Free energy/ perpetual motion car?????

Just watched Future Car "The Fuel" on discovery channel, and they showed this car that ran off compressed air by using it to force the movement of the cylinders. Now bear with me, i'm not very mechanically inclined. They then speculated that with more research, they could run an air compressor off an alternator on the engine, supplying the tanks with enough compressed ir to sustain itself.

So... correct me if i am wrong, but don't the laws of thermodynamics prove this to be impossible?

There's a thread on this, already.

But, there's no way an engine running on compressed air can fuel itself.
Think about it it. If this were the case, air compressors in shops that are
used to run air tools would have no external power sources.

Lex

Discovery stole my idea!!! I said to run an alternator to a compressor....and then suddenly this documentary shows up?

I swear.. either someone is watching me... or I have some kind of ESP...

this isn't the first time I've had a thought or idea, and the BAM! suddenly a short while later - there it is!!! even when it's something I haven't told anyone...

Thermodynamic law would be violated if the invention claimed to be able to sustain itself indefinitely.

I seriously doubt that you could extract enough work from the small amount of compressed air you could store on a vehicle to actually move it very far at all. I suppose it is theoretically possible you might be able to drive a car around that was based on a concept like this, but you'd probably have to fill it up with compressed air so frequently that you couldn't even drive to work or something. Unless I'm really missing something here, I don't see how this invention will ever amount to anything.