FLAT NEEDLE FOR PRESSURIZED SWIRL FUEL INJECTOR

摘要

The injector nozzle includes a cylindrical needle (14) which is axially reciprocated by an armature assembly. The needle has a needle tip (50) terminating in a flat end surface (46) with a spherical transition surface (48) between the flat end surface and the side walls of the needle. Depending upon the diameter of the needle and the included angle of the valve seat, the diameter of the flat end surface may be less than the diameter of the orifice through the valve seat. The circular edge defined between the flat end surface and the spherical transition surface defines a location where the liquid fuel and air consistently separate from the needle in the valve-open condition whereby variations in the spray cone angle and the flow rate are minimized during steady-state and transient operating conditions.