Wednesday 22 June 2011

After water comes air.....

Following this post it seems we will shortly have an alternative form of propulsion for a motor vehicle, namely air. Unfortunately blogger does not wish to post any form of picture at present, so I can but link to the youtube piece.

It would appear that India's largest automaker, Tata Motors, is set to start producing the world's first commercial air-powered vehicle. The Air Car: developed by ex-Formula One engineer Guy Ngre for Luxembourg-based MDI, uses compressed air, as opposed to the gas-and-oxygen explosions of internal-combustion models, to push its engines' pistons. Some 6000 zero-emissions Air Cars are scheduled to hit Indian streets by August, 2011

The Air Car: called the "MiniCAT" could cost around Rs.475,225 ($8,177.00) in India and would have a range of around 300 km between refuels. The cost of a refill would be about Rs. 85 ($2.00). The MiniCAT which is a simple, light urban car, with a tubular chassis that is glued, not welded, and a body of fiberglass powered by compressed air. Microcontrollers are used in every device in the car, so one tiny radio transmitter sends instructions to the lights, indicators, etc.

There are no keys - just an access card which can be read by the car from your pocket. According to the designers, it costs less than 50 rupees per 100 Km (about a tenth that of a petrol car). Its mileage is about double that of the most advanced electric car (200 to 300 km or 10 hours of driving), a factor which makes it a perfect choice in cities where 80% of motorists drive at less than 60 Km. The car has a top speed of 105 kmph. Refilling the car will, once the market develops, take place at adapted petrol stations to administer compressed air. In two or three minutes, and at a cost of approximately 100 rupees, the car will be ready to go another
200-300 kilometers.

Whilst those of my readers who are scientists and engineers may well begin pulling this article to pieces, I would ask one thing of them - please don't shoot the messenger!

11 comments:

A K Haart said...

You can add pictures if you do it in Edit HTML rather than Compose. Switch back to Compose after adding the picture.

Compressed air power has been around for a while if I remember rightly. Don't know how efficient it is.

WitteringsfromWitney said...

AKH: thanks for the tip.....

Yup, I know that this has development has been going on for some years - since 1993 (?) I believe.

It was really a tongue in cheek post following the one about water powered cars........

Edward Spalton said...

I remember reading some years ago about one of the French car makers with a similar project.

The range of the car could be extended considerably by using a gas heater to make the compressed air expand further.

Talk then was that the heater would eventually use hydrogen and so have no "carbon footprint".

DAD said...

When I were a lad.... I had a compressed air model car. It went well, and was 'charged' by a bicycle pump.

My engineering background makes me suspect that it will take longer to recharge the pressure tank(s) than the time stated in the blurb, but not too much longer.

All-in-all it may be OK, but with 4 passengers and holiday luggage it will struggle.

WitteringsfromWitney said...

ES: yes, as I understand it, it was the French who began this research with the help of Negre. Not too sure who the car manufacturer was though - no doubt someone will enlighten/refresh my memory......

WitteringsfromWitney said...

DAD: Thanks for that and thanks for not shooting the messenger!

microdave said...

Several points:

1) The same old lies about "Zero Emissions" - It may be zero emission at the point of use, but you still need energy to compress the air to start with!!

2) It does have the considerable advantage over batteries, of being quick to recharge. Many "Eastern Bloc" light aircraft use compressed air for starting and some other functions, as it's not affected by low temperatures as batteries are. This has already been shown to be a serious problem in The US & Canada over the recent cold snap.

3) As mentioned in the film, large question marks still arise concerning safety, both of the air tanks, and the structure of such a basic lightweight vehicle. There was a recent tragic accident involving a G-Wizz electric car, which split in two and killed the occupant. I do not believe vehicles like this have the faintest chance of meeting current crash - impact standards.

4) I would question why they appear to have used a conventional clutch and gearbox, given that a compressed air motor (like a steam engine) can develop maximum torque at zero revs. Sitting there with the engine clattering way whilst waiting to pull away is absurd, and wasteful...

5) Unless it has an air powered generator it will still need a battery for lights, etc...

6) Assuming it has a pressure regulator between the tanks and motor it will have constant performance available until this lower pressure is reached, then it will rapidly slow down. I can see the boys from Top Gear being filmed pushing one to the nearest garage for a top up...

WitteringsfromWitney said...

md: I just knew some smart.... (no, I jest!)

Seriously though thanks for not shooting the messenger. Fair points, some of which I had not considered in the rush to post this......

microdave said...

Arse, yes.......Smart? - You've obviously never seen me......

I hope some mathematical bod will do the calculations of overall energy efficiency, the same as have been done for battery/electric vehicles. As even the most basic garage compressor gets pretty hot within a short time, one capable of 40bar (590psi) is going to be very wasteful of the electrical energy used to drive it.

Further to my comment about not being affected by low temperatures - I should have added the caveat that any moisture in the air (which is normal in this climate) will freeze in sub zero temperatures, so a desiccant system will be needed.

This is also going to be a risk when the motor is called upon to work hard. When a gas under pressure is allowed to expand it cools down (this principle is employed in domestic fridges, for example). So you run the risk of the control valve freezing up, which could prove embarrassing if you then find you are unable to slow down...

If the charging stations provide dry air this shouldn't be a problem, but you can guess what will happen if one of them didn't maintain their equipment properly (particularly in winter...)

I'm sorry, but this is just another example of trying to hoodwink the general public into "doing the right thing" without thinking it through properly. When all is said and done, the internal combustion engine has been developed and refined for over 100 years, and pretty well all the drawbacks are known.

microdave said...

Oh, and what about heating the vehicle in winter time? You don't even have the option of using the main battery, as is possible in a purely electric car.

So it's going to need something like a diesel fueled Eberspacher or Webasto unit, which in turn, needs 12/24 volts DC to power it...

WitteringsfromWitney said...

md: As ever, an erudite critique! Have seen those Eberspachers in operation on boats - damn good too!