| 摘要 |
PROBLEM TO BE SOLVED: To realize variable control of a fuel injection ratio in accordance with a driving condition. SOLUTION: A needle valve 3 is lifted by generating pressure differential by contracting an extended piezoelectric actuator 18 by furnishing the piezoelectric actuator 18 to be extended and contracted by electrification, the needle valve 3 a tip part of which opens and closes a nozzle hole 1, a main spring 7 to energize the needle valve 3 in the closing direction, a fuel pressure chamber 5 to which fuel of specified pressure is introduced, a differential pressure chamber 10 formed between the needle valve 3 and an actuator piston 20 so as to face against pressure of the fuel pressure chamber 5 and an actuator spring 25 to constantly energize the piezoelectric actuator 18 in the contracting direction. A plunger 11 free to advance and retreat is provided on a stopper block 17c and is projected by a plunger spring 16. When pressure differential to be generated in accordance with applied voltage is small, the needle valve 3 stops at an intermediate lift position making contact with the plunger 11.
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