Would you buy an air-powered car?

[G R 'Scott' Cundiff]

I just read this article about air-powered cars...
http://www.popularmechanics.com/automotive/new_cars/4217016.html

It looks like a pretty nifty commuter car -- 125 miles on a "fill up" of air. The compressed air drives the pistons of the engine, so there is no air pollution.

[Ryan Scott]

This sounds like a fine idea. Although it will probably need to get more range and have an improved power output before it would be worth $12,000 to me, but a great idea for development.

[Dave McClung]

I just read this article about air-powered cars...
http://www.popularmechanics.com/automotive/new_cars/4217016.html

It looks like a pretty nifty commuter car -- 125 miles on a "fill up" of air. The compressed air drives the pistons of the engine, so there is no air pollution.

Can you imagine the amount of shielding that would be required in the U.S. for an air tank with 4,500 psi of compressed air? Air becomes a liquid at about 3,000 psi if it is cooled, so they are talking about compressing the air 50% beyond the liquifacation point, but keeping it in gas form because of the temperature. I can only imagine the force of the explosion if the car is involved in an accident.

Mark me down as one who is skeptical about getting 125 miles on one tank of air. There have been a number of previous announcements of "air" driven cars. So far, none of them have been practical because the size of the air tank has to be too big. When one gets an air tank large enough to hold the necessary volume of air, then the weight is too much to be practical.

I expect the air powered car to be right behind the sun powered car -- possible, but not with today's technology and not without taking unreasonable risks.

[Jerry Frank]

Hmmm. 4350 psi! I'd hate to be in the car if that tank ever blew either from failure or collision! I work for a gas compressor packager (oil and gas industry) and you should see the saftey hoops we have to go through for under 1000 psi pressures.

Jerry

[Kevin Bowser]

I expect the air powered car to be right behind the sun powered car -- possible, but not with today's technology and not without taking unreasonable risks.

Plus, all those evil oil companies will sabotage any possible developments and improvements in the technology. :basic05

[G R 'Scott' Cundiff]

Hmmm. 4350 psi! I'd hate to be in the car if that tank ever blew either from failure or collision! I work for a gas compressor packager (oil and gas industry) and you should see the saftey hoops we have to go through for under 1000 psi pressures.

Jerry

You and Dave are pretty sharp guys! That was the concern of some of the people who responded to the Instapundit blog where I first saw the story.

One of the respondents sent them to the Mythbuster's page for the account of their trying to explode a scuba tank with 3000 psi. The result was not an explosion, although things got rather violent when the tank was shot! The account is around 2/3 ways down this page: http://www.mythbustersfanclub.com/mb2/content/view/40/27/

[Dave McClung]

You and Dave are pretty sharp guys! That was the concern of some of the people who responded to the Instapundit blog where I first saw the story.

One of the respondents sent them to the Mythbuster's page for the account of their trying to explode a scuba tank with 3000 psi. The result was not an explosion, although things got rather violent when the tank was shot! The account is around 2/3 ways down this page: http://www.mythbustersfanclub.com/mb2/content/view/40/27/

When I flew helicopters, we used a compressed air tank called an "accumulator" to start the auxiliary power unit. As I recall, the accumulator used around 500 psi, but required a lot of special care and maintenance.

By "explosion" I don't mean the same kind of explosion that would occur in a gas explosion. I merely mean that a lot of energy is being held in a small tank. If the tank fails, that energy will go somewhere very rapidly. The results would be similiar to an explosion.

Here is a link to photos of what happens when a scuba tank ruptures: http://www.napsd.com/cscuba.htm The tank in the air driven car would be many times the size of the scuba tank.

[Jerry Frank]

Of course Mythbusters were trying to duplicate the movie story by shooting a clean hole into the tank. If you want to see the results of a standard failure of a scuba tank (or something that I think could happen in a collision), go to http://www.napsd.com/cscuba.htm

According to calculations here http://www.combro.co.uk/nigelh/diver/tank.html a typical scuba tank (12 liters at 230 bar or 3335 psi) would hold the equivalent potential energy of 300 grams of TNT. That's about double the amount for a typical grenade. Now convert all that somehow to 360 liters of air at 4350 pisi . . . Well, thanks but no thanks. I won't be driving it.


Jerry

[Jerry Frank]

Gee Dave . . . You're always one step ahead of me. :basic02


Jerry

[Wilson L. Deaton]

If I were going to let the danger of a tank explosion stop me, I wouldn't be driving my gasoline-powered vehicles!

Wilson

[G R 'Scott' Cundiff]

According to calculations here http://www.combro.co.uk/nigelh/diver/tank.html a typical scuba tank (12 liters at 230 bar or 3335 psi) would hold the equivalent potential energy of 300 grams of TNT. That's about double the amount for a typical grenade. Now convert all that somehow to 360 liters of air at 4350 pisi . . . Well, thanks but no thanks. I won't be driving it.
Jerry

Just out of curiosity, how much energy is stored in a tank of gasoline?

By the way Gene Reynolds of Instapundant commented that he doubts the car would ever pass regs here in the U.S.