Abstract: A method for the automatic optimization of an output quantity of a system that is dependent on a plurality of input quantities (for example, an internal combustion engine) with maintenance of secondary conditions determines a theoretical value for the output quantity and for the secondary conditions on the basis of a respective model function having the input quantities as variables, and thereby respectively modifies, in successive individual steps, one of the input quantities within a variation space having a dimension corresponding to the number of input quantities, whereby values, corresponding to the respective input quantities, for the output quantity and for the secondary conditions are also determined directly at the system and are used for the correction of the model functions, until the model function has achieved its optimal value, satisfying the secondary conditions, for the output quantity.