http://www.popularmechanics.com/automotive....html?series=19

um....this seems a rather bizarre idea

Seems rather fantastic - as in related to fantasy. Check out the comments. And really, the power contained in a hundred pounds of compressed air is nothing compared to the power contained in fifty pounds of gasoline. I smell something off on that one. (However, no reason you can't use it as a fictional SR vehicle!)

I remember hearing about these a few years ago. Interesting concept.

iirc, even the most efficient gasoline engines today do not make use of even half of the energy potential of gasoline.

sure, you cant do 100% thanks to those pesky thermodynamics, but one could hope to hit 90% or there about. Not saying that this air engine makes use of 90% of the energy stored in the compressed air, but that a ideal engine of any kind would do so from its fuel source.

btw, rereading the article, it sounds like the air tank is taking the place of a battery in a hybrid kind of setup.

so on longer range drives, it will use a gasoline engine of some sort to get it to highways speeds, while using air for shorter hops.

i would say that given recent experiences with a diesel car, i have more confidence in those, if they can produce enough fuel from waste products of various kinds.

The problem is converting one type of energy to another (and also because we pull so much of that energy for other purposes - power steering, radio, lights, etc.) I'd be surprised if even direct application of that power in the simplest manner - cooking chicken over burning gasoline, for instance, got more than 80% efficiency from that. And even if you got 100% efficiency, how much energy do you think there is in a compressed air tank available to be tapped?



Reading the article, to me it sounded like they intend to use air to run the car, but using gas allows them to heat up the air to get more power from it. But really, they included no engineering details, so I think we're both just shooting in the dark! The comments, however, seemed to mirror my skepticism very well.

Theoretical practical maximum efficiency* is 90%.
Cooking a chicken has a huge heat loss issue as you're also heating the air around the chicken, and that's constantly being exchanged for new (cold) air.

*That is, the highest efficiency value you could achieve in practice, theoretically.