Patent ID: 8640675

Claim:
A fuel injector for an internal-combustion engine; the injector ending with a nozzle for injecting fuel in a corresponding engine cylinder and comprising: a hollow injector body extending in an axial direction; a control rod axially movable in said injector body for controlling opening/closing of said nozzle; and a metering servovalve housed in said injector body and comprising: an electro-actuator; a valve body, fixed with respect to said injector body and comprising a first and at least one second piece; a control chamber defined by said control rod and by said first piece and communicating with an inlet and with a discharge channel, which is made in said first and second pieces and comprises at least one calibrated restriction, an axial guide forming part of said second piece and having a lateral surface through which said discharge channel exits; an open/close element coupled to said lateral surface substantially in a fluid-tight way and so as to slide axially under the action of said electro-actuator between a closing position, in which it closes said discharge channel in such a way as to be subjected to a substantially zero resultant of axial force by the pressure of the fuel, and an opening position, in which it opens said discharge channel so as to vary the pressure in said control chamber and, hence, cause axial displacement of said control rod; a perforated body placed axially between said first piece and said second piece and delimiting radially an intermediate portion of said discharge channel, wherein said perforated body is a deformable ring housed in at least one of said first and second pieces; and an additional element defining said calibrated restriction and placed so that it rests axially against one of said first and second pieces, on one side, and against said deformable ring, on the other side.