Abstract: A direct injection fuel injector and method of operation wherein high fuel pressure exerting an opening force on an injection valve is slightly overbalanced by a return spring tending to close the valve. A first solenoid acts to open the valve against the excess return spring force and a second solenoid acts to close the valve when the first solenoid is de-energized. Rapid valve closing is provided by energizing the second solenoid before de-energizing the first solenoid, the force of the second solenoid when the valve is open being insufficient to overcome the force of the first solenoid holding the valve open. Thus, the second solenoid magnetic force is fully developed and quickly closes the injection valve when the first solenoid is de-energized. Various additional features are disclosed.

Abstract: A direct injection fuel injector and method of operation wherein high fuel pressure exerting an opening force on an injection valve is slightly overbalanced by a return spring tending to close the valve. A first solenoid acts to open the valve against the excess return spring force and a second solenoid acts to close the valve when the first solenoid is de-energized. Rapid valve closing is provided by energizing the second solenoid before de-energizing the first solenoid, the force of the second solenoid when the valve is open being insufficient to overcome the force of the first solenoid holding the valve open. Thus, the second solenoid magnetic force is fully developed and quickly closes the injection valve when the first solenoid is de-energized. Various additional features are disclosed.

Abstract: Inductive energy from the coil of an electromagnetic actuator is stored in capacitive network at a relatively high voltage when the actuator is deenergized. When the actuator is energized, the capacitive network is coupled to the coil thereby releasing the stored energy at a high voltage to the coil.