| 摘要 |
PURPOSE:To restrain needle lift in a low speed low load region, prevent uneven injection due to fluctuation of ramaining pressure by a direct injection system and improve combustion with a single injection system, by a two-stepped opening pressure injection valve for stopping a sleeve provided on the needle at a predetermined lift position with a stopper. CONSTITUTION:As fuel pressure is initially raised, a sleeve 15 is lifted to abut against a needle flange 14 so that lift fuel pressure is applied to both sleeve and flange, which are lifted integrally when they overcome the initial urging force of a spring 6. And when the fuel pressure is slightly raised, the upper end of the sleeve 15 abuts against a stopper 19 so that the lift of a needle 4 is restrained even if the fuel pressure is somewhat raised since the needle 4 is not lifted by the sleeve 15 and in the low speed low load region after a valve is determined to be opened. When the fuel pressure is further raised, the needle 4 is lifted only by the fuel pressure and the sleeve 15 is left stopped at the position of the stopper 19 under the middle and high speed middle load regions. Thus, in the direct injection system, uneven injection can be prevented which occurs when the needle is largely lifted. |
