Compressed Air Cars

Summary:
Email claims that a car being developed in India runs on compressed air and can travel up to 125 miles for only 2 dollars (Full commentary below).



Status:
Prototypes of such vehicles do exist

Example:(Submitted, June 2008)


Commentary:
According to this email, an innovative new compressed air powered vehicle is currently being developed in India. The information in the message is basically true. Such a car is indeed being produced by European company Motor Development International (MDI) in partnership with Indian company Tata Motors.

MDI's founder, inventor and entrepreneur, Guy Negre, is responsible for the development of the revolutionary new engine. A 2007 article about the air cars published in Popular Mechanics notes that the air car "uses compressed air, as opposed to the gas-and-oxygen explosions of internal-combustion models, to push its engine's pistons".

Popular Mechanics suggests that there are several models planned, including the CityCAT which will sell for around $12,700 and cruises along at a top speed of 68 mph. It is claimed that the CityCAT will be able to travel around 125 miles before it needs to be refuelled at a service station equipped with a custom air compressor unit at a cost of about $2. The car also has a built in compressor unit that uses a normal electricity outlet to refill the air tanks over about 4 hours.

Zero Pollution Motors (ZPM), the US representative for MDI, promises that the vehicles will be available in the United States by 2010. There are also plans to manufacture the air cars in Australia and several other countries.

While reliable reports indicate that such cars are really being developed, many commentators have expressed doubts about the true potential of air cars. Some experts doubt that the cars will really be as cheap and efficient to run as claimed by MDI. A CNN article about the cars notes:

It is possible to power a car with compressed air, but the mileage claim is "at the edge of possibility," said John Callister, director of the Harvey Kinzelberg Entrepreneurship in Engineering program at Cornell University's College of Engineering.

He noted that such dramatic fuel efficiency is associated with tiny experimental cars, not bigger mainstream ones.

The article also states:

Another expert expressed concern about the amount of energy it would take to generate the required air pressure: 4,500 pounds per square inch, or more than 120 times the pressure inside the tires of a typical four-door sedan.

"That is above what you normally find even in an industrial setting," said William Bulpitt, senior research engineer at the Georgia Institute of Technology's Strategic Energy Institute.

"That takes quite a compressor to do. ... It takes horsepower to compress the air up to that pressure."

If you count that energy, it's hard to believe the car would be that much more efficient than an electric vehicle, Callister said.

Given their lightweight design, some commentators have also raised safety concerns about the vehicles.

Only time will tell how successful the compressed air driven vehicles will be in the long term.

References:
An engine which uses air as fuel
106 mpg 'air car' creates buzz, questions
World's First Air-Powered Car: Zero Emissions by Next Summer
Zero Pollution Motors
Air car to call Melbourne home
The Air Car - zero pollution and very low running costs

Last updated: 10th August 2008
First published: 11th June 2008

Write-up by Brett M. Christensen

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