METHOD FOR OPERATING AN INTERNAL COMBUSTION ENGINE SYSTEM USING HYDROGEN FUEL

A method for operating an internal combustion engine system using gaseous fuel, the method comprising: injecting, by activating a fuel injector (14) to generate a first injection (1) in association with a compression stroke, a first amount of gaseous fuel (1A) into a pre-combustion chamber (12), wherein the first injection (1) and the first amount of gaseous fuel (1A) are adapted so that an ignitable fuel-air mix is formed in the pre-combustion chamber (12) but not in a main combustion chamber (6); igniting, by activating an igniter (15), the ignitable fuel-air mix in the pre-combustion chamber (12) formed by the first injection; and injecting, by activating the fuel injector (14) to generate a second injection (3) after ignition (2) of the first amount of fuel (1A), a second amount of gaseous fuel (3A) into the pre-combustion chamber (12), wherein the second injection (3) and the second amount of gaseous fuel (3A) are adapted so that fuel is forced through the orifices (13) into the main combustion chamber (6).