| 摘要 |
PURPOSE:To provide the possibility of absorbing quantitative error caused by manufacturing error in a fuel injection nozzle wherein lift of a needle valve can be restrained, by successively forming two tapered parts differing in tapered angle, at the end of the needle valve. CONSTITUTION:Fuel injection is performed from a jet 18 by a fuel injection nozzle 6 such that the pressure of fuel sent into a pressure chamber 15 pushes a needle valve 13 against a spring 24 to be opened. At this time, the lift of the needle valve 13 is restrained by the axial displacement, corresponding to fuel pressure, of a plunger member 33 to which the fuel pressure is applied. In this invention, a fuel setting part 19 which serves as a means for changing the jet area of a jet 18 is formed at the end portion of the needle valve 13. The fuel setting part 19 consists of a throttle portion 38 straightly running from the tip side of the needle valve 13, a primary tapered portion 39 and a secondary tapered portion 40 which has a larger tapered angle than the primary one. The value of the lift is set to the approximately middle of the primary tapered portion 39. |
