umm... is that electrolysis? there’s no way they doubled their mileage by wasting energy producing hydrogen with a very inefficient process such as electrolysis. To explain it a bit further using electrolysis to produce hydrogen is anywhere between 50-70% efficient, therefore by burning gas to produce electricity using the alternator (~60% efficient) then using that electricity to create hydrogen via electrolysis you basically take the efficiency from probably around a net 35% to a disgusting 14.7% (0.35×0.7×0.6). You will NEVER get more energy than you put into ANYTHING. there is NO FREE ENERGY.