Method of controlling an injection time of a fuel injector

A method of controlling fuel injection in an internal combustion engine is presented. A drive signal is generated for each injection event, with which the injector is kept open to spray fuel in accordance with a requested fuel quantity. The drive signal has a duration based on a pulse width that is determined from an injector-specific correspondence function defining the pulse width (PW) vs. a corresponding open time variable (A) representative of injector open time. The open time variable is determined on the basis of a master performance function defining the requested fuel quantity in function of the open time variable.