An electromagnetically-controlled fuel injection valve for i.c. engines

Claim 1

An electromagnetically-controlled fuel injection valve for i.c. engines, including a body carrying a low­er injection nozzle with which is operatively associated a needle controlling communication between the nozzle and an injection chamber communicating with a passage for the supply of fuel under pressure, and an upper electromagnetic metering valve which controls communi­cation between a control chamber to which fuel is sup­plied under pressure through an inlet hole to keep the needle in the closed position, and a discharge hole the opening of which causes a pressure drop in the control chamber and the consequent opening of the needle, where­in the solenoid metering valve (12) includes a ball obturator (8) which is movable in a cavity (7) of the body (2) defined by two annular valve seats (9, 10) aligned along the axis of the injection valve (1), of which the first defines the discharge hole (9) and the second defines the inlet hole (10), the cavity (7) being in communication with the control chamber (5) through lateral passages (6), and the ball obturator (8) being kept in a closed position against the first seat (9) and being movable into a closed position against the second seat (10) upon the opening of the discharge hole (9), by means of an electromagnetically-operated axial push rod (13), characterised in that the force required for operation of the valve, rapidly decreasing with the solenoid stroke, is intentionally associated with the force delivered by the solenoid due to the current pulse fed thereto.