| 摘要 |
PROBLEM TO BE SOLVED: To provide an injector easily performing control of a fine injection amount even in a constitution where a boost device is operated at injection. SOLUTION: Stroke of a boosting piston 51 is started and a fuel pressure of a boost chamber 53 and a fuel reservoir 44 is enhanced on a midway of a differential pressure fuel passage 26 for connecting a differential pressure switch valve 12 and a differential pressure chamber 16. Thereby, a flow passage area of a differential pressure fuel passage 26 (portion attached with a broken line) in which a boosting speed control valve 62 connects the differential pressure chamber 16 to a low pressure side is increased from a small opening area to a large opening area. Thereby, pressure reduction of the differential pressure chamber 16 is suppressed to the midway when the fuel pressure of the boost chamber 53 is enhanced, a stroke speed of the boosting piston 51 is made slow, and rising of a boost value of the boost chamber 53 relative to the stroke amount of the boosting piston 51 is suppressed. An injection amount at the fine injection in which an injection period is short, therefore, is suppressed and the fine injection accuracy is enhanced. COPYRIGHT: (C)2008,JPO&INPIT
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