| 摘要 |
PROBLEM TO BE SOLVED: To provide a fuel injection valve having a control structure of a nozzle needle that reduces irregular variation of fuel injection amount at a lifting time of the nozzle needle, closes the ratio of the fuel injection amount to a conduction time of a magnet of a back pressure control section, and can eliminate variation of the fuel injection amount every fuel injection valve connected to a common rail. SOLUTION: Gradual reduction of the gap between a top (top 31A having arc-shaped cross section) of a valve piston 31 and a facing surface 23B defining an orifice 23 for opening/closing is focused on, the orifice 23 for opening/closing communicating with a control pressure chamber 19 is opened or closed by a control valve body (valve ball 24) to open or close an injection hole by the nozzle needle via the valve piston 31, and throttle cross cross-sectional area between the top (top 31A having projecting arc-shaped cross section) of the valve piston 31 and an opening 23A of the orifice 23 is gradually reduced as it approaches the opening 23A from the outer edge 31B of the valve piston 31. COPYRIGHT: (C)2004,JPO&NCIPI
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