Abstract: A spool slides in a bore to open and close a valve. An armature moveable relative to the spool is biased in a first direction. A coupling biasing member biases the armature and the spool toward each other. When a solenoid is actuated the armature and the spool move in a second direction opposite the first direction until the spool forcibly engages a seat in the bore, closing the valve and stopping the spool movement. The armature continues to move in the second direction, causing the coupling to apply additional force to keep the spool engaged against the seat, until the armature reaches a second position where it forcibly engages with the spool. This stops the armature from moving further in the second direction, but allows the stationary armature to continue applying force to keep the spool engaged against the seat. When the solenoid is de-energized the armature bias sends the armature back in the first direction until it strikes the spool, causing the spool to rapidly unseat, thus opening the valve.

Abstract: A method of controlling a fuel injector assembly of an internal combustion engine includes the stop of generating a first injection pulse with an engine control module. The method also includes the step of injecting fuel into a cylinder of the engine in response to generation of the first injection pulse. The method further includes the step of detecting when fuel is injected into the cylinder and generating a control signal in response thereto. Moreover, the method includes the step of determining a time period between generation of the first injection pulse and generation of the control signal. The method also includes the step of adjusting initiation of a second injection pulse based on the time period. An apparatus for controlling a fuel injector assembly of an internal combustion engine is also disclosed.