| 摘要 |
PURPOSE:To minimize the size of the second spring by providing a push rod to be slided via a rod holder inside a nozzle holder to operate both of the first and the second springs at the time of main injection for reducing the weight of inertia for smooth operation. CONSTITUTION:When a fuel pressure reaches to an initial valve-opening pressure P1, a needle valve 6 goes up overpowering the first spring 10 and stops once when a pushing body 8 touches the lower end face 13a of a push rod. Here, an injection ratio is kept small since an opening volume of an injection hole 7 is small. Then, if the fuel pressure reaches P2, the pushing body 8 pushes up a push rod 13 against the second spring 11 to enlarge the opening are to increase the injection ratio. Here, the needle valve 6 receives the pushing force from both of the first and the second springs 10 and 11 to fall down until the fuel pressure goes down from P2 to P3. When separated from the rod 13, the pushing body 8 receives the pushing force only from the first spring 10 to fall down and close the valve. This construction permits to operate the needle valve smoothly only by lifting operation of the rod 13 and minimize the size of the second spring. |
