Fuel injector variability reduction

A method for reducing injection variability in a fuel injector having an injection control valve, the method comprising:

• monitoring a fuel injector to determine a timing of movement of the injection control valve;
• identifying a change in a variability of the timing of valve movement for the monitored fuel injector over a plurality of fuel injections, indicating an intermittent variability, based on current induced by movement of the injection control valve;
• and
• changing a quantity of current supplied to actuate the injection control valve based on the change in the timing of valve movement.

A controller for use in a fuel injection system that includes an internal combustion engine and at least one fuel injector, the controller being programmed to:

• generate a command for energizing a control valve solenoid;
• determine that a fuel injector movement variability exceeds a movement variability threshold associated with repeated deviations in return timing of a control valve that occur intermittently during operation of the at least one fuel injector;
• and
• based on determining that the fuel injector movement variability exceeds the movement variability threshold, entering a variability reduction mode in which an amount of energy energizing the control valve solenoid is increased for at least a portion of a fuel injection event.