Injection quantity correcting device for distribution type fuel

Abstract

A distribution type fuel injection pump in which a control sleeve is provided for changing a time of opening a cut off port which is shiftable on a plunger reciprocating synchronously with rotation, and an injection quantity is controlled by adjusting a position of the control sleeve by a tension lever that receives an operation of a governor spring and a centrifugal force governing member, the improved pump in which a piston connected to a lever for determining a maximum shifting position of the tension lever is disposed in a sliding hole, and this piston is energized by a return spring, and the return spring side of this piston is made to be a low pressure chamber and an opposite return spring side is made to be a high pressure chamber. A servo valve is provided in the piston and this servo valve is displaced so as to balance the fuel pressure in the pump chamber and the pressing force of the servo spring and the fuel pressure in the high pressure chamber is controlled. As a result, the piston is caused to move by following the servo valve, and the lever for determining the maximum shifting position of the tension lever is moved and a correction of the full load injection quantity against the rpm of the engine is carried out. The setting force of the servo spring that energizes the servo valve is changed by the pressure applied to a pressure responding member, and a shifting characteristics of the piston by the servo valve is changed so that a correction of a full load injection quantity by the atmospheric pressure and the boost pressure is simultaneously carried out.