For years now I have ranted about how HHO is nonsense, that it cannot possibly save you any fuel, how anyone selling the “technology” is either deluded or a con man (or both).
It turns out that I am a little bit wrong about this, there is a tiny bit of truth to it after all! (However you should still not touch it with a barge pole!)
Dr. Stephen Samuel from Oxford Brookes University in the UK has performed some experiments on “HHO” and SAE published his paper entitled Hydrogen Enriched Diesel Combustion in 2010.
I have a copy and have read it but it is copy right of the SAE and so I can’t reproduce it here. Here is a link to where you can buy your own copy.
I have exchanged emails with Dr. Samuel and I have learned a lot. I’m not going to reproduce the entire conversation here, instead I have distilled it down to the important facts about his experiment, what it means, how I was wrong about HHO and why it is still a bogus technology and you should steer well clear of it and anyone selling it. Dr. Samuel has visited this page and read it, he has not chosen to correct me on anything I have written here.
What we know already:
Hydrogen is a flammable gas, it has a lot more energy in it that diesel or petrol, but it is problematic as an alternative fuel as it is difficult to store, expensive to make and when produced by splitting water into hydrogen and oxygen consumes more energy than there is energy in it.
The laws of thermodynamics say that we can’t ever get more energy out of a closed system than we put into it, in fact we can never break even. While running a car on hydrogen is perfectly possible if you are getting the hydrogen from water and the energy to make the hydrogen from the car’s electrical supply then you are going to fail because this would be a perpetual motion machine and they are not allowed.
What I was wrong about:
(the bit HHO proponents will cherry pick and quote me on)
Now Dr. Samuel ran this experiment where he added small amounts of hydrogen from electrolysis into the air intake of a diesel engine and he found that there was a small improvement in engine efficiency, that it burned less diesel. He found that by adding 2.8 litre per minute of the Hydrogen Oxygen mixture that there was a 5.4% reduction in fuel consumption and that this could probably be improved on by adding more hydrogen.
This is partly because the hydrogen is replacing the diesel as a fuel but mainly because the hydrogen is working to enhance the combustion of the diesel.
Additionally one may be able to optimize this by a small amount by optimizing the engine’s timing to take full advantage of the enhanced combustion . Maybe up to 6 or 7%. Not a very big increase in efficiency but certainly not insignificant.
I have always said this is nonsense, it turns out that I was wrong about that. However… on-board hydrogen generation, HHO, is still a nonsense technology that won’t save you any fuel and stronly urge you not to buy into it. Why? Read on.
What I was right about:
(the bit HHO proponents will completely ignore)
Dr. Samuel’s experiment did not use electrical energy coming from the engine to power his electrolysis machine, the energy to split water into hydrogen and oxygen was coming from the mains.
Interesting as it is, Dr. Samuel’s experiment was not to test if on-board hydrogen generators would save any fuel and this is not a valid conclusion to draw from his paper.
It takes a lot of energy to split water into hydrogen and oxygen, had Dr. Samuel’s electrolysis machine been getting its energy to split the water into H and O from the engine then the additional load applied to the engine would probably be greater than any saving made, certainly a lot less than 5.4%.
Increasing the 2.8 liter-per-minute of the hydrogen-oxygen mixture would not help either as the more H and O you make the more load is applied to the engine and therefore the net positive result is still very small, increase H and O production far enough there will be no more combustion enhancement available and therefore the net result will be negative.
How much energy it takes to split water into H and O is very well understood, how much H and O you make is directly related to how much energy is consumed making it, no amount of clever design of electrolysis equipment can get around this.
On-board hydrogen generators will probably burn more fuel that they save, and if you do achieve a positive result it will be very small indeed. So small in fact that is not something you could measure outside of a laboratory in a “on the road ” or “real world” test.
Unless someone finds a way to split water into hydrogen and oxygen that does not consume vasts amounts of energy HHO will not save you any significant amount of fuel.
Anyone that tells you their HHO gadget saves anything more than about 1% has either made a big scientific discovery that no scientist has yet heard about or they are trying to scam you.