Patent ID: 6138923
Filing Date: 2000-10-31
Classification: F02M

Abstract:
An injector comprising an intensified chamber formed in an injector body and supplied with a fuel from a common fuel supply rail, a boosting piston for intensifying the fuel in the intensified chamber, the boosting piston being actuated by a hydraulically actuating fluid supplied into a pressure chamber in the injector body, a needle valve arranged in the body so as to open and close nozzle holes to inject the fuel from the intensified chamber, a control valve for controlling the supply of the hydraulically actuating fluid into the pressure chamber to actuate the boosting piston, a return spring for forcing the boosting piston towards its home position, and a casing arranged around the periphery of the injector body to form a fuel chamber and provided with a fuel inlet and a fuel outlet, both of which are communicated with common fluid supply rail, wherein the boosting piston includes a radially enlarged portion forming a part of a surface defining the pressure chamber, and a radially reduced portion forming a part of a surface defining the intensified chamber, both of which portions are fitted for linear sliding movement in a concave in the injector body, a sealing member is provided between relatively sliding surfaces of the radially enlarged portion of the boosting piston and the concave, and a split ring having a diametrical resiliency is provided between the relatively sliding surfaces at any location determined between the sealing member and the pressure chamber.