| 摘要 |
PROBLEM TO BE SOLVED: To surely maintain a quantity of fuel which is actually injected in regular quantity. SOLUTION: When a needle 12 is seated on a needle seat 22, a fuel pressure pressurized upward is acted on an outside member 25 of a pressure surface pressurized downward, and if the needle 12 secedes from the needle seat 22, the fuel pressure pressurized upward acts on a whole pressure surface pressurized downward. A first and a second back pressure chambers 16, 17, which are isolated from a nozzle chamber and a coil chamber respectively, are demarcated between a housing inner circumferential surface and a needle outer circumferential surface, and pressurizing fuel sources are connected to the first and the second back pressure chambers 16, 17 respectively. An outside member 28 of the pressure surface pressurized upward is formed in the needle 12 locating inside the first back pressure chamber 16, and its area is made almost equal to an area of the outside member 25 of the pressure surface pressurized downward. An inner side member 29 of the pressure surface pressurized upward is formed in the needle 12 locating inside the second back pressure chamber 17, and its area is made almost equal to an area of the inner side member 26 of the pressure surface pressurized downward. COPYRIGHT: (C)2005,JPO&NCIPI
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