Robert Boschgmbh

Hans Brett

Josef Guentert

Karl Rapp

Alex Tyrolt

Gabriel Stabentheiner

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. The control of the end of supply is achieved via an oblique control recess in the piston jacket face, which recess communicates with the pump work chamber, and which is embodied by two oblique grooves, which are offset from each other, whose edges toward the pump work chamber form a first oblique control edge, and a second oblique control edge separated from the first oblique edge by a shoulder; the distance between the second oblique control edge and the second face-end control edge disposed above it in the region of the shoulder is less than the diameter of the control opening, so that a zero supply quantity region is formed without sharply reducing the control path region on the pump piston.

Fuel injection pump for internal combustion engines

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.

Growing community of inventors

Bietigheim-Bissingen, Germany

Hans Brett