A diesel internal combustion engine that is operated advantageously at least predominantly according to the diesel principle, with a multi-fuel adaptation unit that reacts to various fuels of different mixtures and adapts an operating mode of the internal combustion engine to these fuels, wherein the multi-fuel adaptation unit comprises at least the following elements: a fuel characterization, a combustion-chamber filling that can be adapted as a function of a characteristic fuel, external ignition that can be allocated to each cylinder of the internal combustion engine, at least one control device that implements a first control strategy in which, in a lower load range, external ignition is performed, and a second control strategy in which automatic ignition is performed in a load range that is higher relative to the lower load range, a combustion-point control that can be adapted automatically to the characterized fuel, and a conversion-rate control that can be adapted automatically to the characterized fuel.