Patent ID: 6854446

Claim:
A fuel injection device characterized by comprising: a pressure accumulator communicated with a fuel pool in a fuel injection nozzle via a main fuel line, which accumulates pressure to set liquid fuel, which is pumped from a fuel pressurization pump, to a predetermined pressure; a pressure-blocking valve provided partway along the main fuel line that communicates the fuel injection nozzle with the pressure accumulator, which blocks outflow of pressurized fuel from the fuel injection nozzle side toward the pressure accumulator side; a fuel chamber for injection control which communicates at a downstream side, relative to the pressure-blocking valve, of the main fuel line that communicates the fuel injection nozzle with the pressure accumulator; an injection control valve provided at the fuel chamber for injection control, which obtains closure of a needle valve in the fuel injection nozzle by effecting liquid fuel pressure at the fuel chamber for injection control, and opens the needle valve and obtains performance of fuel injection by removing liquid fuel of the fuel chamber for injection control; a pressure intensifier having a cylinder and a piston, which communicates with the fuel chamber for injection control at the downstream side, relative to the pressure-blocking valve, of the main fuel line that communicates the fuel injection nozzle with the pressure accumulator; and a piston control valve which moves the piston of the pressure intensifier by flowing in fuel from the pressure accumulator to the cylinder or by flowing out fuel in the cylinder, and obtains an increase of fuel pressure of the downstream side relative to the pressure-blocking valve, wherein flow amount-changing means capable of changing flow amounts of the fuel that is flowed into the cylinder or flowed out by the piston control valve is provided.