Fuel injector

摘要

A fuel injector has a valve needle (12) slidable within a bore (11) formed in a nozzle (10). The valve needle (12) is engageable with a seating to control delivery of fuel from the bore (11). The injector also includes a supply passage (37) for supplying fuel under high pressure to the bore (11). A surface of a piston (18) adapted to engage with the needle (12) is exposed to the fuel pressure within a control chamber (39) which communicates continuously through an inlet passage (38) with the supply passage (37). The control chamber (39) further communicates, through an outlet passage (40), with an injection control valve (21-25) arranged to control communication between the control chamber (39) and a drain port. The inlet and outlet passages (38 and 40) are shaped to restrict the rate at which fuel can flow to and from the control chamber (39). <IMAGE>