Peugeot Citroen Unveils the Latest Effort to Run Cars on Compressed Air

The auto industry is one of the most innovative industries worldwide. At the same time, there’s a good chance you’re driving a fossil fuel-powered car just like your grandfather did decades ago. There are many reasons for this seeming contradiction, but the fact is that the auto industry wants to change this reality and is constantly looking for alternatives that are cleaner, cheaper and eventually better, from electrification to biofuels. The latest attempt concerns maybe the most available resource of all – air.

The French car manufacturer Peugeot Citroen has just announcet that it is working on a new kind of hybrid car that uses a conventional internal combustion engine and compressed air for motive power. “Intended for smaller B- and C-segment vehicles with output of up to 110 horsepower, it's designed to operate in three modes: internal combustion, compressed air only or a combination of the two,” Kbb.com reported.

The idea of using compressed air to power cars is anything but new, and already in 19^th century you had mine locomotives and trams in some cities using compressed air. The way compressed-air engines work hasn’t changed much since then, explains Michael Coren on Co.Exist, “Fresh air is pumped into a chamber under high pressure, and then released into 'combustion' chambers where the air forces down pistons and turns the wheels.”

So why didn’t it work? After all, compressed air seems to have many advantages, from low price to zero tailpipe emissions (although not everyone seem to agree it’s as clean an option as it appears). Apparently, compressed air has a relatively low energy density and therefore it’s unlikely to provide enough range or speed to appeal to the masses. “Compressed air does not contain much energy–that’s the killer,” Larry Rinek, senior research analyst for automotive technologies at consultancy Frost & Sullivan told MIT Technology Review. “This is more a nice garage project for a Popular Science subscriber.”

Some companies, including Toyota, MDI and Tata begged to differ and tried to develop improved models, but without much success. Now Peugeot is giving it a shot with its new "Hybrid Air" concept that it believes to be somewhat different and better. The planned car's main source of power remains an internal combustion engine powered by gasoline, explains Antony Ingram on Green Car Reports. “But instead of using batteries to supply additional power, or zero-emissions driving when needed,” he adds, “the concept instead uses a compressed air tank mounted in the central transmission tunnel to turn a hydraulic motor.”

When you run this car on highways, it will use the internal combustion engine alone. In cities the engine allows up to 80 percent driving on compressed air with an impressive fuel economy of 81 miles per gallon and only emits just 110 grams of carbon dioxide per mile. The combined economy can reach up to 117 mpg. "This breakthrough technology ... represents a key step towards the two litre per hundred kilometre car by 2020," Peugeot Citroen chief executive Philippe Varin said at a press conference unveiling a series of new technologies.

The new system is intended for smaller and midsized cars and one of its advantages is that it requires only minimal redesign work from Peugeot on a conventional platform like the Citroen C3 or Peugeot 208. Other important advantages include a 45 percent savings in relative fuel usage and up to a 90 percent increase in range compared to a similar vehicle with only an internal combustion engine. Peugeot didn’t say anything about the price yet but it does make sense that the company will also be able to offer a competitive price given the lack of need of an expensive battery pack.

Even if we assume that Peugeot successfully manages to overcome the engineering challenges that prevented compressed-air cars from becoming a serious alternative over the years, the main question is whether consumers will be likely to accept it. I believe that it does have a chance, although probably more in Asia and Europe than in North America given that this system is not a good fit for big cars.

Eventually it all comes down to price and convenience. If these cars manage to combine the advantages of a hybrid car (infrastructure and range are not an issue), the impressive fuel economy of electric cars and significant cost savings, then compressed air might be the next big thing in the auto industry.

Still, before we start daydreaming about how air will be our savior when it comes to private transportation, let’s not forget that we probably need couple of more breakthroughs before we see it becoming the fuel of choice. Until then, we’ll probably keep driving just like grandpa.

[Image credit: PSA Peugeot Citroen]

Raz Godelnik is the co-founder of Eco-Libris and an adjunct faculty at the University of Delaware’s Business School, CUNY SPS and Parsons The New School for Design, teaching courses in green business, sustainable design and new product development. You can follow Raz on Twitter.