A nozzle assembly 14 of a fuel injector 12 comprising a body 16 wherein is guided a valve assembly 18 with a needle member 20 and a needle motion controller (NMC) 22 that cooperates with the inner face of said body 16. The body has an inner space S divided into an upstream chamber UC and downstream chamber DC. The NMC is provided with fluid communication(s) (F1, F2 figure 3) between the chambers evolving from a restricted flow state, when the valve assembly is in a closed position, to an unrestricted flow state when the valve assembly is lifted away from said closed position. F1 may be active when the valve assembly is in a closed position when F2 is inactive, which may become active and predominate over F1when the valve assembly lifts away from the closed position. Preferably there is a shutter member (34, figure 2) that activates F2 after the needle member has lifted away. The NMC is preferable a collar member.
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