| 摘要 |
PURPOSE:To make it possible to atomize injected fuel in a low speed and low load operating range, by limiting the lift of a needle valve in two stages in accordance with first and second set lift amounts which are set to appropriate values. CONSTITUTION:When the pressure of fuel fed into a sump 13 reaches the valve opening pressure of a spring 16, the lift amount of a needle valve gradually increases but a jet hole 13 is maintained at a small opening area until the fuel pressure reaches a first set lift amount L1, and when the needle valve 15 abuts against the lower end of a central plunger 20, it is stopped once. When the fuel pressure further increases, the plunger 20 is pushed up to restart the lift so that the effective opening area is gradually increased. When the fuel pressure reaches a second set lift amount L2, a space 22 is communicated with an auxiliary fuel passage 23 while a return passage 24 is shut off so that the plunger 20 is exerted with a counter-life force, and therefore the lift valve 15 stops its lift to maintain a predetermined effective opening area. Thus, it is possible to ensure a satisfactory operating characteristic over a wide operating range.
|
