Fuel injection pump for diesel engine

摘要

A fuel injection pump (1) in a diesel engine (3) contains a cam plate (17) having a cam face (17a) with nonuniform speed cam characteristics. A plunger (12) reciprocates in a cylinder (11) based on the rotation of the cam plate (17) to allow a fuel to be drawn into a high pressure chamber (13) where it is compressed. The compressed fuel is pumped to a fuel injection nozzle (21) within a predetermined period to be injected into a combustion chamber. The speed of pumping the fuel to the injection nozzle (21) can be adjusted by changing the speed of the plunger (12) based on the cam characteristics of the cam face (17a). The cam characteristics are expressed by the cam speed relative to the rotation angle of the cam plate (17). The cam face is characterized by a first cam portion where the cam speed is increased from zero at a predetermined rate; a second cam portion formed continuous to the first cam portion, where the cam speed is increased to the maximum level along a nonlinear curve so that the cam acceleration may be increased; and a third cam portion formed continuous to the second cam portion, where the cam speed is reduced. The cam speed is a factor decisive of the speed of moving the plunger (12). <IMAGE> <IMAGE>