The Aircar thread, a true unicorn or just very inefficient short range transport.

[Thymeclock]

Originally Posted by cfg83

Thymeclock -



I saw a video of a car that ran on 100% hydrogen where the tank was deliberately breached in a staged accident. It didn't explode. Instead, the hydrogen shot out like a blowtorch, maybe 1 foot long if I remember correctly. If the breach was in your direction, you would be toast. Otherwise the flame would burn itself out ASAP.

CarloSW2

I thought this thread was about compressed air. So what has hydrogen got to do with it?

[rmay635703]

Our 250psi rated (they normally only go to 120psi during use though) air cans for automotive use (aka they are mounted on vehicles with air brakes) at the plant are light as a feather. You don't need to armor them, just put a shroud around them so when they are hit and punctured then blow the air, it is directed somewhere. Not rocket science and air the last time I checked isn't the most flamable or explosive of materials even at 300psi which is all a jake brake could ever develope.

That Tata car is as dead as a doornail, you will never see it and we all know why. It was one unicorn that didn't fly very fast or far or even very well.

Originally Posted by Thymeclock

They weigh quite a lot, as a steel tank used for compressed air or gas needs to be substantial enough not to rupture.

Nah, it depends on the pressure, if used for the 270psi off a jake brake it would be very light, obviously a 3000psi tank is different (multiply by 10) And I agree fully on rust failure, it just makes an irritating leak that grows over time.

Originally Posted by Ryland

The question does not seem to be if they work but how well, I don't think they work well because you are using electricity to compress the air and storing that energy until it's used to power the car,

I fully agree and thats why I posted a little mental masterbation to show a situation where this could potentially be overcome by scale. Remember our battery charging systems (taken as a system) many times are only about 80% efficient (not all but many) And I fully believe compressing the air could be brought up to this efficiency point and beyond with a system as I described to eliminate the 2 of 3 main losses I provided with an existing compressor. The trouble is on the motor side.

Afterall gasoline engines began at about 5% efficiency, perhaps air motors with some work could get beyond this overall efficiency point? I am curious if anyone has some insite into what factors make a air motor more efficient (or make it inefficient) just as I outlined the actual reasons why the compressor isn't very efficient.

Originally Posted by Ryland

there is a power company that is doing something like this to store off peek electricity but they are freezing it to a liquid state then running it in a modern steam engine, more or less what an air car does with the compressed air, thing is, to make this set up work they need a way to keep the air engine warm and that is why it's not done here but they do play around with it in places like India that stay warm and everyone wants air conditioning, gas engines produce heat as a waste, air engines produce cold.

That sounds entirely too complex.

[cfg83]

Thymeclock -

Originally Posted by Thymeclock

I thought this thread was about compressed air. So what has hydrogen got to do with it?

I was just building on your statement :

They weigh quite a lot, as a steel tank used for compressed air or gas needs to be substantial enough not to rupture

CarloSW2

[NeilBlanchard]

Compressors are not very efficient. And to carry a tank big enough to power the car even as far as EV, would be pretty large and heavy. The Stanley Steamer that set the land speed record (that stood for a very long time!) crashed and it's tank shot about a mile down the beach.

[Thymeclock]

Afterall gasoline engines began at about 5% efficiency, perhaps air motors with some work could get beyond this overall efficiency point? I am curious if anyone has some insite into what factors make a air motor more efficient (or make it inefficient) just as I outlined the actual reasons why the compressor isn't very efficient.


That sounds entirely too complex.

Pneumatic technology is very effective for some purposes. For example, it is excellent for running a turbine at a very high speed. The drill that your dentist uses is run by pressurized air. The tiny turbine in it turns a tiny drill burr at 300,000 rpm. However, it produces very little torque. (The ultra high speed makes up for the lack of torque when used for drilling.) But it isn't of much use for applications other than what it is intended to do.

[orange4boy]

I'm not usually a nanny type but compressed air tanks are very dangerous if poorly constructed and sometimes the do fail catastrophically:

Stay from those old compressor--- - WeldingWeb™ - Welding forum for pros and enthusiasts

The guy who had the misfortune to be in the same room when this went off is lucky to be alive.

http://www.youtube.com/watch?v=kIs8c...layer_embedded

[Thymeclock]

Originally Posted by orange4boy

I'm not usually a nanny type but compressed air tanks are very dangerous if poorly constructed and sometimes the do fail catastrophically:

The guy who had the misfortune to be in the same room when this went off is lucky to be alive.

Several comments: The tank was obviously severely rusted. Common sense would be to check the condition of any tank before using it. The anecdote related that the idiot tried to run it up to pressures of 150 psi or more, probably bypassing the pressure switch, which exceeded the recommended pressure range. Obviously the pressure relief valve wasn't working. Lastly, Sears compressors are notorious for poor quality, although the other factors are the cause for the disaster.

This guy would be a candidate for the Darwin Awards.

[gone-ot]

...instead of those welded steel tanks, try looking at the spun, wrapped, fiberglass or carbon-fiber tanks like those used in airplanes, missiles and space craft.