| 摘要 |
A fuel injection nozzle is disclosed, which comprises a nozzle body provided with an injection hole. A nozzle needle is slidably fitted into the nozzle body, to open or close the injection hole of the nozzle body. The nozzle needle is provided with a needle pin which is insertable into the injection hole. The needle pin involves a taper section which is progressively slenderized toward the combustion chamber of an internal combustion engine. A plurality of axially extending flattened surface portions are formed on the outer peripheral wall of the taper section of the needle pin. As a result, the annular gap region defined between the outer peripheral wall of the needle pin and the inner peripheral wall of the injection hole entails wider and narrower gap sections.
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