MDI's AirPod to Go into Production

MDI has a history of making grand announcements.

In year 2000 they announced that thousands of cars would be in the saleroom by 2002. They never did it. Never explained why. http://news.bbc.co.uk/2/hi/africa/988265.stm

Then in 2002 they announced an agreement with the Mexican government to deliver 40,000 taxis. Same story. Never delivered. No explanation. http://news.bbc.co.uk/2/hi/americas/992431.stm

Then in summer of 2007 they said Tata Motors would be in production by July 2008. In August 2008 Tata Motors said the project was still in early development phase and production was not expected in the near future. http://www.cartradeindia.com/car-bike-news/tata-compressed-air-car-to-ta...

The ONLY published test results showed the car as only being able to go 7.22km ... a bit less than 5 miles. But with some innovative math, lots of hand waving and claims of 2 times improvement for this, 1.9 time improvement for that, and so forth, they somehow claim that the observed 5 mile range will be turned into 150 mile range in production models. Unfortunately, they have never actually shown the ability to do this.
This data is no longer on their website but can be retrieved from the wayback machine:
http://web.archive.org/web/20070915070846/www.theaircar.com/tests.html

Maybe there is a reason that people have been sceptical.

Transportion powered by compressed air is indeed feasible, as shown by the mining locomotives built by HK Porter in the 1890's through 1920's. They had the advantage of not having any flame or sparks, which is important in mines where there may be an explosive gas hazard.

They have never been successful for general purpose automotive use because of inefficiency and short operating range.

Energy Efficiency
http://www.efcf.com/reports/E18.pdf is a comparison of battery electric vehicles, electrolysis hydrogen powered vehicles, and compressed air vehicles. One important measure is the efficiency as measured from the electrical input to the battery charger/electrolysis unit/air compressor to the output of the engine to the wheels.

Even using very optimistic assumptions rather than actual measured performance, the electric grid-to-wheel efficiency of a compressed air car is about 37%, while the actual measured performance of an electric vehicle is 76%.

Or to express it another way, 100mJoules of energy taken from the grid will move a compressed air car 46 miles, but will move a NiMH battery car 127 miles (lithium ion battery car a slightly better 133 miles).

A major loss of power in a compressed air car is the heat that is generated when compressing air.

Energy Density and RangeEven with pressure of 300 bar/4350psi and using composite fiber tanks, the energy storage density of compressed air is roughly that of lead acid batteries. So for the same sized car, the range of a the most efficient compressed air powered car will be roughly the same as a lead acid car. And much less than the same sized car powered by NiMH or Lithium Ion batteries.
This is why it is so troubling that MDI has not been willing to give a public demonstration of what range their cars can truly achieve. They seem to keep falling back on the old test run of only 7.22km, which they then say that they will improve on by over a factor of 30. This sort of improvement needs to be demonstrated as having actually been achieved rather than just being theoretically possible (actually, in my review of their own documents their theoretical improvement doesn't seem justified).

If they are really that close to production,then they should have already built and tested some prototypes and have some real numbers, based upon actual performance.

To the best of my knowledge they don't have.

What they do have is an excellent public relations effort, and an excellent program for raising additional investment funds, in spite of a track record of repeated failures to deliver upon promised performance and deliveries.

very good