Hi LP,
Do a search on this forum. It's been kicked around a couple of times already.
My vote is that it doesn't work as advertised.
You can't take a reaction that is only 75% efficient (electrolysis) using power from a source that is less than 75% efficient (the alternator) and burn it in an engine that is 35% efficient at best and get more than 100% back in energy.
Joe