System for determining axial displacement of a rod, particularly the plunger of an electromagnetic fuel injector.

摘要

A system for determining axial displacement of a rod (1) forming part of a device comprising a member (2) in which are formed at least two chambers (4, 5) containing high-pressure fluid and each defined by a respective surface portion of the rod (1). The system consists in forming a sliding coupling between the rod portion (6) separating the two chambers (4, 5) and the seat (3) in which the rod (1) slides; in forming, on the aforementioned rod portion (6), a pair of annular grooves (7, 8) defining an annular surface portion (9); in forming at least a housing (10) on the aforementioned member (2); and in fitting inside the housing (10) a proximity transducer (10 min ) for determining displacement of the annular surface portion (9) parallel to the rod (1).