Not to add fuel on fire but HHO doesn't increase the energy of the mix to the point of counterbalancing the energy taken from the alternator to perform hydrolysis. That would violate thermodynamics.
Instead hydrogen flame front is faster than gasoline. This allows more gasoline to break up and burn faster instead of not being used and destroyed in the catalytic converter.
There is a very interesting article in here (
Car Bibles : The Fuel and Engine Bible) by someone that is an unbiased expert. It also contains links to experimental research on the matter.
Sorry if the topic was considered closed.