IC engine fuel injector - has valve needle loaded to close by spring and fuel pressure via variable throttle and pressure relief valve

摘要

The engine fuel injector comprises a valve needle (2) loaded by a spring (3) in a spring chamber (5) and a storage chamber to control the pressure in the chamber (5) which acts in closing direction on the needle. The storage chamber (6) connects to the spring chamber via a constant-pressure relief valve (4,13;7,8,9) and is itself pressurised by a fuel pressure line (10) via (10') a variable throttle (12). When the valve needle is closed, the surface area of the needle on which the pressure in the needle chamber (11) acts to lift it may be greater than the area of the valve (4) pressurised to admit pressure to the chamber (5).