Dynamic flow calibration of the fuel injector due to divert the magnetic flux from the working gap selectively

摘要

An electromagnetically operated fuel injector (10) has a dynamic flow calibration mechanism in which a control rod (80) that extends between and enters holes (84, 88) in both the stator (28) and the armature (30) is selectively positioned to divert some of the magnetic flux from the axial working gap (51) between the stator (28) and the armature (30) such that the diverted magnetic flux passes through the control rod (80) directly between the stator (28) and the armature (30) without passing through the working gap (51). A non-magnetic tube (82) is disposed between the control rod (80) and the stator and armature holes (84, 88). The portion of that tube (82) which is within the stator hole (84) is joined to the stator (28) while the portion which is within the armature hole (88) provides guidance for the armature (30). In a bottom-feed version of fuel injector (10) the tube (82) also serves to prevent fuel within the injector (10) from wetting the control rod (80). The fuel injector (10) is dynamically calibrated by selectively positioning the control rod (80) by means of an external tool that engages the control rod (80) so that the diverted flux which is conducted between the stator (28) and the armature (30) is conducted through the control rod (80) without passing through the working gap (51).