Fuel Saver Liquid. Burn without ash, clinkers, etc. A properly constructed and installed hydrogen/oxygen gas generator can be safe, economical, and provide a realistic 20% increase in gas mileage.
The pressurized air and fuel mix together in a chamber until the fuel becomes vaporized and is then released into a line that feeds into pcv manifold. Some vapor bleed systems work by taking liquid fuel on its way into the engine, and mixing it with air from a pressure line. The liquid could be a mixture of things, but it certainly isn't the magical substance that you are hoping for.