Abstract: A process and apparatus for utilization of fuels with alcohol additives for an internal combustion engine which are characterized by the fact that at the present time comercial types of fuel have approximately the same molecular weights, which are clearly distinct from the molecular weights of methanol and ethanol. By complete vaporization of a sample volume of fuel, depending on the admixture of alcohol to standard fuel, different volumes of vaporized fuel samples are produced, or different pressures are obtained if the volume is constant. Based thereon and on the sample temperature a correction signal is formed which is characterized by the alcohol and its content in the sample (as compared with reference values stored in a control device), and the correction signal can be utilized to regulate the engine control variables.