Electric fuel injection nozzle for internal combustion engine - is equipped with valve needle movement sensor whose magnetic circuit includes min. gap in closed position

摘要

A movement sensor (30) coupled inductively to the valve needle (14) provides a distance and velocity dependent signal, induced in a coil on a fixed core (33) by movement of an armature (34) at the end of a plunger (38) pinned (39) through a helical closure spring (16) to the base (15) of the needle (14). The air gap within the coil (30) is so small that the start and finish of injection are easily distinguishable. ADVANTAGE - With max. variation of magnetic flux through small gap, needle movement sensor has max. sensitivity at beginning of opening stroke.