| 摘要 |
PROBLEM TO BE SOLVED: To reduce a variation in an injection quantity cycle by restraining a variation in an orifice flow rate by review of an orifice shape arranged in a passage communicating with a control room in an injector used for a common rail fuel injection system of a diesel engine. SOLUTION: This injector 1 lifts a nozzle needle 3 by increasing-decreasing pressure of the control room 4 for making valve closing directional pressure act on the nozzle needle 3 by driving a three-way valve 10. A main orifice 51 is arranged in an orifice passage 52 for communicating the control room 4 with the three-way valve 10, and a sub-orifice 41 is arranged in an orifice passage 42 for communicating the control room 4 with a high pressure passage 15. A shape of a control room 4 side or three-way valve 10 side opening end part of the main orifice 51 and a control room 4 side opening end part of the sub-orifice 41 is formed in the shape of rapidly expanding a flow of a control fluid in the opening end part, and a separation point of an orifice passing fluid is stabilized, and a variation in the orifice flow rate is restrained. COPYRIGHT: (C)2005,JPO&NCIPI
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