Patent ID: 7090152

Claim:
A method of manufacturing a fuel injector, the fuel injector including a tubular casing having an axial fuel passage, a valve seat element disposed within the fuel passage at one axial end portion of the casing, an electromagnetic actuator disposed on the casing, a core cylinder axially spaced from the valve seat element, a valve element axially moveable between the valve seat element and the core cylinder and opposed to the core cylinder with an axial air gap, the casing cooperating with the core cylinder and the valve element to form a magnetic field upon energizing the electromagnetic actuator, the casing including a reluctance portion which has a reduced radial thickness and an axial length extending over the axial air gap, the method comprising: forming an annular groove on an entire circumferential surface of a pipe made of magnetic material to provide the tubular casing formed with the reluctance portion; fixing the valve seat element into an inner circumferential surface of the one axial end portion of the casing; fixing the electromagnetic actuator onto an outer circumferential surface of the casing; and mounting the valve element and the core cylinder into the casing so as to be opposed to each other with the axial air gap to provide the fuel injector.