Bullshit. There are 195 countries in the world, if this had any merit at least one would be profiting off it but they're not.
Its not that the technology is suppressed, the technology is impossible. If every last joule of energy in the gasoline was extracted you would be able to sustain 33KW/h about 45hp. The problem is most of the energy in an ICE is wasted as heat. It has nothing to do with the carburetor and everything to do with combustion.
Think about it logically. If you ignite a vapour, how do you prevent heat and ensure all the energy is converted to kinetic to move the piston? An uncontrolled combustion reaction doesn't work.
A fuel cell does work, highly energetic electrons on hydrogen atoms are oxidized, while oxygen becomes reduced. The potential energy of the electrons is harnessed in the fuel cell and water is produced.