摘要 |
A fuel injector for injecting fuel into a combustion chamber of internal combustion engine with an injection flow rate that changes during an injection cycle. It provides a gradual increase in fuel injection rate near the beginning of the cycle and a substantially instantaneous shut off of fuel injection at the end of the cycle. The valve includes a nozzle body with a fuel inlet and a nozzle portion which has an injection port therein, a first fuel passage for communicating the injection port with the fuel inlet, a first slidable needle valve element, a first spring for urging the first needle valve element to close the first needle valve element, a second fuel passage for communicating a back pressure chamber with the fuel inlet, an ON-OFF valve for opening and closing the second fuel passage and throttling the effective area thereof when the second fuel passage is open thereby controlling the pressure of the first back pressure chamber means.
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