Method for estimating an hydraulic dwell time between two injection pulses of a fuel injector

A method for operating a fuel injector of an internal combustion engine, comprising the steps of:

• determining a fuel quantity to be injected by said fuel injector in a course of an injection pulse;
• estimating a hydraulic dwell time value of a hydraulic dwell time between said injection pulse and a previous injection pulse performed by the fuel injector;
• estimating a pressure value in said fuel injector on a basis of said hydraulic dwell time value of the hydraulic dwell time;
• using said fuel quantity and said pressure value, in order to determine an electric energizing time value of an electric energizing time of the injection pulse;
• and
• operating the fuel injector according to the electric energizing time value of the electric energizing time.

An internal combustion engine comprising:

• a fuel injector;
• and
• an engine control unit connected to the fuel injector, the engine control unit configured to:
• determine a value of an electric dwell time between a first injection pulse and a second injection pulse;
• estimate an injector closing delay value of an injector closing delay between an instant in which an electric closing command of the first injection pulse is generated and an instant in which the fuel injector closes;
• estimate an injector opening delay value of an injector opening delay between an instant in which an electric opening command of the second injection pulse is generated and an instant in which the fuel injector opens;
• and
• calculate a value of a hydraulic dwell time as a function of the electric dwell time of the injector closing delay value and of the injector opening delay value.