The Whole HHO/Brown's Gas/Hydrogen Thing...

Great Debates
1

Hi,

I thought I’d pose this question here, as I doubt Cecil would be interested in this topic, and, in any case, I’m sure one of the teeming millions will be able to answer.

I recently had to write a piece on HHO/Brown’s Gas, and, in the course of my research, I think I have adequately understood both the theory behind why it should work, and the reality behind why it can’t work.

So, assuming anyone reading this know’s the fundamentals of this topic, here’s my thoughts.

Assuming a significant mileage increase can be gained by pumping hydrogen in through the air intake, and knowing that using the cars electrical system to generate hydrogen would, at best (but not likely) result in the same mileage as with no hydrogen system, could a system be put together that uses a separate electrical system to generate the hydrogen?

The main, and most obvious example I thought of was solar panels on the roof. Obviously, you would lose some mileage due to the added weight of the solar panel (and the hydrogen generating system, for that matter), but, if you’re drawing electricity from the Sun, it is possible to get a mileage gain that outweighs what you lose, right? It is, isn’t it? Well, that’s why I’m here; in the hope that someone smarter can answer.

Other energy sources I had considered for this separate electrical system included some kind of turbine on the exhaust. I’m aware that the engine performs better with as few obstacles to the exhaust gases as possible, but would the performance decrease outweigh the hydrogen gain? Also, what about small, side-facing turbines on the side of the car. Again, the extra drag would decrease the performance, but would it outweigh the gain from the hydrogen it created?

Ultimately, I was thinking that, if someone was willing to spend a bit of cash, they might be able to create a super efficient car using a hydrogen system. Saving as much weight as possible (lighter wheels, carbon fiber panels, etc) to partially offset the added weight of the hydrogen system, which would work from an auxiliary electrical system that is a minimal draw on the engine.

Is this possible, theoretically? I realise that the cost of making such a car might need a century of driving before you make your money back in fuel savings, but, you know - theoretically.

2

Bad assumption.

3

You would be better off using the energy from the solar panel to charge the battery of a hybrid-electric car. There would be fewer losses than with a hydrogen generation system, and it would be mechanically simpler. Of course, the actual gain would be minimal, the amount of energy from the solar panel isn’t much compared with what’s needed to move the car.

There’s really not much room to make your car more fuel-efficient by generating and injecting hydrogen this way. If you’re using electricity to generate the hydrogen, you’d be better off using the electricity to just power an electric motor to move the car.

4

The efficiency of producing hydrogen via electrolysis is (highest figure I could find) 80%. Burning the hydrogen in an internal combustion engine is (again, best I could find) 50%, for a combined efficiency of only 40%. Using the electricity directly in an electric motor is close to 100% (you only miss from electrical resistance losses in your wiring, and frictional losses in your motor, both of which can be made quite small). It doesn’t look good for electrically produced hydrogen as an intermediary, no matter how you produced it.

And that was using the most optimistic figures I could find with a reasonable Google search, which no doubt gave me the most expensive (and thus cost ineffective) technologies available. Realistic mass-market-affordable technologies would be even worse. If hydrogen injection was at all viable, some reputable companies would already be selling aftermarket kits, even if the auto makers weren’t doing it on a ‘new production’ basis. The only companies selling it are the ones claiming that they are selling something “Big Oil and Big Auto Don’t Want You To Know” about. An automatic ‘bullshit alarm’ trigger. And that alarm came before I even bothered to Google and run the numbers in my first paragraph.

Judgment ==> Bullshit.

5

The idea in most of these schemes isn’t that the energy from Hydrogen combustion contributes more energy then it takes to make the Hydrogen, the idea is that it makes the gasoline its burning anyway’s burn more efficiently. So the usual rebuttal that it breaks the laws of thermodynamics isn’t correct.

That said, I looked into it a while back and concluded it was still BS. There are some specific scenarios where H burning can make petrol burn more efficently (which is presumably what inspired the scam), but it takes a lot more then just throwing some H into a standard internal combustion engine.

Or put another way, car companies have spent billions trying to make efficiency gains in cars. If something this simple worked as advertised, it would’ve been implemented a decade ago.

6

Yes, good point. The CAFE standards have been around for most (or all, not sure which) of my life, and have been steadily increasing in all that time, and car companies have been pulling all kinds of desperate dodges to try to meet them. They all but killed off the station wagon, because those types of cars pulled the corporate fleet averages down. A simple way to make a Buick sedan get an extra 5 mpg would have been a godsend to them. Nevertheless, the car companies are supposedly hiding these gas saving technologies. Why? The CAFE standards have been brutalizing them. Why are they allegedly hiding simple, cheap methods that would enable them to meet the standards, even selling Buick Battlewagons and Caddy CityCruisers?

7

So, did you write the “piece” before asking here, or did you join specifically to have us help with your [del]homework[/del] “piece?” :dubious: If it’s the former, shame on you for not finding us earlier. If it’s the latter, you did a fine job of making it look almost as if you weren’t asking for homework help. :wink: But did your spell checker miss the superfluous apostrophe in “know’s”?* :smiley:

I know all about having a bout of brown gas while driving. It’s rare enough for me that I fail to see how capturing it will help my gas mileage, but YMMV.

    • Yes, I know the question mark belongs inside the quotation mark, but because I know the rule and purposely violated it to make the sentence clearer I believe this is not a violation of Gaudere’s Law. But if she were to grace us with a visit I will bow to her judgement. I like that kid and wish she would post more, and maybe this will flush her out.
8

Thanks for all the replies. My personal opinion on some of the things said;

  • I don’t think there is any big conspiracies to keep us reliant on oil - oil will run out one day, and the people supposedly keeping us dependent on it must realise that. If I were inclined to find a conspiracy theory in all of this, I’d be looking for those companies trying to get some kind of monopoly on fossil-fuel alternatives.

  • I also agree that, with relatively modern cars, it’s unlikely that anything someone like me might do in their garage would increase the efficiency of their car - this is all more of a thought exercise for me.

  • My apologies for assuming, John Mace

  • I have already written the piece. This question was more for my own curiosity. The brief for the article was to simply look at the evidence on both sides and let the reader draw the conclusions. My own conclusion was that the increased efficiency of the engine due to the hydrogen burning more completely, while not impossible, is total bull until someone runs an empirical test or two that shows an improvement, rather than filming the speedometer as they drive down the road.

  • I don’t use a spell checker… although maybe I should.

Okay, here’s another thought. And, again, this is just a thought exercise, not me trying to solve the fuel crisis.

Would it be possible to have a system that was composed of an internal combustion engine that was designed to burn hydrogen/oxygen, rather than gasoline, combined with the most efficient method of electrolysis possible, and have it all in some kind of enclosed system.

Hydrogen and oxygen would be burned in the engine, creating the drive for the vehicle, and the waste product, pure H2O, would then be expelled into the electrolysis chamber to be split apart again. The electrolysis would be powered by batteries, and “refueling” the car would mean plugging it in, like an electric car.

Would that work? Or would you likely only get twenty yards before needing to recharge the vehicle/wait for more hydrogen to build up?

9

No it wouldn’t work. See my first post. Only about 40% efficient vs. 90s for running an electric motor directly.

10

Sorry Chesire, I missed your first post. You’re right, though, that post answered my second question. Thanks.

I guess I’ll get back to work. Lot’s of other “homework” to write.

Thanks everyone.

11

If HHO gas were to produce a more fuel efficient engine it would have to involve altering the burn rate in such a way as to convert more heat to mechanical energy. Otherwise it would violate the laws of physics.

So, just for the sake of argument, lets say HHO gas was introduced along with water vapor and that during combustion that water vapor flashed to steam which in turn acted against the piston.That would occur by absorbing heat and transferring it to mechanical energy. The result would be a cooler exhaust and improved fuel economy. No changes in the laws of physics just an improvement on the gross inefficiencies of an ICE engine. but that change in efficiency has to be more than the additional energy used to produce the HHO gas.