Patent ID: 7191963

Claim:
Fuel injector ( 1 ) comprising: a cylindrical body ( 2 ), which houses an injection nozzle ( 4 ) regulated by an injection valve ( 5 ) provided with a moveable pin ( 8 ); a first fuel supply line ( 15 ); an injection chamber ( 6 ) communicating with the first supply line ( 15 ), housing a lower portion of the pin ( 8 ) and delimited below by a valve seat ( 7 ) of the injection valve ( 5 ); a control chamber ( 11 ) communicating with the first supply line ( 15 ) and housing an upper portion of the pin ( 8 ); and a control valve ( 19 ), which is actuated by an electromagnetic actuator ( 22 ) in order to be displaced from an open position, in which it puts the control chamber ( 11 ) in communication with a drain ( 18 ) for the fuel at low pressure, against the action of a first spring ( 23 ); wherein the electromagnetic actuator ( 22 ) comprises at least two electromagnets ( 25 ), which are identical to each other, are stacked on top of each other and are arranged mechanically in series with each other so that the respective thrust forces are added together; the injector ( 1 ) being characterised by the fact that each electromagnet ( 25 ) comprises a magnetic nucleus ( 26 ) of toroid shape, which houses a respective coil ( 27 ) and has a central hole ( 28 ) in which a respective pin ( 29 ) is engaged; each pin ( 29 ) being mounted in a sliding manner inside the corresponding central hole ( 28 ) and being integral with a respective armature ( 30 ) made of ferromagnetic material, which is magnetically attracted to the magnetic nucleus ( 26 ) when the relative coil ( 27 ) is energised; the pin ( 29 ) of a lower electromagnet ( 25 ) on the one hand bearing against a valve body ( 21 ) of the control valve ( 19 ) and on the other hand bearing against the pin ( 29 ) of an upper electromagnet ( 25 ); the pin ( 29 ) of the upper electromagnet ( 25 ) on the one hand bearing against the pin ( 29 ) of the lower electromagnet ( 25 ) and on the other hand bearing against one end of the first spring ( 23 ).