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Science

Air-Powered Cars 317

Azanian writes: "Here is an interesting article about a French-designed 'compressed-air' powered car being unveiled in Johannesburg (South Africa) later this week. The first of these 'alternative-energy' zero-emission cars are scheduled to roll of the production line in June 2001." It ain't a hover car, but it looks interesting (a full day's driving on 3 hours of air compression, with dramatically less power consumption). Sounds almost too good. Course the auto companies keep this out of our hands like they do with the engine powered by water *grin*.
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Air-Powered Cars

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  • If you could inject compressed (cooled, right?) air directly into the combustion chamber, wouldn't this then lower T2 without moving to canada?
    No. T2 is the temperature at which you dump your waste heat to the environment. If you have some intermediate "sink" which is artificially cooled below ambient, this just means that you have to have a heat pump (which takes power) to take that heat and pump it back up to ambient temperature so you can get rid of it. If you don't have such a heat pump, your heat sink heats up and T2 goes up to ambient anyway. (Not only that, you haven't returned everything to the conditions at the start so you haven't satisfied the definition of a thermodynamic cycle.)

    For an internal-combustion engine, T2 is the temperature of the exhaust, not the outside air. It's the temperature at which heat is rejected. This can be mighty hot, but ICE's get decent efficiency compared to steam turbines anyway. This shows you the advantage of the high T1 allowed by internal combustion.
    --

  • Zero emission my eye! Slap a HEPA filter on this thing are you've got LESS than ZERO emissions. How's THAT for cool.
  • But how much of a market is there for people who live in cities and drive only short distances.

    Every mother who hauls her lazy brats to school every morning. My mum would love this, and so would my sister.
  • http://www.snopes.com/autos/business/magiccar.htm

    Another tale of supression of a carberator.

    In response to calls to put up or shut up, Pogue's miracle carburetor was heard of no more. Faced with the choice of believing someone had made claims his invention couldn't later live up to or that a monied bad guy had bought up a technology to forever keep it off the market, at least some chose to believe the suppression theory. That the carburetor never made it to the public, they said, was proof enough of its existence.

    Basically, two points:
    1) It is not impossible or expensive to build one's own engine. And if it were quite superior, it would be difficult to hide that fact.

    2) If this poor person is recieving death threats about his compressed air engine, have those threats been investigated? Or is it meerly said to back up and exagerate the claim. Basically, it seems like this car would not be able to travel as far as stated, as long as stated, as well as it is stated.

    I'm skeptical that a "better" engine like this can just pop out of nowhere. Unless, of course, it isn't completely better (i.e. less milage, less speed, less efficiency than is hyped.) Finally, for the ultimate in fuel efficiency for city travel, use a moped, or a bus. I'd bet the efficiency would be far greater than any system moving a car around could produce.

    -Ben
  • The only problem I see is in compressing the air. I used to drive long-haul trucks, which use compressed air for brakes (for slashdotters not in the know).

    Job one every morning was to drain all the water out of the air tanks. You pull a cord which opens a valve and lets the air in the tank blow out the water that settles in the bottom. You wouldn't believe all the muck that is in the air that winds up in that water. If the tanks aren't drained for a few days they will spray out a grey goo that's just nasty.

    My point is that low maintenance will only be moved from the engine to the compressor (another high maintenance item) and the associated holding tanks. Probably not as bad as an engine like you say, but still not trivial.

  • by Monte ( 48723 ) on Wednesday October 25, 2000 @04:03AM (#677726)
    If you ever had one of those cheap "air-pump + water" rockets as a kid you know what I'm thinking

    That a lot of these cars will get stuck on the roof?

  • Funny, I was watching a speech by Bush where he was criticizing Al Gore's "targeted" tax cut. For instance, he cited "photovoltaic roof apparatus" (or something) stumbling in his eloquent way through "photovoltaic". This got a big chuckle out of him and the audience. How foolish! What the heck is a new fangled "photovaltaic roof apparatus". Yuk Yuk Yuk. Everybody laugh at how stupid this is.

    Dolt. It's solar power. Why *shouldn't* we subsidize it?
  • by electricmonk ( 169355 ) on Wednesday October 25, 2000 @02:47AM (#677735) Homepage
    I'm gonna invent myself a wind up car! Then we will see who has the better alternative energy source...
  • by trongey ( 21550 ) on Wednesday October 25, 2000 @02:50AM (#677737) Homepage
    Like most of the so-called Zero Emission vehicles this just relocates the emissions. The car just puts out air, but the horsepower to compress that air came from somewhere. Unless the compressor is run by wind, solar, or hydro power it probably results in a net increase in total emissions.
  • by mr.ska ( 208224 ) on Wednesday October 25, 2000 @04:11AM (#677738) Homepage Journal
    As some other poster mentioned, power density is a real problem here. A compressed gas just doesn't have a lot of energy stored in it compared to liquids or solids.

    If you want an air-powered car, I think they guys at TriTec Power [tritechno.com] have a better solution with their power unit that can be adapted for just about any vehicle. It doesn't run on air per se, but it can run on any expanding gas. Steam (made by combusting diesel, gas, hydrogen, whatever), compressed air, liquid nitrogen... anything. Just imagine how much farther you could go with a tank of liquid nitrogen in your trunk expanding. I don't know the figures for N2, but for our old friend H20, it expands by a factor of 1700 times going from liquid to gas. That's nearly 6x what you'd get compressing a gas to 300 atmospheres.

    For the record, assuming their claims of 200km per "tank" and 130km/h, I'd be right there getting one if they came here. Just think how damned quiet it could be. Yeah.

  • by OlympicSponsor ( 236309 ) on Wednesday October 25, 2000 @02:51AM (#677740)
    1) The constant farting sound of air blowing out the back end
    2) Can't steer, car just flys around the room
    3) High internal pressure means that exiting car too rapidly causes "explosive decompression"
    4) After car has run for several hours, outer surface gets all wrinkly

    --
    An abstained vote is a vote for Bush and Gore.
  • Sure, but it can take a decade or more to get new advances into most of the vehicles on the road. Much quicker to get things installed in power plants.

  • Think again.

    The total loss would still be the same, it would
    just be smaller per time unit.

  • by Anonymous Colin ( 69389 ) on Wednesday October 25, 2000 @04:17AM (#677746)
    Actually, the catalytic converter is a very good argument for the point you seem to be arguing against. A Japanese company (Honda, I think) had a lean-burn engine that emitted less polution than conventional engines with converters. Because of US (read: Californian) regulations requiring converters, they were unable to introduce cars powered by these engines to the States. The result was more polution than would have been the case if the regulations had not applied, at least in this case. This is a problem with mandating means rather than results, and is widespread in American government ($10,000 hammer, anyone?).

    While there would be no guarantee that a few hundred polution sources would be any more sensibly regulated than many million cars are, at least correcting regulatory screw-ups would be a lot easier.
  • by lrichardson ( 220639 ) on Wednesday October 25, 2000 @04:22AM (#677748) Homepage
    That is besides the fact that the quantity of compressed air necessary for a day of driving is one nice small bomb.

    The idea of a compressed air car is nice ... also remarkably similar to the flywheel design. The latter is used in trains (occasionally), and in smaller vehicles - quarry trains, tow-motors - where the environment is closed. There was quite a bit of work done in the sixties about sticking flywheels into buses (AEC, England). A small, highly efficient diesel, regenerative braking, and hydraulic motors at the wheels. Unfortunately, the design group noted that t-boning (i.e. getting hit by a truck at 90 degrees) a vehicle so equipped would have the flywheel perform standard gyroscopic physics, ripping itself from the vehicle and punching through any nearby buildings. Armouring the sucker to prevent this pretty much did away with all the efficiencies. (increased weight and size)

    Compressed air vehicles have, in the past, been scrapped at the drawing board for exactly the same reason - storing that much energy in an extremely volatile format is just plain dangerous. 200 klicks seems rather low compared to other designs (standard IC is closer to 500 K), but still would tend to rip most things to pieces if punctured (if you've never taken a high-powered rifle to a compressed gas cylinder in the middle of a field, you've missed out on an adrenaline inducing experience!).

    On a slight tangent, I'm a little surprised by the latest 'hybrid' vehicles done by Toyota and Honda. They're essentially different from the designs the hobbyists use. These modern things use 50+ HP IC engines, running at variable speeds, bringing in the batteries only when needed (acceleration, up hills, etc). The older design was a 5-20 HP IC engine (it takes only around 8 HP to cruise on the level), running at a constant (i.e. peak efficiency) speed, feeding into the batteries, and the vehicle itself was purely electric driven. Also allowing regenerative braking. I've yet to read _why_ this fundamental change was made - the only reason I can come up with is psychological - people would get upset when they learn their lawn tractor has a bigger engine than their car.

  • The compressor is on board. You just have to plug it in to recharge the air canisters.
  • One word sums up ALL my fears about this concept.

    POP!

    Actually I guess it would be more like BOOM. With gasoline, in an accident, you need many things for a catastrophe: 1) massively rupture the fuel tank 2) provide activation energy (a spark) 3) provide a pressurized chamber to fill with gas, creating an explosion

    With an air powered car, the entire catastrophe scenario is summed up in a single event: crack the fuel tank, even a little. KAPOW! all the energy that car is carrying goes off in a single burst.

    Now imagine a packed, 7 lane freeway of bumper to bumper traffic made up of air powered cars (like we have here in DC). Now imagine a semi rolls over onto one, causing it to explode. The explosion tears through the neighboring cars, causing them to explode. Causing the neighboring ones to explode. Causing the neighboring ones to explode. Causing...

    well, you get the idea.

    Ever seen that experiment where they put a million ping pong balls on a million mousetraps, and then throw another ping pong ball in the room?

    fun stuff.
  • What is it with the French and compressed air? There's the Parisian Pneumatic Mail [cix.co.uk]. There's the Pneumatic Caisson [shiraishi.com]. They used to have Trains driven by compressed air [freeserve.co.uk]. The SCUBA regulator, which keeps a diver's lungs from imploding, was invented in France. They used to use compressed air as a motive power in factories... [zone-tour.com].

    To those concerned about people driving around with big tanks of compressed gas: people already do. A lot of vehicles (mostly small trucks and buses, but also some cars) are power by compressed natural gas -- which is, of course, pretty dangerous even when its not compressed.

    (Someone once showed me a way to take out a whole city using this technology. I hope there was a flaw in his scheme.)

    I have to mention Stirling's Draka Stories [uchronia.net]. Despite its appallingly revisionist social philosophy ("Slaveholders are people too!"), this is worth reading for its speculation as to how the industrial revolution might have occurred slightly earlier than in our timeline. One of the factors is the development of pneumatic power. Stirling envisions cities with compressed air mains, much like our gas and electric mains.

    __________

  • The stated purpose of this first application of the engine is for a car running in the city. From the bbc article, it looks as if it may be used to replace the SABTA fleet of mini-buses that used to (I'm not sure if they still do) shuttle people from Soweto to Johannesburg. I'm sure for other applications, i.e. pulling trailers, long commutes, and rural driving other car designs would be developed with an appropriate shift in effectiveness of the engine. I can't imagine these things replacing all gas engines, but as one who lives in Chicago, I would love to get rid of all the gas burners that are used just to drive around downtown.
  • Contrary to what people believe, Hydro is not a zero emissions system. The dams lower and raise water levels, screwing thing up for the surroundings. The turbines are cooled by the water that pushes them and to an extent, contribute to raise water temperatures. I'd say we could all walk everywhere from now on, but that wouldn't be zero emissions either. I'd warm the air wherever I went, since my body temperature is higher than the October weather here in Iowa. I'd live microsopic shoe remnants wherever I stepped, not to mention footprints if it was soft dirt. Now just imagine if I had chili for lunch!!
    ---
  • I thought it was just because the boilers and expanders of the day were too heavy for their airframes; efficiency does more to determine range and maximum time aloft. For instance, look at this article [deltahawkengines.com], which describes a heavier but more efficient diesel replacing a gas turbine for reconaissance drones. The lower fuel consumption leads to either lower mission weight or greater time aloft for the same gross weight.
    --
  • by dbarclay10 ( 70443 ) on Wednesday October 25, 2000 @04:31AM (#677768)
    It doesn't say in the article, but I imagine there's more than a cubic metre - probably more like 1.5 or 2. They also don't say what pressure the air is stored at.

    There is one thing to keep in mind - we've all been spoilt by e-Press e-Releases. This company already has two factories making these things, and the African government has already bought a budle of 'em. They'll be there before the year's end, by the sounds of it. This is obviously *not* vapourware.

    Anothing thing to keep in mind is the industry that we're talking about. The "computer" industry is still very immature, and it acts that way - look at Rambus, look at Intel, look at Microsoft. For most other industries, to even *try* to bullshit your customers(especially governments) would spell instant death. And don't think that governments don't know exactly what's going on ;) The auto industry is, however, fairly mature despite its relative youth(only going back a couple of hundred years at most, if you count the first steam-engine tests and such).

    The BBC could be mis-reporting that these vehicles will get 10hrs at 80km/h off one fill-up, but I doubt it.

    Dave
    'Round the firewall,
    Out the modem,
    Through the router,
    Down the wire,
  • When I get one I'm going to fit a tyre valve on it, and fill it up free form the air compressors conveniently located on every garage forecourt.

  • by Animats ( 122034 ) on Wednesday October 25, 2000 @08:35AM (#677774) Homepage
    Here's the company's web site. [zeropollution.com]

    This car doesn't run on compressed air. It runs on gasoline or diesel fuel. The compressed air tank is used to provide supercharging for an internal combustion engine of unusual design. [zeropollution.com] It's a highly supercharged lean-burn engine, but that's not "zero pollution". There are no reports of third-party tests of the engine, although prototype vehicles are pictured. (You'd think that if it worked they'd at least drive it to a service station that has smog-measurement equipment.) It's not clear why this arrangement is supposed to be better than an ordinary supercharger.

    Nor does the factory [zeropollution.com] exist. They're still trying to get financing. They claim to be able to build a factory for $8 million, which is very low for an auto plant.

    Something is bogus here.

  • Does anyone remember those toy cars that were powered by air? They looked like little dune buggies with a canister mounted where the driver would go. They had a little clear plastic piston engine, and you would pump them up with an included mini bicycle pump. A little push would start the engine and they'd put-put-put across the room - maybe 10 meters if you were lucky.

    Those were very cool - and I remember at the time wondering if they could make real cars like that. I forgot about it until just now :)

    I can't remember what they were called or who made them. Anyone?

  • Because once a nice little hail storm hits your house, all of a sudden you're replacing a $200,000 roof instead of a $10,000 roof.

    That is what steel shutters are for. In Germany nearly every window has a roll-up, metal shutter than can be lowered like a window-blind to protect the glass for harsh weather, or drop the ambient light to zero when one wants to sleep the day away. :-)

    There is absolutely no reason one couldn't protect photovoltaic roof cells in exactly the same manner for minimal cost. Hell, if no one in the USA makes such shutters, have them shipped over from the EU.

    Couple them to motors and, if you want to get fancy, connect a barometer inline with a trigger to close the shutters should the baromentric pressur drop suddenly within a short time. Not a perfect automated defense, but pretty good should you be on vacation. If you're at home and a storm approach, push a button, shutters closed, roof protected.
  • I kind of like diesel.

    Still, unlike the movies, automobiles rarely explode. Mostly they burn if your luck is really bad.

  • Submit a write-up of what happens here, and if it's interesting I'm sure they'll post it.
  • >I've yet to read _why_ this fundamental change was made

    Actually it was commented on.

    It seems us Americans like stomping on the peddle and having the car move. So, to give the car 'pick up' they gave it a bigger engine. Was one of the only complaints. (and with global warming...the driving around in the cold won't matter!)

    > storing that much energy in an extremely volatile format is just plain dangerous.
    As oppsed to pinto?
    Perhaps with the cheaper carbon-fiber technology, the safty issues have been addressed.

    This gent has links to the concept of air powered cars.
    www.redrok.com [redrok.com]
    the air car link [redrok.com]
  • The functioning of the engine [zeropollution.com] isn't really clear from the company's web page. The drawing shows an "air injector", which I took as being a means for inserting high pressure air into the combustion chamber. But it's more likely that it's an air-powered fuel injector driven from an external compressed air source, something that's been used before on Diesels. The drawing of the injector looks like one.

    Whether the first factory exists isn't clear from the web site, but since the only factory picture shown is an architectural rendering, I doubt it.

  • Like most of the so-called Zero Emission vehicles this just relocates the emissions. The car just puts out air, but the horsepower to compress that air came from somewhere.

    Although I agree that thinking no emissions are created is obviously wrong. A clear point can be made (maybe by someone with more concrete knowledge) that your average NorthAmerican powerplant (all sources on whole) will convert energy (whatever type) to electricity far more efficiently than the many poorly maintained cars/trucks on the roads.

    It wouldnt mean zero-energy consumption for all travel (remember: energy cannot be created or destroyed, only change its form) but it would mean a better controlled system where citizens could force ever increasing rates of efficiency from an overall more efficient system (at present im sure).

    Tell your friends/neighbours/co-workers to:

  • The following is parodied in response to a previous post that someone made about air tank ruptures:

    OK, I want to know how many of you have ever seen the results of a gasoline explosion? Talk about cars blowing up like they do in the movies. GASOLINE at those kinds of pressures is DANGERIOUS. And they want gas stations? What are they going to have, big cans of gas out in the open? Oh yeah, I want huge amounts of combustible liquid underground, right in my neibourhood.

    Oh yes, gasoline is undeniably evil and dangerous as all hell to have around. But in my experience, even when it does get free, it's not *that* likely to catch fire. In other words, the only energy released when you gas tank leaks is the energy that was used to put the gasoline in the tank. It still retains its chemical energy. The more subtle dangers of leaked gasoline (ie. pollution) are less immediate in the case of a gasoline leak.

    A tank of compressed air only provides energy as a function of the pressure at which it is stored relative to the pressure of the atmosphere to which it will be allowed to escape when its work is done. If your tank ruptures, you lose that stored energy. Period. And that stored energy will often cause the more rapid release of further stored energy. How? When the tank fissures, the force of the escaping air will help to push the sides of the crack apart the way a cushion of air suspends a hovercraft. A chain reaction ensues: as the hole gets bigger, the air releases more force as it passes through the hole, and therefore the hole continues to grow.

    Naturally, when a cylinder of compressed gas fails, the results can be quite spectacular. Rarely are things this catastrophic with spilled liquid fuels.

    I work for a marine electronics company. Many large marine engines are started either with a smaller engine, or with a large and sudden injection of compressed air into a cylinder, since a conventional starter motor wouldn't be practical at the sizes we're talking about. I was in the engine room of a fairly small tanker; the engine was a SEMT Pielstick, about 300L in displacement. The engine wasn't running, but they were preparing to start it, so they had the electric-powered compressors (which run off either diesel gensets or shore power) running to charge the starting tank. Then, a weld on the side of the tank failed.

    While no one was killed, the results were catastrophic: the end of the tank, which was by that point charged to about 170PSI, was propelled across the engine room and actually managed to perforate a hull plate into a ballast tank. The hull plate was over 1" thick steel. Fortunately, the ship was loaded so the ballast tank was empty.

    Given that this was in the engine room of an American-flagged tanker (*not* a Russian submarine!), and a well-maintained one at that, I'm not sure how I feel about sharing the road with a fleet of aging cars with aging compressed gas cylinders on board.

    I've also seen a cast iron acetylene tank, uncapped without being secured, knocked over and with the regulator and valve broken off. Sure, someone was being careless; sadly, this sort of stuff happens. 3 square inches or so of leak, tank that weighs 75lbs, and is full of gas at a pressure of (let's guess, I don't know for sure) 130 PSI...

    3 square inches x 130 pounds per square inch of force = 390 pounds of thrust. On the back of a tank that weighs about 75 lbs. For one thing, it's airborne. Secondly, it continues to accelerate until it either hits something or exhausts its supply of compressed gas. Did I mention that it was a cast iron cylinder?

    Fortunately, it didn't catch fire. But it did take out a big piece of a cinderblock wall.

    I think that's my problem. With gasoline, *if* it leaks, and *if* it gets ignited, you're in mortal peril.

    But with compressed gases, *if* it leaks, you're in mortal peril.

  • by fishie ( 100172 ) on Wednesday October 25, 2000 @02:53AM (#677820)
    The link in the article didn't work, but here's another [bbc.co.uk] about the same thing. At a price tag of $10,000 I'd have to consider it for a commute to work car. And at a price of 30 cents for 120 miles??? You know the oil companies hate to hear about this stuff. So does OPEC. :)

  • Sounds like a good idea, but you've got to consider that compressed gas can be dangerous. My friends and I used to build compressed-air powered spud cannons that would throw a potato several hundred yards with less than 100 psi.

    Any one remember seeing this one around?:

    The Sleeping Giant
    I am a high pressure, compressed gas cylinder.
    I stand 57 inches tall.
    I am 9 inches in diameter.
    I weigh in at 155 pounds when filled.
    I am pressurized at 2,200 pounds per square inch (psi).
    I have a wall thickness of about 1/4 inch.
    I wear a regulator and hose when at work.
    I wear a label to identify the gas I am holding. My color is not the answer.
    I transform miscellaneous stacks of material into glistening ships and many other things - when properly used.
    I transform glistening ships and many other things into miscellaneous stacks of material - when allowed to unleash my fury unchecked, I can be ruthless and deadly in the hands of the careless and uninformed.
    I am too frequently left standing alone on my small base without other visible means of support - my cap removed by an unthinking worker.
    I am ready to be toppled over - when my naked valve can be damaged or even snapped off - and all my power unleashed through an opening no larger than a lead pencil.
    I am still proud of my capabilities - here are a few of them:
    I have on rare occasions been known to jet away - faster than any dragster.
    I might smash my way through brick walls.
    I might even fly through the air.
    I may spin, ricochet, crash and slash through anything in my path.
    You can be my master, but only under these terms:
    Full or empty - see to it that my cap is on, straight and snug.
    Never -repeat- never leave me standing alone. Secure me so that I cannot fall.
    --
  • ``a full day's driving on 3 hours of air compression, with dramatically less power consumption''

    Um, did they forget about the power needed to compress the air? Unless they've found a way to build air compressors using room-temperature superconductors and friction-free materials, this is still a net loss of energy. We'd of course have to build a lot more power plants which, given the phobia that many people have regarding nukular (which reminds me of a Simpson's episode...) power, would use just as much fossil fuel as we currently do. Probably wouldn't do much about air pollution either except localize it to the power plant (instead of internal combustion engines spreading it around).

    Nice try. Perhaps an on-board cold fusion generator could compress the air? Might not work but it'll get you on the news.



    --

  • Most of them that I know already do. Well, *compressed* air anyway. Put $0.50 in the machine and get air for five minutes.
    ----------
  • There is a web site full of these kinds of innovations at http://www.futureenergies.com/. They have a hydrogen fuel-cell powered mountain-bike, the quasiturbine engine (as revolutionary as the Wankel) which overcomes the problems of the piston engine *and* the Wankel, a computer screen that is powered by ambient light alone, and loads more.

    Phillip.
  • There's lots of free compressed air in the tires of those cars parked around you...

    Heck, I'm sure you could drain a few miles worth of air from that Ford SUV with the Firestone tires, and the owner wouldn;t know the difference...
  • here [bbc.co.uk] is an article the BBC wrote about it. It claims an initial price of about $10,000 for the car.

    Notice how much uglier it is from the back side...

  • This is from my days as a grader for an intro chem eng class; we asked the students to take a 'touchy-feely' approach to solving some problem as by chemical engineering. One group took the problems with combustion engines. There solution was, as we say, unique.

    The idea was to use reverse electrosis to product energy (that is, hydrogen gas plus oxygen plus spark -> water and lots of energy). So you have to store oxygen and hydrogen on board for this to work. So far, not too unreasonable (though r.e. has long be discounted as a possible fuel source).

    The hydrogen tank, since it's very flammable, couldn't be stored in hazardous places in the car, so they had suggested redesigning the car as to use up the trunk space for the H2 tank, moving the chassis up off the group a bit, and having the space underneath the car for where you could put your "groceries or babies or stuff".

    They suggested a similar thing with the oxygen tank but had a better suggestion - instead of having oxygen onboard, it could be pulled from the air and separated out from the nitrogen, then used in their engine. To do the separation of oxygen from nitrogen in air, they suggested a distillation column be installed on the car. I did a quick calculation and found out that they would need at least an 80ft tall column to be able to achieve this.

    So this group is proposing a car design that is 80ft tall, but you stuff all your possessions underneath it as you go along.

    Needless to say, they didn't get an 'A'.

  • On the company's website, there is one page describing the engine: http://www.zeropollution.com/zeropollution/zero_em issions.html [zeropollution.com]. What I don't understand: How can a compressed-air engine work with comustion?

    -Marcel

  • There's something wrong with your equation: n is not constant either ... when you inflate a tire, you add new molecules into of it ...

    --

  • This air compression stuff kind of reminds me of when we used to act like we were propelled by farts when we were on our 'big-wheels' ;)

    ----

  • Yeah, I cant wait to get one of these, so I can do completely air-powered drive-by shootings with my Nerf Wildfire!

    Baz
  • Look, you keep changing the parameters ... First you said the volume is constant. Then you say n is constant. Nope. Either you consider the tank and tank only, in which n rises and therefore P, or you consider the gas at P=1 atm, whose volume will shrink to fit the tank ...


    --


  • Yeah, guys, I agree with you completely. It's a great idea. I love it, it's the economy car of the future, but with one great reservation: compressed tanks. I've seen compressed air tanks go off, I've seen compressed acetylene cylinders go off, and I don't want to share the road with a fleet of the aging Toyota Tercels of the future, all equipped with thermally cycled, corroded and metal-fatigued compressed air tanks.

    Job one every morning was to drain all the water out of the air tanks. You pull a cord which opens a valve and lets the air in the tank blow out the water that settles in the bottom. You wouldn't believe all the muck that is in the air that winds up in that water.

    <grin> A few years ago, I got my air brake license so that I could drive the company Hino around. (Ugh. Hated the Hino. Loved my TopKick.) This was in the Ottawa and Toronto areas in Canada. Toronto's climate is about the same as Detroit or Chicago's, but Ottawa makes a cold winter's day in Maine seem warm.

    Evidenly, the moisture in the brake tanks collects, and will freeze into ice just with the drop in pressure when you apply your brakes hard and fast, let alone when the weather is really cold.

    Since the average driver lets their car run out of fuel occasionally, or does minimal maintenance, or can drive for miles without noticing the low oil pressure light, do we want to trust them to add air tank deicer? What kinds of weird compressed air fitting leaks and failures are these things gonna develop when they're frozen up? This is scary.

    If the tanks aren't drained for a few days they will spray out a grey goo that's just nasty.

    LOL.... I'm not perfect either. I have a compressor in my garage, and the bottom of the tank is a bitch to get at. Because I don't empty it as often as I should, I'm starting to get corrosion on the inside of the tank from the water just sitting there. I've been spraying air tool oil into the tank lately just to ensure that the corrosion doesn't get out of hand.

    My point is that low maintenance will only be moved from the engine to the compressor (another high maintenance item) and the associated holding tanks.

    I'm only worried about the idiots with whom I have to share the road. The people who aren't smart enough to know that a tractor-trailer can't stop as fast as a car and therefore cut them off are oblivious to the laws of physics, and therefore to the basics of driving and vehicle maintenance. At least if a gas tank leaks, it has to be ignited before you have a problem. If a tank that is compressed hard enough that it powers your vehicle fails, you and your vehicle will be airborne.

    In principle, this is a great way to store the energy required to operate a vehicle. In practice, this scares the shit out of me.

    • This company already has two factories making these things, and the African government has already bought a budle of 'em.
    Not to nitpick ;), but I think you mean to refer to "South Africa" (the country) as opposed to "Africa" (the contintent).

    Alex Bischoff
    ---

  • Sorry, my post was a bit unclear on that. The Oxygen comes from the outside air; the hydrogen, from a fuel tank. Ideally, this would be a tank of pure hydrogen (see the item on hydrogen safety in the FAQ at fuelcells.org before saying anything with the word 'Hindenberg' in it) but a fuel reformer gives us a really nice intermediary step by allowing us to extract hydrogen pretty cleanly from many different fuels, especially methanol and ethanol.
  • That much I know. The trick is to deliver a large amount of pressurized gas to an urban location. My friend thought he knew how. I rather think he was wrong, because nobody's tried it yet.

    __________

  • by OlympicSponsor ( 236309 ) on Wednesday October 25, 2000 @02:59AM (#677879)
    Relocating the emissions can be a good thing, even if they (temporarily) increase. Right now, all the emissions are from "non-point sources"--meaning from cars that are zooming around everywhere. But if all the emissions could be centralized into a few power plants, it's a LOT easier to apply some emission reducing technology to the problem. Just think about the logistics (and legalistics) of making all car drivers install some kind of filter or post-processor compared to doing the same for a few power plant owners.

    Furthermore, it modularizes the problem. Instead of having to come up with an engine for a car (which has to be small, high-power, light, and various other characteristics that vary by car) you can extract all those issues to the power plant where size, weight, cost, etc aren't as important. Imagine, for simplicity, that we were all driving electric cars but that our electric infrastructure was coal-based. Just replace those coal-plants with fusion plants (or solar, or whatever) and the change is transparent to the rest of society.

    This is just like putting wrapper calls around malloc/free--you have all the same memory management issues to deal with, but in only one location.
    --
    An abstained vote is a vote for Bush and Gore.
  • Unless the compressor is run by wind, solar, or hydro power it probably results in a net increase in total emissions.
    Almost certainly, yes. however, given that the compression can take place at a fixed site, and is pretty much danger free, there is no reason you *can't* market solar-powered compressors for the home user. Each car owner could produce their own compressed air at home, unattended, and transfer it to their vehicle on an evening. Firms could run compressors for the convenience of their employees, and so forth.
    --

  • Not to burst your bubble, but why saddle the thing with pistons and all those moving parts and the associated friction? A better idea (maybe in use already?) would be to use the compressed air to spin a small turbine that drives a flywheel.

    Yeah, but the problem with a turbine is that it doesn't make complete use of the fuel passing through it.

    In a car, the piston engine won out over *many* attempts (noteably by Chrysler) to build a turbine car, because most of the force of the expanding gases in a piston engine is used to push down the piston. In a turbine, however, only a small amount of that kinetic energy is used to push the turbine blades and create rotational energy - the rest of that kinetic energy goes out the exhaust.

    Now, in the case of a jet aircraft, the turbine really only needs to power the compressor that runs the engine - the actual pressure of the exhaust gases leaving the engine is what produces the airplane's forward thrust. In a car, this isn't practical; capturing the energy with the turbine blades is too inefficient, and powering your car with the exhaust would cause jet blast in traffic. (On the good side, this would deter tailgating.)

    So, in all likelihood, the automotive turbine will go down in history as a really cool curiosity. (However, it did pioneer the use of many inexpensive high-temperature alloys that are used in today's car engines.)

    The flywheel could then be used to drive a generator and the electricity would power the vehicle. That way you maximize the energy in the compressed air... you spin the flywheel at a constant speed except at startup.

    Absolutely. You spin your engine at its most efficient speed, and then use other technologies to couple that power to the wheels. Let's say this is done with a piston engine. Good idea; this is why hybrid cars are starting to come about. But if the engine is running entirely on compressed air, I'm not sure if the additional cost of a hybrid system will be worth the incremental savings in fuel costs. The marketplace will have to bear out whether the added weight and cost makes that feasible.

    With a gasoline engine, the appeal, in particular, is that when a gas engine runs at its most efficient speed, it produces less emissions for the amount of mechanical power it is creating. It's not the gas mileage, though that's a great selling feature. And it simplifies engine design to meet a given emissions target for a vehicle. If the engine is running off compressed air, though, do you care? The efficiency and emissions questions are mostly going to come about at the compression stations that produce the "fuel" for these cars.

    The wheel motors would also be the brakes scavenging some wasted power during stopping by acting as generators.

    Again, worth the cost, weight, decreased reliability penalty from added vehicle complexity? Probably not. Regenerative brakes are a great idea in electric cars and in hybrid cars (which are that way more for emissions reasons, rather than for gas mileage issues). In either an electric or a hybrid car, this is a very simple extension to the system that you've already implemented to power the vehicle. The cost and impact are minimal, the payoffs are good. But, I don't see them really being important enough to bother on air cars.

  • In that respect, the internal combustion engine is quite a bit more efficient than the typical small steam engine.

    And this is why we didn't have steam powered airplanes, and had to wait on the IC engine before we could create them.

  • While you are correct in saying that this does re-locate the emissions, your assumption that this is a Bad Thing is false. The internal Combustion engine is horribly inefficient compared to most modern power plants. Not to mention power plants could very well be using solar or hydro power to fuel these things.

    ---There is no spoon....---
  • This is how the car operates:

    Step 1: There is a small, circular, pink bag of air that you inflate to be the size of a small cushion.
    Step 2: Place the cushion into the driver's seat of the car, preferrably under the seat cover, in a way that the small pink tab is sticking out.
    Step 3: Have the driver go to sit down on the seat, and distract them so they do not notice the bulge in their seat.
    Step 4: Laugh in a childish manner as a loud "poot" sound comes out of the seat. As an added bonus, you can say something else amusing in a childish manner. e.g. "JEEZ! WHAT DID YOU HAVE FOR DINNER?!?!?"

    As you can see, it will not transport you anywhere, but you'll be having such a good time at someone else's expense, you won't care.

  • Hate to point out the obvious - but during the Reagan/Bush years, both the House and the Senate were controlled by Democrats. You know - those two funky legislative bodies that make the laws of the land and decide what the national budget will be?

    Either the Democratic-controlled Congress decided to cut that spending, or they considered it a minor bargaining point that they were willing to throw to the dogs in order to get some other aspect of the budget past the president's veto. In either case, why do you presist in supporting the people responsible for cutting funding that you consider important?


  • Except that turbine engines are now used in main battle tanks, like the M-1 Abrams, and the T-80-something, or whatever the latest Russian model is, which also uses a turbine engine. So what is the engineering reason which makes turbines practical for tanks, but not for automobiles?

    They don't have to conform to Corporate Average Fuel Economy (CAFE) laws. Or emissions standards. They're an off-road vehicle.

    And the poor efficiency (mileage) of a turbine is probably quite inconsequential when you're talking about something that takes gallons per mile, not miles per gallon, based on its sheer bulk, inelegant steering system, and the friction of treads against the ground, regardless of how you power it.

    In fact, a turbine has a very important advantage here. The reciprocating mass of a piston engine makes it comparably slow to build RPMs, but its greater sealing makes it more efficient. While I know nothing about tanks, I'm sure they've got fairly simple transmissions that can take great advantage of the fact that a good turbine can spool up quickly, can run fairly low (if a 5,000 RPM idle is low) and has a bigger RPM range than pistons. The simpler drivetrain makes it less vulnerable to breakdown under attack, among other things.

    The performance of the M-1 using a turbine is far superior to the older diesel engined tanks.

    Probably, yes. Diesels aren't known for great speed. Volkswagen Turbo-Diesels and a few others have gotten around this, but by and large, diesel engines aren't great for torque or horsepower (which is torque over time, essentially) per cubic inch.

    Diesels are known for great gas mileage, though, because the fuel produces a lot more BTU of heat per milliliter. But they don't do it suddenly the way gasoline does.

    Diesels are known for being tough to start in a cold climate. Since the heat of compression is what ignites the fuel/air mixture, glow plugs are employed for cold winter mornings. Even so, they can be tough to get running. While jet/turbine engines or a gasoline piston motor can have trouble too, I've always dreaded being the poor sucker who gets to help someone start a cold Mercedes/VW/Isuzu/etc. diesel engine on a cold Ottawa morning.

    Half the problem is getting the diesel into the fuel pump. I've seen in jelly up. Neither gasoline nor kerosene/naptha (jet fuel) does that readily, since it's a far lighter hydrocarbon.

    Of course, once the diesel is running, the friction and heat of combustion quickly warm the motor to its normal operating temperature and all is well, even if it's -50C with the wind chill. (And Ottawa does get that cold. Don't believe me? Mid-January, 1993; the only things that started in that cold were *well-maintained* Chevettes, Volares, Ladas (Russian cars that are sparsely sold in Canada), older Volvos and stuff. Seems EFI computers don't use components rated to those temperatures.)

    You don't choose where wars get fought. Nor do you want a tank that wouldn't start easily after it's just been airlifted in the cold of a transport at 20,000 feet and has just been parachuted to troops in the middle of hostility.

    So, while a diesel engine is great for a ship or a big rig or even a commuter car in a warm climate, it's not very good for something where speed might be important - like a tank which may have to get out of the line of fire.

  • Well, its not wonderful - but it is considerably better than you are making out. Check out the Homepower [homepower.com] site for example - a medium (roof sized) solar panel provides enough wattage he can backfeed to the grid while still running household appliances.
    --
  • Well, actually it is possible to generate enough energy for the whole world with solarpanels.
    If you put 100 square km full of solarpanels in the sahara you can produce enough energy to replace all other forms of energy production.
    One of the main ingredients where solarcells are made from is silicium.
    Guess what?
    There is very much sand also available in the sahara.
    The enrgy to make the solarcells you can get from...
    The solarcells themself.
    The only problem is the transport of this energy.
  • glad I don't live in your country...
    I've *never* seen this.
  • The thing that caught my attention is that this car has the same performance as the electrics currently available, with a LOT less troublesome components (start with no heavy batteries), and at a lot lower cost as well.


    Note that it runs on high-pressure air, and 4500 PSI air compressors aren't that common - yet - and not at all at gas stations. (Imagine "Honey, I need to go down to the dive shop to fill up the car!")


    I have to wonder about crashworthiness issues, though.
    --


  • kinda like a large container of gasoline? Besides, I love a glorious death

    If your gasoline tank leaks, it's only deadly dangerous if it also gets ignited.

    A tank of compressed air under sufficent pressure and with sufficient volume to serve as the motive power for a vehicle will be deadly with a simple leak. Forget ignition; a pinhole could kill you.

    In a vessel of compressed gas, leaks tend to spread.

    If, in a controlled fashion, there is enough pressure and enough volume of compressed gas to move the vehicle at respectable speeds over respectable distances through the inefficiencies of tires, transmissions, and the friction incurred in a piston engine, just think of how fast, how far, and in what direction the vehicle will travel if the tank is ruptured.

    And if you think it won't happen, think again.

    If you rear-end a car and split the gasoline tank, chances are you'll just make a (potentially dangerous) puddle.

    But if you rear-end a car and split open a tank of compressed gas, the energy stored in that tank is going to be released like a big strong spring being flicked across a room.

    Ever play with a spring-powered BB gun? Think of your tank of compressed air as being a metaphor for the spring. Think of the BB as being a car, hurtled out of control as the spring is released suddenly.

    Finally, think of how far the BB can embed itself into the object at which it happens to be pointed.

    Any questions?

  • Australia exports to most of Asia.I dunno if this is the case here, but it wouldn't suprise me if it was.
  • by gattaca ( 27954 ) on Wednesday October 25, 2000 @03:01AM (#677916)
    If it was a hot air car, I could run it off my boss - finally, turning him into a useful resource. More generally, We could power entire public transportation systems simply by holding regular meetings to discuss great new e-commerce ideas with venture capitalists.
  • Correct me if I'm wrong..But having the water doesn't so much give you a 'boost', as slow down the rate at which the compressed source is depleted, allowing longer acceleration time. The overlal energy released will be the same, exactly. Water does not compress.

    If you use one of those rockets with no water, all the air comes out 'pop' just like that. with water, it takes considerably longer. In both cases, there is the same amount of energy expended.

  • No flaw. Fuel-air explosions are very real and very deadly.

  • when i was a kid I thought by 2000 we'ld be driving jet cars like in the jetsons and stuff. Now all we have is an air powered one? Millenium schmillenium...wheres my jet car!!!

    "sex on tv is bad, you might fall off..."
  • Contrary to what people believe, Hydro is not a zero emissions system. The dams lower and raise water levels, screwing thing up for the surroundings.

    The turbines are cooled by the water that pushes them and to an extent, contribute to raise water temperatures.

    Needless to mention the massive powergrids of wires, poles, etc. which all consume brute product.

    Hydro is clean.. But it's not Zero Emissions.
  • by Anonymous Coward on Wednesday October 25, 2000 @03:04AM (#677925)
    Here is the Company that makes the Air powered cars.

    Someone please mirror important stuff before it gets dotted.

    http://www.zeropollution.com/zeropollution/index.h tml [zeropollution.com]
  • You know I was pissed off when I saw all the gas stations moving towards these boxes that look the same. I mean, air is *free* right? I dunno... I had to use one the other day, and it wasn't that bad, 'cause the thing was *nice* and had a retractable hose, and a gauge built into the tip. I didn't have to go in and ask the attendant for gauge, and I didn't have to mess with a cumbersomely long hose. Anyway... not that big of a life changing thing really, but I thought it was worth the 50 cents.

    ----

  • Well I'm thinking about the loss due to friction.

    --

  • by romco ( 61131 ) on Wednesday October 25, 2000 @03:08AM (#677935) Homepage
    Your waaay to late on that idea.

    spring car [leonet.it]
  • It was called the Air Jammer - by TOMY.

    Air Hogs from Spinmaster Toys [spinmaster.com] are similar, but use the air to spin a prop for a free-flight toy airplane (BTW, the site isn't there anymore - does anyone have a clue what happened to them?). I bought one of these when they first came out, and I was impressed (damn fun to fly!)...

    Recently I was at a Wal-mart and noticed that this other company (can't remember who) started making the Air Jammer again - except they don't call it as such. It is the exact same car - I own an original Air Jammer (with box, bought it off of Ebay for $15.00 - I collect 80's TOMY), and this car was exactly the same - they either bought or licensed the patents from TOMY.

    IOW, they are still available. Air powered machines aren't new things, esp on the toy front. You used to be able to get compressed air engines for radio control and free-flight model planes (back in 20's-40's), not sure if they are still available or not...

    I support the EFF [eff.org] - do you?
  • I just found something out on Spinmaster Toys. I am not sure what is happening, maybe their site domain name was infringing on something or another (who knows these days - probably had to do with the fishing reel manufacturer!). Anyhow, a couple of links:

    This [spinmastertoys.com] link auto-forwards you to here [air-hogs.com], which proclaims to be a new home for "A retail site for air powered glider planes" - which sounds like it may be the real case, not sure...

    WHOIS lists a Richard Giardini - but this guy doesn't appear connected with the company. I don't know if they have gone out-of-business, or what...

    I support the EFF [eff.org] - do you?
  • Having gone to an engineering school, I was exposed to a few alternative energy cars with similar concepts. I saw a video of a smaller, motorcycle sized car that worked on hydraulic pressure. The fundamental idea was that you could gain back most of your pressure while breaking. The "breaks" on the car were actually just pressurizers for some sort of bank of hydraulic piston looking machines. Then the acceleration was just the release of pressure that was built up from breaking. I think you get the idea. The original pressure was built up with a small diesel engine. The guy that developed the idea is probably a /. reader and I just made an ass of myself with that poor description, but...

    I wonder if this e.Volution uses a similar concept? Anyone have more info?

  • by CaseyB ( 1105 ) on Wednesday October 25, 2000 @03:14AM (#677949)
    This is just like putting wrapper calls around malloc/free

    Only on slashdot would someone use a programming analogy to explain an automotive system!

  • by Hairy_Potter ( 219096 ) on Wednesday October 25, 2000 @03:14AM (#677951) Homepage
    But the Carnot cycle states that the efficiency is increased when the combustion temperature is increased.

    For the average IC engine made of materials that you can afford, the maximum theoretical efficiency is 40%.

    If you double the difference (in Kelvin) of the combustion temperature and the ambient temperature, you would get 80%. But this would melt an engine composed of normal alloys.

    So, it's more efficient to have the electrical powerplant do the combustion, they can afford a turbine that burns at 2,000 degrees and is made out of tungsten-nickel alloys.

    Ultimately, ceramic engines will yeild a huge increase in efficiency, but they are a aways away.
  • And the energy lost from resistance in the power lines?

    Obviously non-zero, but not huge. That's why we have high tension distribution: P = I^2 R. By jacking up the voltage to 20 fold or more, you reduce the current carried by a factor of twenty and drop the power loss by 400 fold or more.

    Thus if you are ten miles from the power station distributing power at 20x the voltage or more, the power dissipated in the lines is the same as if you had low tension distribution but were less than 150 feet from the station -- about what you'd lose in an extension cord.
  • by Skinny Rob ( 110104 ) on Wednesday October 25, 2000 @03:15AM (#677960)
    Well I'm skeptical. It comes down, as always, to the dull and tedious issue of energy density. My back-of-envelope scribblings tell me a cubic metre of air at 300 bar stores about 30 megajoules. That's only 8 kWh. I don't see that little energy lasting any longer than about half an hour: nowhere near the endurance figures mentioned in the article.
  • Most of them that I know already do. Well, *compressed* air anyway. Put $0.50 in the machine and get air for five minutes.

    Sure, and those machines aren't used particularly often, and the cost is based on recouping the cost of the machine and the electricity to use it. As usage goes up, cost per-use goes down.
    --
  • In reality, a car like this succeeding is unfortunately unlikely. They've got a HUGE battle to fight against:
    1.Big Oil companies
    2.Current big car manufacturers (don't want to change out those assembly lines)
    3.Governments of large oil producing companies
    4.Politicians who are controlled (oops I mean lobbied) by the oil companies
    5.Car parts manufacturers (have to start making parts they may be unfamiliar with)
    And the list just goes on...
    It's a great idea, but if you think gaining widespread acceptance will happen anytime soon, think again. Alternative fuel-source cars have made their way into the market, yet the above groups haven't worried about them because they know these cars so far have limits on them that keep the average driver from purchasing them. Either the cost of the vehicle itself or the cost of maintenance is too high, they are limited on distance of travel at one time, etc. A vehicle that could stand up against a regular car in performance, reliability, travel distance without refueling, ease of maintenance and cost would be reason for these guys to worry. A lot.

  • to make a point.

    To see more about the Carnot cycle, you can start here. [taftan.com]

    Maximum theoretical efficiency is

    1 - T2/T1, where T2 is the ambient temp, and T1 is the combustion temp.

    You can't influence T2, unless you move to Canada, T2 is the temp of the air the engine works in, which is why early helicopters had trouble lifting themselves in hot climates, the ambient aur temp was high enough to reduce their efficency.

    Artificially cooling the ambient air won't work either, you'd be battle entropy and thermodynamics.

    So, you have to increase T1, the combustion temperature. But most IC engines have low melting points, because they're made of steel and aluminum alloys.

    If you changed alloys to a nickel tungsten titanium alloys (Inconel maybe) you could increase T1.

    If you could use a ceramic engine block and piston, you could really increase T1.

    Hope this helps.
  • The original article, and the bbc articles listed here didn't really go into it, but it does operate as a combustion engine at speeds of over 50kmh or so (if i'm recalling what i read a few weeks ago correctly, anyway.)

    They also show three different models of the thing...a station wagon of sorts, the taxi, and a pickup truck. (look here [zeropollution.com])

    Max speed was about 63mph, which still isn't too bad.

    I don't know how well it would do here in the states, but I know I'd bloody well buy one (and maybe another for the wife) at the prices they are initially talking about. That is however, a big if. :P
  • Temperature can be raised to enormously high levels.

    Is that your plasma rocket in the newest Scientific American? I'm sure you have few tailgaters, considering what superheated hydrogen fuel does as it mixes with our reducing atmosphere.

  • According to the website of the company designing these things: zeropollution.com [zeropollution.com], the reason why it will run 10 hours in the city is because the brakes are on some sort of generator system which drives an internal air compressor.

    This thing is actually pretty damned cool. I was really skeptical about it when I first ran across it a few weeks ago, but I think I've some idea how it works. Check out the url above for all sorts of interesting info, with a diagram of the engine (I don't think the spark plug is used during the air-only phase of operation...that's what confused me at first.)

    Also, be sure and check out their planned factories. Instead of building huge factories ala Ford/GM, they want to put small factories producing a few thousand units a year outside big cities...I don't know how that would fly over here, but it's intriguing.

    It puts out about 25 hp, which ain't much...but when your fuel is air....

    Besides, these would make dandy emergency generators. Just hook up a number of small air tanks, a few solar cells, a compressor, etc. etc.

  • Slow site... US mirror [flyingbuttmonkeys.com].

    The text is there. The images are coming over very slowly. But at least you can read the article.

    ________________________________________
  • That is besides the fact that the quantity of compressed air necessary for a day of driving is one nice small bomb.

    The fact that this one has no fuel to burn does not mean that the other ones don't. So just when you have thought that the crash flames from the petroleum driven ones have subsided the great pneumatic wonder goes booom and there is a nice crater in the road.
  • From the BBC article:

    There are currently two factories in France,
    with the first models expected on the streets
    later this year.

    There are five factories planned for Mexico and
    Spain, with three in Australia.


    OK, maybe the BBC got it wrong, but why 3 factories in Australia? That seems really wierd to me.


    ...j

  • We'll just end up using all of our air to fuel our cars. Then the French will have to design a spaceworthy version of the Statue of Liberty so we can steal all the air from another planet with an atmosphere.

    Of course, some idiot will decide that it'd be best to choose Venus' atmosphere so that the additional CO2 and SO2 introduced will compensate for the amount not produced by Internal Combustion Engined-vehicles.
    Since idiots run the world, they would listen to him.

    And now, my 2:
    I live in Pittsburgh. Vehicles carrying tanks of flammable gases (not all gases, but most of them) are prohibited in any of our four or five* tunnels (three of which are on major thoroughfares). Would that mean I'd have to drive for an additional 15 minutes around them? If I were to drive such a car through the tunnel and get stopped, would I be cited and have my car repo'd?

    * - Offtopic sidenote: The Wabash Tunnel will be reopening soon as an HOV/Bus-only thruway, for yunz 'Burgh geeks who carpool dahntahn. Which if they lifted the flammability provision and got one of these cars, you could go from Carnegie to Dahntahn in less than 5 minutes!
  • by FreeUser ( 11483 ) on Wednesday October 25, 2000 @03:44AM (#677994)
    Sure it will. Check out this link. Bush is known for his big oil contributors, he will stop all forms of advancement in the alternative energy fuels when given the word of big oil.

    The same thing happened when Reagan was elected. All research into Solar Power a Argonne Natl. Laboratory was killed almost immediately and remained dead throughout their administrations. In many respects the Reagan/Bush administration was to alternative power as Microsoft was to Computer Science -- they slowed the technological development down for at least 10 years or so.

    The other post was correct -- any career politician will be a whore to the contributor with the biggest check, but historically the Republicans have been the worst offendors when it comes to fossil fuels vs. alternative energy, with the Reagan/Bush administrations being the worst offendors by far.
  • by twitter ( 104583 ) on Wednesday October 25, 2000 @03:28AM (#677996) Homepage Journal
    Compressed gas engines are not generally effecient. As anyone who has pumped up their tires knows, it takes lots of work and a good deal of that work is wasted as heat. The compressed gas is hotter than the world, but not for long. When it reaches room temperature you have lost considerable work. You also take losses when you try to use it. As the gas flows out, it typicaly cools down so you need a heat exchanger just to keep from freezing up. Once again, you are loosing work. Other vehicles have been built like this, and suffered from these problems. It's not that they can't be overcome, it's that they introduce a great deal of waste.

    Oh yeah, compressed gas is dangerous. All of the work you put into it can be released instantly if your tank busts. This of course, is bad for people that get in the way. It happens from time to time, especialy when people screw up and put the wrong pressure in a cylinder. Boom, like a bomb. Failures in accidents will be less interesting, but knocking off the valve can give you a thousand pounds of force for a few seconds. If the cylinder is not held down well, it will fly around like a balloon. This is also very bad for people who get in the way.

    All of that said, this might be cost effective if you do all of your gas compresion with cheap nuclear or hydro generated electricity. I have my doubts. Natural gas prices are comming up, :(. Windmills, solar and all that, forget it, it will be cheaper to burn oil.

    Poster would rather ride his bike.

  • Sigh.
    Try this [flyingbuttmonkeys.com].


    ________________________________________
  • OK, obviously slashdot insists on putting a space into the URL. So here it is; copy and paste; remove the space manually:

    http://www.flyingbuttmonkeys.com/mirrors/www.news2 4.co.za/News24/Wheels24/News/0,297 9,2-15-47_929116,00.html

    ________________________________________
  • As an aside, it's not the auto companies that don't want us to have air (or water) powered cars, it's the oil companies. They have the resources to either extinguish or simply buy out any alternative means of powering automobiles. Don't expect breakthrough progress until the Earth's supply of petroleum is nearly exhausted -- and then, expect those "breakthroughs" to come from the very same oil companies (a key thing to look for is when they start calling themselves "energy companies" instead -- similar to the way cable television providers now refer to themselves as "broadband" companies to encompass the data and voice services they want to deliver).

    Sad, but true. Oil companies are way too rich and powerful. And if we end up with W in the whitehouse, look for them to become even more powerful.
    --
  • As anyone who has pumped up their tires knows, it takes lots of work and a good deal of that work is wasted as heat.

    ... but the slower you go to fill that tank, the lower the loss ... limit being 0.

    So if you have time (like, while you sleep), the loss could be very small.


    --

  • This thing only weighs 700 kg (1540 lbs). Can you imagine driving over a large suspension bridge on a windy day? I often travel over the Mackinac Bridge in Michigan and even in a relatively light combustion engine car it can be a tense situation - never mind just driving down the highway at 70 mph on a windy day. In the shelter of the city it wouldn't be that bad (unless you live in Chicago I suppose ;) but I could see there being some serious traction problems at high speed on the highways, not too mention during cold/icey conditions. Does anyone have any ideas? I wonder if you could fit it with a foil or something for high speeds? I guess that would reduce efficiency, but it might be the only way to keep it on the road.

  • by Sebbo ( 28048 ) <sebboNO@SPAMsebbo.org> on Wednesday October 25, 2000 @05:19AM (#678013) Homepage Journal
    That's why it's preferable to use something safe, with no risk of explosion, like...um...gasoline... Oops.
  • by Tau Zero ( 75868 ) on Wednesday October 25, 2000 @05:25AM (#678015) Journal
    I learned it in an engineering class -- something like 1/2 or 2/3 or all the energy put in is lost to resistance.
    Over the line of your homework examples, maybe. In real life energy is money, and power companies work very hard to keep losses down. The power transformers which convert one voltage to another are upwards of 97% efficient.

    Power lines are a lot more efficient than you think, too. I'm having a bitch of a time locating the resistivity of typical aluminum transmission wire (AskJeeves is turning out to be useless), but if we assume that the lengthwise resistivity of the alloy as used would be about 3 times that of pure Al or about 8 micro-ohm meters, the wire has a cross-sectional area of 10 square cm and it carries a current of 50 amps at a voltage of 500,000 volts (25 megawatts) for 160 kilometers, we see that:

    • The resistance is 8e(-6)/1e(-3) = 8e(-3) ohms/meter, or about 1300 ohms over 160 km.
    • Total voltage drop is 1300 ohms * 50 amps = 65,000 volts.
    • This is 13% of the total, not 2/3 or even 1/3.
    If I had a line that was leaving about 3 megawatts undelivered, I'd want to lay thicker wire; at $.05/KWH, that's about $150/hour it's costing me. That's $3600/day, $25000/week, $1.3 million a year. You can recoup some pretty steep capital costs with that kind of return on investment, especially if you are amortizing over the kind of time-frames typical of a regulated public utility.
    --
  • by Tau Zero ( 75868 ) on Wednesday October 25, 2000 @05:35AM (#678024) Journal
    I remember articles in Analog S&F magazine that one of the advantages of a steam engine over an internal combustion engine was that the former burnt the fuel far more efficiently.
    Only if you define "efficiency" as the conversion of fuel into final combustion products. In this context, most people mean the conversion of fuel into work. In that respect, the internal combustion engine is quite a bit more efficient than the typical small steam engine.

    Quick recap of Carnot efficiency: Eff = (Thi - Tlo) / Thi. Thi is the temperature at which you put heat into your working fluid (assuming that it is at a constant temperature, which it isn't in any real engine). This is where the internal combustion engine kills the steam engine. It does it because the steam engine has to run its working fluid below the highest working temperature of its parts (the boiler wall is always hotter than the steam). The internal combustion engine produces heat within the working fluid, so the working fluid can be far hotter than any part of the engine. You can easily have combustion temperatures of 3000 F or more in your car, temperatures a steam engine cannot approach.

    Large steam turbines get thermal efficiencies in the low 30's. Medium-truck diesel engines commonly break 40% (look at the Cummins data sheets if you don't believe me), large marine diesels hit 50%, and combined-cycle power plants (which use gas turbines - internal combustion engines - as the topping cycle) are up to 60%.
    --

  • by RISCy Business ( 27981 ) on Wednesday October 25, 2000 @03:57AM (#678027) Homepage
    I collect cars. Work on 'em, fix 'em, break 'em, and fix 'em again. I know the internal combustion engine all too well.

    How does this car sound? Well hot DAMN, somebody FINALLY figured out something other than (gasoline, alcohol, nitromethane) to inject. Basically, this is a very interesting system that works. How well does it work? Time will tell.

    But you could probably modify any engine in the world to do this.

    Instead of creating compression through combustion, it's direct injection of compression, forcing the piston down, thusly turning the engine. The horsepower potenetial is nil, but it's an excellent economy design. And the kicker is that, despite what others have said, unless there is a genuine combustion cycle, there is no emissions outside of what you put in. If you put in clean air, clean air will come out, in this setup. The engine will probably be low maintenance as well - you don't have to worry as much about rings failing from carbon buildup, or piston failure from using too low an octane rating. Although I wonder if using pure O2 instead of air could cause detonation, heehee. ;)

    Sounds like the best idea I've seen in a good long while. Now all they have to do is figure out how to do it in a better looking car that's smaller, and I'll buy one! :)

    =RISCy Business
    your company here. [fuckedcompany.com]

There is no opinion so absurd that some philosopher will not express it. -- Marcus Tullius Cicero, "Ad familiares"

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