Patent ID: 7216815
Filing Date: 2007-05-15
Classification: F02M

Abstract:
1. In a servo-valve for a fuel injector equipped with a pressure booster whose working chamber is separated from a differential pressure chamber by a booster piston; an actuator can connect a control chamber of the servo-valve to a low-pressure return; and the differential pressure chamber of the pressure booster can be connected to a low-pressure return or to a return system in which the returns are connected to each other, the improvement comprising a first servo-valve piston having a surface continuously acted on by system pressure, with a first sealing seat on the first servo-valve piston, and a second servo-valve piston embodied in the form of a sealing sleeve and accommodated in an axially sliding fashion on the first servo-valve piston, the second servo-valve piston together with a valve housing, constituting a second sealing seat so that after the second sealing seat is closed by the second servo-valve piston, the first servo-valve piston opens the first sealing seat further.