| 摘要 |
A solenoid-operated top-feed fuel injector has a housing which contains a solenoid coil that is selectively energized by electric current to open and close the fuel injector. An inlet connector tube extends into the housing to convey pressurized liquid fuel into an internal fuel passage. Fuel is injected from the nozzle at the bottom. An armature assembly that has a needle valve joined to an armature is disposed within the fuel passage between the inlet connector tube and the outlet, and is spring-biased by a helical spring to seat the tip of the needle valve on a valve seat proximate the nozzle. Slot structure is formed in the armature during its fabrication by a metal injection molding or sintering process. The needle is inserted into the smaller diameter portion and the two are crimped together. Crimping tool access is through the slot structure, which also provides a path for fuel to flow past the armature. In one embodiment fuel can pass axially through the I.D. of the bias spring directly to the slot structure without having to pass radially through the helical free space between convolutions of the helix.
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