A device and a method for controlling an internal combustion engine with an air system are described. At least one variable characterizing the air system is determined on the basis of at least one correcting variable and/or at least one measured variable characterizing the state of the ambient air, using at least one model. The model includes at least one first and one second submodel. Using a submodel, the output variables are determined on the basis of input variables. As input variables of the first submodel, besides at least one output variable of a second submodel, the correcting variable and/or the measured variable are additionally taken into account.