Fuel injector

A fuel injector including: piezoelectric actuation means, a valve arrangement comprising a nozzle including a valve seat, and a valve needle, said needle adapted to be slidable within said nozzle so as to selectively open and close the valve by respective disengagement/ engagement of the needle against the seat to allow fuel from a pressurised source to be injected into a combustion space, and hydraulic invertor means adapted such that activation/deactivation of said piezoelectric activation means provides respective retraction/extension of said needle away or to said valve seat so as to open/close the valve respectively.