PDA

View Full Version : Driving on Compressed Air



johnnymk
05-02-2006, 03:37 PM
With rising gas prices and Peak Oil fast approaching (if it hasn't happened yet), droves of experts are feverishly working on alternative fuel solutions for automobiles. You may have heard of hydrogen or ethanol as gasoline substitutes, but both of those have their own challenges.

Hydrogen is very popular with environmentalists as fuel of the future because of its cleanliness. However, most hydrogen today is made from natural gas (see "Gas Crisis Next?" below), and the final product has only 50% of the energy value of its source... which makes the idea of producing hydrogen using current methodologies ludicrous in terms of energy-saving and fuel efficiency.

Hydrogen is also the hardest gas to compress and may have to be liquefied to be stored effectively. On the other hand, liquid hydrogen would escape from your car's tank at a rate of 3-4% per day. That means every minute you don't drive, your fuel is just sitting there, vaporizing.

Ethanol, which can be mixed with gasoline, is made from renewable grain and vegetable sources, such as corn. While this initially sounds good, keep in mind that one bushel of corn (about 56 pounds) produces only 2.7 gallons of ethanol. And as slate.com recently reported, two professors--one from Cornell University, one from Berkeley--proved that "making ethanol from corn requires 29 percent more fossil energy than the ethanol fuel itself actually contains." And it would be expensive, too: At a gas station, filling up with ethanol could easily cost 6 or 7 dollars per gallon.

Any other ideas, anyone?

In fact, there is another concept for alternative fuel that may just be what the world has been waiting for. A French manufacturer has been working on (and completed) the world's first air car.

Running on Compressed Air Technology and therefore called CAT, the new urban car developed by Moteur Developement International (MDI) has zero emissions.

The compressed air that powers the two-stroke engine is stored in "light-weight tanks [that] are made of carbon fiber and hold 200 liters of air at a pressure of 4,351 pounds per square inch (p/si)," stated a recent report on the Science Channel. "With this amount of air, the car can travel 150 kilometers [93 miles] in the city."

"Air is forced through an injector where it expands, pushing down on pistons that turn the crank shaft to power the car. The engine is also specially designed to [allow] multiple engines to be joined together, giving the car more power. Which means, each air car model comes with the option of a 2-, 4- or 6-cylinder engine."

Fueling up is easy: You fill the tank by plugging into a normal electric outlet at home, which takes about 4 hours. Cost: 1.50 euros ($2.36).

If you don't have that much time, it takes only 3 minutes to fill your tank with a high-pressure air pump at a gas station ("air stations" have yet to be designed). MDI estimates that this will increase the cost of a full tank by 40 to 60 percent--resulting in a whopping $3.53. The same distance (93 miles) traveled in a gasoline-powered car costs Americans around $12 these days.

Sounds too good to be true?

Well, there is a catch: The CAT can only reach a speed of 68 mph and is therefore best suited for urban traffic. Also, while the engine runs solely on compressed air at speeds of 37 mph or less, at higher speeds it still depends on traditional fossil fuel. However, environmentally (and financially) conscious urbanites may embrace this little vehicle as the city car of the future. [To watch the Science Channel report, click here.]

Four models are available so far--a car, a taxi (5 passengers), a pick-up truck and a van. MDI expects to produce 3,000 CATs per year for now, with a final selling price of around $8,670.

A mass launch in the U.S. is not yet planned, but if you're interested in buying one of the prototypes, you can join a list on MDI's website: http://www.theaircar.com/models_iwantone.html


What We Now Know is published by Casey Research, LLC, with contributions from a wide-ranging and well-connected network of researchers, authors, scientists, political analysts, investment experts, and technologists known to Doug Casey and his team to be reliable sources with something interesting to share

hapoo
05-02-2006, 03:48 PM
My best friend from childhood studies mechanical engineering at ucla and he worked on a hybrid compressed air engine. It ran on gas and when the engine needed to be slowed down, the air in the cylinder would compress and be stored for later use. Similar to an electric hybrid.

Houdini
05-03-2006, 12:14 AM
Interesting ideas, especially the hybrids with compressors, but I routinely drive >90 miles, so that would kinda suck.

Hydrogen is very nice, but producing it is expensive. Unless we start using nuclear power or other sources to crack water in lieu of stripping CH4, which also takes some energy and other resources, it's just not that feasible yet. Though water is the byproduct, and exhaust would be hot enough to make it evaporate, so people wouldn't be skidding around on others' exhaust products. :)

Then again, if there were a cheap way to crack water, we could just use fusion. :) Deut and Trit would work nicely. And there's a LOT of water in the world. And the byproduct would be, well, water.

BigJon
05-03-2006, 06:41 AM
The concept of air powered cars would work for me! I live only a couple of miles from work and only drive back and forth. I rarely even move my vehicle out of the parking lot at home on the weekends.

Airencracken
05-08-2006, 11:25 AM
http://forums.gotapex.com/showpost.php?p=1008838&postcount=59

All it takes is one Ford UAV and you're toast.

cheapie
05-08-2006, 11:41 AM
but that's pretty much the case with any small car/motorcycle isn't it?

DarkFury
05-08-2006, 11:41 AM
Heh... the "fart cart". :D

Airencracken
05-08-2006, 11:44 AM
but that's pretty much the case with any small car/motorcycle isn't it?

I suppose. YAR to get rid of SUV's for the most part.

InfiniteNothing
05-08-2006, 11:44 AM
but that's pretty much the case with any small car/motorcycle isn't it?
Well, not really. People on motorcycles have survived crashes. 4KPSI (300 X normal atmospheric pressure at sea level) would cause a pretty big boom. I'd be concerned for nearby cars as well.

Though the air car makers seem to think that it'll be okay:

300 bars of compressed air stored on board the vehicle, Is this dangerous for the passengers?
Compressed air tanks have already been proven safe by one of our partners EADS(AIRBUS). This company's reputation in the aeronautical field is unprecedented, given the reliability of its tanks. What's more, the compressed air does not present any risk of explosion. Countless test have been carried out in the most extreme conditions (gun shoots, resistance to fire...) to guarantee passenger safety in every possible condition. The high pressure tanks have been developed using a similar technology to those used in natural gas vehicles and by firefighters. All are produced with carbon fiber over plastic.
The tanks that MDI puts in its vehicles are similar to those already in use in natural gas busses in Germany and other countries.

cheapie
05-08-2006, 11:47 AM
oh. lol. i was just thinking about the small size of the vehicle.

btw, we're working on that type of system for garbage trucks, except using hydraulic pressure to store, and release energy.

InfiniteNothing
05-08-2006, 11:55 AM
Wow, that's kinda clever. I can't imagine you could store any significant amount of energy in a liquid though.

guiseppewv
05-08-2006, 12:35 PM
Interesting information!!! :)


And it would be expensive, too: At a gas station, filling up with ethanol could easily cost 6 or 7 dollars per gallon.


A little exaggeration here. E85 runs 3.22/gal (last time I looked) at a station near me.

cheapie
05-08-2006, 05:03 PM
Wow, that's kinda clever. I can't imagine you could store any significant amount of energy in a liquid though.


just enough to help launch the vehicle. and it really saves on the brakes. these guys change their brakes monthly.

InfiniteNothing
05-08-2006, 09:03 PM
Makes sense

cheapie
05-08-2006, 09:33 PM
yeah. but like any new technology, proving the value story while you're waiting for volumes to drive down costs is difficult.

Airencracken
05-08-2006, 09:42 PM
yeah. but like any new technology, proving the value story while you're waiting for volumes to drive down costs is difficult.

horse/carriage

cheapie
05-08-2006, 09:48 PM
lol. yeah. well, when you think of early adopters, you don't think of trucking companies.

Airencracken
05-08-2006, 09:56 PM
Yeah....

You think college students in Toyota Priuses. ;)

OC
05-09-2006, 06:20 AM
Interesting information!!! :)



A little exaggeration here. E85 runs 3.22/gal (last time I looked) at a station near me.I wish we had E85 near us. I'd totally be into a Ranger with the flex-fuel 3.0 V6.

Chgoman
05-09-2006, 06:56 AM
I used to have a Flex Fuel Ranger. I looked into E85, but it didn't seem worth the trouble of going out of the way to get it. It was slightly cheaper per gallon than regular gas, but you also get worse gas mileage with it and I read that over long periods of time, it's corrosive to your engine. That was a few years ago. I don't know if they've changed the formula at all since then.

OC
05-09-2006, 07:02 AM
The only real reason to use E85 is that it's not as harmful to the environment as gasoline and it's renewable. You will pay more to use E85 because if its lower energy content compared to gas - you'll get substantially fewer miles per gallon because of this. Running E85 all the time shouldn't harm the engine at all. Pure ethanol would be a different story though.

guiseppewv
05-09-2006, 08:22 AM
I am not sure that pure ethanol would be much more corrosive to the engine. I thought the gas is put in the ethanol to allow the vehicle to start in colder climates and to allow people to see the flames (pure ethanol burns with an invisible flame) from the fuel if the car is on fire.

Houdini
05-10-2006, 01:23 AM
Wow, that's kinda clever. I can't imagine you could store any significant amount of energy in a liquid though.

Heh...already been done. Gas/diesel with internal combustion engines. But we're moving away from that, right? :p