FUEL INJECTION DEVICE

PURPOSE:To add a simple mechanism so as to supply a pertinent fuel injection amount in the whole rotational range required for an engine by providing a means for changing a set fuel pressure value in addition to a correction function for maintaining, to a constant value, the difference pressure between the front and rear parts of the injector of a pressure regulator. CONSTITUTION:Fuel pressure of an injector 4 is controlled by a pressure regulator 9 by returning excessive fuel to a fuel tank 1 through a fuel passage 10, and the pressure regulator 9 consists of a fuel chamber 14 which is surrounded by a cover 11 and a diaphragm 12 and communicated to the injector 4 through a passage 13, and a negative pressure chamber 16 which is surrounded by a cover 15 and the diaphragm 12. The diaphragm 12 is provided with a valve 18 which is paired with a sheet 17 integrated with the cover 11, on the fuel chamber 14 side, and a spring 20 is provided between the cover 15 and a plate 19 in the negative pressure chamber 16. Fuel pressure in the fuel chamber 14 is adjusted in such a way that the diaphragm 12 is deviated so as to have the fuel pressure balanced with summation of pressure of the negative pressure chamber 16 and force of the spring 20, and the interval between a valve 18 and a sheet 17 is changed to discharge excessive fuel.