Patent ID: 8496192

Claim:
A fuel injector comprising: an injection valve comprising an injection nozzle; a mobile needle for regulating a fuel flow through the injection valve and ending with a shutting head, the shutting head for engaging a valve seat of the injection valve and being arranged externally with respect to the injection valve and presenting a predetermined sealing diameter; an actuator for displacing the needle between a closing position and an opening position of the injection valve; a closing spring which maintains the mobile needle in the closing position of the injection valve, for pushing the shutting head against the valve seat in a sense contrary to a feeding sense of the fuel; a supporting body having a tubular shape and presenting a feeding channel within which the mobile needle is arranged and in which fuel is fed at high pressure; and a balancing channel, at ambient pressure, being coupled to the mobile needle and hydraulically isolated from the feeding channel by an elastic diaphragm, the mobile needle having an end opposite to the shutting head that rests on the elastic diaphragm, wherein the balancing channel presents an internal diameter equal to the sealing diameter of the shutting head and the elastic diaphragm is laterally welded to walls of the balancing channel, the elastic diaphragm having a diameter equal to the sealing diameter of the shutting head; and a sealing body where the valve seat of the injection valve is defined for fluid-tightly closing the feeding channel, wherein the sealing body comprises a disc-shaped capping element that fluid-tightly closes the feeding channel, and a guiding element that elevates from the disc-shaped capping element, the disc-shaped capping element having a tubular shape and accommodates the mobile needle therein.