An oxygen separation device includes a substrate and an oxygen ion transport membrane supported on the substrate. The substrate has an air inlet end and a retentate outlet end. An intake air passageway extends through the substrate from the air inlet end to the retentate outlet end. The oxygen ion transport membrane is between the substrate and the intake air passageway and is adapted to separate oxygen atoms from the air in the intake air passageway and to transport the oxygen atoms to the substrate. The oxygen separation device collects the oxygen from the substrate for supply to an internal combustion engine for use as the gas of the gas-fuel mixture.