Join the Car Talk Community!

Discussion Rules

Welcome to the Car Talk Community!

Want to ask a question or join the discussion? Great! Join now.

Sign In Register

Hybrid Cars powered by compressed air

edited April 2012 in General Discussion
I heard about a car transmission that included a compressed air capability to aid in getting the car moving initially, accelerating, etc., saving gas. This story was around about the same time that hybrid cars were first being developed.

The story was the transmission would only add an additional $600 to the price of a car, it added only a little more weight to the car, the energy recaptured while braking or decelerating was around 70% as opposed to 30% for electric cars, and it dramatically improved gas mileage especially in the city.

What ever happened to that idea? I can't find anything on it now.



  • There are a lot of ideas that sound wonderful in theory but never get past the concept stage because of unforeseen problems or limitations. Here are just two that I recall from the past:

    >At one point--probably about 30 years ago--Nissan announced that they had developed a Freon-based propulsion system for cars, and that this system was so economical that it would eventually supplant the ICE. I don't recall the exact details of how this system worked, but apparently it never got past the concept/press release stage, as far as I can tell.

    >I can recall an article in either Popular Science or Popular Mechanics (I read both as a child), back in the '60s, that illustrated and described how a massive horizontal flywheel underneath heavy trucks would essentially store energy while the truck was moving, and allow it to operate in urban conditions with much greater efficiency and with much lower fuel costs. Have you ever heard of this being actually used?

  • I'm waiting for 2015 when Doc Brown returns from the future with his Mr. Fusion-powered DeLorean. Great Scott!
  • VDC

    I read a while back that Porsche incorporated a flywheel into one of their race cars. Whether or not it was practical I can't say.

    Ed B.
  • edited April 2012
    This is my favorite recent 'hybrid' (depending on the horse breeds on the treadmill):

  • Lest we think the OP complete crazy. Ford tried it.

    and so did UPS.

    There are a lot of reasons it didn't pan out.
  • You're right, compressed air has been tested and touted for decades, lots in the last 10 years. Makes a lot more sense than horses!
  • @Texases - The only question I have is...

    What happens to the horse manure??? But I like it....Ingenious.
  • @VDCDriver - The flywheel technology for storing energy ran into a lot of problems. It's being looked at again. The problem was the wheel had to get up to about 100k rpms in order for it to be usable. At that would sometimes break apart. And when this would send pieces of metal flying up to several hundred feet away. If a battery won't kill you (unless your face is right over it when it explodes). This thing could kill you if you were 100' away.

    Last I read..they had some new materials that were more stable...and if there was a would basically break into very small lightweight pieces that wouldn't go far and not hurt anyone. But not too many companies are working on this.
  • The thing to always remember when reading these new ideas is that they generally do not create energy, only store it. And the source from which it comes to them, the source from which they draw the energy they store, is the gasoline. Even the flywheel in only storing energy that the engine (gas) created in the first place. And there is always a loss in converting energy. In the case of the flywheel, the loss would be bearing friction and heat loss. A flywheel will return much of its inertial energy to the vehicle, but cannot return more than it acquired from the gas burned to get it spinning.

    The ideas that conserve energy, like those that reduce weight, drag, or combustion losses, are the ones that interest me. These include improved manufacturing technologies (including casting), better materials technologies such as polymers to replace metals, technologies to improve the fuel's combustability (like direct injection), and even things to reduce losses due to reciprocating masses (like lighter reciprocating parts, and even a rotating ball-valve system that I saw once to replace valvetrains).
  • edited April 2012
    If you want a laugh, google 'compressed air car', LOTS of them, just none in production. I got a kick out of the 2008 article promising one would be on sale in the US by 2010:

    "which runs to 35mph entirely on air, or uses a trickle of petrol to heat and compress more air to reach higher speeds up to 90mph. It'll cost next to nothing to run (how do 30,000km service intervals sound?), have a range of up to 1000 miles, and retail for well under US$20,000"

    From our Indian friends at Tata Motors, of course!
This discussion has been closed.