I think you're missing the claim. They are not claiming a perpetual motion machine by somehow recovering more energy from the hydrogen itself. The claim is that a small proportion of injected hydrogen improves the combustion of the diesel fuel. The hydrogen itself would be burned as well, but that is inconsequential. The efficiency gain would come from burning more of the diesel that would otherwise be blown out the stack. I don't know whether this actually works or not, but the claim does not violate any laws of physics.
This reminds me of the water vapor injector my father had on his 1964 Plymouth Fury. The idea was that the engine works better in a fog so by injecting water into the carburetor would duplicate it.
Hi aaf709, This is yet another invalid application to gas cars from valid uses in different types of engines. Specifically Brayton cycle axial flow turbines is where water injection works. Its acts like a phase-change intercooler to cool down the compressed air, and get better volumetric efficiency into the combustors. Just from the sound of that the amount of water injection is critical to avoid to much extra volume from the expanding water vapor. Older B52's in particular used this technique for extra take-off power.
My boss from a former job had water spraying into the turbo he fitted to his early Celica. It sprayed right into the middle of the turbine to break the water into a mist, it had a genuine power increase but I believe that was due to cooling of compressed air. This was before intercoolers were popular. He would mix about 5% alcohol into the water for more power again.
In 1940 RAF Spitfires had water injection engines. I'm pretty sure Grumman's fighters (and maybe Mustangs) were water injected as well.
I thought I remembered hearing that F4U Corsairs had it too. I used to be a WW2 buff when I was in Junior High and that was a looong time ago and I may be having a senior moment.
So if I understand the nature of the ad, I can get hidden energy from my empty gas tank, right? (All I need to do is fill it with gas.)
Actually, back in the day I believe on certain planes they used to inject just a tiny bit of moisture into a piston in between firings, basically utilizing the hot pistons as a steam engine also, there is some to be gained in that, however I think it wears out the motor quicker? I remember there was some downside to it and it didn't work out well. I guess the steam probably doesn't do well for modern day exhaust systems...
It could very well have made the motor wear out quicker. It seems to me that the water was only injected in emergencies when the extra power was needed to shake someone off their tale during a dogfight in which case engine wear was probably not a big concern.