h a l f b a k e r yLike gliding backwards through porridge.
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A lightweight, but strong, passenger bubble, basically round, it has all the hardware in the floor a la Hywire (although I've had this design in my head for ~6 years). +-6 passengers, 3 in front (driver in center). Now the interesting part.
It's powered by compressed air, like those from MDI, but
the air engine turns a generator which charges a battery pack and moves the car (blah blah regenerative braking blah).
But what if you run out of energy? There's a fuel cell with enough hydrogen to keep you going for a few dozen miles. But what if THAT isn't enough?
UNlike any other car (except the funky electric ones), this vehicle's system allows you to use the batteries themselves to power the car 'til THEY run out. HOPEfully, that will be enough to get you to a station. If not, the handy foldout stationary-bike compressor will let you turn that flab into car power! Yes, it will take 30 minutes to get any useful amount of air into it, but that just happens to be the optimum workout time as well. If you get thirsty from working out, just drink the water from the fuel cell reaction.
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Dual-hybrid? Tri-powered? Redundant backup-powered? What do I call this? |
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So the compressed air is in a charged tank, presumably from a station which uses electricity to drive a compressor. Then you've got an air engine powering a generator recharging batteries driving (presumably) an electric motor. Why not add a pump and hydraulic drive for each wheel just to add a few more losses into the system and a bit of extra weight? |
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If it is so lossy, why is a hybrid system so efficent, e.g. Honda Insight, Toyota Prius? (The Insight gets between 55 and 70 mpg, by the way.) |
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I saw the specs on the air car from MDI, and the engine design is rather ingenious. However, it's got no guts. It would rather be running at constant (optimal) speed, turning a generator, which powers the whole thing. |
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There is nanoscopic loss (i.e. the mass of the shaft) between the engine and the generator, so there's one down. |
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Compressed air is one of the few forms of energy which do not deteriorate in storage, but depend ONLY on the efficiency of their engines, so there's that. |
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Thirdly, electric motors produce much less (and therefore waste a lot less energy making) heat than internal-combustion engines, so they are more efficient. That should negate all losses from the complexity. |
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As for batteries, say what you like. They're good, but there's still improvement to be made. This system could use capacitors, but then what backup would there be? Only the not-yet-to-be-envied fuel cell. |
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This system is designed to be non-polluting, yet have the range and efficiency we're used to in our 'normal' cars, plus double-backups if you don't have enough to get to a station. (That's not mentioning the human-powered fill-up.) |
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What's with the needle, [thimble]? This idea was already 'at the top of the list' when I made that anno. I honestly couldn't figger out what to call it. Got naming suggestions? |
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//It's powered by compressed air//
I'm having doubts about the range of this vehicle on its primary fuel source. |
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By itself, compressed air isn't all that powerful. The range of the MDI cars is something like 150 km. However, if the engine was running at optimum speed, turning a generator, it'd be more efficient, thus a greater range. |
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Compressed air does not deteriorate in storage, but a tremendous amount of energy is lost in the process of compressing it. When the air is compressed, it becomes hot, and this excess heat is quickly lost as the tank cools to ambient. The process of converting the compressed air is also a source of high loss. It is much more efficient to convert electricity directly to a driving force through carefully designed electric motors.
The efficiency gain in gas-electric hybrids comes not from a more efficient drive train, but from having an engine run at its' optimum design speed most of the time. What's nanoscopic loss? The mass of the drive shaft, once rotating, does not contribute to a loss (an object in motion...)
Until we move completely to renewable non-polluting power stations, i.e. geothermal, wind, solar, eventually fusion, there will never be a truly non-polluting vehicle. |
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I build fuel cells, specifically the alkaline variety (the kind on the shuttle, not the PEMs that people expect to use in cars.) "A few dozen miles", depending on the car's weight, is probably about 4 oz of water. |
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I guess it's enough to drink, but not really good enough to quench thirst. |
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Here's an idea: Why not use the bicycling to power an electrolyser, which would then split the water allowing you to use the hydrogen in your fusion reactor. the oxygen would be very useful for breathing if you got out of breath while doing all this bicycling. |
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Then, if you got overheated, you could puncture a cylinder of compressed air, which would get really cold once the pressure decreased. you could use that as an air conditioner for a few minutes. |
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Personally, I'm happy with my Insight....(by the way, the theoretical maximum is around 80 mpg :D ) |
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and finally you wounldn't need to worry about nanoscopic loss. Unless you built every moving part of the car out of liquid helium, you'd still have frictional losses. |
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//a tremendous amount of energy is lost in the process of compressing it// |
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Then again, a tremendous (even more than compressed air, according to an independent study) amount of energy is lost converting crude oil to gasoline, and tremendous amounts of energy are lost as heat in internal-cumbustion engines, and energy is lost through inefficient engine SYSTEMS in traditional cars (inefficient drivetrains, a/c systems, fuel burning)...etc. |
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Whatever the bads of it, it's still more efficient than any car available on the market. |
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[Macwarrior], it doesn't use a fusion reactor, but a fuel cell, as in take H and O, stick 'em together and make electricity. |
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As for current cars, I'd like an Audi A2. Theoretical maximum of 100 mpg. |
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Umm...as I said, I build fuel cells (FCT). I know how they work. |
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The fusion reactor thing was from the previous post as a joke. Apparently I have no sense of humor (*sniff*). |
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Maybe 'tis someone else what don't 'ave a sense of 'umor, eh? |
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Okay, I just didn't get it. |
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I've a differnt sense of 'umor, I 'ave. Thay sigh Oi'm crizy, but chew doun't think Oi'm crizy, dou ye? |
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// Ion-powered spaceflight // |
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No. Ion engines take a very long time to build up speed. I'm not sure they'd even work at all on the planet's surface. They may not have enough initial energy to overcome gravity and friction down here. |
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The most powerful *human-made* ion engine has a few pounds thrust. |
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few pounds? maybe as you say the most powerful. the one used on DS1 was about equivalent to a sheet of paper resting on your hand. |
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Hamsters would be better. |
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That's why I didn't choose such an...*ahem*...ADVANCED technology. |
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Well, of course, advanced technologies can be useful from time to time. Look at ther transporter beam in star trek: nothing can beat five seconds transportation except for 4-second transportation, 3-sec, 2-sec, 1-sec and instantaneous (aka teleportation). |
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I was being sarcastic. Ion propulsion, being very advanced, is in its infancy, even if it's a half-century old. Just not refined enough, tweaked right, or whatever to be of use here. |
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Terribly ineffecient. With each conversion (air pressure> montion of the turbine, motion>electricity, electricity>chemical energy in the batteries, chemical>back to electric, electric>motion of the wheels) you have losses, and you're starting with compressed air which doesn't store very much energy to begin with. Then you're going to throw in a very expensive fuel cell, which only gets used as a backup. |
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