A great development but how will the Government tax the air?!

This seems like an eco-dream come true, a car the runs on air developed in India. I’ve seen stories on this since 2008, but have yet to see the car hit market. Now the claim is in August 2012.

I don’t think you’ll see IPCC chairman Rajenda Pachauri driving one of these though, since he has been prone to booking posh 5 star hotel suites and won’t even drive the electric car he has. And like an electric car, that energy to charge the air tank with compressed air has to come from someplace, and that someplace if you are connected to the grid is likely fossil fuels, nuclear, or perhaps hydro. Though, with no fuel taxes, it might be a hit with anti-tax crusaders. With a claimed top speed of 60mph and range 185 miles, it should be enough to overcome the range anxiety of electric cars, and there’s no worry about battery fires or having to replace the expensive battery pack in 2-4 years. Whether it will ever be seen in the USA will of course depend on its crash worthiness. And when there is a crash, will it do this?
Story submitted by George Lawson

What is this? ‘Alison Italo Aus’
Will it be the next big thing?
Tata Motors of India thinks so.
What will the Oil Companies do to stop it?

It is an auto engine that runs on air.  That’s right; air not gas or diesel or electric but just the air around us.  Take a look.

Tata Motors of India has scheduled the Air Car to hit Indian streets by August 2012

The Air Car, developed by ex-Formula One engineer Guy N. For Luxembourg-based MDI, uses compressed air to push its engine’s pistons and make the car go.

The Air Car, called the “Mini CAT” could cost around 365,757 rupees in India or $8,177 US. 

The Mini CAT which is a simple, light urban car, with a tubular chassis, a body of fiberglass that is glued not welded and powered by compressed air.  A Microprocessor is used to control all electrical functions of the car.  One tiny radio transmitter sends instructions to the lights, turn signals and every other electrical device on the car.  Which are not many.

The four cyclinder compressed air engine

The temperature of the clean air expelled by the exhaust pipe is between 0-15 degrees below zero, which makes it suitable for use by the internal air conditioning system with no need for gases or loss of power.

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, that’s about a tenth the cost of a car running on gas.  It’s mileage is about double that of the most advanced electric car, a factor which makes it a perfect choice for city motorists.  The car has a top speed of 105 KM per hour or 60 mph and would have a range of around 300 km or 185 miles between refuels.  Refilling the car will take place at adapted gas stations with special air compressors.  A fill up will only take two to three minutes and costs approximately 100 rupees and the car will be ready to go another 300 kilometers.

This car can also be filled at home with it’s on board compressor.  It will take 3-4 hours to refill the tank, but it can be done while you sleep.

Because there is no combustion engine, changing the 1 liter of vegetable oil is only necessary every 50,000 KM or 30,000 miles.  Due to its simplicity, there is very little maintenance to be done on this car.

This Air Car almost sounds too good to be true.  We’ll see in August 2012 if it is.

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141 Responses to A great development but how will the Government tax the air?!

  1. PhilJourdan says:

    They will take cues from the post Hotels that charge for air and call it atmosphere. ;)

    (But at least they always have great coffee!).

  2. Jeremy says:

    3-seater with driver in the middle? So if you’re a single person you have to climb over a seat to get in position to drive??


  3. ShrNfr says:

    Somebody is in bad need of a course in thermodynamics. Even with a compressed air engine, you have thermodynamic loss. Of course it is hidden from you. The waste heat in the cycle is the heat that you get rid of when you compress the gas. So, you have a Carnot cycle of efficiency to produce the electric power from coal or whatever, and another to compress the gas. Sounds like a double whammy to me. Better you should burn the fuel at the place where you use the ordered energy to obtain motion.

  4. Ed Caryl says:

    How many pressurizations cycles before the tanks blow? And the driver is sitting on them.

  5. NC Skeptic says:

    I guess the car has cooling but no heating? Not good for cold weather.

  6. Caleb says:

    On rainy days it would beat a bike.

  7. Urederra says:

    I am reading this wiki entry: http://en.wikipedia.org/wiki/Compressed_air_energy_storage

    A standard 20 MPa, 5 L steel bottle has a mass of 7.5 kg, a superior one 5 kg. High-tensile strength fibers such as carbon-fiber or Kevlar can weigh below 2 kg in this size, consistent with the legal safety codes. One cubic meter of air at 20°C has a mass of 1.225 kg.[14] Thus, theoretical energy densities are from roughly 70 kJ/kg at the motor shaft for a plain steel bottle to 180 kJ/kg for an advanced fiber-wound one, whereas practical achievable energy densities for the same containers would be from 40 to 100 kJ/kg.
    [edit]Comparison with batteries
    Advanced fiber-reinforced bottles are comparable to the rechargeable lead-acid battery in terms of energy density. Advanced battery systems are several times better.[2] Batteries also provide nearly constant voltage over their entire charge level, whereas the pressure varies greatly while using a pressure vessel from full to empty. It is technically challenging to design air engines to maintain high efficiency and sufficient power over a wide range of pressures. Compressed air can transfer power at very high flux rates, which meets the principal acceleration and deceleration objectives of transportation systems, particularly for hybrid vehicles.

    (Emphasis mine)

    Also, As we all know, you are going to lose some energy during the compression process, I do not believe the figures they give. I guess they are considering taxes and subsides. If gasoline is highly taxed and air is highly subsidized then the figures may be true, but that is cheating.

  8. KNR says:

    Its been done before and there was a good reason why it failed then , you simply can’t get an range worth a dam and its HIGH pressure which can go bang in a big way . Then there is the problem of dealing with leaks . Lets how this ine works out, but like so many of these ‘new wonder ‘ ideas its not new at all.

  9. Doug Proctor says:

    As usual with new technologies, if the product delivers as claimed, it is a winner. There are a long list of vapour releases for every successful program, however (pun intended).

  10. steveta_uk says:

    Jeremy, look at the picture. Single front seat, two rear.

  11. John says:

    There’s two CARBON fibre tanks, so these would be taxed I guess.

  12. MikeH says:

    I’ve had blog conversations with people who are against Hydrogen in cars, they expect the car to go Boom with leaks, not knowing some of the characteristics of Hydrogen vs. Propane for example. But with this one, how strong are the storage cylinders and what would be the result of a side impact crash with an SUV? No ignition source needed, just a high pressure breach….

  13. Garry Stotel says:

    The idea of a compressed air car is ancient, I remember reading about it ages ago.
    I guess it might work in some circumstances, such as consistently high temperature country like India. I don’t think it would work very well even in moderate climates.
    However, for $8k one could imagine a small natural gas fired car that would do a lot better, and I imagine would have much better overall efficiency (not to mention CO2 emissions), due to gas being burned at point of energy consumption, rather than to produce electricity to produce compressed air to produce kinetic energy, with losses on every step.
    But if you have a dirt-cheap supply of electricity, then why not…

  14. Heck, check me out someone.

    I strongly remember the name TATA (as in Tata Motors?) being a company belonging to / run by Rajendra Pachauri. Tata Institute??

  15. michael hart says:

    I’m with Urederra on this:
    I just don’t believe the figures quoted. I think a bit of “marketing” has been written into it.
    And if you’re going to use compressed air, why not use some compressed hydrogen as fuel? If the tank blows up when you’re sitting on it, then it won’t make much difference.

  16. klem says:

    In Canada we pay a road tax built in the price of gasoline at the pump. So since these vehicles do not consume gasoline, the road tax is unpaid. The government will simply apply a road tax on the car at the time of purchase or some other time. They will not allow a vehicle to use the road without paying a tax for that priviledge. Not going to happen in Canada.

    Besides, getting stuck in a Canadian blizzard with only a tank full of compressed air for warmth is not a place I would like to be.

  17. Matthew W says:

    It does sound to good to be true.
    I guess we will wait and see

  18. Matthew W says:

    Oh, and how will these be taxed??
    MILEAGE !!!

  19. RE: Will a damaged compressed air tank “do this?”

    Well, some tanks in accidents may more act like the climatic scene from “Jaws.”
    Brody: “Smile! you son of a..” BOOM!

  20. Sonicfrog says:

    I like it, but I like all interesting technologies. This is a car design that fits the Indian market well. It’s my understanding that they generally don’t travel long distances the way Western countries do. It won’t work in the US, at least in its current configuration, but expect California to pass a regulatory edict that 20% of all clean cars on the road MUST be this wonderful little car! We’ll save the planet all by our selves!!!!

    That last bit refers to this.

  21. Justa Joe says:

    I’m skeptical. If this compressed air engine was efficient then there wouldn’t be a need to make the vehicle an ultra-light. The vehicle could be as substantial as a conventional car. Just scale up the displacent of the engine. Air is “free”, no?

  22. old engineer says:

    Of course there are lots of ways of storing energy. But I don’t think compressed air would be my first choice. One website quotes the max storage pressure for the Tara Minicat at 4350 psi. I guess if you must carry around cylinders of compressed gas, air at 4350 psi would be safer than natural gas at 3000 psi.

    At least it is good to see other means of energy storage considered. We have been told for 40 years that a battery breakthrough is just 10 years away. My current favorite alternative to batteries is hydraulics. Hydraulic motors are compact and can easily be reversed to take advantage of regenerative braking.

    But good luck to Tara Motors. It will be interesting to see how this works out.

  23. Owen in GA says:

    Just what you want, a pressure bomb under your seat. If a road hazard damages a bottle of highly compressed air, the resulting simultaneous release of all the stored energy will not be pleasant. You don’t need a fiery explosion to die in an explosive release of energy. Blunt force trauma is still there. A battery fire happens up to 3 weeks later, unlikely you would be in the car at the time, but the sudden decompression explosion would happen instantly, with you sitting on top of the bottle. They better reinforce the area of the bottles and seriously protect them from road hazards or this thing will be a death trap.

  24. Sonicfrog says:

    Hey… Maybe if you EVIL DENIER WEATHER MEN will promise to buy one of these when they come out, maybe they will leave you alone!

  25. Joe Crawford says:

    Back in the late ’50s when I was a kid I had a model airplane engine that ran on a small CO2 cartridge. The rig was too heavy for the model planes of that time but worked fine in a model car I carved out of a block of balsa. It was fun to play with but never really competed with the small diesel model engines of that time, especially on a power to weight ratio.

  26. GregO says:

    I want one if only as a “toy” car.

  27. JEM says:

    Tata Motors is a large industrial combine, they own Jaguar and Land Rover now as well.

    I expect this thing will work, within certain bounds – Tata can afford real engineers, so this won’t be a Michael Mann production. That said, as we’ve seen with the Leaf, the marketing guys get a bit ahead of the technology so in the real world you can cut their numbers by 40%.

    My guess on its performance envelope: you’ll get the 60mph top speed OR the 185mile range if operated lightly loaded, and by the time you’re into the last third of usable pressure your top speed will be more in the 35-40mph range.

    Just guesswork.

  28. Justa Joe says:

    “…by the internal air conditioning system with no need for gases or loss of power.”

    Strictly speaking this isn’t true. Ok, By no gases I assume that they mean no refrigerant. As far as a loss of power is concerned on a conventional internal combustion car the engine utilizes some energy to expell exhaust gases. That’s why on performance cars efforts are made to minimize exhaust flow restrictions within certain parameters. If this vehicle partially redirects exhaust flow for air conditioning purposes I believe that it would require some amount of energy by the motor at the cost of some motive efficiency albeit perhaps very neglible. This has to add some back pressure.
    Anyway there’s never a free lunch.

  29. Mike Lewis says:

    Twenty years ago I worked at a utility company that started an internal “green” initiative. While doing research in ways to “go green” I found an article that discussed the pros and cons of electric cars. While most people thought they were a great way to reduce pollution, the article pointed out that these cars merely shifted the location of the pollution. Kind of like wealth redistribution, it’s just another way to make certain groups of people feel better about themselves.

  30. P.F. says:

    “. . . a car [that] runs on air developed in India.”
    Will air developed in other places work just as well in this car, or do they have some special proprietary air?

  31. Urederra says:

    Besides, If it does not produce CO2, then is not good for the environment, since CO2 is plants food and the more they have, the faster they grow.

  32. DirkH says:

    Lucy Skywalker says:
    January 31, 2012 at 8:05 am
    “I strongly remember the name TATA (as in Tata Motors?) being a company belonging to / run by Rajendra Pachauri. Tata Institute??”

    No; Tata is a huge Indian conglomerate; like Siemens in Germany or GE in the US. They did sponsor an institute where Pachauri was/is the director, though.

  33. JEM says:

    Two more remarks:

    I expect the tanks can be made reasonably safe, but at 4350psi if one of those tanks is damaged you’ll find the car and its occupants in very small bits scattered over a quarter-mile radius.

    Even if the car itself works, it is still functionally an ‘electric’ vehicle, with lots of lossy spots in they cycle.

  34. Olen says:

    It beats a water buffalo but then the water buffalo will not explode in a collision.

    But like the water buffalo it has to rest for a recharge. As far as the recharge time is concerned what else have you got to do that is more important? If you are a global warming enthusiast probably nothing is more important.

  35. Scott Covert says:

    OK, I want to see that motor in a motorcycle powered by hydrogen peroxide or hydrazine.

    That would be a good use, but why not use a turbine? I bet a turbine engine with the same horse power would be half the weight and 1/3 the size.

  36. It’s the same device that’s been pushed by the “developers” for a number of years, continuously milking whatever R&D funds they can get.

    I looked at the technology so long ago that I’ve forgotten where I put my copious notes on why such a thing is nothing more than a very expensive toy. Compressed-air drive is useful in a very limited number of applications; which do not include basic transport for a family.

    What struck me is that the useless gadgetry of wireless controls of electrical consumers. Adding not only uselessly to the electronic smog, ignoring cheap and simple 1-wire vehicle communications buses that can be deployed much more cheaply (e.g. LINbus). After all, the wirelessly-controlled electrical consumers are powered from somewhere (a battery) and a thin data wire can be run alongside the power and return lines. You can’t use a composite body as an electrical conductor, nor should one use the aluminium of a chassis.

    The gratuitous complexity of wireless vs simple and secure wired control gives an insight into the mentality of the designers.

    Here’s part of an analysis that I’ve been doing on re-wiring a conventional vehicle to minimise cabling and to maximise utility: http://golf2lin.wordpress.com/bus-architecture/decentral-electrics/

  37. harrywr2 says:

    This Air Car almost sounds too good to be true.

    Tata Motors has trotted out the ‘to be in full manufacture’ within a year more then once on this thing.

    Air-Powered Car Coming to U.S. in 2009 to 2010 at Sub-$18,000, Could Hit 1000-Mile Range

  38. R Barker says:

    According to Wikipedia compressed air has only abour one tenth to one twentieth the volumetric energy storage of a lithium ion battery. We have an idea of the limitations of the electric car eg Leaf. I would assume that battery cars tend to gross out while air cars would tend to cube out. In any case, I suspect the 185 miles between refills might be just a teenie bit optimistic.


  39. More Soylent Green! says:

    Make it run on CO2 and you have a winner! See, you pull the extra CO2 from the atmosphere and then use it to power your car. Al Gore can certify it for carbon offsets.

  40. And with Maxwell’s Daemon doing all the compressing, you’re suddenly in possession of infinite energy, yeah?

  41. Jean Parisot says:

    If it works, why wouldn’t it challenge the golf cart market in Fl or the general purpose ATV for rural users?

  42. StudioBronze says:

    Some environmentalists outside India are worried that Patel Tata will introduce automobiles widely to Indians who now own cars at the rate of 7 per 1000 families. He sees a market niche for a car that replaces the ubiquitous motorbike at nearly the same price. I wonder if that is why he has met resistance to the Tata Nano, and his goal of producing them by the millions for India, and South America.

  43. Alcheson says:

    Bet the car also has a problem with traveling uphill, especially as the air pressure in the tank drops. Maybe it would work relatively well on flat ground, but in hilly//mountainous areas it probably is a nightmare. Top speed of 60mph on flat ground at max tank pressure pretty much tells you how much power it has.

  44. Bob Diaz says:

    It does take energy to compress the air and once you compress the air, heat is generated. I don’t know the amount of heat generated to compress air to 3,000 PSI, but that heat is a reduction of efficiency in the system.

    Also an accident will render the tanks into one impressive bomb. I’ve known of cases of scuba shops receiving major damaged due to a tank rupture. The car must use a larger tank, so bigger tanks result in bigger boom.

  45. Arthur Norton says:

    How are we to get hold of “air developed in India” and how much will it cost?

  46. oeman50 says:

    A friend of mine once had a car that ran on compressed natural gas and gasoline. I looked under the hood and saw a small pressure gauge on the NG line that went up to 5,000 psi! The NG tank was in the trunk just behind the rear seat. So high pressure tanks have been used for transportation in the US and I do not remember any issues with exploding tanks.

    One thing, though. Pressure that high will cut you like a knife. My first full time job was in a plant that had high pressure cylinders of nitrogen. I was messing around with one of them one day and an old hand read me the riot act, telling me how dangerous it was. Even at 1,000 psi, the nitrogen could have punched a hole through my hand. I never forgot it. (Good outcome to the story, eh?) That danger will exist with the air in this car.

  47. NoNegatives says:

    “the clean air expelled by the exhaust pipe is between 0-15 degrees below zero.” How many cars on the road before we return to Global Cooling and a new Man-made ice age? Specialty vehicles like this (including all electric and CNG) can work in a controlled fleet situation, limited mileage and return to a common station.

  48. Douglas DC says:

    Years ago I witnessed a compressed 02 tank dropped from a Welding supply truck, the thing launched like a rocket as it hit on the valve end, found it a mile away, What happens in an accident? TaTa?

  49. Hoser says:

    What about liquid air? That is, LN2. There are a number of issues, positive and negative. Safety is improved since pressure in the dewar would rapidly dissipate with a rupture, the liquid would boil off and not explode.

  50. kbray in california says:

    Gravity will compress the air for free and provide heat for the car.
    I read this recently somewhere.

  51. Neil Jones says:

    Would this run off the “Free air” you get for your tyres?

  52. Tom G(ologist) says:

    Of for goodness sake. With a tubular frame and glued-on, light-weight skin, why do they need any sort of engine. A couple pedals, push rods and a good gearing system and you’re there: the Weight-Watchers Wonder Wagon. Oh, and there could be accessory pedals for those otherwise dead-weight passengers – a three-person-power, emmission-free, heart-healthy, go-green jalopy for the urbane masses. And for all my Canadian cousins (from Saskatchewan originally) who needs a heater when you would be working up a sweat in a capsule? For New Yorkers in August….. the convertible model, of course. There’s no problem and no end of inventiveness which we can’t devise to answer any questions – we have had terrific exemplars this past decade in spinning a good yarn.

  53. kbray in california says:

    Caleb says:
    January 31, 2012 at 7:35 am
    On rainy days it would beat a bike.
    Install pedals in it and you might have something marketable.

  54. MarkW says:

    Going to have to change the name before they start shipping to Mexico. Almost as bad as the Nova.

  55. Alan says:

    Minicars don’t sell except to midgets. And students.

  56. Ben Hern says:

    I am completely sceptical of the gullible warming gravy train and the supposed role of CO2 in changing climate, but guys, a litle perspective before leaping to find fault in the latest innovative thinking. Reading some of the remarks here has me worried we’re all becoming just as entrenched and feeble minded as the ecotards who oppose all development on imaginative environmental reasons have been for decades.
    With the number of respondants concerned about the results of a collision on the compressed air bottles, I assume LPG and CNG powered cars are eitehr banned or the subject of mass hysteria stateside and also that no one has considered the vulnerability of fuel lines in a conventional petrol or deisel powered car in the case of an impact which would be severe enough to induce a loss of integrity in a compresed air storage vessel?
    I see a clear benefit in this type of vehicle in urban use given the absence of tailpipe emissions (of actual pollutants like benzenes and oxides of nitrogen and sulphur).
    True there are energy losses in compressing the air before use, but there are also significant energy losses in producing, transporting, refining and distributing the petrol and deisel burned ‘at the point of energy consumption’, if one wishes to split hairs.
    True enough the efficiency claims are probably optimistic, but who achieves the claimed fuel consumption in their conventional cars?
    With respect to the trifles about the car needing to be light owing to it’s feeble powerplant, tell me why an F1 racing car is featherlight despite it’s powerful V8 powerplant? Adding lightness is in no way to be criticised, it is in fact sound design practice and very long overdue in automotive circles.
    As far as compressed air being a feeble source of energy, who has never heard of industrial complexes using compressed air to drive it’s machinery? Even oil rigs sport pneumatic mains to power tools and equipment, despite production installations sitting on top of a source of hydrocarbon (that really would be using the energy at it’s source).
    And as for the central driving position, how does anyone criticise this? You can drive on the correct side of the road in India or the car can be exported somewhere driving on the Napoleonic side of the road without the need to move the steering wheel to the wrong side of the car (consider the location of the clutch pedal in relation to the gearbox in your conventional car and explain how driving the the left hand side of the car is anything other than a compromise before retorting that the sensible parts of the Commonwealth and Japan have it wrong). And if that doesn’t convince you that a central driving position isn’t as good as it gets, ask any owner of a McLaren F1 what they think of the central driving position and report back here with any unlikely complaint.
    Credit where it’s due, this is a sound idea for urban personal transport and is far better than carting a hefty battery around for a few kilometers before plugging in to trickle charge for the rest of the day and/or night, plus orders of magnitude better than pushing a deadly treadly to work.
    The MiniCat will initially only attract a low sales tax in order to acheive market penetration (on the back of false and pretentious ‘green’ policies), and then will be taxed in the form of the usual annual road tax, registration fee, road tolls and ‘fuel’ excise (charged at the flowmeter on the compressed air charging point at participating garages – guarantee the standard automotive compressed air hose coupling will be unlike an tyre inflation valve, crow’s-foot or Glenlock connection), in addition to attracting a taxable annual fee for a approved stored energy/pressure vessel inspection.
    End of rant.

  57. Mike McMillan says:

    I see great promise here. This could be a “dual fuel” vehicle, also able to run on compressed CO2 sequestered from coal-fired power plants. CO2 liquifies under pressure, so you could squeeze a lot more into a tank, and the pressure would be fairly steady as the liquid boiled off.

    Racing models could use liquid oxygen and liquid hydrogen.

  58. MarkW says:

    “the clean air expelled by the exhaust pipe is between 0-15 degrees below zero.”

    This could be a problem in a country as humid as India.

    I can just see this thing pulling into the garage with 20 to 30 pounds of ice built up around the motor and exhaust.

  59. Mike Abbott says:

    I searched the Tata Motors web site and found no references to “Air Car” or
    “Mini Cat.” What’s up with that?

  60. CodeTech says:

    I like it!

    And hey, I have an air compressor in the garage, too… of course, I’ll have to tweak that a bit because currently it only goes to 130psi. The only issue I can see for here in Calgary is that I’ll have to install a heater. Something like the gas heater my dad used to have in his Volkswagens ought to do it. Then again, I’ll still be burning gas… but oh well, saving the planet and all… maybe the catalytic heater I have for camping would work, that’s just propane.

    Not sure how it will perform going west into a Chinook wind, but I’m guessing that top speed of 60 (100km/h), which is the speed limit on some roads, might suffer a bit. Driving straight into a 100km/h wind ought to give me a net speed of… what… 10km/h? 5?

    And I’m pretty sure I’ll need to leave the battery plugged in all night to run the lights and stereo. It better have a stereo, since it’s against the law to wear earplugs and use an iPod while driving. And I know I’ll use a lot of lighting power, just for the hazard warnings alone. I assume they’ll be LEDs.

    Oh well, if all I’m doing is going from home to the nearest grocery store, which is about 5km away, it should be fine. Then again, as someone already pointed out, the price is going to have to have Canadian road taxes built in, so I’ll be paying more than that estimated price… call it $15k. Not bad for something I can only use a small number of days per year to go a small distance.

    I wonder what the net energy will be when it’s -30C… anyone who ever tried spraying a can of compressed air outside at those temps knows that instead of a sharp blast of cold air you only get a slight breeze.

    But seriously, for certain markets in warmer climes, it should be better than what they currently have. At least more of Canada’s immigrants will have acquired some driving time before they move here to become cab drivers.

  61. polistra says:

    Might work well in India, or permanently warm places like Miami. But in a northern place where the ambient air is often well below freezing, Boyle’s Law would sap your power. You’d pull into the filling station, get filled up with hot and tight air, then your tank would “leak” energy as soon as you started driving across snow!

  62. Hoser says:
    January 31, 2012 at 9:49 am

    What about liquid air? That is, LN2. There are a number of issues, positive and negative. Safety is improved since pressure in the dewar would rapidly dissipate with a rupture, the liquid would boil off and not explode.

    Main problem: the very poor energy balance. You need at least 5 times more energy to liquidize the air/N2 than you can recover. Plus severe problems with icing of the heat exchanger that is needed to expand the liquid N2 into the necessary amount of pressurized gas for the cylinders to work.

  63. Iskandar says:

    Liquid CO2 needs heat to evaporate and generate pressure. No heat, no pressure. Liquid CO2 will solidy due to the heat extraction process, which is why it is used as long term coolant in transatlantic shipments of biochemicals. You will get very cold in a liquid CO2 propelled car.

  64. Andrew30 says:

    Why not a ‘pressure cooker’ type of ‘fuel tank’ with block of dry ice in it?
    Release the pressure, pop off the top, drop in a block of dry ice and seal it up.
    I think it would be safer to handle, quicker to re-fuel, easier to distribute, have a lower explosive potential and have a greater potential energy density. In India (in the always warm parts) you could have an ambient air reverse ‘heat sink/heat pipe’ so that you draw the heat of sublimation from the surrounding air (or internal air conditioning)
    There would be no pollution (at the point of use/driving) and all of the plants along the road would benefit

  65. Ulrich Elkmann says:

    How nice. But if they want to export it – how will they be able able to compete against the Volkswagen Eco Rabbit, or Britain’s Sinclair C5. or the Ford Edsel, or the Ford Nucleon, or the Dymaxion Car, or some other wildly successful dream car? And it doesn’t even fly.

  66. Curiousgeorge says:

    All of this kind of junk, from light bulbs to biofueled aircraft to ‘locovorism’, is driven by some progressive politicians’ unilateral Utopian wet dream. Folks should read up on what Karl Popper had to say about Utopian future states. In a nutshell, one mans’ Utopia is anothers’ Totalitarian Hell.

  67. kbray in california says:


    This video sure leaves one wanting…
    wanting something else.

  68. Mike Monce says:


  69. Mike Abbott says:

    From a January 5, 2012 Tata Motors press release about Auto Expo 2012:

    Tata Motors unveils 3 new vehicles at Auto Expo 2012

    * Tata Safari Storme, the new generation Safari
    * Tata Ultra, the new LCV & ICV range
    * Tata LPT 3723, India’s first 5-axle rigid truck

    Also demonstrates alternate fuel technology capability concepts:

    * Tata Nano CNG
    * Tata Indigo Manza diesel-electric hybrid
    * Tata Starbus Fuel Cell (hydrogen)


    Where’s that Air Car??

  70. WISE Math says:

    “…a car [that] runs on air developed in India. ”

    What’s so special about the air developed in India?

  71. BravoZulu says:

    That sounds great for short commutes in the city like to the grocery store. I wouldn’t want to take it on the freeway in SoCal though or any fast highway for that matter. 60 is not really fast enough for one reason. I like the idea though. There is a lot of potential there with batteries being so expensive and problematic.

  72. Bert Feldon says:

    There is a lot of negativity here. The system being developed by Tata for this vehicle is licenced by a French inventor who had been running his prototypes around for some time. The promo videos that I saw a couple of years back quoted a range of around 300km. But there was also a version with a small paraffin heater unit that extended the range by warming the air coming out of the tanks. The engine does not run at heroic pressures, so the loss of power as the pressure stored in the tanks falls is not catastrophic.

    The engine in the French prototype worked in reverse as its own compressor, but it looks like the Tata has a different approach. Probably much more thoroughly engineered.

    From the promo videos I reckon that the main technical challenge was damping the appalling noise the things made . .

  73. tty says:

    Having some experience both of compressed-air systems and of maintaining pneumatic and hydraulic systems I would like to comment on a few things.
    Compressed air is an excellent power source in many ways. For example it is capable of very large and very fast changes in power, it is extremely simple, reliable and durable while overstraining a compressed air engine is completely benign. The only thing that happens is that it stops.
    The most important drawback is probably the requirement for extreme airtightness. Even a minute leak will completely ruin the economics of a system. The idea that this car will be more or less maintenance-free is optimistic to put things mildly.
    As for the durability of the pressure vessels, if they were made of high-grade steel they would be safe for a few thousand refill cycles, which would be more or less equivalent to the life-cycle a conventional car. However I’m uncertain about the durability of composites in such applications.
    And, yes, these cars will be death-traps. For one thing a “fiber and injected foam” body has essentially zero energy absorption capability which means that even minor collisions will usually result in injury or death. And the pressure vessels will be very dangerous. It is clear from some comments here that many are unfamiliar with the vast difference between compressed liquids and compressed gasses. I still remember the first time I visited a combined hydraulic/pneumatic workshop. Huge hydraulic components were tested without any particular safety measures while even small pneumatic gadgets were tested under heavy steel cages solidly bolted to the floor. I was taught that if a hydraulic machine burst, the only real danger was that you might get hydraulic fluid in your eyes while even a small pneumatic component would throw deadly shrapnel for many yards. So, yes, I am much less afraid of a LNG tank than a of high pressure air vessel, even though LNG is potentially explosive and air is not.
    I wonder by the way how long it will take for the exhaust line to freeze up in Indian climate?.

  74. Justa Joe says:

    Ben Hern says:
    January 31, 2012 at 10:03 am

    (consider the location of the clutch pedal in relation to the gearbox in your conventional car and explain how driving the the left hand side of the car is anything other than a compromise before retorting that the sensible parts of the Commonwealth and Japan have it wrong).</i?
    Sorry Bud, I would like to be able to say this vehicle is decent, but everything I see says, POS.

    As far a clutch pedal location a car's clutch pedal actuates a cable or a hydraulic cylinder both of which are flexible right hand drive or left hand drive won't have the slightest difference in how well or efficiently this simple system will work. It's no more or less a compromise either way. Also some cars have conventionally mounted engines, some cars have transverse mounted engines. Anyway most cars sold in North America are have automatic trans.

    With respect to the trifles about the car needing to be light owing to it’s feeble powerplant, tell me why an F1 racing car is featherlight despite it’s powerful V8 powerplant? Adding lightness is in no way to be criticised, it is in fact sound design practice and very long overdue in automotive circles.
    The car has a claimed 24hp. That’s qualifies as feeble. Comparing the TaTa to a very specialized race-car, which is more a-kin to a Go-Kart than to a conventional car is just silly. Power to weight ratio is of utmost importance in a race car. However, in a convetional passenger car this characteristic takes a back seat to other necessities. Look at the roads your average car weighs in at about 3500lbs. Since most car models actually gain weight over the course of their existence from model year to model year it seems like the public is demanding features and attributes to cars that add weight. Nobody is going to give up their features in favor of this golf cart, sorry.

  75. Mike Abbott says:

    Bert Feldon says:
    January 31, 2012 at 11:25 am

    There is a lot of negativity here. The system being developed by Tata for this vehicle is licenced by a French inventor who had been running his prototypes around for some time.

    Apparently, Tata turned negative on the system. It seems to have been scrubbed from their web site. The French inventor is on his own – for now – and seeking investors. See http://www.mdi.lu/english/index.php.

  76. Brian H says:

    A few things not mentioned yet:
    1) that cold air is REALLY cold coming out of the tank/exhaust. Icing is a severe problem.
    2) The air first compressed into the tank is going to be hot, but gradually cool through diffusion. Managing that is tricky. Assuming it’s at ambient before use, see #1. It’s in effect being expanded by heat grabbed from the surrounding air, so there must be VERY efficient warming as it enters the cylinders. A hot climate is recommended.
    3) It’s LOUD. There exist forklifts etc. for factory floors using this system, and the cylinders really bang away. Think compressed air impact tools, like jackhammers.

  77. Brian H says:

    P.S. to above: the tank cools dramatically as pressure is reduced. This robs power, so the tank needs to grab heat from the environment. Repeat: a hot climate is recommended.

  78. Mike M says:

    It will be interesting to see what happens if one of these cars, with freshly charged air cylinders , gets into an accident that compromises the structural integrity of one or more air cylinders. Batteries and gasoline cares are potential fire hazards but will not release ALL of the stored energy all at once. That is not true for compressed gas; this thing is a potential explosion/missile hazard on wheels.

  79. Alan Watt says:

    Another pipe dream. As others have noted, compressed air at any pressure that can be safely handled in a consumer product has a very low energy density compared even to modern batteries, let alone liquid fuel. Standard SCUBA tanks are filled to 3000 psi (about 200 bar) and must pass a safety pressure test at 5000 psi every 5 years in the US (4 in the UK). The safety test involves putting them in a water bath and measuring (via Archimedes principle), how much they expand when filled to the test pressure. Automotive air storage tanks would likewise have to be certified regularly, at least in any jurisdiction which imposes the same requirement on SCUBA tanks (in the US all compressed gas tanks must be certified and inspected).

    The *only* advantage of a compressed-air car is it shifts the pollution emission point from the car on the road (presumably in an urban location) to the central power plant (presumably remote from urban population). They don’t have the range, the power, or the convenience of internal combustion vehicles. The practical recovery efficiency is only somewhat better than 50%, so you’re net using more energy (burning more fuel) as well.

    You would get essentially the same pollution reduction benefit by running on LNG or LPG, which are much easier to handle (container-wise) than highly compressed air.

    There is work on grid-scale compressed air energy storage (CAES), but that is using industrial size compressors and air turbines and large underground caverns. One reference gave the storage pressure as 750 psi. It makes sense mostly because there are more suitable caverns than there are pumped hydro locations. If you have to build the storage tanks it makes no sense at all.

    If you look at the reference table of energy storage by volume a previous commenter linked to, the futility of compressed air for transportation becomes obvious:

    Medium Megajoules/liter
    Compressed air (300 bar) 0.2
    LNG 22.2
    Gasoline 34.2
    Diesel Oil 37.3

    Even if you raised the pressure to 3000 bar (>44,000 psi — no way I’m going anywhere near a tank with that kind of pressure — that’s the breach pressure of a modern handgun), you are still less than 10% of the energy storage of LNG, and less than 6% the energy storage of Diesel.

    The only way this will achieve any significant use is if government mandates it. It’s much too inefficient to succeed otherwise.

    Please don’t tell Al Gore.

  80. Crispin in Waterloo says:

    @ShrNfr says:
    January 31, 2012 at 7:28 am
    “Somebody is in bad need of a course in thermodynamics. Even with a compressed air engine, you have thermodynamic loss. Of course it is hidden from you. The waste heat in the cycle is the heat that you get rid of when you compress the gas.”

    It seems to me no one above has looked into how these compressed air car motors work. I have not seen the insides of that motor shown above but if it is built on the same principle that the French one is, a great deal of what is written above needs an overhaul.

    First the French motor. It does not work by expanding air into a cylinder the way a jack hammer works. Crummy air motors like that are about 3% efficient and if you multiply the expansions to 4 cylinders perhaps another 3% is available – no further comment because I have not looked at that – it leads nowhere efficient.

    The motor works by using a tiny shot of very cold air to cool the ambient air already in a cylinder. Obviously expanding the highly compressed air cools it. It works on ‘coolth’ and ‘suction’. Stick that in your ‘lost heat, cold air, bad thermodynamics, hidden energy loss, no cruising range’ pipes and smoke it. The motor was developed by an F1 mechanic who was already involved in using this technique to extract more power from an F1 engine (which is allowed because it is not using fuel or increasing the displacement of the engine.)

    So get rid of the idea that the only way to use compressed air it to expand it into a closed space. It is far cleverer to pull on a large piston than to push on a series of small => large ones. I can’t know that is what Tata is doing until I see the insides, but the technology is around.

    Second, the compresion of air (normally only about 45% efficient) can be done in certain places using Taylor Hydraulic Compressors (trompes) that run on water. There is a famous on in Ontaio at Ragged Chute http://www.piclist.com/techref/other/pump/raggedchute.htm and another well studied one in Chicago. The link there says 1910 but I think there was one there in 1888. No matter. It ran for the better part of a century being shut off only a couple of times for cleaning. The air bubbles introduced are tiny – looking like white milk while being compressed.

    The street cars of Paris and Chicago used to run on compressed air supplied by pipelines from outside the city. The development of the ‘trompe’ was very advanced by the mid-30′s. It was used until the Chicago city father were bribed to switch them over to electricity from which money could be continuously made generating it. There is not much money to be garnered from a compression technology that uses no fuel. It is thought the Catalan monks used the system to make iron, keeping the technology secret for centuries.

    It is possible the technology combined with bubble pumps could have raised water in the hanging gardens of Babylon using only the bricks and mortar available. At a low lift it can be made in a primitive fashion and works indefinitely as long as there is lots of water falling in a river nearby. This compression (entrained air in a descending water column) happens naturally in the Alps and gives rise to ‘carbonated water’ emerging from springs that disappear into the rock some distance above.

    Well done Tata.

  81. klem says:

    Um, I think I’ll stick with my gasoline powered car, thanks.

    Its cheap, reliable, doesn’t explode like a bomb, I can refuel it anywhere, it can pull a trailer, it keeps me warm in the winter and cool in the summer, it has a 500km range, it pulls equally hard with a full or empty tank, it’s blue, it does not make me look like a climate alarmist, its large… shall I go on?

    Did I mention that it’s large?

    Yup, I’ll stick with my gas car thanks.

  82. Bertram Felden says:

    Mike Abbott.

    Who knows exactly what is going on here? The Tata bears an uncanny resemblance to the MDI projects. As I understood it the Tata licence was for India only, with MDI retaining the rest of the world.

    If they can get it working I think it will be great to see. Here in France we have a lot of ‘yoghurt pot’ cars, small 500CC single cylinder diesels, restricted to 70kph. The air car would be a much better alternative, and probably no more noisy to boot.

    There is a firm in Australia making air vehicles, mostly small utility trucks I recall, using a rotary air motor. I’d like to see the two technologies put together.

  83. keith at hastings uk says:

    I recall that the key touted advantage was the lack of exhaust emmissions, and the main drawbacks the 5000psi bomb (air tank) and the excessive noise. Range could be extended by burning some fuel to heat the air before it went through the double expansion engine, which had some heat transfer arrangements – can’t recall what that was for.
    However, compressed air can be stored so the nearly useless windmills and solar PV might be used to charge up tanks for use later.
    Remember that the rare earths (for motors) and even Lithium for electric cars may become very expensive/short supply. A compressed air car can be made of fairly ordinary stuff?
    May be only a niche product to start with, but who knows? And if India develops Thorium power plants, they may have cheap ‘lec – unlike the UK, which may have hardly any if the current lot carry on as they are doing! (bit colder at present and CCGT is giving 28%, coal 48%, nuclear 17% and wind 3%, evrything else including interconnectors to France etc, the balance (rounded figures). Coal due to be shut by EU regulation, nuclear ageing, gas from unstable regimes, wind useless …)

  84. jorgekafkazar says:

    Ed Caryl says: “How many pressurizations cycles before the tanks blow?.”

    More than the cycles for a hybrid or all-electric car battery.

  85. Eric Worrall says:

    To compress air enough to produce the stated performance, you wouldn’t have to decompress the air, because you could use the nuclear fusion reaction occurring in the air tank for motive energy.

  86. Gras Albert says:

    Motor Development International have been developing, testing and trying to sell compressed air vehicles for 20 years, the vehicles have performance limitations of about 60kmh (36mph) cruising speed and a range of 200km (120 miles). So about the same speed and four times the range of current battery hybrids on battery alone.

    Guy Nègre, who is the driving force behind the company, is a former Formula 1 race engineer.

    They licensed their technology to Tata in 2009 and cars were displayed at the at the 2008 New York Car Show.

    There’s nothing new here, move along now

  87. Curt says:

    Here is a not-too-favorable article on the French design in the engineering press:


    The big problem that no one has solved (and there may not be any good solution) is the heating on compression (which is virtually certain to be an almost 100% energy loss in any system cheap enough for the mass market) and the cooling on expansion when driving the car. Nobody has figured out how to keep the frost generated by the resulting subzero air from gumming up the works completely. If Tata is keeping the exhausted air at greater than -15C, it means that they are not using the compressed air at a high enough pressure to have any worthwhile storage density. And even so, it may not eliminate the frost problem.

  88. Ed Scott says:

    The Oerlikon Gyrobus. Recharge every 1/2 mile.

    Sounds like the Bob Newhart reporting on the Wright Bros. Coast to Coast Airline limitation of having to land every 150 feet.
    In the early 1950′s, the well known Swiss engineering company Oerlikon introduced the “Gyrobus,” a bus for 35 passengers that ran on electric power generated by a spinning flywheel, which was itself brought up to speed at points ½ mile apart by tapping the electric power net. The Gyrobuses were introduced in 1953 and remained in service (some of them in the Belgian Congo) for 10 years.

    They were pushed out by diesel buses, which were not limited to a route with electrical tap points, nor forced to wait 1 to 2 minutes at each such point to recharge. Fuel cost was not a consideration at the time.

    But diesel buses use more expensive fuel less efficiently and with more pollution than the corresponding amount of electric power, and so the flywheel bus may make a comeback¾with a flywheel that can store more energy per unit volume than two decades ago, and controlled by semiconductor devices, themselves run by microprocessors.

    A four-year, $5 million contract for developing a flywheel bus was awarded to General Electric last year(?) jointly by the Departments of Energy and Transportation

  89. Alan Watt says:

    Crispin in Waterloo says:
    January 31, 2012 at 12:16 pm

    The motor works by using a tiny shot of very cold air to cool the ambient air already in a cylinder. Obviously expanding the highly compressed air cools it. It works on ‘coolth’ and ‘suction’. Stick that in your ‘lost heat, cold air, bad thermodynamics, hidden energy loss, no cruising range’ pipes and smoke it. The motor was developed by an F1 mechanic who was already involved in using this technique to extract more power from an F1 engine (which is allowed because it is not using fuel or increasing the displacement of the engine.)

    So get rid of the idea that the only way to use compressed air it to expand it into a closed space. It is far cleverer to pull on a large piston than to push on a series of small => large ones. I can’t know that is what Tata is doing until I see the insides, but the technology is around.

    Even more of a pipe dream. You’re describing the Sterling cycle (atmospheric) engine. The original steam engines worked this way to pump water out of coal mines. Instead of the expansion side of steam they used the condensation cycle. It’s a common science demonstration to put steam from a tea kettle into a container with a tight screw top. Displace all the air with steam vapor and then screw the top on and as the steam cools and condenses, the container will be crushed by ambient atmospheric pressure. Atmospheric engines “suck” the piston up in the cylinder instead of pushing it down.

    It was James Watt’s magnificent contribution to the Industrial Age to realize that there was much more energy (and therefore efficiency) in the expansion cycle of steam rather than the condensation cycle. In fact the overall efficiency goes up directly with pressure. Once high-pressure steam engines were developed, the older atmospheric engines were obsolete.

    The absolute maximum amount of energy you can develop in an atmospheric engine is the ambient atmospheric pressure (1 bar). This assumes you can create a total vacuum in the cylinder. Whereas if you use the expansion power of pressurized gas, you can create many times 1 bar per surface area. Atmospheric engines require large cylinders because of their low pressure, and therefore tend to have a very low power-to-weight ratio.

    My father-in-law has an old Sterling cycle engine he cranks up occasionally to amuse the grandchildren. It was used by the railroads to pump groundwater back into water towers after a steam locomotive filled its boiler tanks. The reason was that regulations required a licensed engineer to be present when high pressure steam was in use, but the Sterling cycle pump could be left to run unattended. They would fill the firebox with wood, light the fire, and leave it pumping until the fuel burned out. It probably weighs 500 pounds and develops maybe 2 horsepower. Except for this niche use (created by legal restrictions) atmospheric engines were obsolete more than 150 years ago.

  90. beng says:

    I remember a manufacturing plant near where I worked that used an ancient (switcher) steam-locomotive that ran on compressed air instead of steam. Apparently they just pumped the boiler up in the morning & several times during the day & it could serve their modest rail-car switching duties.

  91. Tom O says:

    Dunno about a balloon – but at the pressures this ‘lil guy stores this is more likely ar maybe this

  92. Kieche0y says:

    How to tax? That’s really simple – just look what we Europeans are going to do: a GPS logger with 3G data connection to every car and the government can tax you according to where, when, and how much you drive. And of course they are not tracking individuals… really not – don’t you believe in the overwhelming benevolence of your government?

    BTW that is not a joke. Such systems are proposed in many EU countries.

  93. RockyRoad says:

    Like all the “Electrics”, this is also a car that’s powered by coal.

    You doubt me?

    Then where did the electricity that’s used to compress the air come from?

    An even greater example of compressed air is the “air rifle” Lewis and Clarke took with them on their journey of discovery. It could be pumped up to 800 psi and would fire about 30 rounds on one charge. It is credited with getting them safely through Indian territory because the Indians were so completely impressed with a rifle that didn’t make the normal explosive sound that they didn’t bother them.

  94. Gary Hladik says:

    I understand they’ll be offering a Deluxe model with a rubber band for range extension or extra power when passing golf carts on two-lane roads.

    Rumor has it that the Super Deluxe model will come with an emergency bicycle pump in case you’re ever stranded far from a source of compressed air.

  95. Re Beng’s engine,
    I think they used high pressure steam from a ‘communal boiler’. The ones I saw had heavily lagged ‘steam’ ‘boilers’ to reduce heat loss. So essentially they were passive compressed steam locos. But his may have been different.

  96. It was not all that long ago since I remember it, much mining equipment was pneumatic and many of the mine locomotives (in the days of mine cars on tracks) were compressed air operated. What’s new is old or maybe what’s old is new again.

  97. cui bono says:

    *Sigh*. 2012, and a crate powered by compressed air.

    Where’s my fusion-powered hovercar? And my personal jet pack? And my family-friendly interplanetary runaround?

    Who hijacked the future? This whole planet is going in the wrong direction….

  98. Mike Hebb says:

    This could be just the thing to make solar and wind power viable. When they are producing unneeded energy it could be compressing air for transportation.

  99. L. says:

    Justa Joe says:

    ‘Nobody is going to give up their features in favor of this golf cart, sorry.”
    I think you are forgetting the target market for this car is Indians..in India! The vast majority of which have no features to give up. So I believe this will be an ideal car for it’s intended markets…India, Africa and probably China (assuming the Chinese simply don’t pirate the design).

    Clearly Western design and safety regs will make this car a non-starter in the US, Europe, japan Australia etc. due to the added weight of the legislated crash protections, but for developing and 3rd world markets..yep, as long as it can achieve performance close to what’s being advertised, then it will be a winner.

  100. helder Velez says:

    Public transportation in buses moved by compressed-air already existed aprox. 100 years back in time.

  101. Axel says:

    hey TATA you missed the boat surely ????

  102. Old England says:

    Haven’t had time to read all of the comments but:
    Originally, and this may have changed, the TATA air engine (developed I believe by a Frenchman)included a petrol-fuelled heater to heat the compressed air before entry into the motor to increase power and range.

    In Australia , Angelo di Pietro, has had compressed air delivery trucks running in markets using the compressed air motor he developed using the wankel principle. He, himself, is an ex Daimler-Benz development engineer who spent most of his time working on development of the wankel rotary engine principle. He also has cars he owns running on compressed air using his motor and has a range of other applications including outboard motors – I got a colleague to go and meet him and see the motors in use. Impressive. The chinese, by the way, have tried very hard to obtain one of his engines.

    I don’t consider it a pointless technology as so many commentators seem to above, it may not have mass-market application (unless TATA prove that wrong) but it does have a number of niche market possibilities and can be provided as a renewable resource. Compressed air storage is cheap, effective and non-polluting – unlike batteries. A two stage compressor can be powered by water power, wind power or by electric motor/alternator run from water, wind or solar enabling energy in the form of compressed air to be stored for times when the wind doesn’t blow or the sun doesn’t shine – without the need for batteries. So in remote areas compressed air can come from solar power during daylight hours and at night by running it back through the electric motor/alternator used to run the compressor can produce electricity as and when required. With a little imagination and some lateral thinking there are a wide range of applications which could be powered from genuinely renewable energy – in the right geographic areas and avoiding the need for expensive infrastructure. As one example there are plenty of agricultural applications across the world requiring low power output which have the potential to be powered by compressed air produced through renewable energy sources on farm.

    Sorry to those of you who think it of little value but I think you are wrong and haven’t given it enough thought.

  103. MIKE MIGNANO says:


  104. Smokey says:

    I think the Pachaurimobile will be eclipsed by this, the enviro contingent’s dream car.

  105. Justa Joe says:

    L. says:
    January 31, 2012 at 3:27 pm
    I think you are forgetting the target market for this car is Indians..in India!
    You’re correct. It beats walking, riding a bike, or packing into a crowded city bus if you’re living a 3rd world existence. I was responding more to a commenter who was comparing this vehicle to our conventional cars, which are vastly superior in terms of utility, performance, and safety.

  106. gbaikie says:

    It seems the simplest solution is to use liquid air. One store comparatively enormous amount energy, and you only use high pressure tank to for energy needed in near term. Inject liquid air [or nitrogen] into high pressure tank, and ambient temperature will increase pressure. So to get extend range in a hurry, you increase amount heat you get from ambient air. If you not using car, for long time, remove reservoir, or allow to vent. So have high pressure tank that can get you say 10 or 20 miles, and liquid air extends it to say couple hundred miles. And so fill up similar to gasoline car.

  107. Frank says:

    I used to design compressed natural gas (CNG) fueling stations, so I know a fair bit about putting compressed gas into a car. It is fraught with problems! It is very difficult to quickly fill the tanks; if you fast-fill, the heat of compression heats the gas already in the tank so much that the expansion from the heat creates a spike in pressure, terminating a pressure based fill. You can ignore the pressure spike, and fill by mass flow, but then technically you are over-pressuring the cylinders. Filling by mass flow requires an initial pressure reading, a partial fill, a bit of settling time, after which the computer estimates the volume of the tank being filled using good ol’ PV=nRT, then the tank is topped off by mass flow based on the volume calculation. Too many assumptions in my honest opinion, too many places for something to go wrong.
    Another problem is the pressure cycling of the tanks. All engineers know that pressurizing and depressurizing tanks (or aircraft) causes stress cracks. I occasionally would happen upon CNG station fill storage banks made up of DOT bottles (essentially the same steel bottles welding oxygen or nitrogen come in) which had been overfilled by equipment malfunction or grievous operator error. As I would bleed off the gas to prevent the tanks from popping like balloons, I would hear the DOT bottles making “tink” sounds as the stress cracks would try to close.
    Various schemes have been contrived to pressure test the tanks, either by removing them from the car and hydro-statically testing them, or attaching sensors to “listen” for the “tink” sound of the cracks, but these tests are expensive. Another strategy was to simply replace the tanks after a certain time period or number of pressurization cycles, an extremely expensive option, more expensive probably than what you ever saved on the price of fuel.
    If there is an equipment malfunction or operator error in the fill, the result can be catastrophic. An apparent overfill of the CNG tanks in a small pickup at a utility in Indiana on Dec.14, 2000 utterly destroyed the truck, and a tank landed half a block away, going through the roof of a bowling alley and landing in the bar. This wasn’t a fiery natural gas explosion, it was simply the tank popping like a balloon from over pressurization, and the truck was destroyed; the pickup bed was gone, the truck nearly sheared in half, the back of the cab blown away and the roof blown off. Even the doors were accordioned, the seat and dash destroyed. Fortunately the driver had left the vehicle before the explosion.

  108. Mark says:

    Well, they charge .75 to 1.00 to use the compressed air to fill up your tires, so I could see them charging a bit for it.

  109. Phil's Dad says:

    You first!

  110. Narniaman says:

    Seven or eight years ago I remember reading about another proposed air compression/expansion engine — I think this one was in Seattle, that promised 60 mph and a range of fifty miles or so. I was a bit skeptical and did some actually thermodynamic calculations, and the best I could come up with given the size of the car was maybe a range of 15 miles with a widely efficient engine.

    I learned later that the best range the company actually got was seven or eight miles.

    But who knows. . . . .those chaps in India are pretty smart, and maybe they’ve figured out a way to get around some of those pesky thermodynamic laws. . . . . .

  111. Mike Wryley says:

    Every time this air car story rises like a Phoenix from the septic tank, it brings out the ” even though we lose money on every transaction, we’ll make up the difference in volume” crowd.

  112. Ian Hoder says:

    The Air Car scam seems to get publicity after every car show. The Air Pod scam has been going on for at least the last 10 years with Negre always claiming that the care will be hitting the streets “Next year”. The only independent test resulted in something like a 10km range while going 20kmh. It’s just like the cold fusion reactor scam a few weeks back. I’m actually a bit surprised WUWT readers fall for this type of stuff.

    Don’t believe the hype. Look at INDEPENDENT testing by RELIABLE third party sources.

  113. I agree with Ben Hern’s comment: “guys, a litle perspective before leaping to find fault in the latest innovative thinking”.

    Scepticism is good, scepticism is honourable. But cynicism is something else, cynicism is unworthy of this great blog.

    If the energy density problem and the safety problem can be resolved, this vehicle might well fill a useful niche in the market: short urban journeys in polluted 3rd world cities. Good luck to ‘em, I say.

  114. NovaReason says:

    Would the filling stations have a huge high pressurized tank to fill these or would they use industrial air compressors? If they use compressors, then the air being pumped in with contain added heat from compression, which will slowly be lost through the tank, ensuring that you can never really fill it 100%. If they use air from a large compressed tank, then the loss of heat from the expansion into your Air tank would mean that over a short period of time, the air would heat from the ambient temperature and increase the pressure (depending on how far from the safety thresholds these normally run, that could be an entirely benign issue, or a possible road bomb). Speaking which, has anyone looked into exactly how much localized damage these things could cause if INTENTIONALLY detonated? It would be the most innocuous looking car bomb ever.

    That being said, there’s a lot of people who don’t really seem to understand the heating and cooling of compressing or expanding gases. You won’t freeze the atmosphere by slowly pumping out super cold air as you drive along, because the heat energy you let off from initially compressing the gas and then allowing it to reach thermal equilibrium with the ambient air would be equivalent to the heat needed to warm the exhaust back up.

    Long story short though, Laws of Thermodynamics are still ensuring that you can’t make something out of nothing, but also that you can’t destroy anything, only change it… There’s no way for us to destroy all of our heat energy by repeatedly compressing and releasing air, or all the A/Cs and air compressors in the world would have already offset all of the modern age warming and we’d all be skiing to work right now (before we died of starvation).

    Realistically, is there any heater in this golf cart? Because the A/C is supposed to be a byproduct, but the car isn’t producing any usable heat energy. (BTW, they aren’t pumping air directly from the tank to cool you, they’re redirecting the “exhaust”… interesting aside here, there’s vegetable oil used to lubricate the pistons, and the air you’ll be using for A/C is going through there before it comes to you… will all your A/C air smell like the oil that you’re using? How long before McDonald’s brand oil is available, to give your car that Classic French Fry smell?)

    Finally, I am not an automobile engineer, but is a 4-cyl engine REALLY the best they could come up with for this? I’m going to go way out on a limb here and assume that issues like recycling the fuel/air exhaust to ensure complete burning of hydrocarbons, the ENTIRE compression phase, and proper air/fuel mixing are not an issue here at all… it’s purely mechanical energy, released directly from the tank (most likely) to the pistons. I might be talking out of my ass here, but I’m pretty sure a more efficient engine design is entirely possible. For every PSI over the surrounding atmosphere that your exhaust comes out, you’ve wasted that energy. I’m really starting to think that the people designing this vehicle just took a regular car engine and said “How can we make this run on air?”

  115. John Marshall says:

    The picture of the engine shows the cam belt on inside out. The teeth should be on the inside to match the teeth on the pulley wheels. It would not work as shown due to belt slippage.

  116. John Marshall says:

    Compressed air has a lot of stored energy. A serious accident and those two compressed air cylinders will explode like an RPG7.

  117. Arkh says:

    “This car can also be filled at home with it’s on board compressor. It will take 3-4 hours to refill the tank, but it can be done while you sleep.”
    Not sure you will be able to sleep while your compressor is on.

  118. Dixon says:

    Can I get a liquid N2 powered version? Keep the distribution folks happy…

  119. David says:

    I’ve got an idea..
    Wind is free – right..?
    Why not build loads of windmills – all driving electric generators – which all feed the electric grid – exactly like the windmills of old, which look so cute in Dutch landscape paintings..
    What’s that you say – they went out of fashion in a big hurry when steam and other more reliable methods of grinding corn and draining farmland came in..?
    Oh, well – it was just a thought…

  120. Steve Garcia says:

    I am as doubtful about this as the next guy here.

    I would point out to the people who think that as the tank runs low the pressure will drop that:

    They will not be running the car on the unregulated pressure from the tank. The tank is overpressurized. Based on what I am seeing, there will be more than one pressure stage – it would not be smart to take 3400psi air and only use it once. From what I see in Wikipedia’s footnotes, this is
    a.) not new technology, other than maybe the electronics, and
    b.) certainly well enough engineered.

    I would caution doubters that this is not CRU nor Michael Mann. This is all just engineering, not cutting edge theoretical science. In other words, it isn’t exactly rocket science.

  121. These types of engines used to be called “Steam-engines” in my day.

  122. Steve Garcia says:

    Oh, also, I thought these bits are pertinent (from Wiki):

    Worldwide, there were 12.6 million natural gas vehicles by 2010, up 11.6% over the previous year, led by Pakistan with 2.74 million, Iran (1.95 million), Argentina (1.9 million), Brazil (1.6 million), and India (1.1 million).[2] with the Asia-Pacific region leading with 5.7 million NGVs, followed by Latin America with almost 4 million vehicles.[2]

    This is pertinent, since the pressures are basically the same:

    CNG [compressed natural gas] is made by compressing natural gas (which is mainly composed of methane [CH4]), to less than 1% of the volume it occupies at standard atmospheric pressure. It is stored and distributed in hard containers at a pressure of 200–248 bar (2900–3600 psi), usually in cylindrical or spherical shapes.

    There is an ISO standard for such storage tanks, ISO 11439. Therefore, one would guess that there has been a great deal of solid engineering behind the setting up of that standard.

    ISO 11439:2000
    Gas cylinders — High pressure cylinders for the on-board storage of natural gas as a fuel for automotive vehicles

    The standard itself is behind a paywall, so I didn’t read it. But I’d imagine with 12.6 million CNG vehicles on the road, the engineering and safety are all well understood. Therefore, adapting to compressed AIR – at the same storage pressures – would not be an incredible engineering task.

    One last Wiki mention was this non confidence builder:

    High pressure bottles are fairly strong so that they generally do not rupture in vehicle crashes.

    “Generally do not rupture” is not what I want to hear.

    But then there is this, from http://www.sumanauto.com/CNG%20Safety%20Issues.php:

    At a compressed natural gas fueling station the gas is compressed before being provided to vehicles at 3000 to 3600 pounds per square inch (psi). Stations can deliver a “fast fill” to vehicles in minutes or, using a “slow fill” strategy, in a few hours to overnight.

    Although the use of high storage pressures might appear dangerous, compression, storage and fueling of natural gas vehicles meet stringent industry and government safety standards. Remember that high-pressure gases are used safely every day in industrial and Compressed natural gas ( CNG ) powered vehicles are designed and built to be safe both in normal operation and in crashes. New natural gas vehicles are subjected to the same federal government crash tests as other vehicles. Natural gas or CNG vehicle fuel systems must meet Federal Motor Vehicle Safety Standards 303 and 304. Natural gas cylinders are much thicker and stronger than gasoline or diesel tanks. Cylinders are designed not to rupture when fully fueled over six times a day, 365 days a year, far beyond what they will see in service.

    Industry standards test them far beyond normal environmental and service damage risks. Cylinders must even withstand a bonfire test and penetration by a 30-caliber bullet without No matter what the fuel, fueling stations, indoor parking structures and repair garages must be built to ensure high levels of safety. Requirements for facilities handling natural gas and natural gas vehicles may differ from those for gasoline or diesel vehicles. For example, leaking diesel and gasoline form puddles on the floor. Natural gas normally rises toward the ceiling and disperses. Therefore the danger of fire would be greatest near the floor for liquid fuels and near the ceiling for natural gas.

    …CNG vehicles have been used in the US since the early 1980s. Yet there has been only one fatality in the US caused by an NGV fueling system failure in all that time.

    How do natural gas vehicles behave in crashes? The strength of the natural gas cylinders and fuel system generally avoids any leakage or fire. For example an accident involving a CNG-powered pick-up…proved to be a testimonial to the safety of CNG tanks. As reported When the 1992 CNG pick-up was broadsided in Midland, Texas, the most vulnerable part of the fueling system bore the brunt of the hit. While the force drove an imprint of the tank safety valve into the side of the truck, the CNG tanks did not rupture, and driver Jimmy Oden And in a tragic 1998 accident, a stopped bi-fueled Honda (a vehicle which could run on either natural gas or gasoline) was impacted by another vehicle moving at nearly 100 mph and a fire fed by gasoline broke out. The 50-liter natural gas fuel tank was intact and remained secured in its support brackets. (Reported in a June 1998 BC Gas press

    Nationwide Insurance, in looking at the safety of natural gas buses in a fleet, concluded as long ago as 1992 that “…the natural gas powered vehicles will be the safest vehicles in your fleet and (we) have no reservations about insuring them.” (Palmer, Pat, Nationwide Insurance, letter to Kenneth E. Bauman Bus, Inc., September 10, 1992)

    Again, that is all about CNG vehicles, not compressed air ones. But with the amount of compressed gas vehicle history already out there, this Tata vehicle seems like a natural next step.

    My bet is that it sells like hotcakes.

  123. Crispin in Waterloo says:

    @Alan Watt
    “Even more of a pipe dream. You’re describing the Sterling cycle (atmospheric) engine.”

    A Stirling engine is a heat engine, not a compressed air engine though there is gas compression involved. A thermoacoustic refrigerator is also a type of Stirling engine, whether travelling wave or standing wave. The French car uses a compressed air motor, not a Stirling engine.

    “The original steam engines worked this way to pump water out of coal mines.”

    No, that was the condensation of steam in a closed chamber which is not a Stirling engine either. Watt sprayed water into the chamber to help cool and condense steam faster after the first model worked.

    The release of heat during condensation is a serious impediment to efficient operation. The compressed air motor of course does not condense the air.

    “Atmospheric engines “suck” the piston up in the cylinder instead of pushing it down.”

    Yes. That is how the French engine works. There is more than one way to produce suction.

    It was mentioned by a couple of people that there is a ‘heater’ of some sort on some air motors. It is my understanding that the French design does not heat the compressed air. The flame is used to heat the ambient air that is drawn into the cylinder reducing the mass of air contained at standard pressure at whatever the volumetric efficiency is. This assists the contraction caused by the cooling of the injected compressed air. Such a motor necessarily runs at a fairly low speed.

    The energy lost during compression is in a way, regained by starting of with hot air on the intake and expelling cold air from the exhaust. As there is a temperature drop, there is energy available. The clever part of the French motor is that it takes advantage of the low temperature decompressed air to extract energy from air at the ambient temp. It is nothing at all like the ‘air motors’ one has in shop tools which work on expansion of compressed gas (air).

  124. Craig Loehle says:

    Is April coming early this year? A tank with enough pressure to go 185km? No way. I predict that in India people will charge it using their handy diesel generators which they need (and have) because of an unreliable grid. 1/10th the cost of gas to charge it? Any time there are two steps in an electro/mechanical system there is entropy loss of power. Solar to charge it is not cheaper than gasoline–the push for solar is based on it being low carbon, not cheap.

  125. alex says:

    should be extremely inefficient.
    Most of the energy used to compress the air is spent to heat the air (adiabatic compression). This energy is lost forever.

    The price of 100 rupees per fill is low because electricity in India is too cheap.

  126. Doug Jones says:

    A Luxfer T84A bottle masses 2.3 kg, and at 31 MPa (4500 psi) can hold 3.4 kg of air. At 14 cm diameter and 78 cm long, it’s not small, but it’s among the highest performance gas bottles available today.

    The PV product (total energy) is 280,000 joules. at 30% efficiency in the air motor, that’s about 84 kJ, less than nine seconds of operating time for a 10 kW motor. Even if the microcar only needs 500 W to cruise, that’s less than three minutes of operation. Thenumbers just don’t add up.

  127. Crispin in Waterloo says:

    @Alex and @Doug

    Please read what I just posted above. It is not an air expansion device. It is a thermal device. A great deal of the energy that appears to be lost in compression is regained but only when the pressure is high and retains its cooling ability when expanded (little shots of cold air akin to a diesel injector). If a flame was used to provide the gas that is aspirated into the cylinder, it maximises the cooling potential.

    My stepfather wanted to use a diving cylinder to run a propeller to pull him along underwater but the efficiency and range were hopeless. I suggested he operate a model aircraft engine on the air – it would go much farther!

    I have not heard what the efficiency of the French motor is. If it is slow, it may be much higher than a casual glance might suggest.

  128. Doug Jones says:

    Crispin, the total energy in the bottle is limited by the pressure * volume product. It doesn’t matter how efficiently one uses that stored energy, there simply isn’t enough to be useful. All the handwaving in the world ain’t gonna make it work. No more discussion is needed.

  129. AlanG says:

    Jeez guys, I like steam engines too, but I can also handle new technology. OK, it’s a toy car but a real car with a few more/bigger air tanks will work. In the 21st century, properly engineered things don’t spontaneously explode, leak or whatever.

  130. Steve Garcia says:

    @AlanG –


    There are something like 12 million compressed natural gas cars in the world with tank pressures exactly in the same range as this. If anything the CNG tanks are more dangerous than compressed air, since there are two factors involved – pressure and ignition.

    Given all the engineering – and ISO standards that already exist – the people here worrying about going Boom! basically don’t know what they are talking about. It took me all of 5 minutes, from a dead start, to find all sorts of online info about safety and compressed gas vehicles.

    And as to there being enough available energy, again, the engineers and management at Tatra wouldn’t let the project get off the ground if it didn’t have enough energy. People are acting as if they pulled the number 168 mile range out of some tumbling lottery basket.

    This thing either works or it doesn’t. We don’t have to wait till the year 2100 to find out if it gets falsified. August at the latest. Barring delays.

    Since they already have over 3 million CNG vehicles in India and Pakistan, one has to think the compressed air vehicle will be a spin-off of that. So, the only question is: Does the engine have enough oomph. We can argue the costs here till the cows come home, and it won’t change any reality whatsoever. I doubt the cost claims, too. That electricity didn’t get made for free.

    But this is one of those cases where we just have to be patient, pay attention, and see what happens. They aren’t going to read here that, “Oops! We left out safety and power!” and go tear down their assembly line based on our doubts. Every question we ask here has certainly been asked – and answered – if they have gotten this far with it. That is what engineers do, ask the tough questions and then go out and find real world solutions. This isn’t Phil Jones with his finger up his bum. Skeptical is good, but on a PRODUCT, the thing to do is to shut up and see if it works. We can doubt all we want, but if it is to the stage it has gotten to, someone obviously knows something we don’t.

  131. old44 says:

    If they ran it on nitrous oxide everyone would be happy.

  132. Charlie A. says:

    Going all the way back to 2000 MDI of France has repeatedly announced that production of a compressed air car would start “next year”. Their website is mdi.lu .

    aircars.tk is a good website for info on aircars. It is independently run and not affiliated with MDI.

    As usual, production is scheduled to start ……. next year.

  133. Julian Braggins says:

    Despite calculations ‘” proving” that the air car cannot work to its specifications the fact remains that air locomotives and vehicles have used air as a motive power successfully, to a limited extent in the past.
    ‘Mechanical Movements, power devices and appliances”by G.D.Hiscox, M.E.(pub. 1911) lists two, a locomotive that used a large intermediate cylinder kept at the same pressure as the high pressure motor cylinder used (and presumably normalised temperature to ambient), and a low pressure motor cylinder that exhausted at near atmospheric pressure. Similar designs were used in mines for safety.
    The other used air at 4000psi in bottles that was heated in coils by gas as a power factor for trucks.

    Steam type injector devices can force atmospheric air into cylinders when filling, reducing the high pressure air needed. In a hundred years there should be SOME improvements in overall design.

  134. Saad Faruque says:

    Reblogged this on Building systems that WORK and commented:
    Urban car 300 km or 185 miles between refuels for 2 USD

  135. Abysmal Spectator says:

    The compressed air in a fully charged scuba cylinder has, iirc, about the energy of 300g of TNT, or equivalently 2 hand grenades. I suspect the amount of compressed air in one of these car’s tanks is much, much greater. I wouldn’t want to be in one in a collision, nor in the vicinity of one.

    And here is a picture of what a scuba cylinder can do when it fails:


  136. John M. Chenosky, PE says:

    Notwithstanding the safety aspects and the 15-20 minute fill time ( heat must be controlled at all costs ), one thing must be considered.
    IT TAKES MORE THAN NINE (9) UNITS OF ELECTRICITY TO GENERATE ONE (1) UNIT OF AIR ENERGY. Section 1, Page 28, Compressed Air System Solution Series, R. Scot Foss, 1993

  137. George E. Smith; says:

    That’s not a car; that’s a chicken coop.

    Now speaking of cars; THIS here IS a car.

    That’s what we need to be driving.

  138. Hi Anthony,
    I am from India and I have been hearing reports such as these for the past 2 years or so now primarily through forwarded emails. I have already seen these images around on the internet.
    But, neither Tata Motors nor any other company in India has raised a flag about a compressed gas vehicle till now. So I thing an Aug 2012 release is highly unlikely!
    Usually, before a car is launched into the Indian market, it starts circulating in the media with a lot of testing mule spy shots coming up. But no such thing has happened in India.
    I personally think this whole compressed car thing is a rumor but would love to be proved wrong!
    Our environment is going down pretty bad and something really needs to be done. Reminded of ‘the Unconventional Truth’ by Al Gore.

  139. Keith Sketchley says:

    Some people need to think, and learn, before commenting. They detract from the credibility of WUWT.

    Concerns about air tanks exploding are ignorant of the reality that they are riding around with several gallons or more of a volatile, easily-ignited liquid – gasoline, or a compressed flammable gas like propane or natural gas (in taxis and busses).

    And note the contents of the air car energy tank is air, not an flammable/explosive fuel. The risk is rupture, a rapid release of pressure that could injure people by airflow or projectiles (pieces of the tank or other things dislodged by them or an air jet). But no substantial fire.

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