FUEL ELECTRO-INJECTOR ATOMIZER FOR A FUEL INJECTION SYSTEM FOR AN INTERNAL COMBUSTION ENGINE

An atomizer (10) of a fuel electro-injector (1) for a fuel injection system for an internal combustion engine having a passage (13) that extends along a longitudinal axis (5) and includes a guide hole (46); the atomizer (10) has a sealing seat (21) defined by a chamfer or a fillet, which joins an cylindrical surface (41) inside the passage (13) and an external front surface (40); the atomizer (10) is equipped with a needle (27) having a first slider portion (25) coupled in an axially sliding manner to the guide hole (46), so as to define a dynamic seal and be axially movable under the thrust of an electro-actuator (32) from a closed position, in which a head (20) of the needle (27) is coupled to the sealing seat (21) to close the outlet and define a static seal; the diameter (D) of the dynamic seal is between 2.5 e 3.3 mm, while the difference between the average diameter of the static seal and the diameter of the dynamic seal is such as to generate a maximum axial imbalance of 50 N due to the effect of the fuel pressure around the needle (27) when the latter is positioned in the closed position.