NOVELTY - The process for reforming hydrocarbons or hydrocarbon mixtures (educts) in hydrogen and carbon mono-oxide/their product gas, comprises mixing the educt (3) in first mixing stage (3) with oxygen containing gas mixture, mixing the mixture from the first mixing stage (4) with gas mixture containing oxygen, water (H2O), nitrogen (N2) and carbon dioxide (CO2), in a second mixing stage (4), and reacting the mixture of hydrocarbon oxidation with a catalyst in a reactor (1). The H2O, N2 and CO2-gas mixture is exhaust gas obtained from a hydrocarbon combustion process.    USE - For reforming fuels in motor vehicles.    ADVANTAGE - The hydrocarbon fuel reforming is more economical and simple and avoids high water consumption and the danger of the soot formation by avoiding partial oxidation of the fuels.    DETAILED DESCRIPTION - The process for reforming hydrocarbons or hydrocarbon mixtures (educts) in hydrogen and carbon mono-oxide/their product gas, comprises mixing the educt (3) in first mixing stage (3) with oxygen containing gas mixture, mixing the mixture from the first mixing stage (4) with gas mixture containing oxygen, water (H2O), nitrogen (N2) and carbon dioxide (CO2), in a second mixing stage (4), and reacting the mixture of hydrocarbon oxidation with a catalyst in a reactor (1). The H2O, N2 and CO2-gas mixture are exhaust gas obtained from a hydrocarbon combustion process. The exhaust gas mixture contains 10-15 vol.% of carbon dioxide, 10-13 vol.% of water, 0-5 vol.% of oxygen and 73-75 vol.% of nitrogen. The exhaust gas mixture is subjected to pre-combustion process before the supply to the hydrocarbon educts. An Ambient air is supplied for the first- and the second mixing stage. A diesel fuel is used as the hydrocarbon educt. The hydrocarbon educt exhibits 40-60degreesC, before the mixing in the first stage. The temperature of the O2 containing gas mixture is 15-25degreesC and H2O, N2, CO2 and O2 containing gas mixture is 400-500degreesC. The hydrocarbon oxidation is carried in the reactor at 850-1000degreesC and at 0-10 bar. The ratio between the hydrocarbon educt to the oxygen containing gas mixture is 0.31:0.41, which is defined by the air number lambda (= actually supplied oxygen quantity/oxygen quantity required for the total oxidation). The ratio of the hydrocarbon educt to the H2O, N2, CO2 and O2 containing gas mixture is 0.25:0.5, which is defined by a S/C (steam to carbon) ratio (= amount of material at water vapor in supplied gas mixture/amount of material at carbon atoms in the fuel educt). The ratio of S:C for both mixing stages is 0.2-0.5. An INDEPENDENT CLAIM is included for a reactor for conversion of hydrocarbon educt.    DESCRIPTION OF DRAWING(S) - The diagram shows a reactor for conversion of hydrocarbon educt:    Reactor; (1)    First Mixing stage; (3)    Second mixing stage; (4)    Outlet; (6)    Lateral Opening. (7)