The search for an alternative fuel source other than oil should leave no idea untested. Still, there are some ideas with more potential than others, and some alt-fuel concepts are just plain strange. Compressed air vehicles have been around for around 150 years, but the technology has never caught on with automakers. There’s a reason for that, and it’s called torque, or the lack thereof.
Compressed air has been used to power engines since the mid-19th century, first gaining popularity in coal mines where combustion engines were deadly. Paris famously used pneumatic trains to help dig the tunnels of its vast metro and tunnel system. Pneumatic power even propelled the first naval torpedoes, though the first compressed air car companies did not last long.
Even so, that hasn’t stopped some recent upstart auto companies from penning their own plans for compressed air vehicles. Even Tata Motors, a massive Indian auto company, has pledged to build compressed air vehicles. Then there is the MDI AirPod, that odd-looking concept at the top of this post. But despite building working prototypes, there are a number of design flaws that keep air cars from going to market.
For one, compressed air motors don’t make as much power or torque as car owners are used to, meaning very low top speeds, often around just 40 mph. That is barely enough for city driving, and highway cruising is totally out of the question. It can also take many hours to fill the tank of a compressed air car, despite a seriously limited range, and problems with cooling the tank and heating the air make these vehicles quite power hungry.
Despite these drawbacks though, companies like Peugeot are still exploring the use of compressed air in a hybrid drivetrain setup, allowing for up to 117 mpg. Compressed air vehicles are also remarkably quiet and, discounting the air compressors themselves, produce absolutely no emissions. They’re also very, very cheap to operate.
This could make them ideal tourist buses or city service vehicles, but as actual commuters? Compressed air cars have a long, long way to go.