Patent ID: 7469843

Claim:
A servo valve for controlling an internal combustion engine fuel injector; the servo valve being housed in a casing of said injector, and being characterized by comprising: an actuator comprising a piezoelectric actuator; a control chamber communicating with a fuel inlet and having a fuel outlet passage; a tubular portion fixed with respect to said casing, and defining an inner cylindrical seat extending along a longitudinal axis; and a cylindrical shutter engaging said inner cylindrical seat in substantially fluidtight manner, and defining, together with said tubular portion, an annular chamber in which said outlet passage comes out; the shutter having a discharge passage adapted to be put in communication with said annular chamber and being slidable axially by said piezoelectric actuator from a closed position, in which it closes said annular chamber and is subjected to a zero axial resultant force by the fuel pressure, to an open position, opening a communication path between said outlet passage and said discharge passage, to close and open a nozzle of said injector.