| 摘要 |
In this fuel injector for internal combustion engines, a pressure chamber(8) is provided at an end portion of a pressure increasing piston(9) which is adapted to increase the pressure of a fuel in a pressure increasing chamber(7), and a hollow portion(30) which is on the back side of the pressure increasing piston(9) is opened to the atmospheric air through communication ports(40) formed in an injector body. The pressure increasing piston(9) comprises a small-diameter portion(24) of a plunger which defines a part of the pressure increasing chamber(7), a large-diameter portion(25) of a piston which defines a part of the pressure chamber(8), and a guide ring portion(41) extending downward from the whole circumference of the large-diameter portion(25) and forming a sliding surface with respect to a hollow(26). The hollow portion(30) is provided with a return spring(18) for biasing the pressure increasing piston(9) toward the pressure chamber(8). Since the hollow portion(30) of this fuel injector is opened to the atmospheric air, the resistance to the vertical movement of the fuel pressure i.ncreasing piston(9) is eliminated, and the responsiveness of the needle valve(23) is improved. <IMAGE> |
