A vehicle with a device (6) for converting chemical energy into electrical and/or mechanical energy, in particular a fuel cell unit (6) and/or combustion device (6), such as a diesel or gas engine (6), whereby at least one oxygen-containing source mixture is proved. The efficiency of the energy conversion, in particular, for protection of the environment, is improved relative to the state of the art. This is achieved according to the present invention, in that a separator (7) for separating off at least one oxygen-enriched fluid (2) from a fluid residue (3) of the source mixture (1) is provided.