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Published on September 11th, 2008 | by Dana Nuccitelli

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Air Cars vs. Electric Cars vs. Hybrids – Which are Greener?

An ‘air car’ sure sounds clean.  A car that runs on air?  What’s cleaner than that?  But of course it’s not quite that simple.

ZPM Air Car

The world’s first commercial air car is currently being produced by India’s largest automaker, Tata Motors, who is licensing the technology from European-based company MDI.  A compressed-air car uses the force of super-compressed air to move the engine’s pistons up and down, as opposed to explosions produced from injecting a small amount of fuel.  At higher speeds the engine will burn a small amount of fuel to create more compressed air, sort of like how a plug-in hybrid like the Chevy Volt produces on-the-fly electricity. The hybrid air-car setup should be able use any number of fuels, including gasoline, propane, or ethanol.

So now that we’ve established how the Air Car will work, how green is it?

Well, there are CO2 emissions associated with both the electricity required to power the air compressor, and the liquid fuel required to create more compressed air on-the-fly.

A comprehensive analysis of these emissions is available in the Huddler Air Car Introduction Wiki.  What it boils down to is that on average, the ZPM Air Car produces 0.176 lbs of CO2 per mile, using the average US power grid mix.  If you’re getting your electricity from a greener utility like California’s Pacific Gas & Electric (PG&E), this brings the total emissions down to 0.155 lbs/mile.

In comparison, the second generation Prius emits 0.34 lbs/mile, so the ZPM Air Car does indeed produce roughly half the CO2 emissions of the Prius, as the company claims.

The Tesla Roadster creates 0.24 lbs/mile of CO2 for the average US power grid mix, and 0.093 lbs/mile for the PG&E mix.  The Aptera typ-1e creates 0.114 lbs/mile of CO2 for the average US power grid mix, and 0.044 lbs/mile for the PG&E mix.  So in most instances, the ZPM will produce lower emissions than the Tesla, but not when the power comes from low emissions sources like PG&E’s.  The Aptera typ-1e produces the lowest emissions by far.

The moral of the story is that the Air Car does quite well in terms of emissions.  It will also supposedly seat 6 with a low price tag at around $17,800, so the Air Car could be an affordable and green alternative to fully electric cars.

Posts Related to the Air Car and Electric Cars

Photo Credit: Zero Pollution Motors


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About the Author

Dana earned a Bachelor's degree in astrophysics from UC Berkeley in 2003 and a Master's degree in physics from UC Davis in 2005. Through college, he grew increasingly interested in environmental issues, particularly global warming and alternative fuel vehicles. After earning his Master's degree, Dana became employed at an environmental consulting firm in the Sacramento, California area. He currently works as an Environmental Scientist, primarily perfoming research and contributing to the cleanup of contaminated former military defense sites.



  • http://lumma.org Carl Lumma

    A hybrid can never be superior in terms of emissions or efficiency to an electric (unless the grid somehow became less efficient than an ICE). The only reason for hybrids is their extended range vs. today’s (but not necessarily tomorrow’s) battery chemistries.

    Air cars have crap performance, and that’ll always have crap performance, owing to the low power density of compressed air.

    But perhaps the most important question isn’t about the relative performance of these cars today, it’s about the extensibility of the architecture. With electric cars, you can instantly change the power source for millions of vehicles by upgrading a few dozen power plants. Compressed air, like liquid fuels, is a transportation crap-fest. Grid losses are tame by comparison. And plug-in is a helluvalot more convenient for motorists than fueling up. Hopefully it will also encourage us to stop parking on our f’ing streets.

  • http://lumma.org Carl Lumma

    A hybrid can never be superior in terms of emissions or efficiency to an electric (unless the grid somehow became less efficient than an ICE). The only reason for hybrids is their extended range vs. today’s (but not necessarily tomorrow’s) battery chemistries.

    Air cars have crap performance, and that’ll always have crap performance, owing to the low power density of compressed air.

    But perhaps the most important question isn’t about the relative performance of these cars today, it’s about the extensibility of the architecture. With electric cars, you can instantly change the power source for millions of vehicles by upgrading a few dozen power plants. Compressed air, like liquid fuels, is a transportation crap-fest. Grid losses are tame by comparison. And plug-in is a helluvalot more convenient for motorists than fueling up. Hopefully it will also encourage us to stop parking on our f’ing streets.

  • Andy

    I’m pretty skeptical of the loveliness sound of the “air-car”. The thing is, a gasoline engine pressurizes the cylinders on the go, while the “air-car” pressurizes them all effectively in advance. So there is no fundamental energy savings going on here, you are merely changing where you do the work.

    You could compare this to running a car on batteries that run an air compressor that push cylinders. So in effect, pressurized air is just a mechanical form of ‘battery’. It’s a gaseuous form of a wind up spring powered car. Compression will increase molecular heat/temperature which will tend to dissapate and therefore be lossy. So it can’t be terribly efficient either.

    So hey, maybe this totally novel technology can be made to work. Will it be better than the tech that’s been worked on and refined for decades? Investors, hang on to your wallets.

  • Andy

    I’m pretty skeptical of the loveliness sound of the “air-car”. The thing is, a gasoline engine pressurizes the cylinders on the go, while the “air-car” pressurizes them all effectively in advance. So there is no fundamental energy savings going on here, you are merely changing where you do the work.

    You could compare this to running a car on batteries that run an air compressor that push cylinders. So in effect, pressurized air is just a mechanical form of ‘battery’. It’s a gaseuous form of a wind up spring powered car. Compression will increase molecular heat/temperature which will tend to dissapate and therefore be lossy. So it can’t be terribly efficient either.

    So hey, maybe this totally novel technology can be made to work. Will it be better than the tech that’s been worked on and refined for decades? Investors, hang on to your wallets.

  • Antonio Andolini

    The air car sounded like the car of the future…that is until the French were forced to comply with U.S. car crash standards by increasing the weight of the car with more metal, then having to add a combustion engine to it in order to haul all that extra new weight.

    I think the air car would work better in the U.S. as a legally lighter, 3-wheeled air motorcycle.

  • Antonio Andolini

    The air car sounded like the car of the future…that is until the French were forced to comply with U.S. car crash standards by increasing the weight of the car with more metal, then having to add a combustion engine to it in order to haul all that extra new weight.

    I think the air car would work better in the U.S. as a legally lighter, 3-wheeled air motorcycle.

  • Antonio Andolini

    The air car sounded like the car of the future…that is until the French were forced to comply with U.S. car crash standards by increasing the weight of the car with more metal, then having to add a combustion engine to it in order to haul all that extra new weight.

    I think the air car would work better in the U.S. as a legally lighter, 3-wheeled air motorcycle.

  • Rei

    The linked article is ridiculous. The overwhelming majority of the range of the air car comes from the gasoline, not the air. The simple facts are that air compressors are extremely inefficient (I have no clue where the article there gets off with the unreferenced claim that they’re 60% efficient — they’re generally 10-20% efficient), and compressed air has extremely poor energy density. MDI is largely a vaporware company anyways that’s been “spinning their wheels” for over a decade, with many specious claims. The founder even distorts his own resume. For example, Negre claims that he was responsible for ““development of a 3.5-liter W-12 engine for Formula One toward the end of the ’80s.”” No such engine was ever raced in F1 races.

  • Rei

    The linked article is ridiculous. The overwhelming majority of the range of the air car comes from the gasoline, not the air. The simple facts are that air compressors are extremely inefficient (I have no clue where the article there gets off with the unreferenced claim that they’re 60% efficient — they’re generally 10-20% efficient), and compressed air has extremely poor energy density. MDI is largely a vaporware company anyways that’s been “spinning their wheels” for over a decade, with many specious claims. The founder even distorts his own resume. For example, Negre claims that he was responsible for ““development of a 3.5-liter W-12 engine for Formula One toward the end of the ’80s.”” No such engine was ever raced in F1 races.

  • Rei

    The linked article is ridiculous. The overwhelming majority of the range of the air car comes from the gasoline, not the air. The simple facts are that air compressors are extremely inefficient (I have no clue where the article there gets off with the unreferenced claim that they’re 60% efficient — they’re generally 10-20% efficient), and compressed air has extremely poor energy density. MDI is largely a vaporware company anyways that’s been “spinning their wheels” for over a decade, with many specious claims. The founder even distorts his own resume. For example, Negre claims that he was responsible for ““development of a 3.5-liter W-12 engine for Formula One toward the end of the ’80s.”” No such engine was ever raced in F1 races.

  • http://www.freesand.com/glass/ Matt

    How about a cost/mile comparison for these vehicles?

  • http://www.freesand.com/glass/ Matt

    How about a cost/mile comparison for these vehicles?

  • http://www.myspace.com/lj_toodeep eLJota

    Right, I know I may sound like the perfect candidate for a pro green public stoning for starting my post this way, but:

    I am not TRULY concerned about whether a compressed air car is more green than an electric one.

    I applaud the concept of both, however, I believe that any of the new concepts that needs any amount of petrol (Petrol is what we Britts call gasoline) has failed. Yes, I understand that the ZPM CAN run on ethanol, but if the ZPM is a hit in Europe and the US, I’m sure that petrol will stll be the fuel of choice, since it will still be the most available.

    When the new Lithium bateries with the nano tech applied to it are installed into electric cars, a 200 mile Tesla may become capable of 2000 miles. Or the extra capacity could be used to power larger electric vehicles.

    Already producing faster & more powerfull vehicles (&lets face it, when it comes to cars people want power) the electric car stands high above the compressed air vehicles.

    As for Bio fuels I belive that we should take this extra crop growing capabiltiy and feed the people who need it the most. Firstly within our own counties, secondly we give to our allies, and then to our enemies. (and dont forget, as babies we learned to love whoever fed us. Also, feeding your enemies makes their hatred towards you harder to justify. Why else would our countries deliver food aid to the inhabitants of the countries we war with.)

    I belive in killing two birds with one stone and if you can get even more than that, then call some friends and have a party.

    If the US & Europe switched to cars that required no fuel produced from oil, then that would mean much less dependance on foreign oil.

    This would mean that the tension with the arabs etc would be aleviated and the price of oil would not dictate the rates of inflation, thereby reducing wars and strengthening the economies of those involved with the change over.

    An optimistic view? of course it is and that’s exactly why its very unlikely to ever happen.

    Ps. If you like my writing and would like to pay me per article, then please contact me.

  • http://www.myspace.com/lj_toodeep eLJota

    Right, I know I may sound like the perfect candidate for a pro green public stoning for starting my post this way, but:

    I am not TRULY concerned about whether a compressed air car is more green than an electric one.

    I applaud the concept of both, however, I believe that any of the new concepts that needs any amount of petrol (Petrol is what we Britts call gasoline) has failed. Yes, I understand that the ZPM CAN run on ethanol, but if the ZPM is a hit in Europe and the US, I’m sure that petrol will stll be the fuel of choice, since it will still be the most available.

    When the new Lithium bateries with the nano tech applied to it are installed into electric cars, a 200 mile Tesla may become capable of 2000 miles. Or the extra capacity could be used to power larger electric vehicles.

    Already producing faster & more powerfull vehicles (&lets face it, when it comes to cars people want power) the electric car stands high above the compressed air vehicles.

    As for Bio fuels I belive that we should take this extra crop growing capabiltiy and feed the people who need it the most. Firstly within our own counties, secondly we give to our allies, and then to our enemies. (and dont forget, as babies we learned to love whoever fed us. Also, feeding your enemies makes their hatred towards you harder to justify. Why else would our countries deliver food aid to the inhabitants of the countries we war with.)

    I belive in killing two birds with one stone and if you can get even more than that, then call some friends and have a party.

    If the US & Europe switched to cars that required no fuel produced from oil, then that would mean much less dependance on foreign oil.

    This would mean that the tension with the arabs etc would be aleviated and the price of oil would not dictate the rates of inflation, thereby reducing wars and strengthening the economies of those involved with the change over.

    An optimistic view? of course it is and that’s exactly why its very unlikely to ever happen.

    Ps. If you like my writing and would like to pay me per article, then please contact me.

  • http://www.myspace.com/lj_toodeep eLJota

    Right, I know I may sound like the perfect candidate for a pro green public stoning for starting my post this way, but:

    I am not TRULY concerned about whether a compressed air car is more green than an electric one.

    I applaud the concept of both, however, I believe that any of the new concepts that needs any amount of petrol (Petrol is what we Britts call gasoline) has failed. Yes, I understand that the ZPM CAN run on ethanol, but if the ZPM is a hit in Europe and the US, I’m sure that petrol will stll be the fuel of choice, since it will still be the most available.

    When the new Lithium bateries with the nano tech applied to it are installed into electric cars, a 200 mile Tesla may become capable of 2000 miles. Or the extra capacity could be used to power larger electric vehicles.

    Already producing faster & more powerfull vehicles (&lets face it, when it comes to cars people want power) the electric car stands high above the compressed air vehicles.

    As for Bio fuels I belive that we should take this extra crop growing capabiltiy and feed the people who need it the most. Firstly within our own counties, secondly we give to our allies, and then to our enemies. (and dont forget, as babies we learned to love whoever fed us. Also, feeding your enemies makes their hatred towards you harder to justify. Why else would our countries deliver food aid to the inhabitants of the countries we war with.)

    I belive in killing two birds with one stone and if you can get even more than that, then call some friends and have a party.

    If the US & Europe switched to cars that required no fuel produced from oil, then that would mean much less dependance on foreign oil.

    This would mean that the tension with the arabs etc would be aleviated and the price of oil would not dictate the rates of inflation, thereby reducing wars and strengthening the economies of those involved with the change over.

    An optimistic view? of course it is and that’s exactly why its very unlikely to ever happen.

    Ps. If you like my writing and would like to pay me per article, then please contact me.

  • Travis

    Can someone tell me how many lbs/mile of CO2 something like a full size Chevy 4×4 Suburban releases, or even your standard family sedan….just for comparison?

    These are the vehicles I see most on the road, and would like to know how hybrids/electrics/air vehicles that you report on compare to “the norm”.

  • Travis

    Can someone tell me how many lbs/mile of CO2 something like a full size Chevy 4×4 Suburban releases, or even your standard family sedan….just for comparison?

    These are the vehicles I see most on the road, and would like to know how hybrids/electrics/air vehicles that you report on compare to “the norm”.

  • Travis

    Can someone tell me how many lbs/mile of CO2 something like a full size Chevy 4×4 Suburban releases, or even your standard family sedan….just for comparison?

    These are the vehicles I see most on the road, and would like to know how hybrids/electrics/air vehicles that you report on compare to “the norm”.

  • michael Bryant

    I like the idea of the air car but compress air trains are more likely take off since you can big engouh tanks to go 1000 miles.

  • michael Bryant

    I like the idea of the air car but compress air trains are more likely take off since you can big engouh tanks to go 1000 miles.

  • Dana Nuccitelli

    Matt – a cost analysis is available in the Huddler link.

    Travis – your average sedan emits about 1.5 times more CO2 than a Prius, which emits 2 times more CO2 than the air car (which is roughly on par with EVs). The largest SUVs emit 3-4 times more CO2 than the Prius.

  • Scott Deerwester

    This is a bit disingenuous. A gasoline powered vehicle MUST produce emissions. It’s an inherent property of the internal combustion engine. An air car uses electricity. Granted, there are ways to produce electricity that produce emissions, but there are plenty of others that don’t – wind, solar power, hydro-electric power and wave power to name some of the top contenders. Is it a stretch to believe that someone who’s committed enough to lowering their energy footprint to buy and drive an air car would also be likely to avail themselves of a source of electricity that’s equally environmentally friendly?

  • Scott Deerwester

    This is a bit disingenuous. A gasoline powered vehicle MUST produce emissions. It’s an inherent property of the internal combustion engine. An air car uses electricity. Granted, there are ways to produce electricity that produce emissions, but there are plenty of others that don’t – wind, solar power, hydro-electric power and wave power to name some of the top contenders. Is it a stretch to believe that someone who’s committed enough to lowering their energy footprint to buy and drive an air car would also be likely to avail themselves of a source of electricity that’s equally environmentally friendly?

  • Scott Deerwester

    This is a bit disingenuous. A gasoline powered vehicle MUST produce emissions. It’s an inherent property of the internal combustion engine. An air car uses electricity. Granted, there are ways to produce electricity that produce emissions, but there are plenty of others that don’t – wind, solar power, hydro-electric power and wave power to name some of the top contenders. Is it a stretch to believe that someone who’s committed enough to lowering their energy footprint to buy and drive an air car would also be likely to avail themselves of a source of electricity that’s equally environmentally friendly?

  • Dana Nuccitelli

    Scott – I’m not sure why you think the article is disingenuous. The calculation was simply based on the Average US power grid mix, and also on a more environmentally friendly mix. Certainly emissions can be reduced further by getting electricity solely from renewable sources, but I think that goes without saying.

  • chrisb

    “Is it a stretch to believe that someone who’s committed enough to lowering their energy footprint to buy and drive an air car would also be likely to avail themselves of a source of electricity that’s equally environmentally friendly?”

    yes, I don’t think I can get the permits to build my own clean power plant, or the money to buy a new car AND cover my roof with solar panels (if they’ll even provide enough for the car) AND build a windmill (even if local regulations let me). I’m not a millionaire and neither are most people. Buying an efficient car and improving our windows/doors and insulation in our homes is often the most we can afford.

  • chrisb

    “Is it a stretch to believe that someone who’s committed enough to lowering their energy footprint to buy and drive an air car would also be likely to avail themselves of a source of electricity that’s equally environmentally friendly?”

    yes, I don’t think I can get the permits to build my own clean power plant, or the money to buy a new car AND cover my roof with solar panels (if they’ll even provide enough for the car) AND build a windmill (even if local regulations let me). I’m not a millionaire and neither are most people. Buying an efficient car and improving our windows/doors and insulation in our homes is often the most we can afford.

  • chrisb

    “Is it a stretch to believe that someone who’s committed enough to lowering their energy footprint to buy and drive an air car would also be likely to avail themselves of a source of electricity that’s equally environmentally friendly?”

    yes, I don’t think I can get the permits to build my own clean power plant, or the money to buy a new car AND cover my roof with solar panels (if they’ll even provide enough for the car) AND build a windmill (even if local regulations let me). I’m not a millionaire and neither are most people. Buying an efficient car and improving our windows/doors and insulation in our homes is often the most we can afford.

  • http://5starhair.com Emilio Socci sr.

    To start with the air power tools we have used forever

    operate on rotary power.

    Was there any mention of the engineer in argentina, I believe seen in the, earlier this year, EV report.

    He is experimenting with a 6 port rotary engine that i’d love to hear about!

    The down side I imagine is in the loud noise of escaping air… Used on big trucks no one will notice. Lets start improving all possibilities.

    warm regards,

    Emilio

  • http://5starhair.com Emilio Socci sr.

    To start with the air power tools we have used forever

    operate on rotary power.

    Was there any mention of the engineer in argentina, I believe seen in the, earlier this year, EV report.

    He is experimenting with a 6 port rotary engine that i’d love to hear about!

    The down side I imagine is in the loud noise of escaping air… Used on big trucks no one will notice. Lets start improving all possibilities.

    warm regards,

    Emilio

  • http://www.ACHWorks.COM Marion Tamse

    We need a third party verification done by a credible institution or scientific and engineering organizations about the specifications and performance of the air car. If there’s none, the claims are primarily bogus.

  • http://www.ACHWorks.COM Marion Tamse

    We need a third party verification done by a credible institution or scientific and engineering organizations about the specifications and performance of the air car. If there’s none, the claims are primarily bogus.

  • http://www.ACHWorks.COM Marion Tamse

    We need a third party verification done by a credible institution or scientific and engineering organizations about the specifications and performance of the air car. If there’s none, the claims are primarily bogus.

  • Charlie

    The analysis of emissions is flawed. The range of 800+ miles is achieved (theoretically — they have never managed to get a prototype to go more than 7 miles) by using gasoline to heat the air. IIRC, they figure 8 gallons of gasoline.

    Summary:

    1. You used bogus data supplied by a company known for promising the moon and never delivering.

    2. You ignored the fossil fuel that they intend to burn, even in their theoretical, never-built model.

  • Charlie

    The analysis of emissions is flawed. The range of 800+ miles is achieved (theoretically — they have never managed to get a prototype to go more than 7 miles) by using gasoline to heat the air. IIRC, they figure 8 gallons of gasoline.

    Summary:

    1. You used bogus data supplied by a company known for promising the moon and never delivering.

    2. You ignored the fossil fuel that they intend to burn, even in their theoretical, never-built model.

  • lee andre

    Air car has several other advantages. The materials in the car are not “chemicals”. When the car is constructed and then dismantled the pile of stuff is less complex. Second, I agree that the charge and discharge cycle for a good battery is better then an air tank, but neither is as good as an ultra capacitor. The nice thing about the air car is that the heat losses occur in the owners garage and there can be used for hot water or space heating. The storage of the compressed air can be done at home by PV or wind as the energy is avaliable and the air, with the heat of compression removed, can be transfered to the car quickly or used for air conditioning in the home. PV is especialy attractive since the dark part of the year would provide heat and transportation and the sunny seasons would provide AC and transportation with all the heat rejected.

  • lee andre

    Air car has several other advantages. The materials in the car are not “chemicals”. When the car is constructed and then dismantled the pile of stuff is less complex. Second, I agree that the charge and discharge cycle for a good battery is better then an air tank, but neither is as good as an ultra capacitor. The nice thing about the air car is that the heat losses occur in the owners garage and there can be used for hot water or space heating. The storage of the compressed air can be done at home by PV or wind as the energy is avaliable and the air, with the heat of compression removed, can be transfered to the car quickly or used for air conditioning in the home. PV is especialy attractive since the dark part of the year would provide heat and transportation and the sunny seasons would provide AC and transportation with all the heat rejected.

  • Charlie

    Contrary to what the article says, the air car is NOT in production in India. A month or two ago Tata officially announced that the car is still in the early development phase and is definitely not going to be produced in the near future.

    MDI has a history of promising that their car will be in production “next year”. This has been going on for over a decade.

    There haven’t been any reasonable prototypes. Mockup, yes. Working prototypes have been limited to a couple of very very limited capability (<10km) range test runs.

    Vaporware. Investor scam. Ponzi scheme. Self delusion. Take your pick of what terms best apply to the MDI air car.

    Doing a carbon footprint analysis on a spec sheet for vaporware is a joke.

  • Charlie

    Contrary to what the article says, the air car is NOT in production in India. A month or two ago Tata officially announced that the car is still in the early development phase and is definitely not going to be produced in the near future.

    MDI has a history of promising that their car will be in production “next year”. This has been going on for over a decade.

    There haven’t been any reasonable prototypes. Mockup, yes. Working prototypes have been limited to a couple of very very limited capability (<10km) range test runs.

    Vaporware. Investor scam. Ponzi scheme. Self delusion. Take your pick of what terms best apply to the MDI air car.

    Doing a carbon footprint analysis on a spec sheet for vaporware is a joke.

  • Charlie

    Contrary to what the article says, the air car is NOT in production in India. A month or two ago Tata officially announced that the car is still in the early development phase and is definitely not going to be produced in the near future.

    MDI has a history of promising that their car will be in production “next year”. This has been going on for over a decade.

    There haven’t been any reasonable prototypes. Mockup, yes. Working prototypes have been limited to a couple of very very limited capability (<10km) range test runs.

    Vaporware. Investor scam. Ponzi scheme. Self delusion. Take your pick of what terms best apply to the MDI air car.

    Doing a carbon footprint analysis on a spec sheet for vaporware is a joke.

  • mike faison

    instead of using gasoline to create pressurized air why not use electric motors to create the same results? they can turn higher rpms, the energy used is easily replenished, and ZERO emissions. as long as we, the people continue to use oil products to fuel the world, oil companies will continue to prevail.

  • mike faison

    instead of using gasoline to create pressurized air why not use electric motors to create the same results? they can turn higher rpms, the energy used is easily replenished, and ZERO emissions. as long as we, the people continue to use oil products to fuel the world, oil companies will continue to prevail.

  • Al

    Air tools are great for mechanics because they do not get hot like electric power tools and pack a lot of power in a small tool. A small air die grinder that fits in the palm may put out a peak 3 horsepower (2.2 Kw) while actually getting colder the harder it is worked. It will run all day at full load if the air compressor can keep up. An electric die grinder that is larger but still fits in the hand may be rated 1/4 HP (less than 1/5 Kw) and gets HOT! when it is working hard. Air tools are NOT energy efficient. Air motor vehicles suffer from the same handicap – low efficiency – PLUS the compressed air tanks are HEAVY. It takes a LOT of power to compress air. A LOT of heat is wasted (that’s why air compressor cylinders have deep fins and cooling fans).

    Batteries and chargers are quite efficient today – over 90% charge-discharge efficiency for high efficiency batteries and chargers. Advanced design electric motors are also very efficient.

    Both air motors and electric motors can be used as generators or pumps to regenerate part of the power used, when braking or holding back speed on long steep downgrades. Lightweight electric motors built into the wheels eliminate heavy, power-wasting gears and shafts, and put the motors out in the open air for efficient cooling of what heat is wasted. The weight of wheel motors is partly offset by the reduced need for large, powerful friction brakes. Friction brakes are normally used only for final stopping at low speeds, so they can be quite compact, or even “old-fashioned” and cheap drum brakes. The wheel rims themselves can have the motor rotors embedded in them with the stators integral with the wheel bearing carrier hubs/knuckles. Antilock braking is very easy to set up when using the in-wheel propulsion motors as generators in braking. Emergency braking beyond the drag from using the motors as generators can be provided by reversing the motors, though this uses a lot of power.

    Electric regenerative braking has nothing in common with electric brakes as found on utility and travel trailers. They are conventional drum brakes actuated by electromagnets. Automotive motor-generator regenerative braking is very efficient and reliable, requiring little maintenance. Total failure (very improbable) of one wheel motor can be compensated for by the antilock braking function to prevent “pulling” to one side.

    Air cars require air compressors. They are heavy if carried on the car (for plugging in wherever parked) so the large, heavy compressors that will recharge the tanks on air cars would be installed in home garages. They could not be recharged by ordinary service station compressors, as even the ones used in repair shops go only to about 175 psi. Compressors more like the ones used to recharge scuba tanks (2000+ psi) would be used to recharge air cars. 10,000 psi is more like what would be needed.

    For greater charge density liquid air could be used, but this requires in addition to high pressure powerful refrigeration to liquefy the air. And liquid air is extremely cold, so in a tank-bursting collision it would be very dangerous (anyone around would be frozen) PLUS it would support combustion as it vaporized.

    If modern high efficiency batteries are smashed, only a small amount of jellied or paste electrolyte, which is nothing like as hazardous as gasoline, could be released. If properly designed, short circuiting would be impossible.

  • Al

    Air tools are great for mechanics because they do not get hot like electric power tools and pack a lot of power in a small tool. A small air die grinder that fits in the palm may put out a peak 3 horsepower (2.2 Kw) while actually getting colder the harder it is worked. It will run all day at full load if the air compressor can keep up. An electric die grinder that is larger but still fits in the hand may be rated 1/4 HP (less than 1/5 Kw) and gets HOT! when it is working hard. Air tools are NOT energy efficient. Air motor vehicles suffer from the same handicap – low efficiency – PLUS the compressed air tanks are HEAVY. It takes a LOT of power to compress air. A LOT of heat is wasted (that’s why air compressor cylinders have deep fins and cooling fans).

    Batteries and chargers are quite efficient today – over 90% charge-discharge efficiency for high efficiency batteries and chargers. Advanced design electric motors are also very efficient.

    Both air motors and electric motors can be used as generators or pumps to regenerate part of the power used, when braking or holding back speed on long steep downgrades. Lightweight electric motors built into the wheels eliminate heavy, power-wasting gears and shafts, and put the motors out in the open air for efficient cooling of what heat is wasted. The weight of wheel motors is partly offset by the reduced need for large, powerful friction brakes. Friction brakes are normally used only for final stopping at low speeds, so they can be quite compact, or even “old-fashioned” and cheap drum brakes. The wheel rims themselves can have the motor rotors embedded in them with the stators integral with the wheel bearing carrier hubs/knuckles. Antilock braking is very easy to set up when using the in-wheel propulsion motors as generators in braking. Emergency braking beyond the drag from using the motors as generators can be provided by reversing the motors, though this uses a lot of power.

    Electric regenerative braking has nothing in common with electric brakes as found on utility and travel trailers. They are conventional drum brakes actuated by electromagnets. Automotive motor-generator regenerative braking is very efficient and reliable, requiring little maintenance. Total failure (very improbable) of one wheel motor can be compensated for by the antilock braking function to prevent “pulling” to one side.

    Air cars require air compressors. They are heavy if carried on the car (for plugging in wherever parked) so the large, heavy compressors that will recharge the tanks on air cars would be installed in home garages. They could not be recharged by ordinary service station compressors, as even the ones used in repair shops go only to about 175 psi. Compressors more like the ones used to recharge scuba tanks (2000+ psi) would be used to recharge air cars. 10,000 psi is more like what would be needed.

    For greater charge density liquid air could be used, but this requires in addition to high pressure powerful refrigeration to liquefy the air. And liquid air is extremely cold, so in a tank-bursting collision it would be very dangerous (anyone around would be frozen) PLUS it would support combustion as it vaporized.

    If modern high efficiency batteries are smashed, only a small amount of jellied or paste electrolyte, which is nothing like as hazardous as gasoline, could be released. If properly designed, short circuiting would be impossible.

  • Al

    Air tools are great for mechanics because they do not get hot like electric power tools and pack a lot of power in a small tool. A small air die grinder that fits in the palm may put out a peak 3 horsepower (2.2 Kw) while actually getting colder the harder it is worked. It will run all day at full load if the air compressor can keep up. An electric die grinder that is larger but still fits in the hand may be rated 1/4 HP (less than 1/5 Kw) and gets HOT! when it is working hard. Air tools are NOT energy efficient. Air motor vehicles suffer from the same handicap – low efficiency – PLUS the compressed air tanks are HEAVY. It takes a LOT of power to compress air. A LOT of heat is wasted (that’s why air compressor cylinders have deep fins and cooling fans).

    Batteries and chargers are quite efficient today – over 90% charge-discharge efficiency for high efficiency batteries and chargers. Advanced design electric motors are also very efficient.

    Both air motors and electric motors can be used as generators or pumps to regenerate part of the power used, when braking or holding back speed on long steep downgrades. Lightweight electric motors built into the wheels eliminate heavy, power-wasting gears and shafts, and put the motors out in the open air for efficient cooling of what heat is wasted. The weight of wheel motors is partly offset by the reduced need for large, powerful friction brakes. Friction brakes are normally used only for final stopping at low speeds, so they can be quite compact, or even “old-fashioned” and cheap drum brakes. The wheel rims themselves can have the motor rotors embedded in them with the stators integral with the wheel bearing carrier hubs/knuckles. Antilock braking is very easy to set up when using the in-wheel propulsion motors as generators in braking. Emergency braking beyond the drag from using the motors as generators can be provided by reversing the motors, though this uses a lot of power.

    Electric regenerative braking has nothing in common with electric brakes as found on utility and travel trailers. They are conventional drum brakes actuated by electromagnets. Automotive motor-generator regenerative braking is very efficient and reliable, requiring little maintenance. Total failure (very improbable) of one wheel motor can be compensated for by the antilock braking function to prevent “pulling” to one side.

    Air cars require air compressors. They are heavy if carried on the car (for plugging in wherever parked) so the large, heavy compressors that will recharge the tanks on air cars would be installed in home garages. They could not be recharged by ordinary service station compressors, as even the ones used in repair shops go only to about 175 psi. Compressors more like the ones used to recharge scuba tanks (2000+ psi) would be used to recharge air cars. 10,000 psi is more like what would be needed.

    For greater charge density liquid air could be used, but this requires in addition to high pressure powerful refrigeration to liquefy the air. And liquid air is extremely cold, so in a tank-bursting collision it would be very dangerous (anyone around would be frozen) PLUS it would support combustion as it vaporized.

    If modern high efficiency batteries are smashed, only a small amount of jellied or paste electrolyte, which is nothing like as hazardous as gasoline, could be released. If properly designed, short circuiting would be impossible.

  • Squashoil

    I’m sorta over the air car since I saw this google video about a device that converts the earth’s electro-magnetic fields into rather sizable, seemingly inexhaustible pulsating DC source.

    I realize this is off-topic, but these things could power vehicles as well as everything else apparently completely off grid, anywhere on earth. Since their seems to be intelligent folk interested in alternate fuels, I thought I’d see what kind of info I can gather.

    http://video.google.com/videoplay?docid=167210479374903373&hl=en

    As an Electronic/Computer Engineering specialist, I can visualize this concept working, and the only way I can see this being a hoax is if there were huge transducers radiating at a harmonic of the coils he uses… otherwise, he’s onto something, but the vid (and patent application I researched) date back to summer 2006 and I haven’t heard a peep anywhere but in this vid about it.

    Any comments welcome!

    Brian

  • Squashoil

    I’m sorta over the air car since I saw this google video about a device that converts the earth’s electro-magnetic fields into rather sizable, seemingly inexhaustible pulsating DC source.

    I realize this is off-topic, but these things could power vehicles as well as everything else apparently completely off grid, anywhere on earth. Since their seems to be intelligent folk interested in alternate fuels, I thought I’d see what kind of info I can gather.

    http://video.google.com/videoplay?docid=167210479374903373&hl=en

    As an Electronic/Computer Engineering specialist, I can visualize this concept working, and the only way I can see this being a hoax is if there were huge transducers radiating at a harmonic of the coils he uses… otherwise, he’s onto something, but the vid (and patent application I researched) date back to summer 2006 and I haven’t heard a peep anywhere but in this vid about it.

    Any comments welcome!

    Brian

  • Patty

    Can anyone tell me how the Air Compressed Car or the Electric cars would do at -30 deress below zero? Also I drive 25 miles to work and 5 miles is climbing to just over 1000 ft in elevation. I not heard from anyone how these vehicles do in conditions like these?

    Thank you; PD

  • Patty

    Can anyone tell me how the Air Compressed Car or the Electric cars would do at -30 deress below zero? Also I drive 25 miles to work and 5 miles is climbing to just over 1000 ft in elevation. I not heard from anyone how these vehicles do in conditions like these?

    Thank you; PD

  • Patty

    Can anyone tell me how the Air Compressed Car or the Electric cars would do at -30 deress below zero? Also I drive 25 miles to work and 5 miles is climbing to just over 1000 ft in elevation. I not heard from anyone how these vehicles do in conditions like these?

    Thank you; PD

  • Walter G Connor Jr

    1)The question is whether an air motor is as efficient as an electric motor. So far they are less efficient than a gasoline engine. (2) Air can be compressed and stored with existing technology but emissions depend on what is used to power the compressor. (3) People are fixated on the link between vehicle weight and passenger safety. Three things determine crashworthiness. First design geometry, second is material strength, and third is passenger restraints. Simply adding weight means a longer stopping distance and a higher impact velocity. (4) An air motor whether rotary or pistion needs seals and these wear with use.

    Public acceptance of any new vehicle will depend on factors such as power to weight ratio, torque, range, and average annual operating costs. The more fundamental question is what is the most safe and efficient transportation system possible. This will involve a variety of vehicles and travel modes blending bicycles, automobiles, buses, trains, airplanes and boats. If you are going to say something is wonderful or something is crappy then let’s have some meaniful data.

  • Walter G Connor Jr

    1)The question is whether an air motor is as efficient as an electric motor. So far they are less efficient than a gasoline engine. (2) Air can be compressed and stored with existing technology but emissions depend on what is used to power the compressor. (3) People are fixated on the link between vehicle weight and passenger safety. Three things determine crashworthiness. First design geometry, second is material strength, and third is passenger restraints. Simply adding weight means a longer stopping distance and a higher impact velocity. (4) An air motor whether rotary or pistion needs seals and these wear with use.

    Public acceptance of any new vehicle will depend on factors such as power to weight ratio, torque, range, and average annual operating costs. The more fundamental question is what is the most safe and efficient transportation system possible. This will involve a variety of vehicles and travel modes blending bicycles, automobiles, buses, trains, airplanes and boats. If you are going to say something is wonderful or something is crappy then let’s have some meaniful data.

  • Charlie

    The air car is clearly the most environmentally friendly — it DOES NOT EXIST. Something that has never been sold can’t be used, so therefore its emissions are ZERO.

    MDI continues to delay, delay, delay.

    They are also no longer participating in the X-Prize competition.

    Vaporware doesn’t emit pollution.

  • Charlie

    The air car is clearly the most environmentally friendly — it DOES NOT EXIST. Something that has never been sold can’t be used, so therefore its emissions are ZERO.

    MDI continues to delay, delay, delay.

    They are also no longer participating in the X-Prize competition.

    Vaporware doesn’t emit pollution.

  • Charlie

    The air car is clearly the most environmentally friendly — it DOES NOT EXIST. Something that has never been sold can’t be used, so therefore its emissions are ZERO.

    MDI continues to delay, delay, delay.

    They are also no longer participating in the X-Prize competition.

    Vaporware doesn’t emit pollution.

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