For us Vanagon driver's trying to deal with the $3.25++++/gal. gas prices, is there anything worth considering in these small hydrogen producing units that go under a hood and operate as described below:

What the motor can run on is a combination of Hydrogen and regular fuel (Gas / Petrol / Diesel). Basically water is made up of Hydrogen and Oxygen, the Hydrogen Unit runs a small electrical charge through the water to separate the 2 and creates a gas known as HHO (also referred to as Browns Gas), this gas is directed by a fuel line into your existing carburetor or fuel Injection. The hydrogen then combines with the regular fuel to run the motor while at the same time reducing the reliance on the regular fuel

If no, that's what I expected.....
If yes, then why aren't we all doing this & has anyone ever done this to a 18-20 mpg Vanagon?

Thanks

Larry 
Ga.