Actuator for accumulator type fuel injection nozzle

An accumulator type of injection nozzle comprised of an accumulator chamber adapted to be supplied with high pressure fuel, an nozzle port leading from said accumulator chamber, an injection valve moveable between a closed position and an opened position for controlling the discharge of fuel from said accumulator chamber through said nozzle port, a control chamber for receiving pressurized fuel, an actuating member supported for movement within said control chamber and associated with said injector valve for retaining said injector valve in its closed position when said control chamber is pressurized and for movement of said injector valve to its opened position when pressure is relieved in said control chamber, and relief valve means moveable between a closed position for maintaining pressure in said control chamber and an opened position for relieving said control chamber for effecting fuel discharge through said nozzle port, the improvement comprising electromagnetic means associated with said relief valve means for urging said relief valve means to one of its positions when said electromagnetic means is energized, and electrical resistor means in circuit with said electromagnetic means for varying the force exerted by said electromagnetic means by selecting the value of said electrical resistor means.