What do you think?

See video at: http://got2begreen.com/car-that-runs-200-miles-on-compressed-air/



By Matt Sullivan
Published in the June 2007 issue.

India’s largest automaker is set to start producing the world’s first commercial air-powered vehicle. The Air Car, developed by ex-Formula One engineer Guy Nègre for Luxembourg-based MDI, uses compressed air, as opposed to the gas-and-oxygen explosions of internal-combustion models, to push its engine’s pistons. Some 6000 zero-emissions Air Cars are scheduled to hit Indian streets in August of 2008.

Barring any last-minute design changes on the way to production, the Air Car should be surprisingly practical. The $12,700 CityCAT, one of a handful of planned Air Car models, can hit 68 mph and has a range of 125 miles. It will take only a few minutes for the CityCAT to refuel at gas stations equipped with custom air compressor units; MDI says it should cost around $2 to fill the car’s carbon-fiber tanks with 340 liters of air at 4350 psi. Drivers also will be able to plug into the electrical grid and use the car’s built-in compressor to refill the tanks in about 4 hours.

Of course, the Air Car will likely never hit American shores, especially considering its all-glue construction. But that doesn’t mean the major automakers can write it off as a bizarre Indian experiment — MDI has signed deals to bring its design to 12 more countries, including Germany, Israel and South Africa.

Source and much more on topic: http://www.popularmechanics.com/automotive/new_cars/4217016.html

The version they are planning to release in the US in 2010 has a multi-fuel air compressor which holds eight gallons of fuel. When the air tank's pressure runs down it kicks in to recharge the tank. One gallon of gas or diesel will compress enough air to go just over 100 miles. So it will tout 100+ miles to the gallon. It can also be charged up at home with the electric compressor that takes 4 hours or filling stations with a compressor will be able to charge the tank for those not wanting to use gas.

Hope they hurry. I was kinda dreaming of getting two this year. I need it yesterday. LOL

I heard also something about the possibility that they will install a generator in the car so it can continually recharge the tank. But I suppose that is hoping for too much!

All glue? Wonder what happens during the monsoon season?

Here's some more info on the air-car:

The Air Car is the wider name for a number of models planned for production by MDI, including a 3-seat MiniCat due for 2008 and a 5-seat CityCat, among others. Their engines will either be dedicated compressed air engines—which release compressed air to activate the pistons—or dual fuel engines, using both compressed air and conventional gasoline. Either way, it’s hard to argue with compressed air as a clean, abundant, and inexpensive fuel source.


What We Like

• The price. Depending on the model, these will retail for about $12,500 up to $16,000

• The performance. The MiniCat, running only on a compressed air engine, has a top speed of 68 mph and a range of as many as 120 miles.

• The recharge. Overnight at home, it will require about 4 hours. At a proposed recharging station, as a few as 4 minutes

• The oil needs. A liter of vegetable oil can last the vehicle about 31,000 miles.

• The emissions. At the tailpipe, emissions are zero. However, air compression—whether done at a station or at home—requires electricity, which is typically generated using fossil fuels.


What We Don’t Like

• The construction. These all-fiberglass cars are glued together, meaning they have little hope of finding their way to America, where additional sales could mean a huge boost to alternative fuel vehicles.

• The design. This may seem like nit-picking or like asking too much, but the proposed model designs bear a lot in common with the ugly functionality of Neighborhood Electric Vehicles.

I have an air compressor with a small tank in which the compressed air is stored at up to 125 psi. It will run my air wrench for a couple of minutes before the compressor starts. If the power is off my wrench very soon becomes useless. The small storage tank is quite heavy for it's size in order to be safe at 125 psi.

In short... someone is having fun pulling your leg my friend...better you stay with theology! mel

Do the math! A tiny 50 cc engine at 5000 RPM would use how many litres of air in an hour? How big a tank would be required to store that many litres of comressed air? And performance would drop at a flat rate from max pressure down to zero.

mel

It is no joke. Here is the article from Popular Mechanics.
Air-Powered Car Coming to U.S. in 2009 to 2010 at Sub-$18,000, Could Hit 1000-Mile Range



Couple of things. If it takes four hours to compress the air in the tank with 110 volt the pressure is going to be well above 125 psi. Secondly, there is some kind of a heat chamber the makes the air expand before going into the engine. These guys are thinking outside the box.

The "glue" is probably a type of epoxy. As long as it can pass the safety tests it is undergoing it shouldn't be an issue.

Thank you, Shane. My reason for posting it here was to bring out these very kinds of discussions and points.

Even if it does not prove to be "the solution," it seems to me to be a good beginning contribution to the effort of finding solutions.

Consider a 10 cfm compressor running steady for 4 hours ..2400 cubic feet. How big is that tank and what does it weigh? Do the math!

mel

(for those who missed it in the original article)

It's definitely an interesting technology. Like hydrogen, it's only an energy transfer tool, not an energy production tool. But within that it's interesting - and compressed air is lighter than the batteries in an electric vehicle.

However if the electricity is being generated by a clean source, this is a good solution.

How much will storage tanks weigh that will hold a pressure of 4350 psi? How much heat (wasted energy) is generated in a 4350 psi compression and where will you find all those compressors capable of attaining that pressure? Not in any old garage or handymans basement. Must be uncomfortable to hold your tongue in your cheek so long....lol mel

Some sort of heavy duty screw compressor with a generous reduction chamber...

About a 45:1 ratio - it could be done.

It could be done could it? And the heavy duty fittings and hoses to handle the pressure? And is that all included in the cost of the vehicle? So if you were to buy said vehicle you would also need all that other expensive high pressure equipment that does not now exist. And make sure wherever you go someone will be able to recharge your tank. Did you notice the big grin on the face of the guy in the video? How about testing and licencing those extremely high pressures?

Have fun!!

mel

The high pressure equipment already exists. It is used for power storage by wind turbines and a few power plants in Germany and here in the US.

I anticipate that they would regulate the pressure down right out of the tank, like oxygen or nitrogen tanks. We have several nitrogen tanks that we use to blanket moisture sensitive drums. They come at about 2500 psi, I believe.

I'd have to know more about the air car. I understand your questions Melvin, and we don't know all the specs yet. It's Interesting.


oG

If one compressed air enough it becomes liquid and air is 70% nitrogen so that gives us an idea of what is going on. There is also an Australian car company working on a rotary air motor but it is not as advanced as MDI's.

Yes I have used many "bottles" of oxygen and acetelene etc. and I know what those containers weigh. A few cubic feet of gas at around 2500 psi comes in a very strong container which is relatively very heavy. If there are new materials which are really strong enough and light enough to make the air car practical why are we not using them in the bottled gas industry and saving millions in freight costs?

mel

The tank is made out of carbonate and is made to split during an accident thus allowing the air to escape safely. I haven't read how fragile the tanks are but I would imagine the steel tanks compressed gas is stored in is not nearly as fragile.

At those pressures any air escape would basically be an explosion and would turn the car briefly into a rocket...

Time to bust out the calculator, methinks...

Hmm. Since normal atmospheric pressure is about 15 psi, this is 290 atmospheres of pressure, which is pretty extreme. And if that 340 L of air was measured at normal pressure, then the tank would only be about 1.17 L in size once the air was compressed.

That seems pretty tiny, so let's try it the other way around (which makes more sense in terms of the energy to run a car: assume the tank itself is 340 litres. That's pretty big - about one and a half 44 gallon drums.

But if that's the case you'd have the equivalent of 98,600 L of air at normal pressures compressed into the tanks. That's about 4,400 mol of gas. If we treat air as being all nitrogen (which is fairly close), that's 4,400 x 14 x 2 = 123,250 grams = 123 kg of air, which is not too bad, although it's a lot more mass of fuel to lug around when full than a tank of petrol.

{to be continued}

Have to admit, I'd only read the thread, not watched the video. The video showed the size of the tanks, and the 340 L tank size seems about right. But the video was also filled with extremely bad science (perpetual motion?) and plain nonsense (free fillups).

The concept itself, separate from its promotion by people who don't understand the science and technology, is a very intriguing one... but it's still only an energy transfer technology, and the original energy has to come from somewhere. As Shane pointed out, the possibility of coupling this technology with clean energy generation is also there, but I suspect technologies that provide clean energy directly in cars might have more potential... or hydrogen solutions. After all, no matter what we say about the strength of the tanks, that much pressure is basically an explosion waiting to happen... and as Mel has pointed out, most of our current solutions for solving that problem are made of large masses of metal. So really, the key technology here might be, not the engine, but the 'fuel' tanks.

Right on Bravus!

Let's do some rough calculations!

A 1 litre engine running @ 2000 rpm (2 cycle basis)@ 200 psi would use 2000 litres per minute. Your 340 litre tank reduced to 200 psi would give you around 7000 litres. Have I made a mistake here somewhere Bravus? What does your calculator say?That would give you less than 4 minutes run time. mel

I think that's correct, but why reduce the tank pressure to 200 psi? Their claim is 4350 psi in the tanks, presumably reduced to 200 at the engine. If my calculations are correct the roughly 99,000 litres would give about 50 minutes run time at 2000 litres/minute.

(erm, that's short of 200 miles, unless it is doing 240 mph - at 2000 rpm!)

I meant to show that 200 psi at the engine only gives you around 7000 litres from the 340 litre tank at 4400 psi. (4400 divided by 200 times 340)

Whether 200 psi at the engine is enough I have no idea. I presume the engine would actually be a low speed large bore long stroke configuration similar to steam power but the usage would be the same.

I spent an hour googling air car actually. mel

Ah, OK, I get you know. I was calculating it back to room pressure, but of course you're right that the input pressure to the engine needs to be higher since that does the work.

This discussion, and particularly the video that started it, has made me realise one thing: I don't think there's anywhere in Australian junior high science that we discuss thermodynamics and state that perpetual motion machines are impossible - but we definitely need to start doing so. That will help innoculate people to snake oil as we move to alternative forms of energy.

Con men always give you a little something for a bigger something in return. Anyone remember the rainmaker?

Since Popular Mechanics and NBC's Today Show have bought into the air car as legitimate, are you guys trying to say they are in on the scam?

OK, I printed off the spec sheet on it. The "minivan" model has an urban range of 37 miles. That means it is running on pure air. The compact has an urban range of 62 miles. Because the car is a sort of hybrid, having a fuel-driven air compressor, the non-urban range is significantly more. The minivan can go 800 miles and the compact 500 miles.

If anyone has question they can call (917) 847-3851 or email sv@zeropollutionmotors.us

Given a fuel-driven compressor, the 'zeropollutionmotors' address is a bit of a stretch.

I don't think it's an out-and-out scam. I'm sure it can work in some fashion. But I do think the claims being made for it are far out of proportion to anything that's actually being demonstrated. With more modest claims I could see it as one useful small piece of a much larger strategy. But the whole ignorant 'runs on fresh air, zero pollution, totally free' hype is basically false.

Well that is marketing and business. Just like Spenda tastes like sugar because it is made from sugar.

A 100cc motor at 100 psi could do it then! I didn't find any specifics. Did you? I would like to know the size of the motor and the regulated pressure and the weight of the vehicle. Do you have that data Shane?

mel

The minivan:
Weight: 1,874 lbs
Engine: 41P06
Power: 75 CV

Compact:
Weight: 838 lbs
Engine: 41P08
Power: 22 CV

Yeah, I still have a few questions - the compact is under 400 kilos and my calculation above showed that the compressed air in a full tank adds another 125 kg (bout 270 lb) to that.

Again, not saying it can't work, just saying it's a long way from prime time... and selling it with lies won't help it get there.

Why not email the company with some questions?

Not to dis your subtle reasearch, Bravus, but rather to concur with it...it did seem a bit far fetched to me as well. My understanding was that it also had a piston or two in the system and the air pressure powered that pistion. While I sadly feel that this is a bit far fetched, I am still open to other possible motors/propulsion mechanisms that might power a vehicle using a smaller volume. For example, while the piston is the prime mover of the engine, that energy must be transfered thru the engine, thru the transmission and to the wheel. My understanding is that for each transferance, there is loss of energy to move the vehicle....

Perhaps the piston is directly attached to each wheel, with no transmission...? This would allow more energy of the pressurized piston to reach where it needs to go without kinectic energy loss...Hence, less power for the same amount of movement.

But then again, I am no scientist...nor a mechanical engineer...

According to one article I read the air car has no transmission. I am sure an email with the right questions could get a lot of answers.

342. RE: World's First Air-Powered Car: ABOLISH THE LAWS OF THERMODYNAMICS
If all of you folks are wondering why these cars are taking so long to come to market, I will tell you; I have good sources that say the "inventors" are waiting for the laws of thermodynamics to be abolished. If they are able to operate outside of the laws of thermodynamics, they will be able to do magnificent things with this idea. Pay attention in science class kids!!

MDI is not claiming the air car is a perpetual motion machine. No abolition of the law of thermodynamics is needed. Let's put that strawman away.

I did get carried away there a bit huh? Here is another angle. My son is a fireman and he tells me that they have equipment down at the firehall to compress air to 4000 psi. The claim is that the air cars have a built in compressor that can recharge the tanks in 4 hours. Fine! However my son tells me that their compression eqipment cost around 26,000 dollars. Let's add that into our equation.

mel

I don't know if there is liability involved with that or not. I have built some hospitals and paid of $3,000 for a medical gas valve when the welding supply store sells the same valve made by the same manufacturer in the same plant for under $100.

Time will tell. It will soon be August. Meantime I'm not holding my breath and wont be in the market for an air-car anyhow. I do like to have some steel around me on the highway but some ride motorcycles! It's interesting.

mel