Patent ID: 6431474
Filing Date: 2002-08-13
Classification: F02M,Y02T

Abstract:
An electrically operable fuel injector for a compressed natural gas fuel injection system of an internal combustion engine, said injector having a generally longitudinal axis, the electromagnectically operable fuel injector comprising:a) a magnetic coil; b) an armature magnetically coupled to said magnetic coil and being movably responsive to said magnetic coil, said armature being made of a ferromagnetic metal material and having a first end portion and an opposite second end portion; c) a valve closing element connected to said second end portion of said armature and interactive with fixed valve seat of a fuel valve to selectively permit fuel to pass through said valve seat as said valve closing element is moved to a valve open position by said armature; d) a valve body at least partially surrounding said armature; and e) a fuel inlet connector extending in a generally longitudinal direction and being made of a ferromagnetic metal material, said armature defining a path for fuel to enter said inlet connector and to be directed toward said armature, said fuel inlet connector having an end surface facing said first end portion of said armature across a working gap through which said armature is movable, said end surface of said fuel inlet connector and said armature and said valve body defining a direct path for magnetic flux, said end surface having a chamfered configuration along an outer portion of said fuel inlet connector so as to reduce the thickness of said end surface, said reduced thickness portion is in direct face-to-face relation with said first end portion of said armature and positoned adjacent said armature, thereby providing a ferromagnetic metal-to-metal path for magnetic flux lines generated by said coil and thereby reducing leakage of the flux lines outside of the ferromagnetic metal-to-metal path, wherein said chamfered configuration of said fuel inlet connector is an arcuate notch formed between the end surface and the outer portion of the inlet connector.