FWIW I have a close friend who is pretty high up in General Motors R&D and he sent me this link. He said that this was the first he had heard of it and talked with someone he worked with and the guy told him they have seen some pretty significant increases with these type of systems. What say you?

How Hydrogen Injection System Works in diesel engines - YouTube

I could definitely see how it could help. Just don't know by how much, or how safe it actually is to use. Hydrogen gas is pretty damn powerful stuff. If something went wrong, it could cause a major problem really quick.

At the CB shop in the AC & T truckstop @ x5 on I-81 in Hagerstown, MD, he's got a lot of info about the hydrogen systems.

Hydrogen injection (or, more correctly, "Brown"s gas") has been around for a while that I know of. Several years ago, there was a company in Canada that was offering a system to generate the gas while you drive and claimed benefits similar to the video. I'm also aware of "propane injection" that is supposed to have substantial increase in output horsepower. Adding another fuel to the mix does make sense in order to save the fuel in your tanks because it's another combustible substance. It would reduce the demand for fuel from the tanks. From my own experiments in generating hydrogen, using just 12 volts for the electrolysis process, the yield is very small. I'm having a hard time picturing generating enough to have a noticable effect.

I do know of a farmer that generates his own electricity from a disiel powered generator. He uses very little fuel from the tanks. Only enough to start the engine and run it at an idle. Being a turkey farmer, he has a couple of methane digestors and runs the methane into the intake on the engine. The little bit of fuel that is injected acts like a spark plug to ignite the methane. But, he also reduces the efficiency of his engine because for every cubic foot of methane he injects into the intake, he reduces the air by a cubic foot.

One gallon of water produces 1,700 cubic feet of hydrogen. I'd be interested just how many miles they get on one gallon of water, then compare that to the cubic feet of air going through the engine. The longer the water lasts, the less the benefit you get. If you run through a gallon of water every 15 or 20 miles, you could notice an improvement in fuel economy. But, that won't happen with only 12 volts DC going to the electrolyzer plates. They'd have to run it through an inverter to kick the voltage up to about 40 or 50 volts. That would also mean greater demand from the alternator which would reduce the benefit

Some of the claims about a "Joe cell" are pretty incredible as well, but I never had the chance to try it out. I do know that when you transfer hydrogen, you also pick up a static charge. Properly connected, that static charge might be used to help with the generation process. I have not had a chance to try that out yet. But, for a "Joe Cell" to work, you can not use city water. You must get the untreated water from a well so that it contains a small amount of calcium sulfate. Distilled water does not work.

The Russian Army proved that an engine can run on hydrogen during WWII. It isn't a question of whether it would reduce the amount of fuel you burn. The question is whether or not you would be able to generate enough, as you drive, to make a noticable difference.