Fuel injector for internal combustion engine

摘要

The injector has a spring loaded needle (4) operated by a control piston (5) to open and close the fuel feed. A control valve comprising a spring loaded piston (27) is fitted between the fuel inlet (8) and the feed to the needle. This piston has a sealing profile at the bottom end to locate in a valve seat (16) in the bottom of the injector. The piston only reaches the sealing position if there is a fault in the injector control. This effectively limits the maximum amount of fuel that can be injected in one pulse. The control piston has a flow limiter for the fuel flow between injection pulses. The upwards travel of the control piston is limited by a stop (20) on the shaft of the needle, or by a stop (20') on the inside wall of the injector bore.