| 摘要 |
PURPOSE:To promote the atomization of fuel without the spray angle of fuel being increased, by forming concavities and convexities in the outer peripheral surface of front end section of a needle which forms a jet hole between itself and a nozzle. CONSTITUTION:A jet hole is formed between a nozzle 51 and the cylindrical section 52b of a needle 52 in a fuel injection valve. Fine concavities and convexities are formed in the outer peripheral surface 52a of front end section of the needle 52 along which fuel is guided, and therefore, the outer peripheral surface 52a is roughened. Accordingly, the stream of fuel is greatly disturbed to promote the atomization of fuel, and therefore, the mixing ability of fuel with air may be enhanced. Further, since it is possible to set the spray angle of fuel to be small, the adhesion of fuel onto the wall surface of an intake-air passage is reduced, resulting in enhancing the responsiveness of the engine during transient operation.
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