Abstract: A fuel injection pump for internal combustion engines having a pump piston guided in a cylinder liner and defining in the cylinder liner a pump work chamber, which piston cooperates with a control opening in the wall of the cylinder liner to control the high pressure delivery. To control the supply onset, the pump piston has on its face end three control edges offset from each other along the length of the piston; a zero supply quantity region is provided between the first control edge, which controls a very early supply onset, and the remaining control edges.

Abstract: An edge controlled fuel injection pump for internal combustion engines, whose axially and rotationally movable pump piston, guided within the pump cylinder, has an improved leakage oil return system, which avoids piston wear and increased oil leakage even under very high injection pressures and relatively short piston strokes. The pump piston has an annular leakage oil collecting groove next to, but separate from, the recess that serves to end the fuel delivery, and a plurality of narrow leakage oil return grooves, which are formed in the outer surface of the piston diametrically opposite the recess and are connected with the collecting groove. Of these leakage oil return grooves, at least one is always connected with a leakage oil bore in the pump cylinder to a chamber of low pressure in the pump during the useful stroke of the piston.