| 摘要 |
PROBLEM TO BE SOLVED: To restrict a needle bounce, and to improve injection accuracy in regard to a fuel injection device for injecting and stopping high-pressure fuel into an internal combustion engine. SOLUTION: In this fuel injection device 1, a pressure piston 12 is elevated by a piezoelectric actuator 11 housed in a fuel injection valve 10, and pressure in a control chamber 163 communicating with a pressure chamber 160 through communication flow passages 162 and 162 is increased and decreased so as to elevate a needle 15 slidably held in a fuel injection valve body 100, and an injection hole 106 is opened and closed so as to inject and stop the high pressure fuel led into a fuel reservoir chamber 173. A predetermined part of, at least, one of the inner peripheral wall 141 of a cylinder and a small diameter part 152 of the needle is formed with a back-pressure chamber capacity enlarging chamber 190 or a control chamber capacity enlarging chamber 191. Immediately before fully opening and closing the valve, the pressure in the back pressure chamber 171 or the pressure in the control chamber 163 applied to the needle 15 is instantaneously lowered, and the elevating speed of the needle 15 is restricted to restrict the needle bounce. COPYRIGHT: (C)2009,JPO&INPIT
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