It still sounded like a good idea, so I contacted a longtime friend's husband who is a physicist. He says the technology exists. But I'm certain they will have to revamp those gas station pumps that take five minutes to fill a car tire!

From Steven:

"I first heard of the air powered car about a year ago. I think that it was first developed in France. I'm not sure just how the power cycle on the engine works, but I know there are working vehicles using this technology and the power source is very high pressure air.

"The actual range between refuels will depend on the air tank size, air pressure, vehicle weight, accelerations, driving terrain and driving speeds, etc.

"From what I remember, the vehicle is very light weight and will probably have trouble getting approved here in the US, at least with regards to freeway driving and I doubt that it will have many luxuries (limited power and torque).

"If an owner invests in a commercial air compressor, you could drive one of the cars around town for virtually free. For non freeway driving and two passenger use, I think this technology will blow the socks off of the 'mini/small' electric car market and maybe even put a dent in the mid sized electric vehicles.

"So, to answer your question, yes this technology exists. Whether it becomes commercially viable remains to be seen, but I suspect that there is a market and we will be seeing air powered cars in the near future."

The physicist may not be sufficiently familiar with the problems of very high pressure air. (I've worked a bit with 4500psi air)

Transfer rate of very high pressure air from storage to an empty tank has to be slow because the sudden pressure buildup in the empty tank/lines causes heating. In the presence of combustible material (entrained oil from the compressor) this can cause "dieseling" in the piping which would destroy it. It's also really, really LOUD.

Commercial air compressors are generally not of really high pressure. A compressor capable of very high pressure requires a large motor and thus home air compression wouldn't be "free."

Storage of really high pressure air requires good tanks and piping. I'm sure that there would be certification and OSHA issues that go with.

It's unclear to me whether the energy storage capacity is adequate to serve real needs. Let's see them start out on golf carts and fork lifts before requiring me to buy one....

Newspaper articles often are methods of gaining funding for projects rather than actually informing of breakthroughs in technology.

I'm still waiting for the flywheel-powered buses and the flying cars that Popular Science wrote up when I was a young teen.....
The Moeller Air Car has been a recurring theme for 30 years. But I still don't have one in my garage.

You're pretty much looking at a steam engine powered with compressed air instead of steam pressure.



Accurate. Also, there's a pretty good writeup on it in Wikipedia.
http://en.wikipedia.org/wiki/Compressed-air_vehicle



Whole clothe, marketing hype, and natural fertilizer. Commercial air compressors only generate arounf 0.1 KSI (100 PSI). The car requires an air compressor that can handle up to 4.5 KSI. For that you need a high pressure air compressors, and they typically run $10,000-$20,000. Add to that the loss of efficiency during compression, and loss of heat from the tank, and you're far from "virtually free".



It's been proven in small scale (RC plane engines, etc.), but the physics of scale, and the accident hazards are going to make this a curiosity. But, not a mainstream solution.

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P.S. From my perspective the overriding problems are efficiency followed by infrastructure. The most promising technologies within the foreseeable future will be a combination of alternate fuels (including electricity), hybridization, and cascading power cycles using waste heat (e.g. radiator and exhaust losses).