Patent ID: 8602322

Claim:
A fuel injection valve for an accumulator injection system having a pressurized fuel accumulator and a combustion chamber, the fuel injection valve comprising: a nozzle having a valve seat, a nozzle hole, and an inner space; a nozzle needle disposed in the inner space of the nozzle and reciprocally slidable in the inner space of the nozzle; a fuel passage for conveying fuel from the fuel accumulator to the nozzle hole; a control rod having a groove; and a fuel drain line, wherein the nozzle and the nozzle needle are configured such that lifting the nozzle needle from the valve seat injects the fuel through the nozzle hole, wherein the control rod is configured such that the groove communicates with the fuel passage prior to a fuel injection shot, the groove is disconnected from the fuel passage and the fuel is injected through the nozzle hole during the fuel injection shot, and the groove communicates with the fuel passage at the end of the fuel injection shot, wherein the fuel passage comprises a first port, a second port, and a control port, the first port being configured such that the pressure of the fuel acts on the nozzle needle upward so as to open the nozzle, the second port being configured such that the pressure of the fuel acts on the control rod and the nozzle needle downward so as to close the nozzle needle valve, and the control port being configured such that the pressure of the fuel acts on the control rod and the groove and releases the pressure of the fuel in response to lifting the nozzle needle, and wherein the fuel drain line and the groove are configured such that lifting the control rod brings the groove into communication with the fuel drain line while the groove is disconnected from the fuel passage during the fuel injection shot such that the pressure in the groove is reduced to the drain line pressure level, and the groove comes into communication with the fuel passage again as the control rod is lowered after the pressure in the groove is reduced.