Heres a project for thought....

[burninbriar]

Are you sure about this? To my knowledge its just salt to make the water more conductive.

One of the by products of any kind of combustion is water, only hydrogen combustion makes JUST water.

Not 100% sure. To my knowledge the generator works like a battery, sort of. The design I saw, if I remember it right, used nickel plates and a water and battery acid solution, but you might be correct in that salt is all thats needed to make it conductive enough.

[burninbriar]

Here is a link I found for a home made system. They use potassium hydroxide, so that would be a strong base rather than an acid.
http://www.dangerouslaboratories.org/h2homesystem.pdf

[c wagner]

I agree with the comments about the new diesel trucks getting worse Mpg. They want to release fewer hydrocarbons but burn MORE fuel in the process
It makes me sick!
I would like to know which produces more hydrocarbons:
recovering and refining a gallon of diesel or burning a gallon of diesel?

[Handy560]

I due realize that some vehicles and trains/trollys already do recoup some energy from braking. My point is that it is underutilized. Think about how much cummulative energy is wasted; heat generated by stopping every moving vehicle. (picture a crowded expressway or a looong frieght train grinding to a halt) Because we are stopping the vehicle, a necessary function regardless of the means as opposed to constantly driving a generator or alternator using fuel to do so, once the cost of the equipment is recouped, whatever energy we save for future use is free.

Batteries and storage devices etc. do have some non green issues of course.

Another point is that the simple fact is that by that same 2nd law of thermodynamics we know that of the 3 possible solutions, reduce, reuse or recycle by far the most conservation of energy is through reduction. So we can grow corn for ethanol, recycle tires, and garbage, reuse glass bottles etc., but the most effecient conservation comes from a reduction... higher milage, better public transportation, using resorces that are produced locally, working from home, not welding for fun...

Well, let's not get carried away!

The biggest obsticle is that we are spoiled and wasteful and developing countries are even more wasteful and even less concerned for the environment.

Lastly, as far as seperating hydrogen through electrolysis, simply passing a dc current through water seperates hydrodgen and oxygen. The hydrogen stream comes from the negative electrode. After that, other enhancements speed the process. Adding salt or other ions to the water which increases the conductivity accelerates the reaction. There are other factors such as the conductors (anode & cathode) used, their relative surface area and current. I believe the reaction over time may leave some precipitates depending on the materials used. I think that actual industrial applications use platinum electrodes. The combined proportion of oxygen and hydrogen makes a very combustible mixture, but it is relatively easy to seperate the two as it is captured.

I forsee in the future vehicles will run on alchohol made from all types of fermented sh_t (literally) and other waste. When it brakes it generates electricity stored in a combination of new generation baterries and capicitors and then modulated to zap water and seperate H and O2 and then they will be supercharged back into the mixture...

Lets see: blown and injected with pure o2 and a hydrogen mix... well helllo ladies

J

Just my ten cents before I head to zzzzzzzzzzzzzzzzzz

hmmm maybe I am already dreaming?!

[lens42]

It's too bad the OP started in on perpetual motion because that seemed to sidetrack everyone. The compressed air car is not that crazy:

http://rawstory.com/news/2007/Air_ca..._air_0104.html

[Blue Collar Moto]

I heard this somewhere, take it or leave it. In the 100 years since we've been using oil to run the world, we've used approximately 1 trillion barrels of oil. There are estimated to be another 15 trillion barrels of oil available. That's more than 1000 years of available oil to run the world. With these estimated numbers, mankind has plenty of time to come up with solar, wind or any other alternative, financially viable power.

Oil runs the WORLD economy, whether we like it or not. Fuel prices are dictated by the world economy, not by the big oil companies. With china and india now using cars like we do, prices are going up.

We need to be building nuclear power plants as fast as we can. And if we don't start drilling in ANWR and the gulf of Mexico, America is done. But the eco-freaks won't let us.

You said it. Prices will only go up as the rest of the world plays catch up to US.

Had a engineer friend who was wanting to build a drag bike that would run on compressed air using a turbine like a jet engine. We talked till we turned blue to the NHRA guys but they would not agree to let us demmo the thing on one of their tracks. So much for a good/fun, and potentially lethal idea.

[spotsineyes]

It's too bad the OP started in on perpetual motion because that seemed to sidetrack everyone. The compressed air car is not that crazy:

http://rawstory.com/news/2007/Air_ca..._air_0104.html

I can't believe it took 35 posts to get this answer to the thread starters question. I saw that in some magazine and was going to Google it and post it if you hadn't.
And you're right, once a thread is sidetracked, there is almost no turning back. Maybe my post will help.

[DSW]

Some how I doubt that car shown would comply with most government front and side impact requirements. What happens to the air storage bottle in an accident? Does it go boom or take off like a rocket? If you want a 2 seat moped with a roof ok. Now put something in it. As soon as the weight goes up the concept will fall apart.

You can build a solar car, its been done. Practical he!! no.

It says it goes 125 miles, at what speed? Not 70mph. The 70 mph is most likely for a very short amount of time. I would be real curious to see some real figures for that. Vehicle weight, air tank size and pressure, sustained speed and distance #'s and at what max weight. Like many things I think its a lot of catchy ideas but no solid substance.

I'm curious about the cost of the fills also. It takes a minimum of 10 minutes to fill an alum 80 cf scuba cylinder up to 3000 psi. That is if you don't want to destroy it by over heating it when its filled or don't care if it stays at the filled pressure. Its hard to find places that will fill them for less than $10. I have filled literally thousands of tanks, the info just don't add up.

BTW remember how great your gas mileage is just before you are involved in an accident with one of us in our full size trucks.

[Handy560]

I agree that many of the numbers seem a bit overstated.

Just wanted to say that the scuba tanks may not be a good comparison as they require special compressors with a long slow stroke and a soap type lubricate.

Getting any petro-chemical contaminents into the bottle to breath under pressure would be very dangerous.

J

[DSW]

I don't know about a long "slow stroke" on a "breathing air" compressor. The comps I have worked with are all high RPM 4or 5 stage piston compressors. Most of HP machines I am familiar with run a food safe oil or synthetic as lubrication. There are special filters to filter out oils, CO, and so on. I have dove on 175psi wheelbarrow compressors from Home depot with the correct filters installed. This only works for surface supplied air, not for air storage. You need a HP comp to store air at any significant pressure.

My basic thought is that you need air at a significant psi level to store the air needed to drive the vehicle. I can get 100cf in and 80ft cylinder if I increase the pressure from 3000psi to 3750psi. Same internal volume but more air. A HP compressor is a HP compressor. Screw machines won't generate the psi that I think you would need to make this work.

My basic thought was just on fill mechanics. I seldom fill straight from the compressor itself. It is very impractical and would take even longer to fill. We fill from 4500psi storage banks. The comp kicks in when the bank drops below 3800psi and then refills. Doesn't really mater if this is air or Nitrogen the same basic laws apply.

The faster you fill a cylinder the faster the temp increases. Alum tanks, and the carbon fiber wrapped alum tanks, do not like hot temps. I forget the max temp that they can be subjected to, but I have seen Alum tanks warp from being filled to fast and getting hot. To "fill" the car with the amount of air required should take a significant amount of time if you want the pressure to stay at that level for any length of time. The only way I could see this possibly working would be if you super cool the gas going into the car. This would reduce the amount of heat at the car but increase the amount of energy used. I still think more energy would be required to pressurise the air than it would take to run the car on gas.

I could see a use for something like this however in mines and other environments where exhaust emissions would be a primary concern over energy efficiency.