Patent ID: 7228845

Claim:
A fuel injection apparatus for an internal combustion engine comprising: an accumulator for accumulating fuel therein at a predetermined pressure; a booster provided with a control chamber in which fuel pressure changes in accordance with a fuel inflow into the control chamber and a fuel outflow out of the control chamber, and a hydraulic piston that moves in accordance with a change of the fuel pressure in the control chamber, the booster pressurizing the fuel supplied from the accumulator in accordance with a pressurizing operation of the hydraulic piston; a nozzle provided with a back pressure chamber in which fuel pressure changes in accordance with a fuel inflow into the back pressure chamber and a fuel outflow out of the back pressure chamber, and a needle that moves in accordance with a change of the fuel pressure in the back pressure chamber, the nozzle injecting the fuel supplied from the accumulator or the fuel pressurized by the booster in accordance with a valve opening operation of the needle; a hydraulic circuit provided with a fuel passage for transmitting the fuel pressure in the accumulator to the control chamber and to the back pressure chamber, and a fuel passage for releasing the fuel pressure in the control chamber and in the back pressure chamber to a low pressure system; a hydraulic pressure valve provided with a valve body that is disposed in a fuel passage communicated with the control chamber or disposed in a fuel passage communicated with the back pressure chamber to open and block the fuel passage to control an operation of the valve body in accordance with the fuel pressure that is transmitted via a transmission path connected to the hydraulic circuit; and a control valve provided with a valve body that is driven by a two-position actuator, the valve body connecting any one of a high pressure side communicated the accumulator and the low pressure system communicated with a fuel tank to the hydraulic circuit, to control the hydraulic circuit, and to control the fuel pressure transmitted to the hydraulic pressure valve, one of the fuel pressure in the control chamber and the fuel pressure in the back pressure chamber being directly controlled by the control valve, and the other of the fuel pressure in the control chamber and the fuel pressure in the back pressure chamber being indirectly controlled via the hydraulic pressure valve, to control an operation of the booster and an operation of the nozzle, wherein at least one of the transmission path and the hydraulic piston is configured to generate a delay in an operation of the nozzle or the booster that is driven by the other of the fuel pressure in the back pressure chamber and the fuel pressure in the control chamber indirectly controlled by the hydraulic pressure valve, against an operation of the booster or the nozzle that is driven by the one of the fuel pressure in the control chamber and the fuel pressure in the back pressure chamber directly controlled by the control valve.