Something doesn't add up here. How do you go from 120psi to 4500 psi without using energy? And how do you extract the energy from the gas to lower its temperature to -100?
Admittedly, I haven't studied my Thermodynamics in years, but a little voice keeps telling me something doesn't fit.
You're right there's no way 2 minutes worth of compressed air from a filling station tire hose is going to be able to pack the kind of energy needed to make a car go. That's maybe a 2 horsepower compressor. 2 horsepower for 2 minutes, will barely get it down the block.