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Car that runs on air, from the makers of the world's cheapest car
- illume 18y agooh wow. A pretty cool idea. I wonder how the compressed air is generated. I know that there are some < $100 compressed air generators that run off many other types of power(electricity, petrol etc). I wonder how energy efficient it is in terms of power. I mean, the energy use has just moved from the car to the compressed air generation plants. It seems they have optimized the car for use in urban areas by making it as lightweight as possible. I wonder if it would pass safety tests in other countries -- with the car being held together with glue, and relying on wireless technology (zigbee maybe)? Great ideas... it seems to have used a whole bunch of new technologies.
- prakash 18y agoMore info here: http://www.theaircar.com/acf/air-cars/energy-storage.html http://www.theaircar.com/acf/air-cars/energy-storage.html With all the hype around the Prius, Tesla, etc, I wonder how we never heard of this till now.
- Mapou 18y agoIt has been in the news for at least 10 years, IIRC. There is a Yahoo group that has been discussing it for the last seven years. There was even talk of a bunch of air taxis being built for Mexico city years ago. For some reason, it never attracted serious capital or interest from the big auto makers until Tata came along. We'll have to wait and see. With the price of gas going through the roof, I figure it has a much better chance now than it ever had. One nice thing about it is that it uses regenerative braking. http://autos.groups.yahoo.com/group/mdiaircar/ http://autos.groups.yahoo.com/group/mdiaircar/
- DaniFong 18y agoIt's exciting that they're announcing this. I had actually started specifically working on supporting technologies for this (off-grid sustainable refueling strategies) about a month ago. If anyone is interested, email me for details.
- josefresco 18y agoAnyone who follows auto news knows this is old ... news. Autoblog.com is a good start for the uninitiated.
- vaksel 18y agoisn't compressed air pretty dangerous? i.e. if you end up in an accident
- nirmal 18y agoA lot of people in India drive cars that run off of compressed natural gas.
- mikkom 18y agoIt's totally different, the compression there is just for more effective storage, the power still comes from the gas itself. In compressed air however it's the compression that contains the power to move the car. Drive an accident and the same power that moves your car will release its power with quite an unpleasant speed.
- noonespecial 18y agoFew things in the common life of people are as dangerous as 25 gallons of unleaded. I'd much rather face any compressed air explosion than be soaked in burning gas.
- misterbwong 18y agoI don't quite buy this argument. Gas is far less volatile than people think. In the event of an accident, I would much rather face a tank of gasoline, which most likely wouldn't explode at all, than a tank of compressed air. In the middle of the fire, however, I'm not so sure.
- bprater 18y agoGas vapors are dangerous. Without the air, you can drop a lit match in a gas tank, without a 'big boom'. However, in an accident, you'd want to pick the compressed air tank. The tanks are very strong. Gas tanks in cars are built with very flimsy steel. Industries like welding has been using high-pressure tanks for decades, and bottles rarely fail.
- noonespecial 18y agoNeat. This also opens the door for more energy dense and pressure stable compressed gas fuels like nitrogen and CO2.
- ars 18y agoI'm sorry, but that sentence doesn't make any sense. What is pressure stable? And changing the type of gas has almost zero affect on how much energy you can store in it by compressing it.
- noonespecial 18y agoSorry, its a stupid paintball reference. It probably is meaningless. What its supposed to mean is that as a chemical pressurized (to the point of liquification) boils and creates the pressure in the tank, this pressure remains relatively stable as long as there is some liquid left to boil. So most paintball markers use CO2 because you need a simple regulator to get an even pressure for most of the tank. Some markers use plain air pressure, they require more complicated regulators because the pressure changes dramatically during the entire use of the tank. So the dumb jocks say that the CO2 tanks are "pressure stable", I suppose because pressure in the tank is constant around 850psi so long as there is any liquid CO2 in the tank.[1] I made this comment because this to me seems like a desirable property for a fuel gas in a compressed gas vehicle to possess. I will attempt to be more succinct in the future. [1] And since we are nitpicking, I am in fact aware that that this figure of 850 is variable based on the temperature of the tank.
- ars 18y agoAh! That makes a lot more sense. The only trouble with using a gas like co2 that liquefies easily is that once you reach that point (850psi) you pretty much can't go any farther. And they are running this thing at a much higher pressure than that - about 4500. I'm sure there are gases that would liquefy at this pressure, but none that you would want to release into the atmosphere.
- ars 18y agoI'm sorry but I don't believe them that it can run for 300km in between refuels. Compressed air is just not a very dense fuel. Enough fuel to power a car for that long would be a tank about 1/3 the size of the car. (My calculation: gasoline stores about 3000 times as much energy as compressed air per volume. But a gasoline engine is also only 10% efficient, an air engine would be much more efficient. Assuming 100% efficient, then gasoline stores 300 times as much. I can go about 300km using 11 or so gallons of gas. Lets assume a lighter car, so 5 gallons per 300km * 300 = 1500 gallons of air, which is about 5.5 cubic meters. So you'd need a box 1.75 meters on each side. Which is about 1/3 of a car.) Obviously if they can store the air at a higher density then the box can be smaller, but if they did that it would also have to be stronger and thus heavier. (Edit: they are running at about 1/3 more pressure than my numbers assumed.) And now comes the bigger problem: you waste a tremendous amount of energy by heating the air when you compress it. And then you let the air cool, and lose again, because as it expands it gets _really_ cold, and won't expand as much. On the plus side running the A/C will be free. But forget about heat in the winter. Using higher compression makes this much worse. All in all, I simply don't think this will work for that distance. Maybe as a 30km car it would work fine (and there's a large market for that), but not 300km. And the heating/cooling losses are really going to hurt efficiency. And as an aside using vegetable oil is a bad idea. Unless you can seal it away from air (doubtful) it will oxidize and won't be oil anymore. Now please tell me if I made any mistakes in my calculations.
- DaniFong 18y agoYou've made a few small mistakes, but they're non-obvious. One big thing is that your current vehicle doesn't push the technical mileage limits as far as the Air Car does. You've assumed the car is the same weight. Cars can be made much lighter than those currently on the market today. You can get well below 1000 pounds. For example, one design prototype is the Volkswagen 1-liter car, which gets 282 mpg. (http://en.wikipedia.org/wiki/Volkswagen_1-litre_car http://en.wikipedia.org/wiki/Volkswagen_1-litre_car). This design uses a variety of techniques to get the mileage up, and does so quite wonderfully. With an Air Car it's even easier: you can even do it in a production, mass market system. You need not have a transmission, or an electrical system, or an air conditioning system, so you can get a very good car, a production car, for under 1000 pounds. Also, unlike gasoline engines, it's a comparatively simple matter to have breaks which recover power. Power recovering breaks become simply a system for compressing and releasing a piston: a fairly mature technology actually. So breaking is not as much of an issue, and the energy you'd lose for it can be recovered at about the 70% efficiency level. Also, compressed air, at 300 bar (4500 psi) stores approximately 16 kwh per 300 liters, (via wikipedia http://en.wikipedia.org/wiki/Air_vehicle#Storage_Tanks http://en.wikipedia.org/wiki/Air_vehicle#Storage_Tanks), giving an energy density of 0.0056 of gas (in liters). In other words, gasoline takes 176 times less space, not 3000 times, as you guessed. And given modern tanks, the air is lighter than it is large (compared to gas), though weight is a property of the tank, and does not scale linearly. I haven't factored the efficiency of gas versus air engines into this calculation, as both technologies are varied and evolving. When these factors combine, you can get a much, much more efficient vehicle than ordinary. Getting around 80 km is a no-brainer, and 300 km is well within the realm of possibility. You might go up to 1000km before you start to hit fundamental limits. To address some of your other concerns. The temperature regulation of the compressed air tank is not as much of an issue as you think. There are two temperature regulation problems. The first is heating the tank as you compress it. This is not a fundamental problem, but it's actually a technical detail that I think I've solved, and I want to develop it for my startup. You'll just have to trust me that there's a way to heat this cost effectively. The second direction is when the air is expanding. While the expanding air leaving the tank is quite cold, the tank itself doesn't expand very fast, and air simply doesn't have much heat capacity. Oil and water have a far greater heat capacity, and so running a radiator in a gasoline car is actually a much more significant problem. Also, the oil they use is actually a vegetable oil derivative. They use a combination anti-oxidant and mineral (anti-corrosion) additive (such as http://www.hexion.com/products/technicaldatasheet.aspx?id=3986 http://www.hexion.com/products/technicaldatasheet.aspx?id=39... though I don't know the exact product). Additionally, there are wonderful, wonderful ways in which to improve the energy economy of these vehicles as compared to gasoline (or any other comparable vehicle, including electric). Email me, if you might be interested, since I am working on them, and actually looking for more mechanical engineering and organizational talent, or funding, or mentorship.
- KirinDave 18y agoBurning seawater, water "catalysts", cold fusion, and now nothing but compressed air. Please take this story with healthy skepticism. Until we see it in mass production, it's more likely than not that this story is not what it seems.
- Mapou 18y agoThe MDI Air Car is not a hoax. It actually exists and runs. Tata announced months ago that it would begin to manufacture a limited quantity in India. I guess they want to do a trial run to see how it goes and how it stands to wear and tear. The problem is that, if something goes wrong with the drive train, you can't just take it to the mechanic around the corner. Initially, you will be forced to operate it within a relatively short distance from the dealer.
- DaniFong 18y agoThe difference between burning seawater, water catalysts, cold fusion, and this, is that this is based on science and technologies that have basically been known for more than a hundred years, and many of the technologies used have already been quite solidly demonstrated. They simply hadn't been put together.
- timcederman 18y agoCompressed air engines are fairly common for both cars and other purposes. I wouldn't call it bunk science - it's certainly nowhere near as bad as the 'runs on seawater' cars. http://en.wikipedia.org/wiki/Compressed_air_vehicle http://en.wikipedia.org/wiki/Compressed_air_vehicle
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- gaius 18y agoIt doesn't "run on air". It runs on some traditional power source and stores its energy in the form of compressed air.
- s3graham 18y ago(OT: domain extraction doesn't seem to be working with "trak.in")