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by Brett Davis

Tata Motors and ex-Formula One engineer Guy N. from a Luxembourg MDI have come up with a car that runs on air. Dubbed the Tata Mini CAT, or Air Car, the environmentally-friendly car uses no petrol, requires little maintenance and has a range of around 300km between re-gassing. Tata hopes to have it on the market in India in 2012.

The way the Air Car is propelled is fairly straight forward. There are two tanks of compressed air which turn an almost-conventional piston motor and drive system. The system is said to propel the small van to a top speed of around 105km/h.

Tata says the Air Car stores enough compressed air to offer around 300km worth of motoring. Users will then be able to re-gas the car at certain filling stations that are equipped with special tanks of compressed air, in around three to four minutes for around $2. It will also come with its own generator pack which can be used at home capable of re-gassing the tanks in around four hours.

The vehicle itself is a six-seat mini van using two 340-litre carbon fibre gas tanks which are filled with air to 4350psi. It also uses a tubular chassis design with fibreglass panels that are glued together, helping to keep weight down.

All the accessories and in-car equipment are powered by a microprocessor. From the exhaust the only thing that is emitted is air, of around zero to minus 15 degrees in temperature.

Tata is aiming to release the Mini CAT Air Car in India next year with prices starting at around $12,700.

  • vx

    First question, if technology is available for $2/100km with compress air, why wouldn’t people around the world have done that?

    this is worse than so call $35 tablet and $100 laptop

    • test drive

      Obviously people have. Google MDI or air car. This technology has been around for a long time but I suspect (warning – conspiracy theory) our government makes it difficult to adopt. ADR requirements are not geared around efficiency and the government is addicted to oil taxes. This engine can run on a cup of vegetable oil for lubrication and apart from that you could have a compressor at home to charge it (although it’s no ordinary compressor to produce the super high pressures required).
      It this was available here I’d certainly buy one. It’s ideal for our mostly hot climate because of adiabatic cooling that occurs when the highly compressed air loses it’s pressure though the engine. This means plenty of cold air for air conditioning the car! In fact the biggest problem a car with this engine has is producing heat to warm the occupants on a cold day.

      • GMoney

        Do you know how I would make one of these cars?

    • Jacob

      That’s like saying Tata shouldnt have purchased Jaguar.

    • slugghead

      $2/300km?!!! thats crazy!! that will incredibly boost everyones motivation and hardwork…..negatively

    • JTW

      when someone found a way here to refine cooking oil into fuel for cars, the government (not AU, EU) quickly banned the practice under the “logic” that as cooking fuel doesn’t have fuel taxes added to it it isn’t allowed for use as a fuel for motor vehicles.
      Same would be true for air, unless you’re willing to pay €1.50 per liter for the air you breath, which is roughly the gasoline tax here.

    • carlos

      How stupid of a question is this?  do you know the power the oil companies have, do you think they want this technolgy out< no !  thats why when ever someelse comes up with alternitive enrgy they kill them or make a maulery out of them.  tHis is factual stuff many  inventors are killed and sanction by the CIA wich is owned by the biggest bidder, the oil campanies.  I would love to see this happen in my life time, but people like al gore that say one thing but invest in another will not let alternitive energy sources out.   How about the perpetual motion generator that can power a 5k sq ft home, thats been ridiculed and demonised for 10 years, that dont mean that we dont have it.  its being sold on the black market and you better not let know electric compnay know you have it.  We have enery all sorts but the controller  have not let us have them until they can make money on it.  Just saying

      • GeoffG

        First: Get this straight – There is no such thing as “perpeual motion” or “over-unity.” There cannot be – it flouts all the laws of nature. If it were so, then energy could be created from nothing. Nothing IS nothing.
        Second: There are technically advanced countries such as Japan and Israel that have no oil of their own. Do you really think that the oil industry in the USA could stop them using an alternative energy source if it was to their advantage? If compressed air or “the water powered car”  and other non-sensical ideas worked, don’t you think these countries would embrace it with open arms?

        • Kingswood

          What are you implying —that only Jews, Japs
          and Europeans have innovative mental prowess

          • GeoffG

            You obviously haven’t understood a word I wrote.

          • Llomand

            I guess that not having oil of their own helps in coming up with alternatives .. Mental prowess has nothing to do with it, thanks God …

        • birchbarkbobananda

          who cares about perpetual!??? when the universe supposedly is 16 billion years old and has been running unabated ever since. Aren’t we thus living in what must amount to the closest thing anyone has ever experienced to a perpetual motion mashine.
          Admitted, 16 billion years is a short time compared to an indefinite number of billion years, but again who cares. Perpetuity is perhaps just another word for NOW, since no one will ever reach perpetuity any other way but to remain centered in the Moment, one at a time, how else!
          So then for a vehicle to run for a month without needing to be refueled would really just be a small thing to ask, long from perpetual motion. So what’s your problem, dude?

          • GeoffG

            You should stick to taking drugs. You know nothing about science.

          • jubal Harshaw

             I am not expert in quantum theory, bu I suspect that it could be possible to extract energy from the universe,maybe by  rigging   black  matter. It could be that the second law of thermodynamics is valid in our frame but,as Newtonian physics valid in a certain physical context within a relativistic universe,be part of a more complex, multidimensional energy law. As if  these speculations could be applied  here is  …um…speculative

          • Serteckian

            What is the vacuum? Nothing, by definition, does not exist as it already exists something. So you probably can extract energy from anywhere as the Universe is everywhere. By the way, what is the energy density of the vacuum? I found very interesting the work by Nassim Haramein

        • Eugene

           Part of the reason certain corporations and people have so much control is because sheeple like you believe all their propaganda.  I guess you believe there are no conspiracies either.

          • GeoffG

            You poor little bugger. You are obviously too ignorant to seperate fact from fiction. In fact you are the ideal candidate to believe in all the nonsense about “free energy” “government had the inventor murdered ” “water powered cars” etc. Lots of silly people latch on to this in ignorance and convince themselves that there are conspiracies. I am no lover of governments or the oil industry – in fact, I despise them, but that does not validate engineering nonsense and scams.

          • Nemesis

             GeoffG…..Don’t waste your time on dummies who live on wishful thinking and have not a clue about physics and the shear amount of energy required to move a 1-2 thousand pound car/van. These folks are sadly so dumb that they will believe this nonsense regardless of facts or logic.. If they so believe this car hoax….which by the way has been around since 2000….then I say they should invest in this company and reap the bountiful profits to come from this magic rug….er car. If this concept really worked then it would have been proven so by any bright garage mechanic by just modifying a car….or motorcycle…..or even a bicycle. It hasn’t been done BECAUSE IT CAN’T. People….please grow a brain and develop some critical thinking skills.

        • naturelover

          countries like the US would definitely embrace it if it had been invented in it’s own country and its government benefited from it. 

        • Serteckian

          There are no nature-laws, but only wrong abstractions of what we subjectively and partially observe that appears to happen many times. We have no idea of what energy really is or where it comes from. We are just used to feel and use it in our daily life. Nothing else :-)

      • Devaskand

        hi carlos 
        i would like to know about people getting killed when they have a great invention, help me out with the cases you might have come across
        and what abt the perpetual motion generator ud talking abt 

    • mano

      may be the governement and major oil companies and car makers didnt want it to work + it isnt like ur your conventional car.. so it doesnt matter how many miles u can go but how fast u can go
      what people want = better+faster+cheaper

      it is not much better when compared to conventional cars in-terms of safety aspects

      it  is not much faster too …. ( not proved till date)

  • vx

    Ah it is actually saying $2/300km

  • Kev

    Will this car contribute to global cooling and the need for a compressed air tax

    • Julia

      Yes there will be a compressed air tax , we are currently NEGOSIATING with mr brown on what draconian level we shall impose , but mark my words all poor bogans will be compensated .

    • Rangere

      so hitting a gasoline tank is ok though?

    • Mercury

      Global warming is a fraud based on phony science and falsified data. The sun is in charge and any human who thinks they can make a dent into global temperature has an overblown ego or is making a lot of money from this pseudo-religion.
      All this aside it’s the perception that first: the emissions of an air car will be air, will already be enough to win over everyone except big oil; but second: an exhaust temperature of 12 degrees Fahrenheit will be perceived to be a welcomed side effect for us all. Meanwhile I challenge anyone to scientifically prove that this theory will be anything more than a politically correct selling point. I, myself embrace the hope that we will produce cleaner, cooler air while powering our cars with fossil fuel energy.
      What could prove to be an ironic twist is the day we will have to sell our stock shares in the technology when the scientists announce Global Cooling. Uh oh.

  • http://www.facebook.com/JimmyJoeyJoeJoeJuniorShabado James Hadley

    These have been looked at before and are great! but.. when they have an accident those tanks go off like bombs BIG bombs. They will never be legal in any country that values the lives of its motorists.

    • Wood Duck

      This concept has been around for years. The tanks don’t explode, they are usually carbon fibre wrapped or some type of synethic rather than being alloy or steel. This way if they are damaged they will fracture and release their pressure rather than explode catastrophically. The question does remain though, if this concept is so good why is it still not in mass production.

      • test drive

        All true, the tanks “rupture” which is to say, release the high pressure air over a large area very quickly. It’s not without risk, but neither is carrying a tank full of highly flammable liquid like we all carry in our cars EVERYDAY!

      • Tall Pete

        The problem with the air car is that you cannot store a lot of energy in compressed air. So the range of the car has always been a problem. It was never 300 km. I doubt they really reached that stage unless they are heating the air in it’s way back to the engine to expand it but then you have emission.

        I’ll wait to see one before believing it has so much range and so high a top speed.

      • Tbenke

        Follow the money… Existing entities protect their turf i.e. the oil companies.

    • Azzaa

      So LPG then.. Does not go boom?

      • http://www.facebook.com/JimmyJoeyJoeJoeJuniorShabado James Hadley

        LPG isn’t at 5000PSI

        • Curby Weaver

           No, LPG is more like 900 psi, but CNG is 10,000 psi.

      • Freddo

        Nope- they have pressure release valves these days

      • The Rite Man

        LPG and Hydrogen is a gas that disipates too quickly to be a real threat!  Gasoline is more dangerous.  What about Electric cars?  The battery acid is a huge issue in auto accidents.  All you idiots who bought a Toyota Prius never though you were killing the environment with your battery acid and recycle costs not to mention it still runs on Gasoline.   Why are we even concerned about oil when most of our oil is used up in plastics, tires and almost everything else we take for granted.  Gaslone is a small consumer.  Global Warming is fake anyway and just because the threat of killing the world outweighs basic logic.  There is so much money to be maid in global warming it is as bad as the oil companies.  We are all screwed by the corruption and our ability to make informed descisions.

    • Lalit Joshi

      They have thought of this, the tank is made of a material which in event of accident will break but not explode. Its tested for being safe in an event of collision.

    • http://www.facebook.com/micheal.kaplan1 Micheal Kaplan

      wow you fail at life. what about lpg tanks? hell right circumstances a petrol tank will explode aswell.

    • B Street

      I think you will find petrol can explode in an accident as well

      • Curby Weaver

         B Street . . . yes and no.  Gasoline only explodes in Hollywood.  Everywhere else it burns. 

        • moviefreak

          lol i saw it on mythbusters. they dropped a car on a full tank of gas from a height of 50ft or sometihng and inside was a burning grill and they made the dummies smoke cigarettes. it never exploded!! hahahahaha

    • Anon E. Moose

      Actually, the tanks are made of carbon fiber composites and will rupture cleanly instead of exploding into shrapnel.

      • Curby Weaver

         “Rupture cleanly” may not be a great way of expressing it.  The fiber will prevent the tank from exploding.  Depending upon the force of impact, it will either leak slowly or leak quickly, but the tank will not explode.

    • Tbenke

      Not too much different from a 20 gallon gasoline tank!!

    • Zdano69

      Not at all actually,…The air tanks will be manufactured by AirBus and they are designed to rupture in the event of an accident, and no they are not bombs by any means.

    • jim

      Consider the number of people that carry SCUBA tanks in their cars.
      These tanks are carrying air compressed to 3500-4000 psi without any problems.

  • Daniel

    Nice Taxi. This will never see light of day in “Western” economies. The Oil wholesalers and retailers will make sure of it. Although, $2 a refill for a resource that is free (like water) means they could make alot of profit…

    • bob

      You didn’t think that through did you? The resource (compressed air) is not free. Compressing that much air requires large amounts of energy in the form of electricity to run the compressor. Where exactly do you think that electricity come from? From the main power line…. which is mostly coal power plants. This thing would not have cheaper nor cleaner overall costs then basic gas cars.

      • dougie_s

        bob, sound’s like *you* are the one not thinking it thru –  while it certainly will require electricity from power plants to compress the air, it won’t be too much; otherwise, it wouldn’t cost only $2 to refill a tank to go 300km.  duh!

      • http://www.webayunate.com/ Ger

        Bob, I have the same approach than yours.

        Air compressors take energy from the grid, and they obviously don’t have 100% efficiency, so we would be adding more steps in the energy conversion chain, from the coal – hidroelectric or what-so-ever primary font used to the cinetic energy of the vehicle in movement. It’s the same that when we are talking about electric cars, as they are sold as “0 emissions”, but this is only true if the grid where fully powered by green sources, like solar or eolic (even that it’s not true, because you need a lot of energy and emissions to make a eolic generator or a solar cell)I also don’t see people having industrial compressors in they own houses to recharge their tubes.

        But, if the 2 $/ 300 km data is true, it would be far more economic than a conventional car. 

        Let’s see where this is going! We shall wait for a couple more months 😉

        • idris83

          Sounds like you’re over-complicating it. A windmill spinning on the breeze could compress air directly. No electricity required. Much more efficient.

          Imagine windmill filling stations dotting the horizon. Stockpiles of cannisters inside them, some full of compressed air ready to go, some empty ones that have been left by previous motorists, waiting to be refilled. Pull your Tata in, swap the empty tanks for full ones, and off you go. 

          On calm days, the stockpiles of cannisters inside the windmill pick up the slack. In very long calm spells, solar power could drive the compressors instead. On incredibly long calm periods, as a last resort, power can begrudgingly be taken from the grid.

      • ABC123


      • Curby Weaver

        If I bought a compressed air car it would be both cleaner and cheaper as I have $24,000 worth of solar panels on my roof. 

  • http://www.aircars.tk Aircars.tk

    I don’t know where the author got his information. Tata has signed an agreement with MDI early 2007 to use the compressed air technology of MDI in India only, in any way it wants. The photos shown are of a kind of early prototype by MDI that has been abandoned since long, and also the name Minicat has been abandoned in 2008. After having lost interest for a while, Tata now considers seriously the possibility of bringing to market a car that runs on compressed air(possibly in a hybrid version). MDI itself is ready to produce its first tiny city model, the Airpod, but for the time being lacks the finances to do so. The audience is divided between people who applaud this new green mobility, and others who say it cannot work or even those who call the whole thing a scam. I have driven an Airpod myself in May 2011 and therefor I can testify that it works. Have a look at my website http://www.aircars.tk if you want to know more, and read the regularly updated news section.

    • peter

      “…and therefor I can testify that it works.”

      Yes, for exactly 7 kilometers.
      Now stop this publicity for a dead-born project. If you can’t resolve a 100 year old thermodynamic equation, you shouldn’t at least fool other people with it.

      • Fazwood

        The voice of reason speaks!!  all the talk of oil companies stopping this technology is a laugh, all the talk of danger from compressed air tanks vs LPG or petro is nonsense.  Compressed air is not comparable to today liquid fuels in terms of engery storage. The cooling effect is offset by heat generated during compression. We need more real scientists and engineers if we are ever going to solve our looming peak oil challenges/catastrophe (depending on your optimism 😉   Joe the engineer, USA

  • Stumpy

    This system makes more sense then any electrical system that has been put forward or hydrogen system.

    But no one will make enough profit out of the refueling/taxing so we won’t see this as wide spread as it should be.

    No fuel no massively expensive battery no chance in hell it’ll it’ll make it to a western market on a large scale because there’s no huge mark up to be made on the post sale running of the system or taxation kick back to governments.

    Sad really.

    • Matty B

      I would love to know how many patents for Air and Water engines big fuel companies own. Cause unfortunately that where they normally end up.

      • http://freedom00is00earned.blogspot.com Patrick Donnelly

        All patents run out before 20 years pass!

  • Jerrycan

    The claim of $2/300 klm seems a bit low, you still have to use electricity off the mains to run the pump and I don’t thnk it will much more efficient than charging a battery.

    The ‘exhaust’ could be used to run an aircon system, but forget heating in winter. I cannot see western drivers suffering that.
    Also power for radio wipers, headlights cannot be provided by air power very efficiently.

    And yes compressed air engines were around when steam engines were considered state of the art.

    • James

      Tractor and trailers use compressed air to powere the wipers and the braking systems.  There are many ways to power an air compressor. Solar, wind power would do it,  I understand that it may not be completelly free of oil, but it is a start.  The other items such as radios and headlights can be actually generated by the cars movement in to a battery for later use.  Also heat can be supplied from an electric powered source also powered by the on board battery recharged also by a  generator that is operated by the vehicles movement.

  • jaiHIND

    onya, TATAs are many steps ahead than mahindras and of many others; with wealth over $100 Billion they got enough to do aquisitions and experiments.

  • Charlie A

    Would the author of this article provide some references?

    It appears to be a rehash/reprint of announcements made in 2008 saying that the cars would be on the streets of India in Summer of 2009. (Or maybe it was 2007 articles with planned intro in 2008).

    Since then, Tata Motors has said that the range was inadequate and there were technical problems and that the project was indefinitely suspended.

  • Peanut

    Solar Panels on the roof could power compressors to refill the tank while your are parked at work for example.

    • Jerrycan

      Not really, the roof area is only enough to power one of those really cheap compressors that are only just good enough for footballs. They take over 10 minutes for a tyre.
      Your normal commercial compressor/tank operates at about 150/200 psi and this operates at 4350 psi.
      Do you know how hot things get compressing air to that pressure.
      Much as I like the idea I think some of the claims are a bit optimistic, which is not uncommon.

      • Mike Kelly75

        SCUBA tanks are 4500PSI and I get mine refilled all the time!  They are also safe and very hard to punture.

        • DJ

          I am really not worried about the “Exploding” scenario. Myth Busters has proven that the tanks will NOT explode, but IF punctured, Which is not easily done, they can fly into any direction for a short amount of time. A crash could possibly puncture the carbon fiber due to minimal protection from the roll cage and plastic body. However, Tata and MDI have yet to produce these lil cars commercially. It looks more like another scam.

    • DJ

      Try pricing the solar panels. Solendra in the US has went bankrupt twice because they are not cost efficient. Over 30K to provide power to a small house. Ultimately though, seeing is believing. Tata and MDI have been talking a good game for almost a decade and we have yet to see any results other than their “Prototypes”.

  • Hung Low

    Sounds good but I really think the re-gassing procedure will be more complex than stated as that is a massive amount of pressure that needs to be squeezed into those tanks. At least you wont need to worry about a flat tyre anymore!

  • http://seventhsonrainmaker.com GEORGE RHODES

    My father invented inflight refueling and designed dc 10 dc12. he told me his idea about air poured cars a long time ago. I have made improvements, are you able to buy one can I get on the waiting list or better yet may
    I become a distributing company in Fullerton CA. please I love your air power cars. There are many empty car lots to fill please let me create the best show room and maintain a high volume import deluxe platform for this master piece. thank you.

  • Javed Khattak

    I would like to join the queue ,where I can deposit the money to own the car.

  • Jacob

    The compressed air tank might be a good alternative to KERS in Formula 1 or normal vehicles.

  • Gurjeet

    Hope someone is not making an “October Fool” of us ! If its true, then nothing more amazing. Great going….we need to have something like this to save all falling world economies

  • http://www.higear.com/brands/lincoln/ Lincoln Rental

    What do the police need with a car anyways? Probably to go run the chief’s errands

  • kiwiguy

    Just waiting for the day when a car manufacturer miraculously comes up with a Wind-up rubber band car and say they have developed the technology to make it go 400km at 150kmph. Just takes 4 days to wind up and no power just muscle!

  • Haha


    6 persons travelling 300 km Or 300,000 meters = 600 Kg X 300,000 X 9.81N = 1765800,000 nm (Newton meter)
    = 490 Kwh (Kilo Watt hour)

    1 Kilo watt hour = 1 unit of electricity = Rs. 4.5

    Even if we assume the compressor efficiency as 100%, you need Rs. 2000 ($ 40) of electricity to move those people.

    This is definitely an October fool news, as $2 of electricity to move 6 persons over 300 km is not possible.

  • Yesiam

    I have a rubber band powered car that I will sell you at half the price. and you don’t have to get to a station, just rewind it where ever it stops.

  • R. A. Woodman

    Thoughts: 1) something that a wind turbine in the back yard might provide enough juice for recharging. 
    2) I never heard of tata can they actually make something that works or is this another Tucker automobile

    • Shakeel-ali

      Google them. They are a filthy rich conglomerate who just happen to own Jaguar and Land Rover.

    • SS

      Mate… You don’t know tata? Time to google.. you will be surprised at what all they do.. :)

  • Avagadro

    Charlie A, you are right on.
    Aircars.tk,.. you spout nonsense, and time has proven Negre to be a liar, his promises never come to fruition, face reality, if the car worked as promised, money would not be an issue.

     This “Air Car” has been promised for over the last 10 years.
    taxis promised for Mexico City in 2001, factories in South Africa in 2003, Air cars from Tata etc…
    Tata has made announcements that they have no plans to produce this car because it does not live up to the claims. Negre was a failed Formula 1 designer, his race cars never completed a Formula 1 race. Spend some time, research, before you believe this scam. Ask the investors who put money down on franchises 10 years ago how they feel about this.
    The test vehicles never came close to their claims. Anyone can promise, few can deliver. This is a fool’s dream. Simple thermodynamics refutes the claims.

    • Srcaipira

      could not have said it better

  • David

    According to Popular Mechanics we were due to have this in 2008. See http://www.popularmechanics.com/cars/news/preview-concept/4217016
    Many other references to it around the net, always coming next year.

  • Vabreland

    “Since then, Tata Motors has said that the range was inadequate and there were technical problems and that the project was indefinitely suspended.”….. this sounds like “PR speak” for the oil companies have bought the patents….     

    • GeoffG

      Nonsense – it was just a flawed concept!

  • Jim Yates

    How fast would this thing be moving when the psi drops to a few hundred?

  • Morganbrody28

    sure itll be cheap to use but im sure it will cost you your am and leg and perhaps your backbone to fix it.

  • Morganbrody28

    plus its ugly

  • Michael Rowlett

    compressed air was a common way to move steam trains in munitions yards… so there is certainly enough power for work if the tank is large enough to hold a sufficient store of pressure.  is it practical for a car – steam might actually be more practical, but it just sounds so last century.  even if it is actually a very reasonable technology.

    • Triumphcub62

      good bye last century; welcome 2012 hot air

  • Lazzarin Patrizia

    MiniCat on google by typing in Italian does not get anything. I had to type on google in English  to find some information.

  • http://www.facebook.com/vegaspartycrew.net Bella Rossi

    I hope for the best:)

    What i do know is there in NO reason we should still be using gas
    i wish the scientists would stand up to the oil companies for the rest of us.

    We are actually having a discussion about this…..


    • Chambersburgpabear

      I also hope for the best.  I live in the United States – so i drive a Hyundai Elantra.
      It is a good car with little effect on the environment.  If you buy an electric car in
      the United States – you’re electricity is probably coming from a coal burning plant.
      So I think it is better to just buy a small gas vehicle.
      I also own Tata Motors stock – because they are the future.  And it is a good way to
      slap the oil companies in the face.

  • BaldBird

    This is a SCAM. I can’t believe people fall for this. Negre is getting rich selling licenses to distribute this thing. Oh well, suckers and their money are soon parted.

  • Alphonse

    J’en veux UN!!!!!

  • Adam

    Compressed air can provide a decent amount of power – it used to (and still can) power all sorts of heavy underground mining equipment. My only doubt is how far you can really go on a couple of 350 litre tanks of compressed air…

    • Mauricio Larios

      This is a city car I guess, so it is perfect !

  • Millsy_666

    i have seen a working compressed air “golf cart” it fills up via a normal factory type air compressor, of corse it’s range isin’t far and it’s not for heavy loads but the theory is solid, like others have said tho i am scepitical about the range and top speed, also if u have ever used any compressed device you should realise the emptier the tank gets the slower the flow.

  • Daniel M

    An electric car with regenerative braking goes 3-4 miles per kwh of energy. At a cheap rate of $0.1/kwh, a $2 charge would mean 20kwh, or 60-80 miles ideal NO LOSSES range. Assuming NO LOSSES for the compressed air car, the range would be ideally 60-80 miles. But the cruel reality is that no energy transformation from one form to another can be done with 100% efficiency. For electric, the battery charge has about 80-85% efficiency (good batteries), and the motor about 85-90%. So the overall efficiency (multiply the individual efficiencies) for electric is about 75% or 45-60 miles range.
    For the air car, I expect even less efficiency due to the thermal energy lost in the compression of the air, let aside the Carnot cycle efficiencies in converting pressure and thermal (from ambient 25 degrees centigrade-high pressure to let say -10  degrees centigrade for exhaust, a total of 35 degrees – about 10 times less than the gas combustion engines). An idealistic educated guess would be about 50%, or 30-40 miles (48-64 km).
    But lets be generous and consider efficiencies close to the electric car, you can count on a 40 miles (64 km) range for a $2 charge. This would be equivalent to about $1 per gallon of gasoline on an average small car (20 MPG).

    Maybe somebody smarter will calculate the real potential energy stored in this tanks (2×340 liters at 300 bar and 23 degrees Celsius).

    • Tjgray

      Hi Dan
      Good to see some solid engineering in this thread..
      You are correct in that the energy efficiency of compressing the air is brought down by the loss of heat to the environment in the process, so about half of the energy provided by the windmill/Donkey/Electric Motor or “Man on bicycle” is lost in the form of heat.. but in a multi stage machine, the thermal efficiency of expanding it again would be excellent, because the gas laws (P1xV1/T1 = P2xV2/T2) mean that the temperature of the end of each stage of expansion would be lower:- If you doubt this, then hold onto the discharge nozzle of a CO2 extinguisher and learn it at “first hand”..
      And this is the “secret” of that engine. The act of holding that exhausted low temperature air in a small sealed buffer space which is then heated by ambient temperature is then to massively raise its pressure all over again – so you could then re-expand it several times. More bangs for each buck.. hence the multi-stage expansion that you see on the prototype engine and its much higher isentropic efficiency.
      The energy from expanding the gas is thus added to the energy “gained” from the environment in warming the exhaust gas at each stage. Energy per second would be equal to the sum of the specific heat value for each kg of compressed air, multiplied by the difference in temperature and the flow rate of air at “full power” (In units of kg/sec). My estimate for temperature at end of each expansion stage would be minus 60C, so you’re gaining about a third as much energy by conduction from the outside air as you are in releasing the potential enery held in the form of pressure, at each subsequent expansion.
      Driving in India, I noticed that the two things most frequently used were the horn and the brakes.. The horn would be air powered. The braking, regenerative – providing power for a normal battery to power wipers and washers and re-heat exhaust air for a heater in the car.
      In India, this would work really well – fully laden, those “tuk tuk’s” have a third of the mass and 50% of the rolling resistence of western cars, so multiply your 60 miles by 1.5 for the more efficient expansion, and then by 2 for the reduced friction and hey-presto – a 300km range.
      Frankly – I think the engines will work well.. but the problems will be infrastructural at garages and distribution points. One dodgy canister of dusty air, and you’d wreck an engine really quickly.
      Tim Gray (London,UK)

      • Nemesis

         Once you allow the air to expand it then takes “energy” to re-compress that air….so you just can’t compress and de-compress over and over unless you are using ANOTHER/ADDITIONAL energy source to re-compress the air. Sorry….but your engineering logic is not sound. Also if this defied the laws of physics and worked efficiently, kookoo conspiracy thinkers aside, the military’s of the U.K. or U.S. or Russia or China, etc…. would be utilizing it as fuel consumption/cost is a huge consideration. No big bad oil company could keep capitalistic and communist countries and their military’s from using it to power everything fro aircraft to ships at sea to ground forces transportation. C’mon……think about it for a few minutes….before hitting the pub.

  • http://profile.yahoo.com/EQNIEJSJFQJUSM4DT5JZZUT5YA John

    how come there is no mention of this on TATA;s web Site….

    • 5cups

      This is not new.Google Mini Cat and you’ll get info. One of the features that shot this idea down before was the idea of riding around on the equivalence of 2 oil drums, pressurized to a level that could level a duplex on rupture that could happen after a 10 km impact , appealled to few.

  • Eric Fowler

    Very dangerous even if it works … the tanks will become rockets if breached in an accident. 

  • Lou Soileau

    All the comments below are typical of the fear of old technology being refined and repackaged for a new time. TATA! please make this available is a US approved shape and package so I can buy one. At $5 per gallon for a poluting fuel like gasoline, I would be happy to do my part to save money and cut my contribution to polution.

    • Srcaipira

      It would be interesting to know what your background is. It’s obviously not related to anything mechanical. This is all compressed air (smoke) and mirrors.
      You’ll pay more for this than gas propulsion and not have anything to show for it.
      By all means, get one for yourself and then give us a report on it 2 years later.

  • Billwfan1985

    How did the price jump from around $8,000.00 up to $20,000.00 so quickly?

  • GeoffG

    I first read about this about 10 years ago. And still it isn’t on the market. Guy de Negre was once a well respected F1 engine designer, but now it looks like he’s become another conman. The efficiency of compressed air engines is something like 10%. They might have a place as forklifts in ultra clean environments, where efficiency is not a prime concern, but for road use – forget it. The YouTube demo showed the vehicle to be slow, noisy and plain ugly. In addition, the idiotic media goons were touting it as “free fuel” because it used air, conveniently ignoring the fact that the air has to be compressed to thousands of psi by another energy source. De Negre sounds like Moeller with his SkyCar – he’s spent so much money (and other people’s) that he’s blinded to the truth.

  • Syed Imtiyaz Desnavi

    Its great, could hardly believed it. Can I reserve one for me?

    Imtiyaz Desnavi

  • Prof. F. H. Alberts

    Wow I can’t believe how many ignorant retards have commented on this post. Compressed air powering a vehicle is oooollld – its called the steam engine…the first engine ever to power trains and the first personal motor vehicles. The new technology that has made compressed air as a fuel feasable is in the engine (the air engine – try googling it) and advances in high pressure storage. Air powered vehicles are already been used in small work vehicles such as fork lifts, golf carts, boats and others. If a cylinder/tank containg highly compressed air is ruptured it does not explode – the air is just released rapidly. The tanks used in new air-powered vehicles are made of hybrid composite materials and will not rupture and will be malleable under high forces and will safely leak/release the air in a worse-case scenario. Technology is advancing exponentially – get used to it (just look at how cell phones have changed in the last 10 years), only greed will slow its progression.

    So please, educate yourself before sticking your foot in your mouth.

    – Prof. F. H. AlbertsHarvard School of Engineering and Applied Sciences

    • GeoffG

      You may argue with Wikipedia, but here is what they state:

      “The overall efficiency of a vehicle using compressed air energy storage, using the above refueling figures, is around 5-7%. For comparison, well to wheel efficiency of a conventional internal-combustion drivetrain is about 14%.”

      Even worse than my estimated 10% (below). Fine if the electricity is free, or extremely cheap, but it isn’t, is it? About the only advantages that I can think of that a compressed air vehicle has, is low maintenance, high reliability (hopefully, but not guaranteed) and zero emissions at the point of use. These are worthy attributes, but may be beaten by high running costs.

    • Tim Gray

      I’m with you on this one, Prof.. Carbon fibre tanks don’t “rupture” – they split, leak and delaminate in a controlled manner, and the ensuing gas is cold – further supressing fire.
      The other point here is that the energy in the compressed air doesn’t have to come from fossil fuel, it can come from a windmill, or a micro-hydro water turbine (Peltham Wheel)or any other “green” electrical source. 
      Yep – I think these multi-stage air engines look like solid engineering and zero emissions at point of use has to be good for Indian ciies – visit Delhi and you’ll soon know why!

      All good things.

      Tim G

    • Nemesis

      Ok…here are some facts and observations. Those of you who hate facts because they always reveal the stupidity of your arguments just skip this response.

      1. An esteemed Harvard Professor would likley not refer to those who comment as “ignorant retards”. That was my first clue this poster was a fake….and a flakey flake at that. I think if anyone here is an ignorant retard it is this imposter who wishes he were something or somebody of relevance. Alas….he is not.

      2. There is no Prof. F.H. Alberts listed on the Harvard website. Even when you look at the entire faculty. There IS a “Frederick H. Abernathy” but I doubt he’d froget his own name and spell it “Alberts”. It’s more likely F.H. Alberts is really just Fat Albert.

      3. quote: “Technology is advancing exponentially – get used to it (just look at how
      cell phones have changed in the last 10 years), only greed will slow
      its progression.” Wrong!!! GREED is the reason that things, like the cell phone, HAVE progressed/changed over the years. It’s greed…or the desire to make money that propels innovation so more money can be made by capitalistic “for profit” individuals and companies. Funny how capitalistic countries provide all the new innovations and inventions while the communist/socialist countries can only keep up by “stealing”/copying those innovations and inventions.

  • Doooiiiit

    Even If you used electricity to refill the tanks that would be 60% more efficient than using fuel. Furthermore, with most electrical companies you can opt for green energy – where you pay a little extra and they will buy clean energy from renewable/green sources and inject that into the grid (you might not directly use that energy but that energy will be substituted into the system).

  • Clemente pretel

    la energia ni se crea ni se deatruye solamente se trasforma,LO HAN OLVIDADO.
    si muy bien aire comprimido,y con que lo hacemos ,sin electricidad,sin gasolina,con, la mano .analicen señores hay que comprimir el aire eso es energia,es gasto.
    O; NO ??????

  • Olcaptk

    This type auto makes a world of sense.  Now…if the US would just not make it so difficult for the Tata to enter the market and actually cause the other automakers to change their addiction to Exxon and the other oil companies, things would be great.  The worry over an explosive air tank is poppycock.  Most folks don’t realize that the vapors from just one gallon of gasoline carry the same explosive capability as 12 lbs. of TNT.  The oil companies will fight this car concept tooth and nail, as oil changes only come every 30K/mi, as there is no combustion.  If this car was allowed to freely be sold in the US, gasoline prices would plummet, and the demand for oil usage would drastically decrease.  Much more electric usage would take place, but this would probably happen with NG power plants or folks would buy a few solar panels and batteries and be charging up their own car.

  • chris

    this technology has been around for a while now.  Oil companies and other special interests including the automoto industry are probably the reason we don’t have this in the US already- Speculation of course.  I’ve been waiting for the MDI for nearly 10 years.  

  • http://www.facebook.com/AnnieNanney Hannah Roberts

    I’ve been waiting for this car to debut in the US for several years…  Where can I buy one?

  • guest

    It’s called greed. Watch the movie Tucker and maybe you will understand vx

  • Alvertte

    If there are better ways than oil developed and used it.Unfortuntely we are in economy driven by greed so whre does it lead us ?

  • LostRoo4

    It is amazing how people can deeply discuss science before they can spell their own language!
    I am impressed and, in my profound ignorance, I prefer to wait until the car is launched, test drive one, check its specifications, price and, if I like it, I will buy one.

  • Haltsr1

    I really don’t think that we will ever see one of these cars in the USA, because our government officials get too much money from kick backs from the oil companies..

  • imu

     wonderful car design but comperssure are use this car, body can vibration in start motion and body can heating so use vigtable oil  after some year vegtable oil cost is high . ithink  not be permisstion for indian goverment. but nice idea….. yar.
    heats of TATA motors.

  • nilrocks

    I’ve been reading all the comments above…..just wanna say, every technology takes its own time. The first full proof technology that challenges oil is Electric power and we all know why still it is out of reach from 99% people….there r many reasons to discuss (infrastructure, gov policies, political games etc.).
    But speaking truth, I am feeling confident about this technology in one sense that, self depedancy.
    Owner can fuel it at home also….and this is the game changer. Here it defeats one hurdle of Gov infrastructure, which must b in place for all the other technologies.
    There might b one obvious Q regarding this is….infrastructure is needed as where to fill Air if it goes out….but TATA is claiming that we can even fill it up on any Petrol/Diesel station through Free Air points… (For the people not from India: All the Oil stations in India have Air filling points installed and they are free)…. So, that means currently Indians can feel happy about it as Petrol/Diesel prices are sky high.

    • GeoffG

      The compressed air needs to be at about 3,500 psi! It’s no use trying to use the “free” air for inflating tyres at filling stations, which probably maxes out at about 100 psi. Air at 3,500 psi requires a very large amount of energy to produce and is energetically very wasteful. Have you thought about where that will come from?

      • Sds

        If you ever went diving you might have noticed that the air on your back is compressed to almost 300 bars. Which is almost 350bars of the Tata car.

        • Nemesis

           GeoffG……give it up……this discussion is filled with morons and greenies and conspiracy freaks who don’t know science and can’t grasp the energy requirements to start, stop and keep in motion a 1-2 thousand pound car/van. Just because something is “feasible” on a tiny scale does not mean it can defy physics on a large scale. Anyway…GeoffG….just quit trying to educate these idiots and wishful thinkers. As far as the scuba tanks some have mentioned ya know how large they are and they are only good for about 3/4 to 1-1/2 hours of just BREATHING! Imagine how long they would last if they had to propel something. Oh well I had enough fun….er time waste here.

          • GeoffG

            Yes, you are absolutely correct. It’s like trying to explain the concept of television to a caveman.

      • Nilrocks

        Yes…you are correct …
        But to implement this will not be too difficult or costly, as machines to fill it up are not too expensive that a small comunity or group of 50 residents can not buy with financial contrubution. Even if Gov tries ….these machines can be fitted and per fillings can be too too too cheap.
        Atleast we can give it a chance to this technology to evolve…

  • Laliiitsharma

    The Indian gov.should ensure to provide all help to TATAS so that the first compressed air car comes to the market.To start with it should wave of all the duties & taxes on it for first few years, so that it becomes an attractive proposition to buy it.It can save valuable foreign exchange.

  • Andrewgoodall

    Awesome! Take that petroeconomy!!

  • Donald

    Also, “refueling” stations can easily be placed. Currently the Nissan Leaf is coordinating their introduction into the US with a supplier, backed with Obama money, to set up electric charging stations. That could be easily be done with the introduction of any air car and probably without Obama money.

    • Milan

      In the end, it doesnt have to be perfect. the Europeans start to hit the 1,80 euro mark for a litre, at the brink that more work cant cope this costs, and under 3 litres/100 km cars will never fall.
      Not the equal perfect but the effortable solution will make it. If the car has a range of 100 km, ok, thats enough for the daily needs to work, supermarket and pick up children. The user has to step back from sone conveniences,simply. Main goal is to come from a to b.

  • BaldBird

    I’m amazed people buy into this crud. Do they think the air compresses itself? They should teach children science in school. 

  • coffee

    the tank is filled with air , you need to refill it , either on board compressor or  generator compressor or  gas station  tyre pump up compressor ,not complicated but it is free , there is no limit  , same can be used in house,factory, car ,bus ,truck,.
    there is a blue printed  plan all ready used in today’s factories of a  electric motor that never stops ?producing 240 volts ac or dc current ,free you just  kick start it and once running it never stops it uses its own power to run but amplified to  power all house .?or car,bike etc , a smaller version can be used to  recharge  air in tank to never  run out of energy ,
    no batteries,no oil, no pollution,tax free so you don’t need to pay MAFIA tax $