| 摘要 |
PROBLEM TO BE SOLVED: To prevent generation of pressure decrease caused by a flow of contraction in a high-pressure side seat part, and to ensure stable operation of a three-way valve. SOLUTION: In a injector, the three-way valve 4 is driven by extending/contracting a piezostack 1, and is selectively seated on a low-pressure seat 45 leading to a low-pressure passage 12 or a high-pressure seat 46 leading to a high-pressure passage 11, and pressure in a control chamber 5 applying back pressure to a nozzle needle 51 is increased/decreased. The three-way valve 4 is comprised of a valve part 41 with a large diameter and a sliding part 42, and pressure is balanced. The overlapping width of the high-pressure seat 46 and a valve face 41a of the three-way valve 4 opposing to the high pressure seat 46 is set to be small, for example below 50μm, and 2°or more of taper angle difference are secured. A flow passage is rapidly expanded in a downstream side of the seat position, and flow speed is reduced. Accordingly, the pressure decrease due to the flow of the contraction is suppressed. COPYRIGHT: (C)2005,JPO&NCIPI
|
