Dosing arrangement for direct fuel injector

摘要

The arrangement has a nozzle needle (3) movable axially in a bore (201) divided into a working chamber (5) subjected to pressure via a choke and a fluid chamber (7) which can be pressurised. An injection opening leading outward from the fluid chamber can be closed by the needle. An outlet opening into the working chamber has an associated sealing element. An upper pressure loaded surface (12) of the needle is larger than a lower pressure loaded surface (9) of the needle. The sealing element (13) can be displaced by actuating a piezoelectric control drive (16) to open and close the outlet, varying the working chamber pressure, altering the needle stroke and controlling opening and closing of the injection opening.