Sorry, didn't mean to imply dumb as in a useless manner, more that I've seen a lot of gimmick/false praise for them. The concept is neat, and I've read a lot about truckers using them on semi's, which makes sense considering the excess power being wasted by a giant diesel while cruising along the highway and at idle.

The problem I see though is that with an engine the size of ours, even though the amount of power needed is significantly reduced once a steady speed is reached, is that we still don't have all that much spare power at our disposal, without burning a little more fuel

Assuming that we're talking about the same thing here, the idea of course is to use the excess energy being wasted by the engine at cruise to pump more electricity out of the alternator and electrolysis (the opposite of a fuel cell actually, not really sure what the device should be actually be called) of the water. Then inject the hydrogen that has been seperated into the intake and in turn burn less fuel to get better gas milage (by allowing the engine to run a leaner mixture, at a reasonable temp).

It sounds good, but it seems to me that if you take into account the low efficiency of the process (somewhere between 50 and 90 % depending), combined with the less than 100% efficiency of the alternator, plus losses of energy due to wiring and other losses, it just seems like very little return. On top of that, in order to truly see a mileage increase you would have to adjust the timing to account for the leaner air/fuel ratio. So you would either have to have a reserve tank of H2 to run the timing like that all the time, or have a way to switch the timing back and forth.

I like the idea, I just don't think it works on something small like these toyota engines. Now, what if you hooked up a solar cell on the roof and used it instead of the alternator? Then it TRULY would be free energy, when it was sunny of course. If you were to do something like that you would definitely have to rig up a system to adjust the timing, but I think the gains could be worth it. Any thoughts?

Oh, and as a side note, it does apparently reduce emissions, which could perhaps mean that in emissions states you could remove the cat and run one of these systems, getting the benifit of a free flowing exhaust while still being legal (gutted cat I was thinking). Just a thought.