September 23, 2002
Cars powered by compressed air

French company Moteur Developpement International (MDI) has developed a car powered by compressed air. The air expands to push pistons and then the pistons drive a crankshaft in a way similar to the way an internal combustion engine works. The vehicle has a compressor driven from plugging into an electric socket that recharges the compressed air in 3 to 4 hours. From an MIT Technology Review article:

Negre, who was interviewed through an interpreter, explains that, in the tanks, the air is both cooled to minus 100 degrees Centigrade and compressed to 4,500 pounds per square inch. Then it’s injected into a small chamber between the tanks and pistons, where it’s heated up by ambient outside air that forces it to expand into a larger chamber situated between the small chamber and the pistons. That heat exchange between the two chambers, he continues, creates the propulsion that drives the up-and-down strokes of the engine’s four pistons. Finally, the air is passed through carbon filters like those in scuba diving tanks and expelled as pollutant-free exhaust. The dynamic is not unlike that of a spring that takes in energy when it’s compressed and gives it back when it expands.

The MDI "How It Works" web page has a picture of the 4 cylinder engine and an animated image of the engine's operation.

Share |      Randall Parker, 2002 September 23 09:01 PM  Energy Transportation


Comments
Luther Rangeley said at September 9, 2003 11:24 PM:

My air car website will be up in an couple weeks. Please remember to look it up, I've been researching air cars since 1979 and you will not be disappointed.

SEBASTIAN JOHN said at September 11, 2003 1:26 AM:

i am a mechanical engg. student.
i am doing a seminar on air powered cars
could u please sent some informations

Luther Rangeley said at October 28, 2003 9:27 PM:

Please refer to the website www.aircaraccess.com which is now up and running. It has lots of free information and more you can send for.

Scott Robertson
air car researcher

Scott Robertson said at October 28, 2003 9:31 PM:

Has anyone heard of an air car project by Baruch and Isaac Leibow in Israel? Their U.S. Patent is very interesting.

Scott Robertson said at October 28, 2003 9:43 PM:

I would be interested in corresponding with anyone who is interested in compressed air for automobiles. Especially engineering students. Air cars were commercially available in the U.S. and Europe (air powered locomotives) from the 1890s to the 1930s. There is lots of information available and this really is the best of all the alternatives. The key to it is that the energy that pushes pistons in an air car is heat, which was put there by the sun. So compressed air is solar energy, and if used properly it is free.

Scott Robertson said at November 3, 2003 3:53 PM:

My e-mail has not been working properly till today. If anyone has tried to reach me and had their message returned, please try again.

Scott Robertson
aircaraccess@millenicom.com
www.aircaraccess.com

Scott Robertson said at November 25, 2003 10:53 PM:

The official website for the MDI air car is www.theaircar.com. A list of other websites on air cars can be found by going to www.AirCarAccess.com or by clicking on my name below which links to my air car website.

Kevin E. vonMoses said at January 28, 2004 4:06 PM:

A couple of things to note:

a 10.5 gallon, (1.4 cubic feet) containing gasoline, (114,132Btu/gallon) has a horsepower/density of 20,568 hp/CuFt, based on 41.42Btu/hp. Show me any air storage capable of that power density... The functioning vehicle almost HAS to compress air on board to have sufficient range, ESPECIALLY if it is going to be more than Urban Transport...

I wrote to a colleague:

John…

I just I just reviewed the segment on CNN of the French air powered car…

Yep, it runs, a great noisy clattering, boxy piece of work…

A couple of things are obvious… To get the huge money he has tied up, he has traded on his and his son’s name in Formula 1 circles, and basically sold the concept before he had it fully tested, relying on the sheer mass of the investment to leverage Investors into ‘staying the course’…

The other is he has some of the French government in his pocket somehow… The infrastructure of air filling stations has GOT to be coming from the socialized system the French have… Which means the car will never see more than the city centers of France…

The Investors are getting taken for a ride if they expect to go international with the design, and at some point, the French government would have to ‘outlaw’ petrol based transportation in the city centers to give this company the volume it would take to keep the doors open… The odds don’t favor that in our lifetime, but you never know…

Taking a look at the design itself, It is complex and probably fragile if not built massively, which means it can’t be produced economically… I have the luxury of SlowMo on my tape machine, so I could watch it articulate… It has counter-coupled pistons driven by linkages to a common crank eccentric… This gives the pistons more or less linear travel, so the piston travel/speed/volume is stable… a Plus…

HOWEVER when you look at the pistons, they have as the linear stabilizing rod down their centers in varying diameters… A very small diameter stabilizer rod opposing a very large diameter stabilizer rod… The difference in diameters adjusts the volume of the cylinders, and the Torque they will produce for a given pressure applied…

One would think that at any given time, the smaller effective area would be over-powered by the larger effective area linked to it, depending on Load and pressure applied, so the net result is that the cylinder pair will only produce the average of the two for torque…

This means they have all this ‘busy work’ going on inside the motor with complex and heavy linkages, when they could have coupled nominal cylinders together and gotten the same results… The real evidence of this is that it still has a gearbox/transmission that has to be shifted… My work on the VPDrive proved that a gearbox could be dispensed with if the full energy of the air was delivered, because the Torque for a given air pressure is so massive.

The layout is that of an opposed four, (at least in the rendering) which means that they are developing four power strokes per revolution… My work suggests this is un-economical in terms of the volume of air consumed for the work done… I suspect that the running motor was an opposed six, which would put the power strokes 120 degrees apart, (remember that one piston is going to be driven to the bottom of it’s bore and trapped there, every time pressure is applied because of the linkage to a ‘weaker’ piston, so the net effective number of cylinders is three) and sustain crank rotation more economically… The sheer size of the block running on the test stand suggests this too. Noted that there was some sort of valving driven by belts to the heads that are not depicted in the rendering, which shows 'poppet' type valves... a little 'bait and switch' for the Investors?

Given nominal gauge values selected for the gauges, the pressure differential is about ten to one of the stored pressure and the running pressure… My research suggests that the differential has to be at least 30:1 of the maximum applied pressure, and perhaps as much as 150:1 for the nominal running pressure to take advantage of Boyle’s Law…

The performance indicated by the news clip suggests the nominal displacement of the motor to be under half a liter for the vehicles, and no where does it state the range the vehicle can achieve even at low consumption levels… It DOES say that it takes a couple of hours to refill the three massive bottles, so this suggests a Medium pressure fill, (4000 psi) on what appear to be the equivalent of three 200 SCFM tanks… My guess is the range at 25 KPH, (about 17 MPH) steady state, to be around 60 miles or so…

Now that I have seen the running design, the opinion that this guy is a huckster and a grand magician at making Investors money disappear is pretty well confirmed…

BUT given the French Governments arrogance, they will probably prop him up for a while, so he can fleece the Investors and retain his image…


******************************************

AND for those that don't know me... Yes, I AM that damned smart! (Gee, I hope that made Ya laugh!)

Steve said at January 31, 2004 5:59 PM:

The question is can an air compressed engine such as decribed ever be made workable?
It seems to me that if this proto type can be made to work on a small scale then someone as smart as yourself or some of your coleagues should be able to improve on it so that we the people of less intelagents can quit worrying about green house gases.

Steve said at January 31, 2004 6:02 PM:

why are air powered cars unavalible in the United States.

Scott Robertson said at February 3, 2004 5:43 PM:

Air cars and air engines have been workable since the 1800s. The term "air engine" hasn't been used in pneumatics textbooks since 1930, and thousands of air powered mining locomotives (partially solar powered) were destroyed in Europe during World War II. Some of my correspondents are helping me put together a master list of surviving and restored air trams or "air bags" as they've been called.

For a brief history of air cars of all kinds, see www.AirCarAccess.com/history.htm.

It has apparently become the specialization of modern humans to do what they are told, and the time spent getting our instructions from the TV set is the time we should be out in the garage building the first generation of backyard air cars. Detroit is not going to do this for us.

Scott Robertson
Pneumatic Options Research Library

Ioan Bortos/Romania said at April 21, 2004 10:22 AM:

hello, everybody!

I.m interested like you about compressed air engine. I think the liniar engine is not the solution, but I don't know alternative. Send me your mail adress and I'll describe my ideea. Let's make a club!

edvin said at May 28, 2004 1:31 AM:

Hello, can you tell me is it possible to throw compressed air into a cylinder at the same time with gas and without a compression tact to cause a combustion by a sparkle plug, If yes, how to do it, with what kind of machine should beused to compress the air turbocharger,....?), how much pressure is necessary to assure a good combustion?
Do not think of the entire 4 tact proces used by the Otto engine, I am not intereted in the otto engine i merely want to know is a combustion possible without the compressing tact.


Thank you very much for your time,
Edvin

Enthusiast said at April 11, 2005 8:47 PM:

Yo,

Check out the rotary air engine developed in melbourne australia
www.engineair.com.au

Eddie said at May 10, 2005 2:29 PM:

What is the latest on "self" fueling air engines? Seems to me that this would be the best option unless you want to mount a 10,000 PSI carbon-fiber tank to increase range.

JohnW said at September 6, 2005 9:21 PM:

I saw a website where a guy in Florida USA CONVERTED a 4 cylinder Ford motor to run on air. It had a compressor mounted on a 5th wheel and recharged itself......

Anyone know of this?

This aint rocket science, it could be done.

Also, how do these air motors do in cold climates? What about freeze ups? Condensation?

Keep this going!!! Our future depends on it!!

Reynolds said at September 7, 2005 11:02 PM:

Stop thinking small. Commerical applications of power plants have always followed down in size. Coal-fired Steam started with ships and trains, then tractors and trucks, and finally to automobiles. Same deal with nuclear power, from large applications to small applications. It was not because no one wanted a replacement for horses and mules.

Thinking small results in high pressure tanks which require tremendous amounts of energy to sustain. Thinking small leaves less room for recharging ability, so we get the silly notion of air stations or hours trying to compress air with 220 volt sources. Thinking small keeps the concept from being applied because the style and appeal is more important than the obvious environmental benefits. Thinking small is not thinking smart. Don't be in such a hurry to add sex appeal to the concept.

Clearly, the tanks need to be continuously charged with a solar powered compressor. Need surface area to allow for the current state of solar panels. Another reason to stop thinking small.

Stop trying to think of this concept as some kind of retrofit for the current automotive technology. Give up the heavy storage tanks. Give up the heavy metal block engines. Give up on trying to replace gasoline without giving up our favorite family member, the automobile. A plastic engine can run on compressed air. Where plastic cannot cut it, think in terms of ceramic parts. Weight savings will extend range and performance. Let go of the conventional way of looking at automobiles in the same way that we dropped the conventions of the horse buggy and cart. Some of the early automobiles tried to look like carriages without horses, so we spend decades trying to figure out what the front of a car should look like, without the horses.

Free yourself of conventional thought when embracing new concepts. Do not try to get new concepts to immitate what is more familiar and friendly. If I can do it, you can too.

Reynolds said at September 7, 2005 11:02 PM:

Stop thinking small. Commerical applications of power plants have always followed down in size. Coal-fired Steam started with ships and trains, then tractors and trucks, and finally to automobiles. Same deal with nuclear power, from large applications to small applications. It was not because no one wanted a replacement for horses and mules.

Thinking small results in high pressure tanks which require tremendous amounts of energy to sustain. Thinking small leaves less room for recharging ability, so we get the silly notion of air stations or hours trying to compress air with 220 volt sources. Thinking small keeps the concept from being applied because the style and appeal is more important than the obvious environmental benefits. Thinking small is not thinking smart. Don't be in such a hurry to add sex appeal to the concept.

Clearly, the tanks need to be continuously charged with a solar powered compressor. Need surface area to allow for the current state of solar panels. Another reason to stop thinking small.

Stop trying to think of this concept as some kind of retrofit for the current automotive technology. Give up the heavy storage tanks. Give up the heavy metal block engines. Give up on trying to replace gasoline without giving up our favorite family member, the automobile. A plastic engine can run on compressed air. Where plastic cannot cut it, think in terms of ceramic parts. Weight savings will extend range and performance. Let go of the conventional way of looking at automobiles in the same way that we dropped the conventions of the horse buggy and cart. Some of the early automobiles tried to look like carriages without horses, so we spend decades trying to figure out what the front of a car should look like, without the horses.

Free yourself of conventional thought when embracing new concepts. Do not try to get new concepts to immitate what is more familiar and friendly. If I can do it, you can too.

Paul McGriff said at September 16, 2005 7:15 PM:

Isn't it time to mass produce this technology? Isn't Guy Negre selling cars with air compressed engines?

Why are they not available anywhere on the globe?

alternate fuel technology has been around for over 200 years. The only reason we are not using it today is that industry leaders can't make money with it.

richard said at September 28, 2005 4:08 AM:

MDI, through the program BEYOND TOMORROW (australia), suggests they are going to go into production mid 2006, but they seem to be saying this since 2002. I just wonder if he is jerking everyone around hoping for more investors money.The bloke in Melbourne seems to be on the right track with a rotary engine, but has thought small so far, not going beyond, outboard motors and a cart for a fruit market. If he had the investor dollars, he might get a lot further and get it closer to a small car product. He at least was not jerking people around when he proved his motor only rode up to 35kph for a few hours. Honesty would be nice in the car industistry if we are to find cheap, clean, reliable alternatives to Petroleum fuels. Of course, if we go through all the oil, no longer will we drive petrol driven cars, but we will run out of plastics, being petroleum based. I'm only an ordinary bloke in a mid paying job with a small house in the suburbsm just waiting for someone to help. If they produce air compressed car, with an optiumu 110 kph, a 250km range at $15,000 AUS than I would take out the loan to buy one. Cheap to run and no pollution. Who could ask for more>

Murray Pryor said at September 28, 2005 5:55 PM:

The concept of widespread air filling stations is a bit optimistic. Compressed natural gas distribution for transport use is a concept which has been around for 30 years in Europe, and for a much shorter time in Australia, but, in spite of the considerable advantages of price and usage of available resources, it has never really taken off. The flavour of the month is Hybrid Technonogy, and this is because of massive publicity. The advantages of the current forms of this technology are largely illusionary, particularly when 65 KW output is considered just enough. The FJ holden had considerably less than this, and was perfectly capable of exceeding the speed limits then and now.
A possible niche for compressed air power is in natural gas/compressed air hybrids. The compressed air motors can be light weight, supply a lot of power when required, yet run economically under cruising conditions. A small natural gas fuelled charging engine can run continuously and, hence, efficiently, and provide waste heat for the air reheat exchangers to give a high overall thermodynamic efficiency. Overnight charging of compressed air and natural gas at home would be a way around the lack of charging infrastructure. All this is not without its complications, and would require very high fuel prices, or draconian greenhouse legislation to make it attractive to non-enthusiasts.

drayzen said at September 29, 2005 12:48 AM:

I have just started reading about these air powered cars and there seems to be one major efficiency point they are all missing.
What about some regenerative braking? (Use the back pressure of a pump to apply braking force and recharge the tanks at the same time)

They are talking about air stations etc to recharge the tanks. It seems some comentators are (reasonably I think)suggesting that the pollution is just being moved from the cars exhaust, to the local power station...

I guess it will be up to the enthusiasts to modify the final products to add regenerative braking...

cheers all. :)

Drew said at October 5, 2005 9:34 PM:

Hi everyone
I had a bainstorm several years ago on a water-powered engine, using the concept of expansion rather than combustion. I know it sounds far-fetched, but I've run it past several brainiacs, including one engineering major, and nobody can seem to point out anything inherantly wrong with it. The beauty of this engine is that it would be capable of re-using the fuel over & over again, and never need refueling. This may sound rediculous as I've already said, but if somone with a bigger brain than I would be interested in taking a look at it and potentially playing with it, they can have my idea. I'll never have the capabilities to do anything with it, and if somone even just gets some fun out of it, it'll be more productive than it is now. Anyone who is interested please drop me a note excelciorATshopwyomingDOTbiz (I don't want spam =-P )

Angus Rex said at October 16, 2005 9:08 PM:

Is anyone out there prepared to make a compressed air engine? You need to be in AUS and have some engine experience, i am willing to pay you. The catch is the engine must be able to be mass produced and power a car up to 110km/h and run for at least 200km. Interested? Please reply to arex@optusnet.com.au

Bi-energy said at October 18, 2005 1:39 AM:


am a mecatronics engeneer ,my graduate project about air car ,i try to build one ,
but i need to ask ,is air motror like (gear motor) and only compressed air in a tank can operate it ??? and if anyone have informations or links please give me .

Mantody Nikhil Saseendran said at October 28, 2005 1:01 AM:

Respected Sir,

I think that the concept of compressed Air driven vehicles is great. It will definitely work. And this will be the future of automobiles.

Please inform me about air engines.
Thanking You,
Yours truely,
Mantody Nikhil Saseendran.

Ted Dever said at October 28, 2005 6:24 AM:

I have put all of my research into a book that might be of interest to you called "How to Convert Your Car to the Air Engine". It explains the technology and presents 15 patents that have been filed since 1976 on air power. In my early stages I converted a lawn mower engine in my garage into an air engine to prove it would work. I double lobed the value cam and powered it up. Amazingly simple. However, the main showstopper is producing enough air to keep it going. Some of the patents address this really well and some don't address it at all.
Good luck,
Ted Dever
http://www.tbhi.net

Ken DeSerio said at October 28, 2005 2:21 PM:

I and another design engineer have come up with a "New" technology air motor that would be very easily modified for use in a small vehicle. or tractor. We expect to have a prototype running in early 2006. Our experience expands over 45 years in the pneumatic air tool / motor business. Tis new concept will utilize the latest composite construction and newest low friction lubrications. We are looking for a grant or someone with a high tech vision to invest in the prototype for a piece of the company. I would welcome any comments or inquires. This design is not as complicated as the Austrialian, French ot the 2 stage 4 cyl engine that has a long way to go to be manufactured at a reasonable cost. Our design lends itself to excellent manufacturing costs for a much better installation in a mid sized vehicle.
E-mail me for more details and a phone number.
Air is the future of our transportation.
Regards
Ken DeSerio
ata@stny.rr.com

Sonny said at November 23, 2005 1:59 PM:

Hi everyone.
I have experimented alternative energy using fuel cell, super magnets, static electricity, solar and others.

When I read about compressed air, I got this strong feeling that this is the way to go for alternative energy and strongly believe that this will work.

I have been reading your postings and as Reynolds suggested, we should think commercial (big) and not small. I think we should not only concentrate compress air on automobiles but for all sort of power usage such as for homes, cars, computers, phones, etc.

There seems to be a lot questions on how keep the compressed air charged.

According to Ted Dever, he has successfully converted a lawn mower into an air engine. Basically for self-recharge, we may need to combine other alternative source. There are a number of natural sources to charge (generate) compressed air such as solar panel. So, for the lawn mower, maybe adding a solar panel compressor to keep it going.

If we have all these ideas put together we may come up with one solution.
I am proposing that we join hands to work on this.

I have set up a yahoo group and the goal is to get everyone who is interested to contribute and work together to make compressed air as an alternative energy to power homes, cars, computers, phones and others.

Anybody who is interested in joining, please go to the site, http://groups.yahoo.com/group/compressedairenergy and indicate why you want to join and what you can contribute. A brief description about you and your experience is helpful.

roddy said at December 6, 2005 6:05 PM:

Oh my god.

Ask yourself two questions. 1. Where does the energy come from to compress the air? What efficiency can the system run at. Boyle law: P1V1T1=P2V2T2, when you compress the air you heat it. Remember how hot an air compressor gets. Well all that heat is energy wasted.

Air motors are good for specific applications such as in markets and mines and warehouses etc. If everyone used them then the net energy requirement would go up, not down. Running a compressor on solar cells is simply putting an extra two stages of inefficiency into the equation. If you have solar cells why not simply use an electric motor. It is much more efficient.

Please try to think straight. There is no great bogey out there trying to stop efficient engines developing. It is simply difficult to find energy sources which do not stem from either fossil fuels or nuclear. Solar systems are very diffuse and hard to store.

Casey said at December 8, 2005 9:58 AM:

I can't believe this discussion has made it this far.

Everyone here seems to be focused on a mechnical device for converting air pressure into useable work (crank rotation) without giving any thought to the source of the compressed air. Compressed air does not just exist, it has to be compressed by some means. Unless you have some novel idea for generating compressed air without a conventional fossil fuel engine or an electrical motor (powered by a fossil fuel power plant), the compressed air is simply an unnecessary step from just burning the fuel in a standard car engine. And no, you can't just drive a compressor off of a 5th wheel, the energy source to compress the air has to come from somewhere. That would be like hooking up a motor to a generator and convincing yourself that you are making power.

If someone has some specific thermodynamic and heat balance data on the entire process (ie Btu or kw input / to HP or KW produced) I would sure like to see it.

Harry Valentine said at December 11, 2005 7:57 PM:

Compressed air has been used in railway mining locomotives. The last such loco's were built during the mid-1950's and carried 2,900-psi in their storage tanks. The running tank that supplied the air motors operated at a much lower pressure (the high-pressure tanks fed air into the low-pressure tanks).

Thermal energy can be stored in insulated containers to heat the air prior to expansion in the air motors. There are a variety of eutectic metal-oxides that may be stored in ceramic containers (they have high compressive strength) made from silicon-carbide or silicon-nitride. One promising eutectic mixture I would investigate would be H-O-Al=O that melts at 350-deg C to 450-deg C plus O=Al-O-Al=O that melts at 2045-deg C and needs 460-BTU/lb. The eutectic mixture would have a lower melting point than the H-O-Al=O and its latent heat of fusion may be double that of O=Al-O-Al=O.

There are many eutectic metallic oxides and eutectic salts that melt between 50-deg C to 250-deg C that could be used in a pneumatic vehicle. If I were to propose a pneumatically propelled vehicle, I would choose a bus (with a full length frame). The air cylinders may be attached outside the frame rails, ahead of and behind tandem rear axles. A low-pressure running tank to supply the air motor (that would drive through a multispeed automatic gearbox) and the insulated thermal tank would be located under the floor, between the frame rails and ahead of or behind the axles.

Based on the performance capabilities of the last pneumatic locomotives that were built, this type of bus may be used in school service, in short haul commuter service or rush hour city transport service. It could be used on short-haul charters or short-distance intercity routes, however, it is NOT a long-distance bus.

Harry Valentine

Doug Hubbard said at December 28, 2005 8:05 AM:

Somebody has to look at the basic physics, here. They have a 300 liter tank at 300 atmospheres of pressure going through (nearly) isothermal expansion. Depending on what they consider the ambient temperature to be, you get total Megajoules of energy to be in the range of 30's to 40's. Under those conditions (300 liters at 300 bar, -100C) you have an air mass of about 173 kg. That is about .2 to .26 MJ/kg of "fuel" (ie. compressed air). That is about 150 times LESS than a kilogram of gasoline! In fact the entire compressed air tank has about the energy storage capacity of roughly 1 kg of gasoline (about one THIRD of a gallon of gasoline). The range and performance of this car seems to have little to do with any innovation with the use of compressed air. Its just a very TINY car with regenerative braking. I weigh about 200 and I'm 5'10". I don't think I would be very comfortable in this car.

Furthermore, the complexity of the compressed air-driven motor is absolutely irrelevant for the energy-storage limits of the system. In fact, I doubt an engine with this many moving parts could really be all that efficient compared to simpler existing systems. The couldn't patent the basic idea of a compressed-air driven car, so they could only patent a particular type of engine and system - for which I see no advantages over the public domain methods.

Doug Hubbard

Casey D said at January 3, 2006 8:19 PM:

I'm new to this site, so I'm trying to catch up. If I understand correctly, there is no current technology that will allow you to run 100% efficient (without an energy source such as fossil fuel or recharge from an external source...........as Casey was saying above). I've searched the internet for months and have found no evidence that leads me to believe it can be done 100% efficient. Out of curiosity, why has the current technology (such as the Air Car) not taken off? If it is truly cost effective, why are these cars not driving down the road? I guess my main questions are..........what is the latest development in this topic, and what is the closest anyone has come to achieving 100% efficiency?

chris said at January 7, 2006 2:44 PM:

i want to convert a v-8 motor to compressed air engine. is it possible, i would use a big air tank in the back of my truck to push the air into the engine. and how big does the tank have to be if i want to run it about 350 miles at 65mph.

John Baltic said at January 11, 2006 7:57 AM:

Even a simple battery electric still has enormous environmental benefits over IC. True the energy has to come from somewhere - whether one is just charging a battery or running an air compressor. However, with a fossil fuel power plant, all of the emission controls are stationary. They can be as large and heavy as necessary. With an IC vehicle, the emission control devices must be MOVED with the vehicle every time it moves over the life of the vehicle - even when it is being towed or shipped! Multiply this by the number of IC vehicles on the road, the lifetime of those vehicles, and the total millage they are ever driven or shipped (even to the junkyard), and you get a very large number.

Now look at idling. In every major city and even tiny burgs most drivers spend a LOT of time sitting in traffic with their IC engines merrily burning away. Or waiting in line at the burger king, etc. Again, we multiply this number by the total "lifetime" hours the car is running - and multiply it by all the IC cars on the road (more or less, depending on total milage. Perhaps we can use the median?). In any case, we again have a very large number.

If we add in regenerative braking, the weight of fossil fuel (is it greater than the weight of batteries or compressed air? I know it changes as the fuel is used up), the ability to use less steel because we don't have combustion, possible savings on oil as a lubricant, and the weight of the radiator and cooling system (which also must be MOVED every where the vehicle is driven, towed, or shipped - as opposed to a stationary cooling system at the power plant or compressor). Multiply these by all the cars on the road and their various lifetime milage - we may have a substantial net gain.

Ken DeSerio said at January 18, 2006 9:21 AM:

My comments posted October 28, 2005 on this site has certainly brought some positive and negative discussion. I received an e-mail today from another gentleman who is also interested in an alternate fuel power system. He phrased it very nicely when he wrote "The Stone Age did not end because man ran out of stones; it ended because something better came along." Thank you Richard Duffy. That man has a vision of what it is all about and where we need to go and be if we are going to solve this alternate power source/supply. I am involved with several groups that are trying to come up with a solid, reasonable, safe power source that will cover all the bases. One of the groups/forums that I participate in is http://groups.yahoo.com/group/compressedairenergy. Sonny has started an excellent discussion group and I believe it will bring some outstanding results. It would pay you to take a quick look and decide for yourself.

I want to devote this papagraph to Doug Hubbard, Casey, Casey D and Roddy. I would venture a guess that only one out of the four of you really understand what pneumatic compression and air motors is all about. From the input you all have written it sounds like a lackluster science class for pre-college enrollment. Don't get me wrong, but I believe in the old saying "Been there..Done that" I have well over 45 years of pneumatic design experience including air tools and compressors from air vane motors to high speed turbine type - commercial, industrial and aerospace environments. I know how they work and I know how to wring every drop of energy possible from them. There will be heat..There will be exhaust.. There will be many other factors that go along with all compressed air / N2 gas power systems.. Gentlement.. The trick is HOW TO HARNESS IT.. and I and my associate have devoted many, many years to doing just that. Our new technology CA / N2 power system.. I can say with great pride that no one else has come close to solving the CA / N2 power systems downfalls and we are probably the closest yet. Our prototypes (generator and VW size vehicle) will be forth coming sometime in 1st quarter or early 2nd quarter 2006. Harry Valentine and John Baltic are on the right channel of thought in a very positive way.

In closing, I hope all of our contributions are positive as sometimes you don't need all the scientific notation to prove out a design.. It just muddies up your creative juices. Experience and education in "THIS" venue dictate a lot of truth in the final result. Thanks for listening to me on my soapbox, I hope I didn't offend anyone as that was not my intention. Keep the forum upfront, simple for all to understand and by all means think positive to find the end of high prices at the gas pumps. I am open to any discussions at any time. I welcome comments regarding the pneumatic venues.

Micheal Jones said at February 1, 2006 2:18 AM:

Get over the piston motor. Its to sluggish and friction prone and dont tell me about no silicon nitrate piston rings and cylinder coated walls. The motor takes 2 steps for rotary motion which makes it suck hard. the first thing is a motor that does pure rotary motion no wasted steps. How about a styrofoam screw compressor with a 0.05 in carbon fiber wrap floating on air bearings? Loose the wieght free less power to do the same work

Ravishankar said at February 2, 2006 9:52 AM:

I think the compressed air car has noice and other problems in the system. I am working on this tech since fifteen years.I have better technolgy on compressed air engine which does not require gear box and breaking system. The engine is simpler than the existing ones and less parts in it. so it will not require more maintenance. My engine will perform more than the excisting ones,very smooth (noiceless) and easy to operate. By this method cost of the vehicle will come down. If we do more research on this to complete we will be able to rule the world in automobile industry. I am interested to talk more with interested people. I am ready to talk with other AIR CAR companies.

Billy Bowers said at February 8, 2006 9:00 AM:

I would like to discuss a applacation for the air engine with someone . I have a hybrid type scooter for the disable,its small light and has proven to work. I can go 100 miles on less than gallon of fuel. However i'am thinking that the air engine maybe better, but not sure, any one interested can email me for more info.

Stefanos Horianopoulos said at February 11, 2006 6:31 PM:

Reading about the air car is very interesting concept. The answer to the problem as how to have ample energy either for electric or air cars you can find it with kinergypower.
I'm the inventor of kinergypower an invention that is register w/U.S. patent office. kinergypower converts the kinetic energy from passing vehicles, pedestrians, trains, trams,large livestock etc.(any mass in motion creates kinetic energy)
kinerypower could provide energy to the size of a nuclear plant production.
Please check my web site www.kinergypower.com

Stefanos Horianopoulos said at February 11, 2006 6:32 PM:

Reading about the air car is very interesting concept. The answer to the problem as how to have ample energy either for electric or air cars you can find it with kinergypower.
I'm the inventor of kinergypower an invention that is register w/U.S. patent office. kinergypower converts the kinetic energy from passing vehicles, pedestrians, trains, trams,large livestock etc.(any mass in motion creates kinetic energy)
kinerypower could provide energy to the size of a nuclear plant production.
Please check my web site www.kinergypower.com

arvind said at March 10, 2006 3:49 AM:

i am working on a project but a main difficulty is that how can we store this air and also the size of cylinder is bigger than the other parts and how it is cheaper compare to fuels as we are using other power to compress air and then using how will it cost per kilo meter

Timothy Bailey said at March 19, 2006 9:02 AM:

I have some Ideas on an air engine and how to produce the power to continually compress the air tanks. I have a schematic that would work by "recycling" the air that leaves the engine... I just need an air engine that works efficently on low psi. If anyone has compatable engine I would be willing to go in together on producing it.

hugh o rourke said at April 23, 2006 4:28 AM:

Just as a battery is a power storage device,compressed air can be viewed as a device for storing power potential.In itself it is not a fuel source but can store the power produced by other sources

Daniel said at April 25, 2006 1:07 PM:

Cash is the bottom line. I do 90% of my driving intown under 45 MPH. If I can get to and from work for 25% the cost of Gas I will buy an air car. I dont give a rip about saving the environment or "well I could think of a better way". Save me $$ and you have a customer. Give me a car that uses compressed air over batteries!

Lars Persson said at May 2, 2006 7:32 AM:

Hello,
I just found this discussion, and I find it interesting.

It is possible to compress air almost free of charge....

The principle was first dicovered by Nikola Tesla and it is quite easey to understand. We need 2 systems separate from each other.
system no1 is an mechanical oscillator. any mechanical oscilator will do, but here is one: A piston is placed inside a housing with air cushions on each side. A rod goes through the piston and out of the housing. Bang the rod and the piston will oscillate back and forth inside with a set frequency. this frequency is determined by the mass of the moving parts, how big the aircushions are etc.

system no2 is a driver circuit. it could be lots of things. for example it could be a set of magnets mounted on the rod, with a loudspeaker coil sort of setup around it. feed the coil with a sinus signal with the same freq. as the system1 resonates at, and the rod will start to move up and down... system no2 is not directly coupled to system no1. it is not the elctrical energy that moves the rod. we have a resonance phenomena here. there are no direct relationship between power input into the driver and the kinetic energy that the bobbing piston shows.

a more fun driver would be to use compressed air to a piston with timing slots so arranged that when the driver piston is near it endpoint the pressure switches side and drives the rod in the other direction, where the same thing happens. we only need a tiny ammount of "help" from this driver to get the bigger and heavier oscilattor to, well oscillate... ;-)

if we now have a linear compresor attached to the rod, and yes this will upset the resonance freq. a bit because the moving mass is now different, we have a complete set. a large and heavy oscillator, a driver and a compressor. the oscillator is so large that the added resistance of the compressor is not very important. the driver consumes only small ammounts of energy but the timing is critical.

when set in motion this device will just rock on endlessly. store the compressed air in an underground large tank at your backyard. drive an air turbine -> generator -> electricity. fill up your car from this storage too etc etc..

Lars
sweden

Rolf said at May 10, 2006 4:04 PM:

I like the idea of Micheal Jones on February 1, 2006 02:18 AM, which suggested the use of a screw compressor as an engine. but no one has mentioned here that one of the original air engines was infact a steam engine. Instead of storing the air pressure in a tank, It was produced through steam production. Check this link for some more ideas on what you are trying to achieve here. http://www.stanleysteamers.com/

Mohammed Irshad Baig said at July 20, 2006 12:17 PM:

I am currently pursueing Mechanical Engineering.
I am from India.
I would like to know air engine specifications as I am doing a project on it. Kindly co-operate
Thank you

anil sankar said at July 24, 2006 8:59 AM:

im a new one to this discussion.im a mechanical engineering student.i only came to know about air cars recently.i want to know more about it. also i like to make a simple working model.pls send me the informations and latest news to harindd@yahoo.com.
i ve also a lots of doubt.we are saying abt this techonology for a long years.and MDI said they had mane air cars.then why there is no mass production.

anil sankar said at July 24, 2006 9:15 AM:

im a new one to this discussion.im a mechanical engineering student.i only came to know about air cars recently.i want to know more about it. also i like to make a simple working model.pls send me the informations and latest news to harindd@yahoo.com.
i ve also a lots of doubt.we are saying abt this techonology for a long years.and MDI said they had mane air cars.then why there is no mass production.

You people are all crazy said at August 2, 2006 5:17 PM:

I have no idea how people like you continue to exist in this world. Lars, what you're proposing is perpetual motion, it's utter bullcrap. It's quite apparent that most of the posters in this forum have no understanding at all of thermodynamics. Compressing air is plainly wasteful. The energy density that it gives is ridiculously low. There will never be a practical method to store the amount of air needed to give the power and range of a modern gasoline car. For those who are claiming to be engineering and science students, bollocks, you know nothing and if you did you wouldn't be asking online for designs that you can build for your projects.

Compressing air with electricity in order to run an engine is a waste, there is no argument. Current electric battery far surpasses energy densities attainable by compressed air. Why would we convert electricity to compressed air and back? Adiabatic heating of the gas wastes significant amounts of the electrical energy.

Stop this discussion as a hope of finding a storage method to fuel your car. It is pointless and physically impractical given other existing and less complicated technologies that do not involve gasoline.

Arthur said at August 13, 2006 8:05 PM:

Like agent Mulder from X files I also want to believe (in air cars), but nature has rules. The facts are simple and you engineers and enthusiast don´t need to know a lot of physics to see the truth: I´m engineer and diver, to dive I have to fill the tanks, an electric 1.5 HP compressor working for about 1 hour is enough for pumping 2000 Liters of air into a 10 liters tank, this means final pressure is 200 bar (200 times ambient pressure)and a lot of heat is lost to the atmosphere. So if I have a 300 L tank, and charge it at 200 bar I can store the energy of the compressor´s electric motor running for 30 hours, this is enough to power a small vehicle for a few hours. It seems air car might work but the whole process is not as efficient as using electricity directly after storing it in batteries, but also we know that batteries are not strong to withstand severe charge/discharge cicles at high intensities, trouble with cold weather, etc., so is worth to look for another method of storing energy. There are other interesting options to store energy without batteries, some years ago I heard about the HIDROSVOL a car invented by an uruguayan that used a heavy and large disk at high rotational speed to store energy (alike some toy cars), disk was driven by an electric motor at home, then energy was used at demand by means of an hydraulic pump and hydraulic motor. Thanks you all for reading his.

John Menendez said at August 23, 2006 8:43 PM:

It is a terrible shame that some of the posters don't think past their noses to mentally explore innovative technologies.
Lars is NOT proposing perpetual motion, it is similar to a pendulum clock verge where the inefficiencies of the pendulum linkages are supplemented by the comparatively miniscule injection of energy from the large hanging masses. He said that the system is timed to the resonant frequency of the oscillator, and a small impetus with each stroke keeps the system running.
Unfortunately, we do have to think energy balance here-- so the energy stored in (Tesla's) Lars's compressed air tanks would be equal to the sum of those tiny impetuses that are added to each stroke, which isn't terribly helpful. Just eliminate the oscillating masses and compress the air directly. It's similar to the scenario described above where an electric motor is wired to drive the electric generator that is powering it. A small battery can be connected to start it running and overcome the frictional losses, but you'll never get any more useful output from the system than some lesser percercentage of that oversized battery.
The key to an air engine, or any alternate power plant, appears to be centered on the addition of energies from a 'traditional' source (IC engine) and a 'free' source (heat addition from solar, chemical, or nuclear heat exchanger). The laws of physics require-- absolutely require-- that the energy removed from a system cannot be greater than the energy put into it, but it doesn't say that energy all needs to come from a single source. Today's hybrid electric cars are a good start-- where a small IC motor drives a generator to store power in batteries. The IC motor itself is too small to drive the car itself, but the sum of its energy output running constantly is greater than the needs of the intermittently running car. The benefit is that the small motor/generator system running constantly can be made quite efficient, and the battery/electric motor connection is inherently very efficient-- so the combination is still more efficient than a heavy and hot mechanical IC engine coupled through mechanical transmission to drive a car.
We need to come up with a system where a larger percentage of the stored energy of gasoline can be harnessed by utilizing the heat of combustion as well as the mechanical expansion, AND claim even more energy from solar, braking, wind, etc... that is what automakers everywhere are working toward.
Utilization of heat energy for kinetic motion is almost exclusively the domain of expanding fluids (and gases), which points back toward compressed air (or maybe revisiting steam power as suggested by Rolf and possibly unwittingly by Drew).

Forrest Erbe said at August 24, 2006 12:31 AM:

Hello Everyone,

I just ran across this site and probably like others, I found it after seeing an article on the MDI car. My first impression is that MDI is inefficient and incapable of being an alternative to the current automotive industry. However, while researching this topic I also ran across the Di Pietro air motor. This looks like a workable modification of the Wankel Engine and I believe the manufacturer's target of marketing it in replacements for warehouse vehicles and other small vehicles is totally feasible. In addition, if the targeted market of warehouses, loading docks, etc. were to take advantage of the small wind generators and solar collectors currently (or soon to be on the market) at the same time, I believe the argument of transferring the emissions to power plants would be greatly eliminated.

Although this isn't a replacement for automobiles or trucks which are the major emitter of greenhouse gases, it could, if implemented concurrently with other alternative energy sources, a good way to start down the road to reducing greenhouse gases. I would, like everyone else, to see some solution to replace our current dependency on oil, but I don't forsee a widespread solution coming to the market in the near-term. BMW does have a workable interim concept car that may hit the market in three years which employs an engine capable of using both hydrogen and gasoline. Again, this isn't a solution, but it might be a workable interim messure which could (if accepted by the market enough to force the building of infrastructure) be a first step into weening the world off gasoline powered cars.

What I would like to see is the adaptation of the Di Pietro system into products for the homeowner (maybe in conjunction with a wind-powered compressor station) to replace tools in the home such as lawnmowers, chainsaws (if possible), and other home gardening tools.

DJ said at August 25, 2006 9:30 PM:

Mass Production will never happen. All the members of a company in Cali were threatened when they tried to market a new hydrogen engine. I honestly believe the only way to own this type of vehical is to develope it ourselves. I want an air powered vehical as much as the next person but I won't hold my breath waiting on mass production.

Robert said at September 11, 2006 7:07 AM:

Hello All,

This is my first post. I think that this MDI car is nothing more than moving the pollution from the gas pumps to the local electric utility. This is definitely not a "pollution-free" car as MDI advertises it, IMO.

Here is a link to an article about a South Korean company that has developed an air-compressed car.
http://edition.cnn.com/2005/TECH/03/30/spark.air.car/
This car has an onboard compressor that can compress the air on demand. It seems to me to be the best way to go.

Paul Dennis said at September 30, 2006 3:29 PM:

Hi,

Suppose you build a large pressure container with a volume of 1000 cubic meters and let it fill when the atmospheric pressure was high in the day, then used the pressure difference when the atmospheric pressure was low at night to generate electricity. Assuming the low pressure was 95 kPa and the high was 105 kPa, how much energy could be produced? Actually, you could generate electricity twice a day, during the filling and emptying of the container.

My math isn't good enough to solve this problem, but I'm interested in the potential energy source. Can anybody here define the potential for me?

Thanks,

-Paul.

mechanic said at October 3, 2006 3:17 PM:

i think that the air powered car is not going to be the best thing to do yet. i know that it will have no polution and what not, but it is still not the answer. i think that an alcahol powered car would be better. any gasoline powered car can be converted to alcohol, and if you have an alcohol stil of your own, the cost would be about 40 cents per gallon. an air powered car is a good idea, but it would be like an electric car, you would need to recharg it every so often. it is also about the same design as the steam engine, and they exploded. i'm not saying that the tank will explode because there is too much pressure, but if you get into an accident, and the valve gets nocked off, or something punctures it, with all that pressure, it could be fatal. in closing, i think that the four cycle internal combustion engine is the best way to go, and once the air powered car makes all the improvements it needs to, i might consider buying one. but until then, i think i'll stick to alcohol or gasoline

merl said at October 29, 2006 9:42 PM:

what a wounderfull site this is, really good stuff.
now i have an answer that none of you have considerd.
push yourself away from your desk, stand up and, look down (at your feet!)
yes, like all of you ,i too am currently stuck in the inexcapeable daily driving cycle(about 400 ml. every 7 days)
i live out in the country and must drive to work or town nearly every day.
in the us we are trained to depend on personal transportation.
we must improve our mass transportation in all areas (urban and rural)
my two cents on the topic is,to produce electricity on board as needed by a generator
beeing driven by a rotory(vain type)expantion cycle engine using high pressure(300 bar)
steam that is made from recaptured condenced steam and the h2o exsaust of the hydrogen flame
used to create the steam.
not perfect but i think any system with a rotory will do better than the best recipricating
engine.?

lobster 7000 said at October 31, 2006 5:18 PM:

as the air engine becomes more developed over time i still need 2 know if air (compressed) will be a fizable energy source 4 the future . service center possibilities

John said at November 6, 2006 3:19 PM:

I don't pretend to know anything about the physics involved but it seems to me that in order for a compressed air engine to be efficient the compressed air needs to be re-used. Additional compressed air also needs to be generated using the motion of the vehicle and compressors driven by a battery charged by an alternator.

The general disregard for this suggestion seems to be that the tanks will require recharging from an external source at some point and therefore it achieves nothing. I drive over 30,000 miles a year and have to fill my tank 3 times a week.

What about having two tanks one which is being charged whilst the other is inuse and then switching them when tank two is up to the required pressure, and then begin recharging tank one. And yes I know that you don't get something for nothing but we are not looking for free perpetual energy just an addiquate source to get us 500 miles or so.

The engine does not need to drive the vehicle permanently when it is going down hill little or no compressed air will need to be used and during this time the reserve tank will effectively be charged foc.

If something turns it can be used to create energy.

Lets stop saying why it wont work and start thinking about how we can make it work.

merl said at November 7, 2006 9:27 PM:

please remember, you can not get more out of a system than you put into it.
i'm quite certain that it would take much more energy/effort to charge a compressed air system
than you would get back in the form of usable work.
also, i think that just because an idea comes into beeing doesn't mean its a good one.
if i build an engine that runs on endangerd spoted owls but, doesn't produce any polution is, that a good thing?
even with a solar powerd compressor you would still be better off using that power to charge batteries.

John said at November 10, 2006 1:42 PM:

Surely any moving vehicle could use a cam/piston system to charge a compressed air cylinder which in turn could be used to drive the engine. Even the actual pistons used to drive the engine could be used to recharge the cylinder. As I said in my previous post we are not looking for perpetual motion, just a system that partially recharges it's self to enable travel of 500 miles or so. It could even be an electric/compressed air engine.

I don't think that one could say that current engines are 'efficient'. With petrol in the uk at £4 per gallon I'm spending £400 per month!!!

merl said at November 13, 2006 10:05 PM:

john,i do not want to get into a pissing match with you but, i am mearly trying to point out that the amount of effort/energy you will have to put into your "on bord "compressor will negate any additional range you might acheive. I'm sure you have a vision of somthing like a wheel riding along on the road way wich in turn drives a small compressor that is used to extend the range of the vehicle? all i ask is that you try it and you will see what i mean.
rig somthing up on a bicycle- find a small shaft driven compressor head, make a rub wheel to drive it,and mount it so it can be engaged/disengaged at will on the rear wheel of a bicycle.
ride the same route engaged and dis... and see what you think
it would be an interesting study but i'm not going to try it myself, i'm satisfied with my own estimation of the resaults.
what we need to do is find the best and safest way to produce 300 bar steam under the hood and i garentee you'll loose all interest in a recipricating engine that runs on compressed air.

merl said at November 13, 2006 10:06 PM:

john,i do not want to get into a pissing match with you but, i am mearly trying to point out that the amount of effort/energy you will have to put into your "on bord "compressor will negate any additional range you might acheive. I'm sure you have a vision of somthing like a wheel riding along on the road way wich in turn drives a small compressor that is used to extend the range of the vehicle? all i ask is that you try it and you will see what i mean.
rig somthing up on a bicycle- find a small shaft driven compressor head, make a rub wheel to drive it,and mount it so it can be engaged/disengaged at will on the rear wheel of a bicycle.
ride the same route engaged and dis... and see what you think
it would be an interesting study but i'm not going to try it myself, i'm satisfied with my own estimation of the resaults.
what we need to do is find the best and safest way to produce 300 bar steam under the hood and i garentee you'll loose all interest in a recipricating engine that runs on compressed air.

paul said at November 15, 2006 1:02 PM:

Unfortunately, much of this discussion seems to fall into 2 categories:
1) People who don't understand the 1st law of thermodynamics and think that an air car is an alternative to a gas engine
2) People who are trying to explain the 1st law of thermodynamics to the 1st group

Compressed air is clearly just another storage mechanism (like batteries or hydrogen). What I'd like to know is:
--> How does the overall energy density and efficiency compare to that of a battery-system or hydrogen system? Unfortunately, much of this discussion seems to fall into 2 categories:
1) People who don't understand the 1st law of thermodynamics and think that an air car is an alternative to a gas engine
2) People who are trying to explain the 1st law of thermodynamics to the 1st group

Compressed air is clearly just another storage mechanism (like batteries or hydrogen). What I'd like to know is:
--> How does the overall energy density and efficiency compare to that of a battery-system or hydrogen system?

Let's assume that you've got some method of generating the energy more efficiently elsewhere, and that you've now got xxx number of Joules of energy ready to plug into a vehicle, and let's also assume the "conversion loss" of transferring it into compressed air, hydrogen, or charging a battery has already been taken into account.

So considering the differences between a vehicle with Li-ion batteries and an electric motor, a vehicle with an engine that runs on compressed air, and a vehicle that runs on hydrogen:
Which storage system is the most efficient considering size and weight required in the storage and transfer of that energy into the wheels of the car [KWH/kg or KWH/kg/cubic meter]?

Batteries are much heavier, and my understanding is that the tanks they're using for compressed air vehicles are 4500psi or more. That's a lot of energy depending on the size of the tank. Has anyone done this calculation?

John said at November 17, 2006 2:32 PM:

Merl - I'm thinking more in terms of feed back. Once a compressed air engine is running valves could be used to push the air back into the tank(s) on the exhaust stroke using valves. Kind of like how the exhaust is got rid of in a petrol car. The MDI car seems to just dissipate the air used as waste. In this way the ammount of energy lost would be minimised and additional compressors on wheels could be used to replace the rest. In this way the range would be increased.

With a higher number of gears the revs needed could be reduced as well. It would be interesting to see if this approach would improve the range of the vehicle.

If I ever get the time I will try and latch up mini version.

Merl said at November 23, 2006 8:42 PM:

Drive on John.
The best way to learning is in the doing, I always say

Szybowski said at January 5, 2007 4:18 PM:

As I was reading this thread I thought of a couple of things. First one advantage of compressed air I see over batteries is that even though it takes a fair bit of time to charge either one normally, with compressed air you can have extra tanks at home in your garage that are filling while your at work and when you get home you don't need to switch out the tanks in your vehicle. Just simply and quickly mostly full your vehicles tank(s) from the none moving ones. You may no get a complete fill to max pressure unless you have more none moving tanks then you have in your vehicle, but you'll be able to leave again right then with a mostly filled tank or just let the compressor finish the job if you have the time.

The second thing I see is that since batteries are much heavier then air aluminum tanks or the like your vehicle is that much lighter and if you want or need to you can put that weight you saved into heavier safety features in your vehicle and or cargo. This is all assuming that what ever air engine you use is comparable to the electric motor alternative power wise as well as energy stored to get that power are the same and that the stored power of the tanks matches the batteries.

The third thing is that even though I believe battery powered vehicles a good technology to explore, especially since the Li-ion and Zebra batteries are getting quite good. It's much cheaper and easier to get high pressure tanks then great batteries and the manufactures of said batteries can't mess with you by stopping production to the public at high volume or raising their prices.

I would also venture to guess that there is less toxic waste and less materials used to produce tanks then batteries. Of course in the reverse it is currently easier to acquire good electric motors then good air engines but that can change. Also electric high pressure compressors can be onboard your vehicle(s) so you can plug it in just about any where like you could a battery powered vehicle. That same compressor could be tied into a regenerative breaking device as well as small solar panels that can fill your tanks if you have sunny weather. I just heard of some serious upgrades in the density of power that a new type of solar panel can acquire in a small area.

In regards to safety if one or more tanks or valves are ruptured I think it would be safer if instead of one or two big tanks in your vehicle you use many small tanks that have triple collars welded to the tanks and then bolted to the frames of the vehicle as well as to each other so if one or more get broken they won't fly off and kill some one. Of course compressed air can cut someone but if you have a aluminum panel above the tanks with carpet over that or some other strong covering I think it would be unlikely the pressure would cut through that if the tanks are properly secured to the frame of said vehicle. Also each tank can have a solenoid valve or the like on it so that you or a computer can open each one as you need them so that if one or more tanks are ruptured they wouldn't get more high pressure air from the others.

As far as noise is concerned there are lots of ways to deal with it that I'm not aware of but one is a very small simple device used on hyperbaric chambers and now ATV's and generators the does not restrict the air flow but sends the air in all different directions which makes the exhaust very quiet. One good brand is called the Toy Sneaker since it's used on ATV's so they can sneak up on elk and the like when hunting.

I'm well aware that it takes allot off energy to compress air but the source of that energy is always changing and getting better so just because we can't currently make all the energy clean and easy to get does not mean it can't be that way in the future.

Cheers

Dennis Gearon said at February 4, 2007 4:29 PM:

The REAL 'Final Solution' to personal transportation, is to do away with it - except on a use as needed, rental basis. Have Mass transportation wherever possible, and rent personal transportation at the endpoints. Even the use of the Segue would fit into that quite well. (BTW, the Seque is the lowest 'fuel cost' per mile of any vehicle short of a bicycle or sail powered vehicle.)

The infrastructure would be space developed electricity beamed to the Earth as microwave energy. The batteries would be CAPACITORS. www.treehugger.com/files/2006/03/eestor_capacito_1.php

The reason is that all future energy will have to be non polluting. Cars need PORTABLE energy, and since putting energy into capacitors is VERY efficient, and involves no conversion to chemical or thermal stages, they are the most efficient, non polluting way of carrying energy for moving cars.

The current calculations for using CAPACITORS for a car with a total energy storage of 200 HorsepowerHours (a compact car) is about $88,000 (2006-02-02 using carbon foamed 'Super Capacitors'.) Obviously, this is not realisitic.

The INTERMEDIATE solution is tri powered cars - Extremely optimized internal combustion engine, batteries, and a burst source of energy (Capacitors, compressed air, accumulated hydraulic pressure, even a tightly wound spring with gears) for increased acceleration from stop signs and for passing at freeway speeds. The burst energy would probably be set for 10 to 30 seconds of total duration, and about 1 to 5 minutes for recharge. To keep idiots from killing themselves by passing w/o enough burst energy, some BIG indicator would be required showing burst energy availability. A good example of this is:

www.worldcarfans.com/news.cfm/newsID/2060724.006/page/1/country/ecf/lang/eng/mini/pml-builds-640hp-electric-mini

I USED to think that Fuel Cells, ("so simple"), would be the 'Solution'. But all the discussions on this blog, and other places, show the following:
A/ Hydrogen only comes from electrolysis, chemical reaction from certain mixtures of substances, extraction from hydrocarbons, or cryogenic extraction from air. The only ones of those with enough available quantity to power the planet's cars are electrolysis and chemical reactions.
B/ Electroysis is inefficient and still demands a non existent source of global electricity big enough.
C/ The existing materials for chemical reaction and then throw away the byproducts are not in enough supply. However, using some of existing materials for storage will probably be the best choice for hydrogen, since certain things like Borax hold large amounts of hydrogen in them. But this will require electrolysis as the source of the hyrogen, and simply adds two more stages of conversion efficiency ( into the 'Borax', out of the 'Borax')
C/ the conversion efficency of the Fuel Cell itself, after all the conversion/storage inefficiencies of the hydrogen fuel, just mulitiplies the total inefficiency of the hydrogen car.

It's better to convert solar energy (limitless) in space so the heart from solar energy absorbed but not converted to electricity due to solar cell ineffciencies stays in space, GET solar energy on Earth in the form of electricity (via microwave) and store it as electricity (in capacitors) or transmit it via distribution wires.

(As a side note, transporting charged capacitors on rail cars might be a LOT more efficient than sending electricity down transmission lines)

If the solar energy were taken in via satellites over the poles, we could kill two birds with one stone. Bring energy to the planet, re cool the Earths rotational poles.

Jay Dillon said at February 26, 2007 6:26 AM:

Using photovoltaic rooftop, you can partially and continuously recharge your compressed air tank not only when it is parked during the day outside, but also when you are driving your car. (Recharge is also done using regenerative braking and/or air braking through a wind electric generator onboard.) I found a portable photovoltaic solar air compressor online at http://www.solar4power.com/store/005-001-portable-solar-power-devices.html . This device is only for 250 psi or perhaps somewhat greater. Some of the compressed air could be used to run a very small Ranque-Hilsch device to cool input air as it goes into the compressed air tank such as QTWW air tank. If practical, perhaps even a small amount of frozen air or supercooled air will boost compression efficiency enormously; and this is what the Ranque-Hilsch device does. In fact, it might be best to use one portable air compressor for the Ranque-Hilsch cooling alone, while another compressor provides compressed air to be cooled by Ranque-Hilsch prior to being compressed into the air tank for storage and use. Anyway with an efficient system especially a superefficient engine, even the relatively low but continuously regenerated 250 psi provided by portable solar air compressors could be made more effective. Is it possible to utilize the Tesla surface boundary layer effect turbine patented early 1900s, to produce higher torque from lower input air pressure? (as compared to a piston engine). Also the system would be made more efficient if lightweight materials can be used such as carbon fiber or graphitic fibers for all parts of the car structure and exterior surfaces. I think it is also worth considering that any car of this type would normally be built by gearing shaft power to the wheels, although it seems likely that the same power applied to turbofans might be better and eliminate need for roads, bridges, tunnels etc. Even if you take the power of the system to run air powered turbofans for thrust (and reverse them for air braking/regenerating) on road surface, this would obviate the need for gearing and shaft power linkage to the wheels, thus reducing weight of the vehicle greatly. (I have more ideas along these lines but have no engineering lab or skills so please excuse me if I am making some overly optimistic assumptions.)

vince said at February 28, 2007 6:51 PM:

hey! i think this is a great site and there are great minds here. i live in Detroit, MI and would love to share my idea's and/or work with someone on a Air powered car. i dislike the use of pistons and cylinders in compressed air cars. i have some other compressed air motor idea's that could be more economical. if anyone is interested and lives near Detroit please send me an e-mail at: trancesounds@hotmail.com

thanks
~vince

Mahesha said at March 4, 2007 6:49 AM:

I gave up...

I couldnot not read till the end before I ran out of my patience. Well let me ask these simple questions.

1. Are we assuming that total cost to run an air car (or any other new type of car) will work out cheaper than the car that runs on gasoline.

If the answer is yes, then how do we justify it. Let us try to answer the following few questions get a better idea.

1. At the present rate of gasoline (2.5USD per gallon) and average fuel efficiency of the cars (25 miles per gallon), it costs 10 cents per mile. Now the question is how much it costs to travel 1 mile by an air car. Can anyone please answer this if you have information.

2. From my reading, I am sorry to say that majority of you do not understand that basics of energy systems. You may say air comes free of cost so cost to run a mile on air car is NOTHING. But please remember that you are using an electric motor to compress air. Now my question is, how much electricity (in Kilo watt hour) is required to compress air that is sufficient to run the air car for a distance of 1 mile. If this cost is 10 cents (cost for gasoline) then it makes sense to look at the air car (or any other car that one is proposing).

3. If we were to fill the compressed air at nearby air station, how much we need to pay to fill enough air to run 1 mile (is it less than 10 cents).

4. A related question would be, how much air is required (volume and pressure of required air) to run the air car for 1 mile.

5. What is the cost of the air car (a normal gasoline car costs about 20000 USD) and what is the expected life of the air engine ( gasoline engines lasts atleast 100000 miles).

Well, I broused through the websites of both www.engineair.com.au and www.theaircar.com but found no information. It is clear that these guys do not want to give out these information, because it is not favorable yet. So the moment the people understand that it is not economical, people will quickly loose interest.

Mahesha.

Daroga Mishra said at March 7, 2007 6:34 AM:

I am preparing seminar on Air Power Cars (CAT).
Can some one please send me some good presentation material with some nice video which i can save on my desktop.
Thank you in advance.

Daroga Mishra said at March 7, 2007 6:35 AM:

Sorry i forgot to mention my mail id ..

It is mishra.daroga@gmail.com

Alex Thuronyi said at April 12, 2007 10:41 AM:

Goals of air cars:

1) transfer impact of energy generation from urban centers, to improve local air quality.
Alternatives: Public transportation, such as light rail, buses with overhead transmission lines like they have in the Boston suburbs.
2) transfer the generation of power from a relatively inefficient IC engine to a central Power Plant with greater efficiencies.
Alternatives: Batteries...
How to evaluate? Compare environmental costs, manufacturing costs, relative efficiency, relative range, time to recharge.

Primary goal of any sort of alternative energy generation: reduce costs associated with generation of energy. (There will always be some.)

Most efficient way to consume energy? Don't. Stay at home, pump (relatively)cool air out of the ground in the summer, (relatively) warm air out of the ground in the summer, grow crops in your back yard. Walk. Think. Slow down. Quit your job. Take up time-consuming hobbies. Poverty is a virtue.

Alan Henderson said at April 14, 2007 9:52 PM:

I've been working with compressed air for 40 years - air compressors, air motors, air turbines.
This is a pipe dream.
Compressing air is a very inefficient process. These engines will use far more energy than my conventional diesel.
Thermodynamically it just doesn't add up and I don't doubt that the peddlers of this snake oil know that.

Dave said at May 15, 2007 9:04 AM:

Very interesting.

One thing we haven't mentioned is this.....SAFETY. Cars going down the road with high pressure tanks strapped to them. What happens in a crash? Wouldn't it be like a bomb going off? I know that compressed cylinders in welding shops become missiles when dropped and the regulator breaks off. Right through cement walls. Seems like that issue needs to be addressed before we worry about whether it's efficient or not. Just a thought.

Frenchie said at May 27, 2007 11:38 AM:

Hello,
I'm a french student, in two years I will be an engineer student and I'm preparing a report about the MDI air car. Could anyone tell me more about the compressed air motor's working? Actually I'm looking for a thermodynamical study of this motor, and I hope it's not under a patent.I let my e-mail: emilie-re@hotmail.fr

Thanks

Åke Olofsson said at May 30, 2007 6:47 AM:

Hello,

I am interesting in rotary machines for compressed air and for combustion engines. I would be interesting with comments about my invention on WWW.AUCON.SE

Åke Olofsson

CP said at May 31, 2007 2:15 AM:

What a thread!

Tata says they will build an MDI-based air car next year. Maybe.

It seems pretty clear that www.engineair.com.au rotary engine would be better in many ways, so one wonders why they went for MDI's engine.

I'm struck by the thread above from Doug Hubbard (December 28, 2005) that says 300 litre bottles holding air compressed to 300 bars would have less energy than a Kg of gasoline. I know the ambient temperature of the compressed air makes a huge difference, but can anyone else confirm the miniscule energy in the compressed air tanks? I've heard that the compressed Nitrogen in some of the hydraulic hybrid trucks being tested only holds about 2000 HP seconds, which takes a truck about a half mile, so that seems to be a significant indicator this is a very constrained energy storage technology. Light-weight components and optimized conversion techniques don't get around that very much.

Dave said at June 1, 2007 8:21 AM:

That is true......unfortunately.

Safety is a huge issue too. I'm just not sure this is the direction to go. It would make more sense to concentrate on solar and wind collection and use electric cars. Clean, quiet (have you heard those air cars......just like a gas engine)and completely renewable. Compressing air is just another step stealing energy from the source. We are so used to processing everything like our food, that we don't realize the vast amount of energy stolen or consumed by preparation. Why use electric to compress air, when you can just use the electric?

Robert Bogoslowski said at June 7, 2007 12:18 AM:

Please read the previous post from "Mahesha" about cost per mile (or p/km) and total cost per vehicle. It is a very truthful insight. I am sure the operating costs are far greater than those of what we run now. Would anyone with an average job be able to afford $100,000.00 US. for a vehicle that can't even get to 55mph (100kmh)??? I think not! The research and development invested into these projects have to be paid for somewhere (A.K.A. Consumer, IE: U & ME!) because the people that have invested thier money expect a return. That is why it is called investing. There are other design possibilities and better ways to re-engineer the vehicles we have making them energy efficient as well as pollution free. I have had an idea for a design that would work as a retro-fit for 90% of the current vehicles we use today with self generating power. it is not quantum mechanics. To create a device such as this is very cost effective but it isn't fuel efficient. The power suppliers we use today all supply fossil fuels from crude oil. Imagine if you would at current ($60.00us per barrel) stopping consumption virtually overnight. Shipping rates would skyrocket! Postage would go through the roof! and your average heating/electricity bill would be so expensive that you would have to be an oil broker to get your lights on at night. So when thinking about all of these nifty pollution free cars please consider this statement: Can this design be used for all fossil fuel usage? Please think about all of the demand we have today for fossil fuels even a simple campfire burns! I am not kissing major oil co's butt. I am trying to enlighten a few minds and get a creative spark ignited. Think on a global scale not just your garage.

A. Nother Person

AUGOLDMINER said at June 13, 2007 7:31 PM:

If you look at electric cars the major part if the power consumption is used to push the batteries around. Some pure battery powered cars the battery weight close to a half ton.

Carbon fiber wound air tanks weigh only a small % off that.

For a diesel air hybrid the air tanks would weigh a lot less.

And what many do not know is batteries in hybrid cars are highly dangerous. They are explosive when charged and when they explode they throw acid in all directions. The fumes are a hazard. Short circuits are a greater hazard due to the hydrogen released during a sudden discharge.( FIREFIGHERS ARE NOW REQUIRED TO TAKE SPECIAL TRAINING FOR HYBRID CARS)
The toxic metals used in them are a hazard to work with and some day they will have to be recycled.leaving hazardus waste to be desposed of.

Air tank are a lot less dangerous then batteries. Air tanks can be rapped in a foam capsule that will protect them a lot better then batteries that can not be rapped.

Built right a air diesel hybrid car could easly last 500.000 miles between overhauls.

Battery hybrids will need the batterys changed every 10 years or less.

A air diesel hybrid could use the waste air from the air motor to supercharge the diesel engine letting it run cleaner and be smaller and could also be run off biodiesel

Also wrecked air diesel hybrid could have there power units pulled for use for as power supples for other projects.

I have over 30 years working with air powered mine equipment and have used the old air powered loccomotives and other air motor powered equipment.

AUGOLDMINER said at June 13, 2007 7:51 PM:

If you look at electric cars the major part if the power consumption is used to push the batteries around. Some pure battery powered cars the battery weight close to a half ton.

Carbon fiber wound air tanks weigh only a small % off that.

For a diesel air hybrid the air tanks would weigh a lot less.

And what many do not know is batteries in hybrid cars are highly dangerous. They are explosive when charged and when they explode they throw acid in all directions. The fumes are a hazard. Short circuits are a greater hazard due to the hydrogen released during a sudden discharge.( FIREFIGHERS ARE NOW REQUIRED TO TAKE SPECIAL TRAINING FOR HYBRID CARS)
The toxic metals used in them are a hazard to work with and some day they will have to be recycled.leaving hazardus waste to be desposed of.

Air tank are a lot less dangerous then batteries. Air tanks can be rapped in a foam capsule that will protect them a lot better then batteries that can not be rapped.

Built right a air diesel hybrid car could easly last 500.000 miles between overhauls.

Battery hybrids will need the batterys changed every 10 years or less.

A air diesel hybrid could use the waste air from the air motor to supercharge the diesel engine letting it run cleaner and be smaller and could also be run off biodiesel

Also wrecked air diesel hybrid could have there power units pulled for use for as power supples for other projects.

I have over 30 years working with air powered mine equipment and have used the old air powered loccomotives and other air motor powered equipment.

Mike Rose said at July 21, 2007 10:58 PM:

Haven't all these questions on alternative
power in general, and air cars in particular,
already been answered?

I'm building a prototype 2-wheel car and I've just
scored a tiny turbocharged 16-valve twin-cam engine
with a multi-speed transmission. That neat power
unit at "only" 250 lbs is the lightest way I can
harness 100 horses. It's ready to drop
straight in, but it's still far more weight
than I need to power my bamboo-plywood aerodynamic
ultralight insanely over motorway cruising speeds.

Have we forgotten just how little power we
actually need, provided we get the design right?
We pay a very high price for the complexities
of 4 wheels, as 90% of travelling time there's
only the driver: we rarely need space for
more than 2 people. Tandem seating gives
luxurious space in streamlined comfort.
My passenger's legs are so long, her feet don't
even touch the back of my seat *grin*

We only need 2 wheels, power requirement
is down by 400%, weight is similarly reduced.
The Acabion prototype 2-seater will out-tonk any
2-seat Lamborghini, while consuming one sixth
of the Lambo's fuel.

My own design is too radical for public disclosure
right now: so here's a couple of websites guaranteed
to keep your eyes on the screen the rest of tonight:
http://www.peraves.ch
http://www.acabion.com

I've finally realised that ALL the information
I need is available now: an entire encylopedia
all on DVDs, all on Air Cars, and all for the
cost to fill the tank of your average family Ford.
(er, sorry family, it's the Ford that's average)

Scott has devoted the last 28 years to collecting
this stuff, and I think it's a priceless goldmine
of info. He's made contacts with the right guys,
and the obvious questions which have been so
often asked on this website, are all answered.
It's NOT perpetual motion, but it IS inexpensive,
it IS practical, it IS for real, and it IS available
now... provided we're prepared to follow instructions
on available plans.

Anybody wanting 21st Century technology right now,
grab it while Scott's website is still online.
Don't wait for E**on to buy him out ;)

The info is available direct from Scott at
http://www.aircaraccess.com/encyclop.htm
Send him a blank email, and he'll respond with
an unbeatable offer to send you all of the largest
research library on air car stuff in the world.
All your donation goes to Scot's research kitty,
I don't get any affiliate fee ;)

Then if you're not able to or willing to make your
own air car, have a quiet word with me, and let's
see if I could help you for the right price ;)

BTW If anybody is still determined to set
world speed records, I've planned an aerodynamic
100 BHP 2-wheeler weighing about 500 lbs.

It will feel like a Boeing at zero altitude,
with far more armchair comfort and way
better onscreen entertainment.

But don't start me on that mythical Pentagon
Boeing at zero altitude, not to mention
911 conspiracy theory Boeings that never
flew anywhere near WTC...
....that's all way off topic.

Mike Rose
Auckland, New Zealand
marros@clear.net.nz

Maurice O Hanlon said at November 9, 2007 8:53 AM:

Hi. I am studying Mechanical Engineering in Napier University in Edinburgh and I am doing a project on Compressed Air Powered vehicles. Please could you send me some information about the engine design etc. Thank you. Maurice

Jay said at December 3, 2007 7:54 AM:

Commisioner of Patents
Provisional patent.
P.O.Box 1450
Alexandria ,Va 22313-1450

James W Blevins
6224 Dryburg Road
Scottsburg ,Va 24589

jay19482000@yahoo.com
www.wateredu.com
www.hurtback.org


A camshaft made that would fit in the existing cam area of an internal combustion engine
That would open the exhaust valve to drivethe piston down with pressure and the intake valve to exhaust air as the piston comes up and vice versa,the oil viscosity lowered,air put into the exhust manifold and vented from theintake manifold or vice versa .An iternal combustion engine could be run off of air.Pressure in the tank would be 8000 PSI with a regulator to lower it to 1000PSI.
Thank You
Jay

To make camshaft based up on the combustion cycle
2 lobes for each existing lobe or double the rpm of the cam shaft. and grind down the intake cam
Intake lobe to be .010 in with 6 degrees of rotation opening
Exhaust same lobe structure

At 500 psi the opening would be a lobe .010 in 12 degrees rotation.
A cubic foot of liquid air has about the energy of a gallon of gas and weighs 60 lbs.


Bill Todd said at May 12, 2008 9:46 AM:

I am investigating the use of using compressed air storage as an alternative for batteries in an off-grid solar system. One key advantage is potentially the savings of storage batteries that need to be replaced every 5 years and all the environmental ramifications that goes with that. Another might be cost; the deep-cycle batteries required are not cheap. I am also aware that compressors generate heat and can be noisy whereas batteries are nice and quiet. The system I envision is a compressor that derives its power from the solar panels, stores the energy as compressed air and has an alternator to generate the AC. I am not sure what the overall efficiency comparison to batteries might be. I would be interested in any comments the audience might have. Has anyone done this?

jay said at September 3, 2008 10:11 AM:

Hi ,
I am investigating on the same for hybrid of Compressed Air + Electric Power vehicles .
In the present scenario we can’t ignore the potencial of both kind of powers .infact this will be very practical also .
As highlighted by Bill “One key advantage is potentially the savings of storage batteries that need to be replaced every 5 years and all the environmental ramifications that goes with that. Another might be cost; the deep-cycle batteries required are not cheap. I am also aware that compressors generate heat and can be noisy whereas batteries are nice and quiet.” advantages and disadvantages of both and its very true . but in this way we can take advantages of both power and develop zero pollution and practical vehicles .
In one side the electric engines are more responsive , fast and almost sound less and vibration free ,in other side Compressed air engine provide additional power other than batteries ,low maintenance Zero pollution with cold Air ( That helps to decrease the Road temperature in many Asian countries ) . we can generate and store power from poluted fossil free sources like hydro power, solar,wind power etc.
Even the batteries cost ( Li –Mg for deep and fast storage ) will decrease when production of these will be in mass .

Plz mail me if any one want to contact me : sarvesh.jai.mishra@gmail.com

Regards
jay

jim said at May 30, 2010 3:44 AM:

Why not have a compressed air generator, to charge the batteries, and run car solely on batteries. Therefore the compressed air, could be used for extra mileage

Philip Wong said at June 10, 2010 2:06 AM:

Paul Dennis asked:
Suppose you build a large pressure container with a volume of 1000 cubic meters and let it fill when the atmospheric pressure was high in the day, then used the pressure difference when the atmospheric pressure was low at night to generate electricity. Assuming the low pressure was 95 kPa and the high was 105 kPa, how much energy could be produced? Actually, you could generate electricity twice a day, during the filling and emptying of the container.

Answer:
Under ideal reversible isothermal conditions, the energy that is stored is
= p1 * v1 * ln(p2 / p1)
= 95e3 * 1000 * ln(105 / 95)
= 9.5 MJ = 2.64kWh

Maybe it will be better to use the sun to heat the container to increase the air pressure.

Philip Wong said at June 10, 2010 2:57 AM:

http://www.efcf.com/reports/E14.pdf
Thermodynamic Analysis of Compressed Air Vehicle Propulsion

This report analyses the efficiency of air car.

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