pump having a plurality of fuel pumping plungers corresponding in number to the number of engine cylinders and each mounted for a reciprocatory movement in a plunger barrel through a fuel pumping stroke in one direction and a fuel intake stroke in the opposite direction, a number of fuel distribution plungers having a source of fuel under pressure connected thereto, the latter number being less than the number of pumping plungers, the distribution plungers also being reciprocably mounted in a plunger barrel for movement between fuel supply positions alternately supplying certain ones of the pumping plungers separately with fuel during the pumping intake stroke of the respective plunger while blocking the return flow of fuel from other pumping plungers during the pumping stroke of the respective pumping plunger, and vice versa, as a function of the position of the distributor plunger, the pumping and distribution plungers all being adapted to be reciprocated in timed relationship to one another by a common engine driven camshaft, each of the plunger barrels defining a fuel chamber at one end for pressurization of the fuel in the pumping plunger chamber during the plunger pumping stroke and for the intake of fuel thereto during the return intake stroke of the plunger, a number of open/closed fuel spill control valve means associated with and equal in number to the distribution plungers, passage means connecting fuel from the distribution plunger fuel chambers to each of the pumping plunger chambers past the spill valve means and back again through the fuel distribution plungers to the source, and electromagnet means operable selectively in timed relationship to reciprocatory movement of the plungers to open and close the spill valve means to control the return of fuel to the source and the pressurization of fuel in the pumping plunger chambers.