Water-powered cars?

[Stargate525]

http://www.keelynet.com/energy/garrett.htm
http://www.spiritofmaat.com/archive/feb2/carplans_doc.htm

So, from my quick skim, this looks like a simple electrolysis machine, which then combusts the resulting gasses. Anyone with a passing knowledge in chemistry would know that this works in theory. My question is, does this work in practice? In other words, does the resulting explosion generate enough energy to make back the power spent separating the water, with enough to spare to drive a vehicle?

[SDragon]

No. It'd be more efficient to just power the car with the electricity used to split the h2o.

That said, it's still a really cool idea :)

[Xeviat]

This has one advantage; you are able to convert a gas powered car into a "water powered" car, rather than having to start from ground up and build an electric engine. But it is far from efficient.

A friend of mine recently got it into his head that he wants to be an engineer, and he's gotten big on the "alternative engineering" type stuff. He showed me the water car, and I had to explain this part to him:

The more times you convert energy into a different form, the less efficient the process is. This car turns electrical energy into chemical energy (splitting the water into H2 and O2), chemical energy into mechanical and thermal energy (burning/exploding the H2/O2 mixture), then applying the mechanical energy to the wheels and to the alternator to reconvert it back to electrical energy.

It's a silly process really. A Hydrogen powered car would be a great idea if you got the Hydrogen purely from solar power or another truly clean source. As it is right now, you need to use electricity (usually made from fossil fuels) or methane (getting the hydrogen free from the carbon, which releases carbon just like burning fossil fuels).

[Stargate525]

what's what I thought. Thanks.

So after a time, you will have to put something more than water into the system. Moronic.

[snakefing]

Although, methane is a worse greenhouse gas than CO2, so there is a (small) net gain to burning (or converting) methane vs. just venting it to the atmosphere.

Still, there's a lot more gain to be had from simply driving less than from improvements in efficiency. If you just share your ride with one other person, that's a major gain. My wife and I decided to start car pooling when gas started going up, and we ended up saving about USD 200 a month.

[SDragon]

The more times you convert energy into a different form, the less efficient the process is. This car turns electrical energy into chemical energy (splitting the water into H2 and O2), chemical energy into mechanical and thermal energy (burning/exploding the H2/O2 mixture), then applying the mechanical energy to the wheels and to the alternator to reconvert it back to electrical energy.

Which makes sense, really, when you think about it. The conversion from one form to another, itself, uses energy. Because of that, energy is "lost" (for practical purposes, anyways) at each conversion.

If it were a fantasy world, however, you cold design a way to magically retain the energy that would otherwise be "lost", and make it considerably more efficient. Of course, as long as you're taking that route, you could do the same thing, only instead of retaining otherwise lost energy, you could replace it (as well as any other energy needed for this to work). Then, at that point, you might as well just throw out the entire idea and say that proper magic can create the energy required, as well as sustain it.

In short, real-world or fantasy, when it comes to car fuel, just don't add water ;)

[Xeviat]

From my understanding, it's not really that energy is used in the conversion (except for the "activation energy to get the reaction started"), but that energy is expended in unusable forms. An explosion in an engine is done to create force, but it also creates electromagnetic radiation (heat/light) that's rather useless to the engine.

This is why fuel cells are a great idea, it converts chemical energy directly into electrical energy; a more efficient conversion (they work by stripping electrons away from a compound and letting them recombine after moving through a converter; you can take the electrons off hydrogen by putting it near a proton permeable membrane, where it instantly will bond with the oxygen in the air and pick up the electrons again. Fun stuff chemistry/physics is.)

[SDragon]

From my understanding, it's not really that energy is used in the conversion (except for the "activation energy to get the reaction started"), but that energy is expended in unusable forms. An explosion in an engine is done to create force, but it also creates electromagnetic radiation (heat/light) that's rather useless to the engine.

Right. I'm aware that energy is never truly "used up" or "lost", only changed, but for all practical purposes, that's what happens to it.

[Atlantis]

thers a new car coming out where they r getting rid of all the things that make it less aerodynamic, etc. it has 300mpg. still concept car though. they say its comin gout around october 9i think 2008) in Northern california

[Xeviat]

thers a new car coming out where they r getting rid of all the things that make it less aerodynamic, etc. it has 300mpg. still concept car though. they say its comin gout around october 9i think 2008) in Northern california

Link?

I'm not saying it's impossible (there's a train than can pull 1 ton and get 100 mpg, so I think a car could do that easily since it isn't pulling a ton).

[Higgs Boson]

BMW Hydrogen 7. All that needs to be said. 125 miles on one tank of hydrogen fuel, 325 on regular gas. Also, that car Atlantis is referring to was in PopSci. It should be somewhere on their site.

[Higgs Boson]

heres a link  Aptera

[Xeviat]

BMW Hydrogen 7. All that needs to be said. 125 miles on one tank of hydrogen fuel, 325 on regular gas. Also, that car Atlantis is referring to was in PopSci. It should be somewhere on their site.

Where do you get your Hydrogen from for that BMW? How much does a tank of fuel cost compared to gas? If that Hydrogen is made through electrolysis, I don't believe you've done anything to help the environment.

[Stargate525]

er, electrolysis via nuclear energy?

And the question, I don't think, was answered. Using this device, would you have to put in something more than water to run it long-term? Is the engine at least able to produce enough to continue the electrolysis? If the answer to that is yes, efficiency be damned. It runs completely clean, it uses a readily available fuel source which is, to the majority of people in my area, completely free, and the only difficulty would be filling it up on longer trips.

[Xeviat]

No, the engine goes battery to electrolysis, 2H2/02 mixture explodes in engine to turn pistons, this turns motor and turns tires while also turning alternator. Less power makes it back to the battery than leaves it.

If you were to put a solar panel array on the car, maybe you could keep the battery going in the sun. But you still might as well go completely electric/solar.