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Old 12-30-2008, 02:46 PM   #1 (permalink)
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Zero Pollution Motors

Does anyone know anything about the Zero Pollution Motors compressed air cars?

Zero Pollution Motors - Air Car

A friend of mine who is a hydraulic engineer says that their mileage claims must be highly exaggerated, and that a compressed air car would be a traveling bomb if it got into an accident and the air tank exploded. He also said that a compressed air engine is very inefficient.

I was especially taken with the little AirPod urban transport... I hope he's not mistaken

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Old 12-30-2008, 02:59 PM   #2 (permalink)
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Your Hydraulic Engineer freind is under informed.
Thes have been here on the site in some other threads, (and I am too lazy to search right now) and the concept is proven.
The air tanks are woven carbon fibre and in the event of an accident would only rupture in a controlled manner.
As to the mileage claims...
Yet to be seen, but the math seems right. IIRC.
they work similar to an old steam engine but with many efficiency improvements.
Use the search engine here and Google to find info, and formulate YOUR own oppinion.
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Old 12-30-2008, 05:20 PM   #3 (permalink)
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Even steel (welded or formed) air tanks have a compression (crush) idea behind them, due to the danger of compressed air explosion... that's why they're always a seam-welded tube with end caps that are nearly spherical... the entire weld won't fail, and the air will rush out before it can explode.

Lots of people make compressed air lawnmowers, it's quite easy, if you can get someone to weld the cam for you... the real kicker is that you can make more or less power and use more or less air based on the cam profile you decide to grind into the new cam.

Also, with a single cylinder air engine, it completes it's power cycle EVERY revolution, rather than every other. (intake and power are the same cycle, there is no compression, and exhaust is obvious.) So it essentially becomes a two cycle engine.

Ever wonder what to do w/ that old Two cycle weedeater you don't use anymore? Got an old plastic water tank from an RV laying around? 40 PSI in a 10 gallon tank strapped to your back will eat your weeds for free! :P

You can also get air to fill a small tank or a tire free at some gas stations.. (most are 25-75 cents though, for 3 mins.. enough to fill at least 2 10 gallon steel tanks to 120 PSI (max))

So I hope that gave you something of a starter to work with, but the information is readily available, you just have to peek around the right corner

Happy searching! Oh, and welcome to EcoModder!
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Old 12-30-2008, 06:26 PM   #4 (permalink)
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The problem is that the air compression operation is only about 25% efficient and the air motors are only about 80% efficient.

A lot of electricity for not much motion.

Compressed air vehicles are used where fire safety is at a premium. The US Navy operates a compressed-air locomotive at its ammunition storage depot at Pearl Harbor.

Compressed air stuff has been around since the 1870s and is well-developed. Does it ever occur that if this refined technology made the least bit of sense for transportation, it would have been adopted long ago? Is everybody's brain so corroded by conspiracy theories?
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Old 12-30-2008, 06:36 PM   #5 (permalink)
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Conspiracy Theories - I LOL'd...

I thought the same thing - but if there is a more efficient way somewhere out there to create compessed air... or anyone can think of one, it might become a viable solution...

I have an idea... get a box truck that is environmentally sealed... open it up in the coldest climate possible at sea level, then have it transported to the warmer climate somewhere in Detroit... the result (once the air warms up) will be compressed air... In fact, it will be a large volume of air at just slightly more than atmospheric pressure... which isn't going to do squat. Ok, I'm done. LOL.

BTW - if you can design the cam to make enough power with low enough air use, an air-powered lawn mower is cheaper than gas-powered. The reason is that you can in fact get 20 gallons of air @ 120 PSI for 75cents... which should be enough to mow your lawn... a gallon of gas is $1.52 (nat ave.) so unless you can mow your lawn on half a gallon of gas, you benefit from the air powered mower.

*This, of course, considers that you're not wasting car-gas while you're airing up your tanks.
*In some cases, it may be cheaper to use an electric air-compressor at home.
*Some people would rather use inefficient alternative fuels than pollutant "efficient" fuels.
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Old 12-31-2008, 08:01 PM   #6 (permalink)
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Quote:
Originally Posted by Serafina_tikklya View Post
Does anyone know anything about the Zero Pollution Motors compressed air cars?

A friend of mine who is a hydraulic engineer says that their mileage claims must be highly exaggerated, and that a compressed air car would be a traveling bomb if it got into an accident and the air tank exploded.
Zero Pollution Motors is the US fanchisee of MDI The president of Zero Pollution Motors is on the board of directors of MDI.

Your friend appears to be correct about the mileage claims being highly exaggerated. The only test results that MDI published showed their car running out of air after 7.22km (less than 5 miles). MDI refilling stations.
At the bottom of that rather old webpage (no longer on the MDI website) they go through a series of potential future improvements to convert the actual tested range of 7.22km to a 150 or 200km range.

It doesn't appear that they have ever actually managed to achieve this range, but they keep using those figures in announcments of production. Almost every year from 2000 onward, MDI has announced "cars go on sale next year or the year after", but none have ever gotten to market.

Google "e.Volution car" and "eolo car" and "Mexico City taxi MDI" to see the long history of non-performance by MDI and Zero Pollution Motors.

Your friend may be right about the compressed air car operating range being exaggerated, but he exaggerates the hazard of exploding tanks. CNG (compressed natural gas) cars have high pressure tanks similar to that of the air cars, but filled with flammable natural gas. So far, their safety has been acceptable (as has driving around on top of 15 gallons of highly explosive gasoline in a normal car).

Charlie
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Old 12-31-2008, 08:13 PM   #7 (permalink)
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Quote:
Originally Posted by Big Dave View Post
Compressed air vehicles are used where fire safety is at a premium. The US Navy operates a compressed-air locomotive at its ammunition storage depot at Pearl Harbor.
Compressed air locomotives were also popular in mines in the early 1900's. HK Porter was the leading manufacturer. Typically they were 3 or more stages, with reheaters between stages.

Compressing air generates a lot of heat. In mines, they would use that heat to heat up water, then load that hot water onto the locomotive. The hot water would then be used to reheat the air between the stages of the air motor.

All of this was to make the whole cycle run closer to the more efficient isothermal cycle rather than the very inefficient adiabatic cycle.

MDI's Guy Negre has developed a cute technique of compressing some ambient air (which heats it) and then mixing it with a burst of air from the high pressure tank to drive the piston back down. This appears to be another way to get the engine efficiency up by making it run closer to isothermal.

But the low energy density of compressed air is still the big problem. At best, compressed air is about equal to that of old technology lead-acid batteries in watt-hours per liter or watt-hours per kilogram.

The real competition for the Airpod are the many neighborhood electric vehicles (NEVs) that are being announced. They are what you get by taking golf carts and making them look pretty.
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Old 12-31-2008, 08:18 PM   #8 (permalink)
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I happen to like NEV's.. Ford had a decent bubble car idea thing... and it might even be the family "car" that Bill Gates has, iirc. It's basically a 4 seater golf cart with a bubble roof, for lack of better memory.
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Old 12-31-2008, 08:29 PM   #9 (permalink)
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Quote:
Originally Posted by Big Dave View Post
Is everybody's brain so corroded by conspiracy theories?
Sadly , YES .
Saves them having to read , analyse and eventually think for them selves.

Pete.
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Old 12-31-2008, 11:16 PM   #10 (permalink)
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Compressed-Air vehicles have too many functional negatives to outweigh the positives. The efficiency just isn't there for them to be practical for daily use by the public.

Compared to an electric vehicle, the Air car will take more electricity to "charge" and a significant portion of that energy will be wasted as heat (no matter what kind of exchange system you setup). There are also more moving parts to service.

The only thing MDI seems to be really good at is roping in investors with spurious claims.

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