| 摘要 |
PROBLEM TO BE SOLVED: To provide a fuel injector capable of controlling a needle lift stepwise so as to stably obtain an injection rate while restraining useless work without discharging high pressure fuel supplied to a control chamber to a low pressure passage for controlling the lift in a multistage shape. SOLUTION: A communication control part 10 for controlling a communicating state between a high pressure passage 51 and a second pressure chamber 65 for controlling second lift operation, is arranged between a housing part 11 and a second cotrol piston 24 for cooperating with first lift operation of the needle 21, and is constituted to control so as to restrict a high pressure fuel quantity flowing in the second pressure chamber 65 from the high pressur passage 51 when the second control piston 24 completes the first lift operation. This communication control part 10 controls fuel discharge to the low pressure passage 56 from the high pressure passage 51 to thereby provide this fuel injector for contributing to improving fuel consumption by restraining the useless work.
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