Engineering360: "What are compressed air cars?"

Compressed air is not free, nor is it efficient. It takes energy to compress air, and there are losses from heating, including the heat of condensation of water vapor in the air. The latter is not only generally unrecoverable, but from time to time the water must be removed from the system to prevent corrosion, loss of tank air capacity (volume taken up by the liquid), and possible damage to the motor. This typically requires releasing compressed air via the drain valve.

The idea that compressed air "with a small amount of heating" can compete with electric, direct internal combustion or hybrid drives in the general vehicle market seems like a pipe dream. This proposal is like a gas turbine engine with the compressor section removed to a remote location, or a Stirling engine with air as the working fluid - it's not going to evade the thermal engine efficiency limit. It may have a niche in an explosion hazard environment where electromagnetic emissions must be avoided - in such cases range is not quite as much of an issue.