Internal combustion engine system

A method for controlling an internal combustion engine (ICE) system, said ICE system comprising:

• an internal combustion engine for combustion of gaseous fuel and having a combustion chamber at least partially delimited by a cylinder, wherein the internal combustion engine is a hydrogen internal combustion engine operating on hydrogen gas as the only fuel, a reciprocating piston moveable within said cylinder between a bottom dead centre (BDC) and a top dead centre (TDC), said reciprocating piston having a piston top end comprising a piston bowl intended to form part of the combustion chamber, said piston bowl further comprising a plurality of spaced-apart protrusions circumferentially distributed around a centre axis on a bottom section of the piston bowl, each one of the spaced-apart protrusions extending a substantial part in a radial direction towards the centre axis, and a controllable fuel injector arranged to inject gaseous fuel into the combustion chamber and toward the piston bowl, wherein said method comprises:
• controlling the fuel injector to inject at least one gaseous fuel jet towards the bottom section of the piston bowl during a fuel injection period occurring prior to an ignition event of the gaseous fuel, and wherein the protrusions are configured to improve the mixing of hydrogen gas and compressed air prior to the ignition event.