Fuel injection pump for internal combustion engines

Claim 1

In a fuel injection pump the improvement comprising A. a first cylinder, B. a main piston slidably disposed in said first cylinder and defining therewith a pump work chamber, C. means for reciprocating said main piston, D. pressure conduit means communicating with said pump work chamber to carry fuel pressurized in said pump work chamber by each pressure stroke of said main piston, E. a second cylinder, F. an auxiliary piston slidably disposed in said second cylinder, G. means to operate said auxiliary piston synchronously with said main piston, H. a third cylinder, I. a regulator shuttle slidably disposed in said third cylinder and having a work face and at least one oblique control edge, J. a channel connecting said second cylinder with said third cylinder to carry to said work face liquid pressurized by each pressure stroke of said auxiliary piston for displacing said regulator shuttle, K. spring means in engagement with said regulator shuttle for opposing the hydraulic pressure generated by said auxiliary piston during its pressure strokes, L. a bypass channel communicating with said pump work chamber and with said third cylinder, said bypass channel being opened by said control edge during the reciprocation of said regulator shuttle to interrupt the delivery of fuel through said pressure conduit means, M. r.p.m.-dependent means connected to said regulator shuttle for angularly displacing the latter to vary the position of said control edge as a function of the r.p.m., N. a stationary abutment engaged by said regulator shuttle in the initial position thereof, said spring means urging said regulator shuttle into engagement with said stationary abutment and O. an unthrottled conduit means communicating with said third cylinder adjacent the work face of said regulator shuttle for carrying in a free flow the liquid displaced by said work face of said regulator shuttle when moved towards said stationary abutment by said spring means, said unthrottled conduit means permitting said regulator shuttle to return to said initial position during the suction strokes of said main and auxiliary pistons regardless of the magnitude of the r.p.m.