A method for controlling hydrogen combustion in a hydrogen internal combustion engine system includes a combustion chamber linked to an intake port via an intake valve, the hydrogen internal combustion engine system comprising a piston slidably moving between a top dead center position and a bottom dead center position, characterized by the steps of: injecting water in liquid phase in the intake port when the piston is between 0 and 40 crank angle degrees before opening of the intake valve, injecting hydrogen after opening of the intake valve and when the piston is between 0 and 60 crank angle degrees after the top dead center position, stopping hydrogen injection when the piston is between 0 and 100 crank angle degrees before the bottom dead center position.

A method for controlling hydrogen combustion in a hydrogen internal combustion engine system includes a combustion chamber linked to an intake port via an intake valve, the hydrogen internal combustion engine system comprising a piston slidably moving between a top dead center position and a bottom dead center position, characterized by the steps of: injecting water in liquid phase in the intake port when the piston is between 0 and 40 crank angle degrees before opening of the intake valve, injecting hydrogen after opening of the intake valve and when the piston is between 0 and 60 crank angle degrees after the top dead center position, stopping hydrogen injection when the piston is between 0 and 100 crank angle degrees before the bottom dead center position.

Methods and systems are provided for an engine configured to deactivate at least some cylinders. In one example, an engine system may comprise a first group of cylinders having a first compression ratio and a second group of cylinders having a second compression ratio greater than the first.

Methods and systems are provided for an engine configured to deactivate at least some cylinders. In one example, an engine system may comprise a first group of cylinders having a first compression ratio and a second group of cylinders having a second compression ratio greater than the first.