Abstract: A distributor-type fuel injection pump is provided with a hydraulic injection adjusting mechanism whose injection adjusting piston adjusts the cam gear unit for driving the pump plunger to execute strokes corresponding to the desired position of the start of injection. The injection adjusting piston defines a control space on one side and a spring space receiving a return spring on the other side. The control space is connected via a throttle bore with the pump interior space which is filled with fuel by a delivery pump. The fuel pressure is adjusted by a pressure control valve. To prevent unstable pressure vibrations on the injection adjusting piston, which leads to defects in the operation of the fuel injection pump, the spring space is connected on one side with the suction side of the delivery pump via a first throttle and on the other side with the pressure side of the delivery pump via a second throttle having a smaller throttle cross section.

Abstract: A delivery valve for controlling fuel flow from a fuel-injection pump to an internal combustion engine and comprising a seat member, a closing member movable relative to the seat member for controlling flow of fuel through the passage channel of the seat member, and a spring for biasing the closing member into engagement with a valve seat on the seat member. The closing member includes a return-flow collar sealingly displaceable in the passage channel and located outside of the passage channel in an open position of the delivery valve, and a control collar located closely adjacent to the return-flow collar. The control collar has a diameter corresponding to a diameter of the passage channel, a periphery and at least one recess formed on the periphery and extending along an entire length of the control collar.