US 5,291,867 AGranted

Fuel injection pump for internal combustion engines

AssigneeRobert Bosch GmbH

InventorsKarsten Hummel, Karl Rapp, Ernst Ritter

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Abstract

A fuel injection pump for internal combustion engines having in-line cylinder bushes, in each of which a pump piston defining a pump work chamber is guided, the piston being rotatable by a governor rod for the sake of fuel supply quantity regulation. Mounted on the pump housing is an adjusting device, in which an adjusting piston is guided axially parallel with the governor rod; the adjusting piston has a radial pin, which protrudes through a slit in the wall of the adjusting device and pump housing into an oblong slot of the governor rod, thus limiting the adjusting motion of the rod in certain operating ranges. The position of the adjusting piston determines the maximum governing travel of the governor rod in the full-load direction upon engine starting. The adjusting piston is variable via an adjustable stop acting upon one face end thereof and is also variable as a function of temperature via a temperature-dependent spring element disposed on its circumference. In addition, with its face end, the adjusting piston defines a pressure chamber, by way of which the adjusting piston can be adjusted pneumatically in the direction of a zero supply quantity; via two stops of the oblong slot, the adjusting piston moves the control rod with it in the process and in this way interrupts the fuel delivery.

Claims7

Dependent claims

A fuel injection pump for internal combustion engines, comprising in-line pump pistons guided in cylinder liners (3) and each defining one pump work chamber;

a governor rod (5) is supported longitudinally of the fuel injection pump in a pump housing (1) and is displaceable by a positioner in order to adjust a fuel injection quantity by the pump pistons and is joined to the positioner via a resiliently yielding drag member;
and an adjusting device (7), said adjusting device including an adjusting piston (9) adjustable away from a stop (41) by a pressure medium counter to a force of a restoring spring (35), the adjusting piston acting upon the governor rod via an intermediate member (13) positioned between first and second stops (19, 21), said stops being located in succession in the direction of motion and disposed on at least one part that is moved with the governor rod upon its fuel injection quantity adjusting motion, said stops being arranged for limiting a governor rod travel that is predetermined by the spacing of said stops, the adjusting piston (9) of the adjusting device (7) is displaceable as a function of the engine operating temperature by a temperature-dependent spring element (49), which spring element is disposed on a circumference of the adjusting piston and is supported at one end on a further third stop (51) that is structurally connected to the housing and acts counter to the restoring spring (35), the displacement of the adjusting piston (9) being such that the possible adjusting travel of the governor rod (5) is variable in the direction of a full-load supply quantity by contact of one of said first and second stops (19, 21) with the intermediate member (13).

Dependencies are inferred from the claim text.