Become a fan of Slashdot on Facebook


Forgot your password?
Power Technology Science

Car Powered by Compressed Air 409

gripperzipper writes "CNN reports that a Korean company created a small car powered by compressed air. ENERGINE created its PHEV, or Pneumatic-Hybrid Electric Vehicle, which uses a two-stroke compressed air engine for start, acceleration, and uphill climbs. The car switches to an electric motor when its speed reaches 20-25 km/h (32-40 mi/h). Although major auto manufacturers have invested heavily in gasoline hybrids, it will be interesting to see if a market will open for this type of vehicle." Update: 04/04 17:18 GMT by T : Reader Tapsu spotted the incongruity here, writing "Interesting post, but the speed conversion has gone wrong way: "20-25 km/h (32-40 mi/h)". ... Thus the correct speed range in miles would be something like 12-15 mi/h."
This discussion has been archived. No new comments can be posted.

Car Powered by Compressed Air

Comments Filter:
  • by BobPaul ( 710574 ) * on Monday April 04, 2005 @03:51AM (#12131614) Journal
    I hope it has an external refil port for the compressed air tank. This will be a great way to take advantage of stations that offer "Free Air" (and also, unfortunately, prompt a decrease in the number of stations offering "free air"...)
    • Doesn't matter that actually you can buy many kind of 'air' gases - oxygen and carbon dioxide included, helium too - in many places of the world :)

      Free air is what outside is, go and breathe it while it is... here :)
    • by Anonymous Coward
      On the contrary, the pressure available at a gas station might be as high as 140 psi (if you're lucky), but the diagram in TFA indicates that the high pressure tank is pressurized to around 300 bar, or ~4200 psi. This doesn't seem much of a threat to the station's business model.
    • by Rei ( 128717 ) on Monday April 04, 2005 @04:00AM (#12131657) Homepage
      The compressed air from a gas station could barely provide any stored energy.

      Compressed air has great power density, but awful energy density. I.e., you can unload power incredibly quickly from it, but can't store much at all. Even batteries store far more energy in a given mass. This sounds like a big step in the wrong direction, honestly.
      • by XMyth ( 266414 ) on Monday April 04, 2005 @07:02AM (#12132229) Homepage
        Yea. A friend of mine recently researched using compressed air to run his house (and subsequently creating a solar powered air pump, using a sun-tracking reflective satellite dish) and eventually came to the same conclusion you just said.

        What is interesting about compressed air though, the energy you get out of it is NOT what you have put into it. The energy comes from the ambient temperature of the air. This means that if a compression technique could be found that is efficient enough then you could have a potential self filling energy tank.

        Unfortunately, like you said, the air doesn't have *that* much energy. Still thought that concept was interesting though.
      • by Moderation abuser ( 184013 ) on Monday April 04, 2005 @07:36AM (#12132354)
        Depends on the pressure.

        e.g. []

        The MDI aircar proposes 400 atmospheres. They don't have a production model with tanks to hold that though. Energy density is similar to recent (but not cutting edge) batteries.

        The problem with compressed air is that it is basically still a heat engine whereas electric motors are not. Electric motors are 90%+ efficient and compressed air motors, well, 40% maybe.

        • by pfdietz ( 33112 ) on Monday April 04, 2005 @08:14AM (#12132491)
          Efficiency is not a showstopper. Even a very inefficient 'electric' car still can beat a gasoline engine in marginal cost per mile.

          Where electric cars (including those that store energy in compressed air) have problems is energy density. The compressed air car could do a bit better there if it also had a resistively heated thermal mass to heat the air before expansion. The thermal mass would be recharged from the wallplug at the same time the air tanks are refilled. Low atomic number materials can store a great deal of thermal energy; LiH heated to a vapor pressure of 1 bar, for example, stores several megajoules per kilogram.
        • Imagine a tank that holds compressed air at 400 atmospheres...

          Now imagine that tank being rear-ended by a Hummer H2!!!


          I'd think safety would be a big issue here.
          • If you've ever played paintball or anything else that uses gasses compressed this much, you'd have seen the tanks that will be used.

            Typically, the tanks are some sort of high-tensile metal with 15-20 layers of kevlar wrapped around them. They can be shot with a bullet and not release their contents. So, safety considerations of the tank are less important than a thin metal tank full of a combustible material, such as gasoline.
            • So, safety considerations of the tank are less important than a thin metal tank full of a combustible material, such as gasoline.

              Perhaps, but a thin metal tank of gasoline won't do anything without an outside force acting on it. A pressurized container can explode from fatigue or a flaw in the construction just sitting there. Commercial containers of pressurized materials (Oxygen, propane, whatever) have usage dates on them so this fatigue doesn't cause a rupture. This would probably be an issue with
      • by Tristandh ( 723519 ) on Monday April 04, 2005 @07:39AM (#12132364)
        Well, it only uses compressed air for accelerating and climbing up hills. So it does make sense to use air: short burst of acceleration on air (much power), steady driving on battery (lower power)
    • The high pressure tank in that vehicle is charged to 300bar, or 4350psi.

      That's higher than a SCUBA tank and it requires some heavy duty air compressor rigs to charge it.

      I'd hate to be anywhere around that car in a crash or if it catches fire...
    • Show me a station offering free air at 300 bar. Wanna see one...

      The basic problem with this car is that it will require extra infrastructure. Not terribly expensive, but quite noisy. Compressing air to 300 bar is not a very quiet affair.
    • Conversion problems? (Score:3, Informative)

      by xezas ( 213596 )
      20 km/h = 12.5 mi/h, not 32 mi/h

      25 km/h = 15.625 mi/h, not 40 mi/h

      Guess someone goofed up on the metric system once again :)

  • Still energy (Score:5, Insightful)

    by Zorilla ( 791636 ) on Monday April 04, 2005 @03:53AM (#12131626)
    But does it take more electricity to compress the air into the tank than it does to just run the car on electric power? Sounds like just another degree of separation from energy we'll be getting from oil, anyway.
    • by FluffyPanda ( 821763 ) on Monday April 04, 2005 @03:56AM (#12131643)
      Not in china, there you can pay 20 small children and a man with a whip to squeeze balloons all day for less than the cost of a sack of coal.
    • Re:Still energy (Score:5, Interesting)

      by homer_ca ( 144738 ) on Monday April 04, 2005 @04:11AM (#12131699)
      Yes, but it might be cheaper than a pure electric car because they they can get away with a less powerful motor and power controller. The motor charges up the air tank when the car is idling or braking. Then the compressed air is used for short bursts of extra power when needed like accelerating or climbing hills. Otherwise it's just like a battery electric car with a heavy, expensive battery pack.
      • by TapeCutter ( 624760 ) on Monday April 04, 2005 @05:07AM (#12131883) Journal
        When an electric car is standing still the motor does not draw power. Converting energy expended while braking into compressed air has been done on normal trucks and busses for years. Converting the batteries stored energy into compressed air is gaurenteed to loose some of the energy in the conversion and therefore will not last as long. Every time you convert energy you loose some so it makes sense to save the wasted braking energy. There is nothing really "new" about this car except they have taken a common fuel saving technology used on heavy transport fleets and applied it to an electric car. If it works for an electric car it would work for a normal car but with electric cars you can't just get a bigger fuel tank.
    • Re:Still energy (Score:2, Interesting)

      by qewl ( 671495 )
      My question is why does the engine still look like a gasoline engine with compression chambers, pistons, cylinders, and the works? Is that just like some clipart, or am I completely missing something?
      • Re:Still energy (Score:2, Informative)

        by qewl ( 671495 )
        Okay, the compressed air tank powers the engine, which works like a hydrogen powered engine which requires compression. The electric motor is relatively small and only used in certain low power requiring situations.
    • Re:Still energy (Score:4, Insightful)

      by Anonymous Coward on Monday April 04, 2005 @04:50AM (#12131827)
      Why does this type of comment end up in every alternative energy thread, and get modded up as 'Insightful'?

      Centralizing the energy generation can take advantage of (a) economies of scale for better efficiency and (b) a varied portfolio of generating sources like hydro. For electric or fuel cell cars, this allows you to take advantage of the network effect of everyone already having electric wires as a means of transporting energy. I agree, compressed air is a bit silly b/c of its poor energy storage, but to knock it because of off-site production is simply wrong.

      In this era of high oil prices, why are people so quick to complain about any alternative fuel?
  • by Capt'n Hector ( 650760 ) on Monday April 04, 2005 @03:53AM (#12131629)
    ...this thing is gunna be loud.
  • New? (Score:5, Informative)

    by Cyno01 ( 573917 ) <> on Monday April 04, 2005 @03:54AM (#12131633) Homepage
    Havn't they had something like this comercialy avalible in France for a while IIRC? Its has a ridiculously strong carbon fiber airtank that's presurised at home by a compressor using off the grid electricity. Its basically a small comuter car, but it has decent range and speed.
    • IIRC Top Gear reported on that car once. It was noisy, slow and had short range.
    • Havn't they had something like this comercialy avalible in France for a while IIRC? Its has a ridiculously strong carbon fiber airtank that's presurised at home by a compressor using off the grid electricity. Its basically a small comuter car, but it has decent range and speed.

      No, this is a hybrid that charges itself. RTFM, etc.

      At some point I read that Ford was considering a hybrid pneumatic system for their heavy trucks. Braking would charge a cylinder which would later be used to drive acceleration, c
    • Re:New? (Score:3, Informative)

      by Anonymous Coward
      Do you mean the MDI air car [] ?
    • Re:New? (Score:5, Informative)

      by imr ( 106517 ) on Monday April 04, 2005 @06:02AM (#12132010)
      This comment talks about him and his car in fact:
      MDI car made by Guy Negre []
      No surprise it's italian, iirc he was working in Nice near the itlian border and the car lobby in france is too strong.
    • Re:New? (Score:5, Informative)

      by ksp ( 203038 ) on Monday April 04, 2005 @06:08AM (#12132030) Homepage
      One really cool thing (IMHO) about the French/Italian "air car" is the electrical system:
      Technical details []
      Using a radio transmission system, each electrical component receives signals with a microcontroller. Thus only one cable is needed for the whole car. So, instead of wiring each component (headlights, dashboard lights, lights inside the car, etc), one cable connects all electrical parts in the car. The most obvious advantages are the ease of installation and repair and the removal of the approximately 22 kg of wires no longer necessary. Whats more, the entire system becomes an anti-theft alarm as soon as the key is removed from the car.
  • by Dancin_Santa ( 265275 ) <> on Monday April 04, 2005 @03:54AM (#12131634) Journal
    This website provides the perfect fuel for this car.

    But I'm probably just repeating the first several dozen comments...
  • Wrong conversion (Score:5, Insightful)

    by evn ( 686927 ) on Monday April 04, 2005 @03:57AM (#12131646)

    when its speed reaches 20-25 km/h (32-40 mi/h).

    The car swtiches to electric when it reaches 25 km/hr according to the Energine website which is actually more like 15 miles per hour [].

  • by nacturation ( 646836 ) <nacturation@gm[ ].com ['ail' in gap]> on Monday April 04, 2005 @03:58AM (#12131648) Journal
    From the manual:

    "Should you find yourself approaching the state of being in an accident, please yourself to duck so as to avoid looking at your previously attached body before the shrapnel took off your head." (Safety tips, Appendix A, P.232)
  • Nothing But Hot Air (Score:5, Interesting)

    by pressesc ( 873084 ) on Monday April 04, 2005 @03:58AM (#12131649) Homepage
    Here [] is another take on the same story, but with a little bit more science. The bottom line is there's no such thing as free energy... or lunch. You don't get owt for nowt. CNN needs to learn science
  • by SSChicken ( 872688 ) on Monday April 04, 2005 @04:00AM (#12131660)
    First off, like someone said, that the energy it takes to compress the air can be inefficient and still polute the air if the energy to compress came from fossil fuels/coal. Secondly, while it is an "Engineering Marvel" to drive up a hill using compressed air, it's very dangerous. For any of you who have ever worked on high pressure AC systems, any pressure higher than 500psi or so can be deadly if anything at all goes wrong. It's not like a battery, where a little acid can spill if it's broken. Nor is it like gasoline, cars are built to prevent explosions, and the worst case scenario is lots of fire. If you puncture a high pressure tank or lines, you have a disaster on your hands; theres no avoiding it. Besides, the entire problem with a gas induction engine is that they are horribly inefficient anyways unless they are running at their optimal RPM.
  • by Ray Radlein ( 711289 ) on Monday April 04, 2005 @04:02AM (#12131664) Homepage
    The car switches to an electric motor when its speed reaches 20-25 km/h (32-40 mi/h).

    Now we know why this car keeps crashing into Mars.
  • Is high torque. This means that it can take the work that electrical engines don't like, low speed high torque work. A air engine give a damn about the speed it is running at...
  • This technology will never go anywhere. I worked on a liquid nitrogen powered car at UNT, which is basically the same as this thing except the nitrogen can be stored more densely when it liquifies, at moderate pressures. Expanding the nitrogen requires a rack of heat exchangers on the roof. However, since all the energy is stored mechanically rather than chemically, the Joules/Kg is about 40x lower than than of gasoline. It's even less dense than batteries. About the only market for this technology wou
  • From The FA: "The air is compressed using a small motor, powered by a 48-volt battery, which powers both the air compressor and the electric motor." and "The system eliminates the need for fuel,..."

    Oh yea, this makes sense, because we all know you get more energy by first compressing air with a battery and then using it to power a motor than you would by powering the motor with the batter directly. Right. And it's not dangerous at all haveing a high pressure air tank sitting in a hot car that sits in the

  • Man, this gives a new meaning to the phrase "passing gas" ;-)
  • by EdZ ( 755139 ) on Monday April 04, 2005 @04:09AM (#12131696)
    It switches to electric at 25, what happens at 80?
  • If you can find a good way to store the compressed gas this is an excellent idea. Expansion engines like this air engine (and steam engines) produce maximum torque at zero RPM, which is perfect for pulling away from a standstill without the complexity of a clutch and a gearbox, whereas internal combustion engines (and turbines) need to be turning quite a bit before they produce and torque.
  • The tank contains 40 liters of oxygen at 300 bar. According to the specs, it'll run 130~150 times for 3~4 sec. Best case that's 600 s = 10 minutes. Which is pretty awful for 60 kg of added weight.
  • It takes a LOT of energy to compress air.
    And an air tank can't possibly hold enough air to power a compressed air motor for more than a few seconds.

    MAYBE, if the air were liquefied, it might be feasible but still, the energy consumbed to liquefy the air would negate any possible savings that the vehicle would hope to achieve.

    Sorry, I don't buy it..
    • by dbIII ( 701233 )

      It takes a LOT of energy to compress air.

      It's not about the energy, it's about moving the pollution. As for the other points, we are talking about tanks bigger than soda bulb, so you can run motors - also the air may well be partially liquified - just like the CO2 bottles used in pubs to make beer foamy have some liquid in them.

      I've seen a 50kg piston moved a fair way with a small portion of a bottle of compressed helium just like you would use to blow up balloons - it was the first stage of a shock tunne

  • The air engine is only used to accellerate the car from a standstill, and from TFA:
    "EV usually needs 30(A) of electrical current on driving and it consumpts 3~4 times more by starting or go up a hill."
    Getting past 'All your base', they're doing all this to get past the high initial power requirements of a pure electric vehicle. IDK if the weight and complexity penalty is worth it, though.
  • French (Score:3, Informative)

    by deafff ( 604798 ) on Monday April 04, 2005 @04:16AM (#12131718)
    There are french cars that run completely on compressed air around for years. []

    slashdot, wake the fsck up.
  • by ihavnoid ( 749312 ) on Monday April 04, 2005 @04:21AM (#12131738)
    This compressed air engine isn't directly related to a environment-friendly fuel. The fuel of the car itself isn't compressed air - it's electricity, the battery. Electric cars, or hybrid cars, have the problem that they can't obtain high torque instantly. However, compressed air does give high torque. The idea is to store compressed air in a tank, and use it as a booster when high torque is needed. The air will be compressed later on with another compressor.

    Now, combine the compressed air engine with an hybrid car. You get an hybrid car with instant high torque when needed.
  • Old News (Score:3, Interesting)

    by pklong ( 323451 ) on Monday April 04, 2005 @04:22AM (#12131740) Homepage Journal
    This is old news. The Frenchies have been there and done it [].

    It's even been tried in African [] (same company).

    The company's own website seems to have gone. I would be suprised if this wasn't because the company has also gone out of business.

    Why does it only get on Slashdot when it's an American company?
  • We had great news of this kind in Europe exaclty one year ago, but at the end card didn't show up in our roads. News in Italian: []
    Site of the company in English: []
  • another (small and under the radar) company also has a working 100% air powered car that can either be refilled by plugging it in, or with a high pressure external compressor that could be found at gas stations:

    see []
  • by TigerX ( 859482 ) on Monday April 04, 2005 @04:39AM (#12131796) Homepage
    The author of the post got the units backwards...

    The line should read:

    The car switches to an electric motor when its speed reaches 20-25 mi/h (32-40 km/h).

  • by panurge ( 573432 ) on Monday April 04, 2005 @04:40AM (#12131798)
    If the Toshiba announcement about a better traction battery is correct. Electric motors can have practically an ideal torque/rpm curve, but the current demands for high starting torque are a problem. The holy grail is a battery which has effectively an enormous surface to the electrodes without corresponding fragility, and so can be quickly recharged and discharged. (Traction batteries currently have a long service life but relatively slow charge and discharge. Starter batteries have a fast discharge for starting but are fragile and do not deep discharge well). Such a battery would completely supersede the inefficient compress air/decompress air cycle. So whichever compressed air tools division of this Korean manufacturer came up with this job preservation scheme - forget it and retrain as battery engineers.
  • by zijus ( 754409 ) on Monday April 04, 2005 @04:56AM (#12131844)

    I can spot posts on the net at least from year 2000 about Mexico city running taxis and public buses on compressed air.

    Am I missing the point ?


  • Already Been Done! (Score:5, Insightful)

    by phobos13013 ( 813040 ) on Monday April 04, 2005 @04:57AM (#12131850)
    A completely compressed air vehicle has been made before and is a production model called the air car by a company MDI [] in italy. They have produced models for street use, you can see a video of it here [].
  • by joestar ( 225875 ) on Monday April 04, 2005 @06:47AM (#12132173) Homepage
    It's the MDI Air Cars [] "The world's cleanest cars", developed by Guy Negre.

    It doesn't use any fuel at all, only compressed air, and the features are good:

    Weight: 750 kg
    Maximum speed: 110 kmh
    Mileage: 200 - 300 km
    Maximum load: 500 Kg
    Recharging time: 4 hours (Mains connector)
    Recharging time: 3 minutes (Air station)
  • The Explosion Factor (Score:5, Informative)

    by beej ( 82035 ) on Monday April 04, 2005 @07:06AM (#12132247) Homepage Journal
    Someone mentioned the problems of having a (scuba) tank of compressed air sitting in the hot sun...yes, it can be a problem, obviously, if the air heats and expands above the pressure rating of the tank. I am assuming they thought of this and would make the tank adequately strong. (With scuba, the shop fills your tank to the limit, and then the hot sun gives you another 1000 psi and your burst disc goes. This is less than the five-thirds working pressure they push your tank to when they hydro [] it--I'm sure the tanks on the cars would have some kind of overpressure relief like a burst disc.)

    The French air car article [] points out, "In the case of an accident with air tank breakage, there would be no explosion or shattering because the tanks are not metallic but made of glass fibre. The tanks would crack longitudinally, and the air would escape, causing a strong buzzing sound with no dangerous factor."


    It's great to know that it's a carbon fiber tank so it won't turn into a screaming cloud of schrapnel [], but isn't there another issue at work here?

    Now, I don't know exactly where on that tiny car the tank is, but I'd assume it's under the seat someplace.

    The volume of that car is what...two cubic meters? What happens when you instantly put 90 cubic meters of air inside it? (Or under it?)

    Have a look at this rather larger car [] for an example. Look, ma! No fragmentation thanks to a steel tank, but all that air introduced to an enclosed space jiffy-pops a car like a cheap paper cup.

    I'm more than willing to admit there's more to carbon-fiber tanks than I know. Maybe there's some property that prevents them from releasing all that energy in less than, say, 10 seconds, no matter how badly crushed. But I'm officially skeptical.

    They say there's enough energy in a scuba tank to lift a hook-and-ladder fire truck 20 meters in the air. That's exactly the sort of energy I don't want released near me in a short timeframe. Gasoline is good in comparison because it doesn't tend to do this when the tank is ruptured.

    Then again, a compressed air tank explosion might be just what I need to get ahead in today's Bay Area traffic. Up yours, Fastrak!
    • > Now, I don't know exactly where on that tiny car the tank is, but I'd assume it's under the seat someplace.

      In the prototypes, it was apparently under the chassis [] (look at the third picture). I suppose the separation would prevent the air from entering the passengers' area.

      > The volume of that car is what...two cubic meters? What happens when you instantly put 90 cubic meters of air inside it? (Or under it?)

      Maybe the car will be lifted up a bit, but remember the tank is supposed to crack and l

  • by bjb ( 3050 ) * on Monday April 04, 2005 @08:31AM (#12132559) Homepage Journal
    The engines of large trucks (think 18 wheelers or similar sized cabs) start with compressed air, and have been for years. You know those air guns that service stations use to tighten/loosen lug nuts on car wheels? Same idea, just use that instead of an electric starter. Next time you're standing near a truck when the driver starts the engine, you'll hear it plain as day.

Federal grants are offered for... research into the recreation potential of interplanetary space travel for the culturally disadvantaged.