An internal combustion engine (1) having a regulating device (C) wherein an air-fuel mixture with a combustion air ratio (λ) which is adjustable by the regulating device is burnt in the internal combustion engine, wherein the regulating device (C) has a power output regulating circuit adapted to adapt an actual output (Pg) of the internal combustion engine (1) to a reference power output (Pdg) of the internal combustion engine (1) by way of an adjustment of the combustion air ratio (λ), and a NOx emission regulating circuit adapted by way of a functional relationship (2) to actuate actuators influencing a charge pressure as an alternative parameter for the NOx emission by the charge pressure such that a charge pressure reference value (pdim) can be set for each reference power output (Pdg) of the internal combustion engine.