Talk:Compressed-air car

message: There is an Australian television series "Beyond Tomorrow", which examine objects and concepts of the future. One of its episodes featured the Air Car, and the link to the episode can be found at:
There is an official website of the vehicle too, at: 
It is certainly not a hoax.
I agree.  If something appears on TV and has a website, it cannot be a hoax.  —Preceding unsigned comment added by 72.83.112.79 (talk) 02:32, 9 July 2008 (UTC)
replies: text: I agree, the thing exists and has a range of at least 7 km. However, whether it ever makes money for its investors is another matter entirely. So, to that extent it many be a financial scam. Greglocock 21:06, 9 November 2006 (UTC)

text: Theoretically it can go 7km on flat ground, but it only has to overcome friction, lets see it get up a hill. I could probably get a 9-volt Duracell battery to send a toy 7km if the ground were smooth. 24.17.29.190 00:07, 22 March 2007 (UTC)
replies: text:  Drag is the main resisting force at higher speeds. 75.37.14.12 (talk) 19:44, 16 August 2008 (UTC)

text: Pretty much, as anyone who has pulled or pushed a railroad car on a bit of flat track can testify.24.17.180.126 (talk) 08:37, 25 April 2008 (UTC)

text: Are you talking about the efficiency as mentioned here ? That seems to deal with temperatures rather than pressures. Are you sure it's directly relavant? And what kind of people gave the presentation? Marketing?Your second point is a good one. Existing car manufacturers just love throwing away their own research and investing in unproven technologies</sarcasm>.It could still be a hoax or fraud, but I find your arguments perhaps even less convincing than theirs. Either way, this talk page is not meant for such discussions. V 15:21, 23 February 2007 (UTC)
replies: text: Carnot efficiency is very relevant. It is the fundamental way of calculating the efficiency of any energy process involving the expansion of gases Greglocock 23:22, 23 February 2007 (UTC)
replies: text: Okay. V 00:11, 24 February 2007 (UTC)

text: Bear in mind that the original ridiculous claims for range on air-power alone have been modified, and that the current claims, while still unproven, are substantially less. Using hysterical TV programs as a source is dubious at best, particularly since the manufacturers own websites are far more conservative. At some point we are going to have to get to grips with the appalling passive safety of these vehicles, but I suppose the fanboys will destroy any rational discussion of that. Whoops, yes they did. It actually doesn't matter, these aircars will never be anything more than a curiousity. Greg Locock (talk) 12:26, 17 July 2008 (UTC)
replies: text: MDI has updated their web site.  Still long on conceptual drawings and speculative specs (http://www.mdi.lu/english/miniflowair.php).  I think it's pretty clear this is a hoax.  The SmartCar, at 1800 lbs. with a 1-liter engine, gets around 45 mpg, and could go 20 miles on 1.7 liters of gasoline on the highway; they're claiming 180 km (108 miles) on the equivalent energy in compressed air in a 1200-lb. vehicle, in city driving.  If the SmartCar has 25% efficiency, they're positing over 100% efficiency using a proven low-efficiency energy storage medium.  More to the point, however, they're now stating that the highway vehicle would be a hybrid, and would achieve 1500 kilometers (900 miles) on 1.8 liters of gasoline.  This is clearly perpetual motion country. Wikidondi (talk) 15:34, 18 December 2008 (UTC)
thread_title:  Clarification 

message: The sentence of the first point "Refueling can be done at home using an air compressor [1]..." is untrue and the website referred to does not claim this. Air cars require pressures of 4,500 psi, a home compressor has a maximum pressure of around 125psi. The car supposedly has a compressor built in, which can be run from mains power (this is claimed by the cited article). 73BlackWhite9 (talk) 20:41, 22 February 2009 (UTC)
replies: text: Well, I suppose the editor was suggesting that a company that has been promising to introduce this innovative technology for 10 years, at an amazingly low price, and yet has conspicuously failed to justify ANY of their performance claims, and that relies on investors for its income, may not be a particularly accurate source for estimated prices. It is hard to see how a vehicle can be sold for around $5000, when for example most electric cars with a reaonable range have prices of $15000 and upwards, excluding batteries. The inability of governments to tax air cars will merely stretch their ingenuity a very little, I agree. Greg Locock (talk) 22:15, 21 February 2008 (UTC)
thread_title: Removed from Advantages

message: Tata Motors and MDI signed an agreement very recently. Perhaps a place can be found for it in the article. V 02:15, 12 February 2007 (UTC)
thread_title:  recent news 

message: Should this article be about all air cars and not just the
ones from this particular company? --Gbleem 00:37, 3 June 2007 (UTC)
replies: text: I think it should.  At present this article reads like an advertisement for MDI and its products. -- Johnfos 05:24, 25 June 2007 (UTC)
replies: text:  Is Air car a generic term, for what I would be tempted to rename compressed-air car? It seems to me that MDI are using it as a registered name. Frankly, the whole article needs a rewrite anyway, it is far too credulous. Greglocock 05:37, 25 June 2007 (UTC)

text: Yes, I've added Cleanup and Rewrite tags. -- Johnfos 05:49, 25 June 2007 (UTC)

text: how so? Torpedoes were using compressed air engines in the late Victorian era, why is that not relevant?  Greglocock (talk) 22:41, 18 December 2014 (UTC)
replies: text:  More to the point, torpedoes were using (as MDI are describing) compressed air engines with fuel-fired heaters or reheaters. Andy Dingley (talk) 23:14, 18 December 2014 (UTC)
thread_title:  MDI Air car 

message: IMPORTANT NOTICE! I feel that it is only fair that I post this amendment to the matter that I had posted earlier, after working on the problem for some time, I have come to the following conclusion.  The MDI air car is NOT a scam. It does work, every bit of data supplied at the MDI air car web-site IS TRUE. The car does work as stated. A 320 litre tank filled with compressed air at 4200 psi (300 bars) WILL power the car at whatever speed is desired for 7 – 8 Hours.  The tank CAN be refilled at home using a 4KW compressor in 3 – 4 hours. The end conclusion is that the car is no more dangerous than carrying around a couple of filled scuba tanks in the boot!  DDjames 00:38, 20 October 2007 (UTC)
replies: text: Sorry, you are wrong. The air car does not do what they claim.  —Preceding unsigned comment added by 75.37.14.12 (talk) 19:47, 16 August 2008 (UTC)
thread_title: Amendment

message: One of the most seemingly convincing claims for MDI is that they have a deal with Tata Motors.  This is repeated endlessly across the web.  Well, I was just on the Tata site, and did a search on compressed air.  The site has two articles about the use of compressed air in the factories that manufacture ICE- driven cars, but no mention of a current or prospective compressed air-driven car. 
This tends to confirm the view, stated elsewhere on this discussion page, that the compressed air car has no potential to be a practical vehicle, due to the low energy density of compressed air, which is limited by the laws of physics, but is simply a way to make money by selling manufacturing licenses.  —Preceding unsigned comment added by 71.191.145.53 (talk) 02:17, 16 September 2008 (UTC)
replies: text: Two years have passed since that original announcement. The Tata air car was supposed to be out in 2008. Now all Tata talks about is the Nano. Looks to me like MDI's air car failed to make the grade .. even in India. "No its not dead, its resting."ToolmakerSteve (talk) 06:49, 15 May 2009 (UTC)
thread_title:  Tata deal for real? 

message: I do not believe such a deal exists.  I could find no reference to it on the Tata site.  The so called "reference" provided simply pointed to another Wiki page, which had a reference which pointed to a third Wiki page, all presumably written by the same shill for MDI.
You can find claims all over the web citing this relationship, but no reliable sources attested by Tata. 
I do not doubt that MDI will restore the claim, but the only way to avoid an editing war is to point to a press release on Tata's site announcing the original deal, and if that deal is more than a year old, announcing recent progress.  —Preceding unsigned comment added by 71.191.145.53 (talk) 02:28, 16 September 2008 (UTC)
thread_title:  Took out the part about a deal between Tata and MDI 

message: Can somebody find a good reference for the statement that it is more efficient to burn fuel in a power station, generate electricity, transmit it to a pump, and compress air in a tank, than it is to fuel a car directly? Given that the power station could be burning brown coal (etc) Greg Locock (talk) 07:49, 14 January 2008 (UTC)
replies: text: For instance I found this (unreferenced) "Electricity from fossil fuels burned by public utilities in the USA in 2005 averaged 33.4% efficiency,". The efficiency of the power grid is well known. The efficiency of the air pressurisation process is easily calculable. I shan't put this into the article since apparently multiplying 3 numbers together is OR.  SO... unless someone can find a good reference that supports the claim in the article, out she goes. Lest anyone is under any other impression, I fully acknowledge that I think MDI is primarily a financial construct and will never make money for its licensees or make a significant contribution to reducing emissions. Greg Locock (talk) 21:51, 23 January 2008 (UTC)
replies: text: In any case, for an encyclopedia, there sure is a lot of time spent DEFENDING this technology (references or not), rather than just stating the facts, and leaving it alone.  Youdontsmellbad (talk) 05:56, 20 April 2008 (UTC)
thread_title:  Emissions Dubious tag

message: Is the PHEV link messed up? --Shanedidona 01:43, 14 August 2006 (UTC)
thread_title: PHEV

message: I've added the section comparison. Although my statements can easily be proven, I havn't found a reference. --Theosch 08:52, 26 January 2007 (UTC)
thread_title:  Comparison 

message: The sentence about Energine: The domain energine.com exists but it isn't being served and there is nothing in the Google cache except possibly a Flash video. I suggest removing this sentence a few weeks from now if the site is still down. --Theosch 08:55, 26 January 2007 (UTC)
thread_title:  Cleanup required 

message: Merge with Compressed-air vehicle?
I suggest this page is merged with the very similar page, Compressed Air Car
--
Tones22 (talk) 17:18, 20 March 2008 (UTC)
replies: text: AGREE.  The two articles are very similar -- actually the Compressed-air vehicle article is superior as it reads less like an advert.  71.199.115.131 (talk) 12:59, 31 May 2008 (UTC)

text: DISAGREE - the vehicles article covers all the various types of vehicle, this one is just for cars. Remove the advert stuff from this article instead. Greg Locock (talk) 23:44, 31 May 2008 (UTC)

text: You can see compressed air vehicle and improve it. --Mac 13:12, 24 October 2007 (UTC)

text: Both articles cover very much the same area. In fact, the advantages & disadvantages are for the most part copied verbatim. I suggest the articles be merged and a subsection be added with additional information on compressed-air passenger vehicles. Also, I agree that this article reads like an ad. I have made some changed to the pros & cons, but the entire article is pretty much a mess. — Stimpy talk 00:54, 17 July 2008 (UTC)
thread_title:  Merger proposal 

message: Regarding - "This confusion arises because hydrogen, electricity, and compressed air, are all energy transfer methods, not actual sources of energy." Electricity is energy, hydrogen can produce energy through combustion or by other means such as a fuel cell, and compressed air has a great deal of kinetic energy; however, it is simply incorrect to call them energy transfer methods. I have therefore deleted the offending sentence. --Darkdaedra 04:20, 20 March 2007 (UTC)
replies: text: The amount of energy that gets one to their place of work constitutes a 'useful range'. You haven't addressed the weight of the vehicle, the driving profile (i.e., SAE, etc) nor aerodynamic drag (CDa) in your calculations. 66.225.251.176 (talk) 22:44, 13 February 2008 (UTC)
replies: text: And yet I answered the question that was asked. Read for comprehension next time. Greg Locock (talk) 01:14, 14 February 2008 (UTC)
thread_title:  Emission Free? - Cleaned Up 

message: curiousity :o)
if the air is already compressed send it out of something like a water sprinkler? why drive a piston and a crank shaft?
::A piston and crankshaft is more efficient - you get more of the energy back if you expand it via a piston and crankshaft. Even modern jet engines are not as efficient as a normal diesel engine, largely because of this.  Greglocock 11:19, 25 March 2007 (UTC)
replies: text: Some research has been done with scroll expanders. A paper from the University of  Southern Illinois said they reached high efficiency at relatively low pressure differences (in an Organic Rankine cycle). פשוט pashute ♫ (talk) 17:52, 13 March 2011 (UTC)
thread_title: cool stuff

message: Where are the safety reports for the vehicle?  30 MPa (4500 psi) is no laughing matter.  Getting hit at 100km/h would probably cause some pretty intense air to expel from the tank if punctured.  Probably safer than a propane tank leaking by a exposed flame... but if one of these tanks even gets a small hole, the pressure would probably be able to cut a hole in someone.  Would the material mushroom out, the tank explode, a puncture slice through things, a burst under the car flip/launch the vehicle? - Jasonlouie 17:39, 16 April 2007 (UTC)
replies: text: It has indeed been shown that a tank of compressed air, when released all at once, has enough energy to take it through a brick wall, and still have enough energy to cause a significant dent in metal. Shadowedmist 03:53, 27 May 2007 (UTC)

text: A 1500psi release (without combustion) can obliterate an entire room and collapse the ceiling and floor.  This car uses a 4500psi tank.  The driver of this car has a death wish. --128.135.60.4 07:08, 31 May 2007 (UTC)

text: They mentioned on the Beyond Tomorrow video that carbon fiber tanks split but do not release shrapnel and are therefore safer than aluminum tanks. --Gbleem 00:36, 3 June 2007 (UTC)
replies: text: Even though the material does not release shrapnel the force of the air being released would still be much more lethal than hitting another type of fuel such as battery cells, petroleum gas, or even propane, (minus the heat source to ignite).  Even on Mythbusters a 3000 psi Oxygen tank smashed through a brick wall and nearly a second brick wall.  Unless there are significant safety measures that can prevent this, it will never meet safety standards to be on the road. -- Jasonlouie (talk) 05:59, 20 March 2008 (UTC)
thread_title:  Safety? 

message: I'm tempted to put a POV tag on this article, since the last time I visited this page, the section on the comparative green house gas emissions of air cars and IC engines has been rewritten; I presume by IC adherents. I believe that the fact that 78% of French electricity in France is generated by nuclear means, would be a significant factor in reducing total green house gas emissions  if the air car was widely adopted in France. The French could expand her nuclear power production to total replace the need to burn fossil fuels. You might dislike nuclear power and there are disadvantages to its use ( you might decide you prefer green house gases to radioactice waste), but to just delete this section smacks o dishonsety.Koonan the almost civilised 11:33, 27 June 2007 (UTC)
replies: text: I'd stick a POV tag on it anyway, since it reads like an ad. But to answer your question -why would the emissions status of a very small market, globally, be considered significant? The marginal electricity used, even in France, (that is, the extra electricity generated specifically for this application) is likely to be fossil fuelled.  Greglocock 12:32, 27 June 2007 (UTC)
replies: text: Actually with the French propensity for energy security, I'd suspect that they'd build more reactors. However that point could be made rather than just ignore the fact that emissions could be reduced. Yes France is a special case, but this is the market in which context MDI is designing for, what would make sense for this market, high "clean" electricity production, and its train network that mitigates against the need for long distance car journeys means that the aircar could be viable in this market. To highlight the point that the aircar would only be viable in such special circumstances could actually be a used as a put down. As to the significance of reducing greenhouse gases in a small market, every little reduction in overall emissions helps. POV wise I must admit that I'd like this project to come to fruition and work, even if just in niche markets, however I'm not going to hold my breath, nor will I be surprised if the whole project ends in failure. What I really don't understand is what seems to be the active dislike that the project seems to inspire in some editors.Koonan the almost civilised 14:26, 27 June 2007 (UTC)
replies: text: Active dislike? Yes, I actively dislike articles that support projects that stink of investor-manipulation, based on an idea that cannot live up to the hype. Predicting a 200km range on the basis of one vehicle that got to 7 km is absurd. Since the licenses have been sold worldwide I see no reason to limit analysis of emissions to France.Greglocock 23:01, 27 June 2007 (UTC)
replies: text: I've just stumbled into this page, and my response is also "active dislike". This article is based on unsubstantiated claims by one self-interested party. Is "wishful thinking" enough justification to be in Wikipedia? NO. There appears to be a fundamental problem of density of energy storage; I'd like to see a reference to some comparison with batteries and with H2 fuel cells.  Also there is a serious problem of the INEFFICIENCY of converting electricity to compressed air, as mentioned by an environmentalist in [1], though I haven't seen a reference with numbers yet. So the "active dislike" comes from not wishing to join in this unsubstantiated self-delusion. If there is a reference that can prove otherwise, that would be great, but without that...ToolmakerSteve (talk) 06:03, 15 May 2009 (UTC)
thread_title: pro IC POV ??

message: It appears, from the bit and pieces that I've seen, that there are two possibilities for air-powered cars. Therefore, in rewriting this article, it can start out in a much more generic fashion, with more details following, specific to each kind of technology.
The first kind is MDI's CAT technology. Developed by Guy, in Nice, France. We've seen some prototypes, and heard that the Indian car maker Tata intends to start making some. 
The second kind, taking up half of this Beyond Tomorrow clip, comes from Melbourne, Australia, and was developed by Angelo Di Pietro. A Google search tells me that the company EngineAir R&D is running with this idea. From the video clip, and the website (and other places), there's a lot of info to fill out this article with info on this 2nd type of compressed-air technology. Especially, discussion of how the rotary engine works, how it's different from an IC engine or from MDI's engine, and how wear & tear aren't as much issues with this engine. 
Now, Angelo's rotary engine prototype is a trolley (small industrial truck, similar to a forklift) as opposed to something that looks like a production car, but it still looks like a possible way of using compressed-air innovations to operate future automobiles. Doran Routhe 05:39, 15 July 2007 (UTC)
thread_title: Generic Air Car Rewrite

message: I do not know much about engineering so I would have needed extensive help. I had a similar idea but my idea was to use an electric motor to get up to speed and for slower speeds. My idea was to have an air intake behind the front grille and once the car generated enough wind from its speed it would kick in the compressed air tank, and would then work similar to the non IC engine. Filling the compressed air tanks from the front air intake, I believe that with the proper sub method this would not only keep the air tank full but the turbine in the engine might also keep the battery charged up.
I welcome your thoughts. If you believe my idea is utter tripe say so politely. On the other hand if you think it has potential spread it around.
--Ghaulx (talk) 03:41, 26 January 2008 (UTC)
replies: text: Sadly that will not work. That is, it will always take more power to force the air into the tank, than you will get from the air to propel the vehicle. The basic reason is known as 2LOT. Greg Locock (talk) 05:31, 26 January 2008 (UTC)

text: "My idea was..." Believe it or not, this isn't a forum. There are green/alternative energy sites that are the appropriate place to discuss such ideas.ToolmakerSteve (talk) 06:07, 15 May 2009 (UTC)
thread_title:  I agree That this idea seems  feasible but... 

message: Seems to me efficiently fits better.
"There is already infrastructure in place for creating massive amounts of compressed air inefficiently"  —Preceding unsigned comment added by 24.207.179.67 (talk) 06:27, 26 February 2008 (UTC)
thread_title:  inefficiently in advantages? 

message: this is a copy from Griminis talk page
Please, visit www.theaircar.com, in the home you will find an important news where this point catches on: '...This being said any affirmation of fraud can be criminal and constitutes a serious fault of the truth of which the viability is being studied by our lawyers at this moment.'.
I think this is not the place for this discussion. User:Grimini 29 February 2008 (Talk | contribs)
:I agree wikipedia is not the place to discus if the accusations are true or not. But mentioning that MDI accuses Celades is not the same as saying the accusations are true. Instead of removing the reference to the accusation, you could've added something like:
:"In response to the statements made by MDI, a notice has appeared on the AirCar website disputing MDI's claims."
:Next time, use the talk page of the article.V (talk) 17:35, 1 March 2008 (UTC)
replies: text: That link is currently broken, try this one. Grimini, you have not explained why that sourced information should not appear on this article. Until you do so I will reinsert it. Greg Locock (talk) 03:35, 9 March 2008 (UTC)
replies: text: I believe that it is only in the interest of fairness that this dispute be mentioned in the article, though only by a sentence or so. I have inserted the statement that the two firms are locked in a bitter dispute. I did add sources referring to both sides of the dispute. If anyone cares to look further into the particular nature of the dispute then they can view the links. Piercetp (talk) 20:13, 26 July 2008 (UTC)
thread_title:  theaircar.com vs. mdi 

message: Pro:
*Compressed air not subject to fuel tax at present (one taxing method would apply also to electric cars by taxing the electricity used for compression or charging).
Con:
*Governments would either lose tax income or have to adapt their taxation strategies.
Discuss. --70.128.112.146 (talk) 12:06, 18 June 2008 (UTC)
replies: text: These are not inherent pros/cons of the technology, so I don't think relevant to this article.ToolmakerSteve (talk) 06:10, 15 May 2009 (UTC)
thread_title:  Advantages/Disadvantages 

message: see WP:DEADREF - the wayback machine is an acceptable source for a dead webpage. The link in question is . Obviously there is no practical use for a car with a range of 7.22 km, therefore all we need is a reliable source for a measured range of more than 7.22 km. Otherwise it remains as a gross disadvantage.Greg Locock (talk) 12:15, 14 July 2008 (UTC)
thread_title: Range

message: Many of the exaggerated performance claims that are being made assume that some fuel is being burnt in the engine. Surely this no longer qualifies them as pure air cars, and renders much of the wittering about emissions free at the tailpipe etc irrelevant. So I think this article should clarify exactly what claims are made for pure compressed air cars, and those which might be described as internal combustion engine/pneumatic hybrids. Any objections? Greg Locock (talk) 23:10, 15 July 2008 (UTC)
thread_title: Fuel assisted air cars

message: is that electricity is an all-use energy nowadays. you power your stereo, your lights, anything. I think that is an obvious extra disadvantage as the electric car wouldn't need extra power sources. I guess there are may even be sources supporting it to be included in the article. --Leladax (talk) 14:54, 22 July 2008 (UTC)
replies: text: Um, no. Unless you believe an electric car is somehow plugged in WHILE you are driving. An electric car uses a battery to store power; an air car uses compressed air. Both cars plug-in while parked, in order to re-charge their form of storage. But more importantly, WE AREN'T SUPPOSED TO BE DOING ORIGINAL RESEARCH HERE: anything you think might be worth saying, GO FIND SOME RELIABLE SOURCE AND QUOTE IT!!! Hint: If you can't find such a source, that should be a clue.ToolmakerSteve (talk) 06:15, 15 May 2009 (UTC)
thread_title:  an obvious disadvantage compared to the electric car 

message: "The rate of self-discharge is very low opposed to batteries that deplete their charge slowly over time. Therefore, the vehicle may be left unused for longer periods of time than electric cars."
This directly contradicts the fact that air is heated when it is compressed, and will quickly cool down, losing a significant amount of energy in a matter of hours. 
Also, "Lower initial cost than battery electric vehicles when mass produced. One estimate is €3,000 less." Is completely rediculous. Anyone who's layed up carbon fiber knows how expensive and labor intensive it is.
75.37.14.12 (talk) 19:53, 16 August 2008 (UTC)
thread_title:  Advantages 

message: The article uses both Euros and Dollars. It should be more consistent and only use one. I'd recommend Dollars because the car market is larger in America than it is in Europe. Plus this is an English article and the US and UK more prominently use the English language than the EU countries, but neither use the Euro. 72.93.100.30 (talk) 15:06, 27 October 2008 (UTC)
thread_title:  Currency 

message: I quote "zero-emission power sources such as wind." The article is comparing different power production in different regions. However, the section neglects to include the indirect emissions from the manufacturing, fabrication, installation and maintenance of wind power sources. I believe this section is misleading, to the point where the statement makes the assertion that wind power has no direct or indirect emissions, of which is a factual misrepresentation.  —Preceding unsigned comment added by Frahnie (talk • contribs) 04:30, 21 November 2008 (UTC)
thread_title:  Emission Output 

message: The air car is working on the same basis as CAES (Compressed air energy storage) power plants that already work for 
20 years.The MDI air car also works but not as you believe just compressing the air ( and heating it ) in the air tanks and then just puting the compressed air to drive the air motor.There is the possibility to improve the thermodynamic efficiency by some tricks.The technology already exists. By the 2006 Internationale Salon for Inventions and New Technologies in Bruxelles an invention of Mr.Ion G. Nemes from  nemes.invent@gmail.com, called by the author "The Regenerative Isotherme"-the way to achive "Active Energy Storage" was awarded by  Gold Medal. The patented (RO-120353 B1) procedure is working like this: during the compression of a gas in one insulated , pressured tank, the gas is simultaneous cooled by some heat exchangers and the cold side od a heat pump achieving an isotherme which virtualy compress the gas for free : whole compression energy is recovered as heat.The extracted heat is stored in other good insulated device containing salts, vaxes or bitumen or other materials with high latent melting heat, melting them by the hot side of the heat pump.The own heat of the heat pump is also added and stored in the heat storing melted stoff.By the time of use the stored heat,it is used to heat the compressed gas inside the tank, by transfer tubing and by engine itself.If the expansion is an isothermic one, the whole heat is conversed into mechanic work .So the efficiency of the "Active Energy Storage Car" reaches virtually 100%.The technology is also very useful in the energy storage domain including peak power plants and wind energy storage .If the primary energy
comes from wind or solar station , the car is also 100% clean and economic worthy.There is also an older patented
(RO-116494 B)invention of the same author :the thermo-hydro-pneumatic (THP) engine, where the cooling and exhaust heat of any engine is recovered by a similar procedure to cool a monoatomic compressed gas inside one tank during the compression phase and to move the compression heat , using an absorption heat pump driven by the cooling heat , to an other tank to heat the already isothermic compressed gas (in prior cycle) before overheating it by the exhaust heat of the engine in order to expand and produce work.This engine was patented in 1992 and sent in 1993 to  all carmakers   ,institutes and publications like : Mercedes Benz, Ford , Wolkswagen,MAN,Combustion Institute , University of Wien,and magazines like Auto Bild ,Car Design & Technology ,etc. but nobody wanted to learn more about the invention.Let see what the future will bring !  —Preceding unsigned comment added by 84.232.168.232 (talk) 18:30, 11 March 2009 (UTC)
replies: text: Gaaah! What we need are REFERENCES, not discussions of whether this works or not.ToolmakerSteve (talk) 06:18, 15 May 2009 (UTC)

text: Great idea, and you can burn gasoline to heat the compressed air ! Wait... 76.209.223.126 (talk) 04:06, 14 October 2009 (UTC)

text: Also, you used too many words, and in your effort to sound credible, sound like a retard. Please 1) Take a thermodynamics class. 2) Draw a schematic and T-s diagram of the cycle because you obviously can't explain it in words. 3) Realize that the efficiency doesn't approach 100%, but rather 40%. 76.209.223.126 (talk) 04:10, 14 October 2009 (UTC)
thread_title:  The air car is working 

message: I note that both air vehicle articles cite (without reference) the claim that compressed air cars are lighter weight. I haven't been able to find any verification of this. After all, a given vehicle must be compared against one with comparable abilities. So the correct comparison is to a LIMITED RANGE vehicle, whether all-electric or gasoline. Similarly, how much torque does this air car generate? Compare to a gas engine with same torque. Looks to me like this car is competing with other mini-cars, that are also lightweight. Bottom line: should the 'lighter weight' claim be removed as unverified? I see that MDI's air cars use lightweight construction approaches, but that seems independent of their use of compressed air...ToolmakerSteve (talk) 06:56, 15 May 2009 (UTC)
thread_title:  Advantage: lighter weight -- I can't find any reference that backs up this assertion. 

message: I've removed 'by about 20%' from the reduced cost of production advantage, because the cited reference is MDI. That's not a good enough source to be that specific. I think the basic point of the systems that are eliminated is worth retaining .. though whether that OVERALL reduces the cost of the car is debatable. Especially now that Tata's Nano is a reality, demonstrating what can be done to make a low-cost conventional car. http://wheels.blogs.nytimes.com/2009/03/25/tata-nano-test-drive/?hp ToolmakerSteve (talk) 07:06, 15 May 2009 (UTC)
thread_title:  Reduced cost of production 'by about 20%' isn't sufficiently proven 

message: I have been looking into the issue of compressed air cars, my conclusions are that their validity is borderline.
I rather get the impression that air car developers are not so much fraudsters as over enthusiatic inventors who have wooed investors with claims that they seriously believed they could achieve, but have had trouble actually achieving due to unforssen difficulties. None of these difficulties have been total show stoppers, and so they continue to keep trying to fix the one last bit that will get them 'on the road'. As such, I would say that people who have not relised the investment they hoped for have been foolhardy investors rather than being conned. On the other hand I no nothing about what 'concrete' data was presented to potential investors.
Just to run through the issues:
1) It seems that Guy Negre was inspired by F1 racing teams who typically use a compressed air bottle for thier power tools, in particlar for the pistols used to change tyres and for starting the engines. A single compressed air bottle of high pressure air is enougth to power their tools over a whole race weekend, and provide air at higher than normal pressure for airtools. The motivation appears to be that it is simple, more reliable, and more portable than a high pressure compressor. However, whilst the tools that F1 mechanics use pack a high power in a small lightweight handheld device, they are used very breifly, there is nothing about F1's use of compressed air bottles that demonstrates it's praticality as a source of energy for motor vehicles.
2) Air cars do not seem to compete against convential cars, but against electric cars with rechargable batteries. In both cases the only ecological advantage per se of using air is that there is no harmful pollutants released in the environment where they are used. This is important for congested urban traffic areas and indoor use (where battery powwered vehicles are also deployed), but in both cases the overall emissions must take into account what was required to generate the energy used to compress the air in the forst place.
3) Comparing air cars with rechargable battery cars, using air to store the energy does not appear to have particular advantages. Compressed air can have a specific energy/weight ratio of around 40 to 70Wh/Kg, the higher figure assuming very high pressure lighweight carbon fibre based tanks of novel (and unproven) design. That figure is roughly equivalent to lead acid batteries, and is quite significant as it means that even for a modest performance/range vehicle, the air tanks provide the bulk of the weight, several hundred Kg. And in this situation youare working 'uphill', as carrying more energy means that you require more energy to accelerate the car, an important factor in a vehicle intended for urban/indoor use. Many electric vehicles use NiCad batteries, which have roughly twice the energy density. Lithium batteries have about three times the energy denisty but are also very expensive which limits their use, however the deployment of hybrid cars has led to major manufacturers taking steps to drive down the cost of mass produced high performance traction batteries. With better batteries the vehicle can carry the same energy with significantly less weight, hence improving the acceleration, range and efficicieny to the extent that it could carry even less energy to achieve the same performance, and reduce the structural requirements. Or in other words, doubling the energy density could yield e.g. a threefold increase in range. Air does not offer the same potential. Stored energy can be increased by increasing air pressure, but quoted pressures are allready at limits that are raising serious safty concerns. Even ignoring safty concerns, the weight of the air increases (air compressed to 100 times normal pressure weighs 100 times normal weight), plus one can saftly assume that at least a small weight increses will be required in the tanks to support the higher pressures. So significant gains in in overall energy density cannot be achieved.
4) Service station recharging of air vehicles is potentially quick, assuming the station has a large reserve of air to draw on. Batteries cannot be recharged quickly, however much instant energy is on hand. Theoreticaly it would be possible to 'recharge' an electric vehicle in less than a minute if the battery were detachable and could be e.g. swapped out from underneath using something like a fork lift, but I have never come across any serious proposals for such a scheme apart from a home pizza business who use electric bikes and have reserve batteries on charge that the riders can swap in when they ome in for fresh deliveries.
::Project Better Place is building such a system. Also there are batteries that can be 'recharged' at the same speed as a gas tank, but they are not much used. 
5) Home recharging is primarily limited by the limits of the domestic energy supply, which is small compared to the energy requirements of even lightweight vehicles, so several hours charging time will always be inevitable. If home charging of either type of vehicle became commonplace, it would be no suprise to see legislation comeing into place to restrict this. Not because of tax issues (they are easily resolved by our ever ingeneous politicians), but because of the overload it will present on the electricity network itself, both generating and distribution. The amount of energy people use in their cars often matches or exceeds domestic energy consumption, and a rapid wide scale adoption of home charged vehicles would send the whole system in tilt. A similar scenario has allready presented itself with the rapidly increasing deployment of air conditioning systems. Goverments have counteracted the AC problem by subsidising the adoption of photovoltaic cells, which inject energy into the system locally with peak production neatly matching peak AC consumption. Such a soltion would not be so easy with vehicles, however air is potentially easier to deal with as far as 'service stations' are concerned, as they can charge air tanks at convenient times and 'load shed' (switch off) as required by the network operators (allthough of course battery change stations could also do this).
6) Allthougth high pressure air tanks made of carbon fibre will certainly not be cheap, it would appear from the pricing that is being touted around that air vehchles could have a great cost saving as rechargable batteries capable of deep charge/discharge cycles are not at all cheap, and are the primary reason behind the high cost of battery powwered cars. In addition, batteries wear out with each cycle and with age, whereas an air tank could potenitally have the same lifespan as the vehicle.
7) Battery powwered vehicles are a well proven technology. Simple vehicles with just batteries and DC motors have been in widescale use in industry for decades. In the UK, house to house milk deliveries using electric vehicles took over from the horse and cart. Modern electronic technology allows more efficient use of motors, and refinements such as regenerative braking are being added. Batteries, likewise, are being continually improved. Air powered cars are a very much emergent technology. Allthougth essentially simple, there are major hurdles. In particular, the expanding air requires heat to be drawn in from the ambient to allow it's temperture to rise. Many early experiments with air cars suffered from simply freezing up. Current solutions for air powered vehicles propose solutions to this problem. Guy Negre uses a multi cylinder approach, but that seems to just increase the thermal mass and delay the onset of the problem more than resolve it, for a given energy out at the wheels, a given amount of energy must be drawn in from ambient heat, and if you draw too much in a small space, the temperature plumments. It would appear that this is THE major problem with air powered cars at present. Indeed it is noticable that whilst air cars have been demonstrated doing short stints, I have never come accross a situation where a journalist or the public have been invited to take a car for a non stop test run, underlining the possibility that air cars are still unable of sustained running and require time to 'warm up' after even short stints. The theory is further support by Guy Negres latest engines which use hydrocarbon fuel to warm up the cyclinders, essentially making it a competitor of hybrid cars.
So I see the whole air car issue of being a technology that could potentially have some small advantages over battery cars and possible over hybrid cars for urban use, but at the same time it is a technology that it is still under development and may not actually surpass they actual battery/hybrid vehicles. It will certainly not offer world shattering changes, at best a small step forward in certain niche vehicles.
I think the main article needs a complete re-write in order to put air cars in the perspective of their potential application and advantages, showing how they can fit into the scale of other vehicles. Fundamental to this would be a correctly calculated and referenced table showing the power to weight ratios and other factors which would make it clear just what air cars would be competing against if the technology was made to work.
:The probelem is that the various air car promoters are strongly averse to releasing such information. Please sign your posts in future. Greglocock (talk) 01:29, 22 September 2009 (UTC)
replies: text: In addition to being rewritten, the article should be added to the category "Internet and Media Hoaxes."66.122.68.55 (talk) 03:20, 22 October 2009 (UTC)
thread_title:  A summary 

message: The article claims well to wheel efficiency of a combustion car is 20%. The pump to wheel efficiency of a conventional car is less than this, and the source listed was blank. Can someone find a source for this? 207.47.227.208 (talk) 01:21, 8 February 2010 (UTC)
thread_title:  Well to wheel efficiency 

message: This text is technically inaccurate and misleading:
"However the modern internal combustion engine has only around 15% percent[2] engine efficiency and requires a significantly more massive engine so these numbers may be somewhat misleading."
This is the reference used:
http://www.fueleconomy.gov/feg/atv.shtml
However, the article does not describe engine efficiency, it describe the overall automobile's efficiency on an overall use scale. Also will compressed-air engines require drivetrains? Will they power accessories? Will the driven turbine have imperfect thermal efficiency? Will the initial compressor have imperfect thermal efficiency? Will the plant producing the electricity to run the compressor have imperfect thermal efficiency? Probably yes on all counts, so many of the same spark-ignition losses also apply to compressed-air engines, and has some new ones thrown in as well. So you can't use a figure of 15% efficiency, *that* is somewhat misleading. I'm removing that line.  —Preceding unsigned comment added by 188.141.51.243 (talk) 22:14, 30 August 2010 (UTC)
thread_title:  Misleading assessment of spark ignition engines 

message: The Swedish representative for MDI Air Cars, Ms Eva Magnusson from Nora, Sweden, has been found murdered and dismemberedhttp://na.se/nyheter/orebro/1.1062849--mycket-tyder-pa-att-det-ar-ett-styckmord-  under mystical circumstanceshttps://www.flashback.org/sp28246720. She was the Swedish representative for MDI Cars as early as 2001 when she collected up to 5 million Euro from investors to build a Swedish air car factory.http://www.nyteknik.se/nyheter/it_telekom/allmant/article219473.ece http://www.teknikensvarld.se/provkorningar/mdi/air_car/index.xml 81.227.230.210 (talk) 14:51, 18 January 2011 (UTC)
replies: text: The name of the Swedish company drawing investors to invest in MDI Aircar factories was 'Zero Pollution Svenska AB'. Eva was also running a company named U21 Partner AB 81.227.230.210 (talk) 15:19, 18 January 2011 (UTC)
replies: text: You mean mysterious? Mystical is something like magic, but then again... פשוט pashute ♫ (talk) 17:14, 13 March 2011 (UTC)
thread_title:  Swedish representative for MDI air cars has been murdered and dismembered 

message: Including these is misleading since the cost will be roughly that of a normal car PLUS the air engine and tanks. Greglocock (talk) 22:12, 8 March 2011 (UTC)
thread_title: Pneumatic combustion hybrids

message: Can someone mention the Proe's Ericsson cycle engine system in the article ? This system has several huge advantages over the conventional compressed air system when used with vehicles:
* when using the system in combination with a compressed air tank, the vehicle can be started immediatelly, as opposed to ie a Stirling engine vehicle (which requires a 10-15min warm-up time)
* compared to a regular compressed air vehicle system with just a compressed air tank, the vehicle has far greater range, as (most of) the fuel can be a liquid or solid fuel which is more energy dense and doesn't need a tank
* the fuel can be biofuel (for example wood pellets, see wood pellet stove) so that emissions are extremely low to non-existant (if trees are replanted), and the amount of smoke produced is minor aswell (the first part of the trip is even run on compressed air which is completely smokeless). 
(Note that wood pellet stoves are probably the most practical as the pellets can be fed automatically, and they also burn extremely efficiently -only the required amount of pellets are administered per turn-)
109.130.235.128 (talk) 09:15, 31 May 2013 (UTC)
thread_title: Proe's [[Ericsson cycle engine]] system with compressed air tank

message: Article says:
Conversely, when air is compressed to fill the tank it heats up: as the stored air cools, its pressure decreases and available energy decreases.  It is difficult to cool the tank efficiently while charging and thus it would either take a long time to fill the tank, or less energy is stored.
Could someone explain: 
a* 'it heats up' - the tank or the air (or both)?
b* 'as the stored air cools' - you just said it heats up. When does it cool, after it was heated up?
c* 'It is difficult to cool the tank efficiently' - wait a minute. Why do we want to cool the tank?
d* 'or less energy is stored' - if I cool the tank more energy can stored? But isn't cooling the tank - taking away energy?
Or perhaps just explain it in a different way? (If you do, please tell me here, thanks!)
Thanks!  -- (My birthday, 8 Adar2 5771) פשוט pashute ♫ (talk) 17:27, 13 March 2011 (UTC)
thread_title:  Wording (clarification) 

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thread_title:  External links modified 

message: Here's a useful paper on this ridiculous idea http://iopscience.iop.org/article/10.1088/1748-9326/4/4/044011/pdf Greglocock (talk) 12:04, 14 May 2017 (UTC)
thread_title:  academic analysis 

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thread_title:  External links modified 

message: "The rate of self-discharge is very low opposed to batteries that deplete their charge slowly over time. Therefore, the vehicle may be left unused for longer periods of time than electric cars." Lithium-ion batteries have almost no self-discharge, less than 1% per month. The electrical system will slowly use up the 12V battery's charge and some cars like Teslas will use the EV battery to maintain a certain temperature or to run the computers, but the battery itself does not lose charge at any significant rate. B5429671 (talk) 05:03, 13 August 2019 (UTC)
thread_title:  Inaccurate statement concerning self-discharge 

message: I'm not invested in the tech at all, but I think that the article deserved better grammar so I rewrote it. My work needs a review. I'm a software engineer, but I work with power systems. Ray Van De Walker (talk) 06:49, 26 April 2022 (UTC)
thread_title: Rewrote it for grammar and run-on sentences

message: >Isothermal compressed air energy storage (ICAES) energy density is good, whether measured by weight or volume: It can be as much as 2.7 MJ/kg or 3.6 MJ/m3, which is four times that of a lithium-ion battery. This might be improved with higher pressure vessels, better motors and better heat exchangers.
2.7 MJ/kg (0.75 kWh/kg) are not the same as 3.6 MJ/m³ (1 kWh/m³). Even assuming the vessel has no weight, the density of air at just 1 bar is already more than 1 kg/m³. At more realistic >200 bar we are at well above 200 kg/m³. So 3.6 MJ/m³ are <0.018 MJ/kg and the other way around, 2.7 MJ/kg would be >500 MJ/m³ (140 kWh/m³).
Assuming more realistic numbers, see above in other discussions here or the wiki article, of ~25 kWh/m³ at 300 bar, we arrive at these numbers:
90 MJ/m³ at 0.25 MJ/kg (70 Wh/kg)
Compare that to Li-Ion with >200 Wh/kg and >500 kWh/m³.
In short: I remove this nonsensical claim. Eheran (talk) 15:37, 29 August 2023 (UTC)
thread_title:  Absurdly high energy density - numbers do not add up