Importance

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Abstract

A common rail fuel injector includes a fuel inlet, a set of nozzle outlets, a drain outlet, a nozzle chamber and a needle control chamber. A needle control valve includes a ceramic control valve member movable between a closed position in contact with a flat valve seat to block the needle control chamber from the drain outlet, and an open position at which the needle control chamber is fluidly connected to the drain outlet. A solenoid actuator is mounted in the injector body and includes an armature movable between an overtravel position and an energized position, but the armature has a stable un-energized position between the overtravel position and the energized position. A needle valve member is positioned in the injector body and includes an opening hydraulic surface exposed to fluid pressure in the nozzle chamber, and a closing hydraulic surface exposed to fluid pressure in the needle control chamber. Armature overtravel is facilitated by a telescoping armature pin that includes a stem affixed to the armature and telescopically received in a pusher in contact with the ceramic control valve member.

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First Claim