Patent ID: 7527036

Claim:
An internal combustion engine fuel injector comprising: an outer casing ending with a nozzle for injecting fuel into a relative cylinder of the engine; a shutter pin movable for closing and opening said nozzle; a rod member housed in said outer casing and slidable along an axial direction to and configured control the movement of said shutter pin; a control servo valve housed in said outer casing and comprising: a) an actuating device; b) a control chamber, which communicates with a fuel inlet and a fuel outlet passage having a calibrated portion, and the pressure of which controls axial sliding of said rod member housed in said casing; and c) a shutter movable, along a longitudinal axis by said actuating device between a full closed position, in which said outlet passage is thereby closed, and a fully open position, in which said outlet passage is thereby opened, to vary the pressure in said control chamber in order to close and open said nozzle; wherein said control servo valve also comprises an axial rod in a fixed position with respect to said casing; and wherein said outlet passage comes out through an outer lateral surface of said axial rod; said shutter being fitted to said outer lateral surface in an axially sliding and substantially fluidtight manner, and, in said fully closed position, closing said outlet passage so as to be subjected to a zero axial resultant force by the pressure of the fuel and wherein said axial rod and said shutter pin are coaxial with said shaft configured to control said shutter pin, wherein said outlet passage is formed in an end portion of said axial rod and formed in a base fixed to said casing by a ring nut and integral with said axial rod.