Motorbikes could “run on air” says Indian researcher

[bogan]

stated that you have to burn something, at this point it's simpler to use the methane to drive a simple 4t engine...
same exhaust, less stages where you could lose efficiency into...

considering he just described a steam engine I'm gonna assume he was joking, though steampunk is pretty awesome.

[bogan]

Actually, I'm facinated by rotary stirling engines.

they do look quite interesting (http://www.nemitz.net/vernon/SPARLVE.htm), anyone made one to get some efficiency figures etc?

[davereid]

Compressed air of course is not a source of energy, its just a store of energy. And not a very good one. 350 bar would provide an energy density about the same as a lead acid battery. But Boyles law tells us, as others have noted, that we will lose massive amounts of energy as heat when we compress the air, and will suffer extreme cold when we use the fuel. A dead end I think..