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The Quest for the Car of the Future 434

Posted by Zonk
from the zippy-go-fast dept.
Lux writes "Where will the car of the future come from? It's unlikely to come from anywhere you'd expect it to. Wired's money is on the car of the future coming from NASA. 'New technology that promises to revolutionize the automobile as we know it is emerging from research institutions and startups — and these innovations won't set you back $100,000 like a Tesla will... One experiment involves small electric motors located in the wheels of the CityCar, a tiny, nimble and practically silent vehicle with wheels that turn 360 degrees, enabling it to slip neatly into tight urban parking spaces. Others are looking to revolutionize the automobile's engine, not replace it.'"
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The Quest for the Car of the Future

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  • Google? (Score:5, Informative)

    by GillBates0 (664202) on Tuesday June 19, 2007 @04:17PM (#19570857) Homepage Journal
    A clean energy update [blogspot.com]
    Google pushes 100-mpg car [cnn.com]
    Google plugs in and goes green [ft.com]

    Frankly, I'm surprised this hasn't made it to a /. article yet.

  • by ducomputergeek (595742) on Tuesday June 19, 2007 @04:18PM (#19570879)
    I think that's called the Smart car. It may still run on gas, but can park backing up to a curb. And I guess if you want more style, you can go with a Mini.
  • Re:water (Score:1, Informative)

    by TheRealMindChild (743925) on Tuesday June 19, 2007 @04:20PM (#19570911) Homepage Journal
    Technically in a perfect world, even gas combusts into water vapor. But the world isn't perfect. To quote wikipedia http://en.wikipedia.org/wiki/Combustion [wikipedia.org]:

    Combustion or burning is a complex sequence of exothermic chemical reactions between a fuel and an oxidant accompanied by the production of heat or both heat and light in the form of either a glow or flames.

    In a complete combustion reaction, a compound reacts with an oxidizing element, such as oxygen or fluorine, and the products are compounds of each element in the fuel with the oxidizing element. For example:

    CH4 + 2O2 CO2 + 2H2O + heat
    CH2S + 6F2 CF4 + 2HF + SF6 + heat

    A simpler example can be seen in the combustion of hydrogen and oxygen, which is a commonly used reaction in rocket engines:

    2H2 + O2 2H2O + heat

    The result is simply water vapor.

    In the large majority of the real world uses of combustion, the oxygen (O2) oxidant is obtained from the ambient air and the resultant flue gas from the combustion will contain nitrogen:

    CH4 + 2O2 + 7.52N2 CO2 + 2H2O + 7.52N2 + heat

    As can be seen, when air is the source of the oxygen, nitrogen is by far the largest part of the resultant flue gas.

    In reality, combustion processes are never perfect or complete. In flue gases from combustion of carbon (as in coal combustion) or carbon compounds (as in combustion of hydrocarbons, wood etc.) both unburned carbon (as soot) and carbon compounds (CO and others) will be present. Also, when air is the oxidant, some nitrogen will be oxidized to various, mostly harmful, nitrogen oxides (NOx).
  • Re:Heh (Score:3, Informative)

    by HTH NE1 (675604) on Tuesday June 19, 2007 @04:22PM (#19570959)

    wheels that turn 360 degrees
    Indeed, that is a revolution.
    Nice pun.

    But yeah, if wheels don't spin a full 360 degrees on their axle, how would they roll?

    I think they meant that they could be turned to point in a direction within a 180-degree range (reverse gear gets you the other 180, unless you really do need to drive towards, say, your 8 o'clock position at 75 MPH).

    That is, unless the wheels are spherical. Then there's no need to point them: just roll them the way you want to go. (Spinning them around an axis perpendicular to the road though would be a pointless exercise.)
  • Re:water (Score:5, Informative)

    by moderatorrater (1095745) on Tuesday June 19, 2007 @04:26PM (#19571013)
    No offense sir, but assuming you're saying "gasoline" when you say "gas", you're absolutely, 100% wrong and never should have been modded informative.

    When the article says "perfect combustion", it's referring to oxygen and hydrogen and nothing else. As it points out, most combustion occurs with a component that involves carbon, which is why C02 is present in most combustion reactions. The truth of the matter is that "perfect" combustion only occurs with pure hydrogen, which doesn't exist in the real world because hydrogen is so reactive.
  • by mpoulton (689851) on Tuesday June 19, 2007 @04:34PM (#19571139)
    Quite true - present battery technology is pitiful for bulk energy storage. Compared to any combustion fuel, batteries are at least an order of magnitude worse in terms of watts per kilo or watts per unit volume. The Tesla used a giant array of lithium polymer batteries, which is the best we can do right now. Consider this: An electric car like the Tesla has a battery pack several times larger and heavier than a normal car's full gas tank. The drive system and the vehicle as a whole are much more thermodynamically efficient (miles per watt of input). Yet, the vehicle's range is at most a third of a normal car's. Until electrical energy storage makes at least an order of magnitude improvement in density, electric vehicles will remain highly inconvenient compared to combustion engines.
  • by soren100 (63191) on Tuesday June 19, 2007 @05:14PM (#19571663)
    If you're at all interested in the forces at work behind the "car of the future" topic, you owe it to yourself to see the movie Who Killed the Electric Car? [wikipedia.org]

    The state of California mandated in the 1990's that 10% of the cars sold in California be emission-free, so GM and Toyota put out all-electric vehicles. The cars had a top range of 80-100 miles before recharging, but since most people only drive around 36 miles a day, that was a non-issue for many people.

    Here are some of the issues the film discusses:

    1) the people who leased the cars were absolutely in love with them and thought that they were very well-engineered
    2) The people who leased the cars tried desperately to buy them, but were never allowed to. GM turned down $1.9 million for the 78 uncrushed EV-1's before they were finally crushed.
    3) All of the electric cars were crushed, even the brand-new ones, after the companies who made them promised that wouldn't happen.
    4) The drivers of the electric cars really loved the engineering and handling of the cars.
    5) The federal government joined the car manufacturers in a suit against the state of California fighting the 10% zero-emissions law.
    6) one person in the movie told about a congressman who told him to get the electric car killed before it spread to other states (or the congressman would "battle" him)
    7) The electric cars were so simple to work on that major dealership revenue sources would have been lost.
    8) Consumers were very interested in lowering emissions and helping the environment, and were also willing to pay to do it.

    The top 3 oil companies in America pulled in well over $700 BILLION [marketwatch.com] for the last two years, without even looking at the record profits for the previous years. The movie makes a serious case that there was a serious push against the electric car to preserve those future profits from harm and keep the electric car from being a mainstream idea / product.

    Some might call this a conspiracy theory and there are market forces involved, but it also really just sounds like intelligent business practices by the oil companies. Given the tremendous needs in the marketplace now, and the advances in technology, it will really be very interesting to see how this market develops.
  • Re:Heh (Score:3, Informative)

    by drinkypoo (153816) <martin.espinoza@gmail.com> on Tuesday June 19, 2007 @05:17PM (#19571701) Homepage Journal

    I (perhaps erroneously) assume the small motors inside the wheels are gear free.

    You are almost certainly correct. For low speeds there is no need to gear down, as electric motors make peak torque at 0 RPM. And this is a city vehicle that is clearly not designed to travel at high speeds (witness the aerodynamics, or lack thereof.) Adding gearing would just mean adding geartrain loss, not to mention complexity.

  • Re:Heh (Score:3, Informative)

    by DragonWriter (970822) on Tuesday June 19, 2007 @05:22PM (#19571767)

    I would think that 90 would be enough, no? With a forward and a reverse...or am I missing something?


    To be able to move in any direction with a forward and reverse gear available, you need 180 degree rotation on the wheels. If the wheels lined up straight forward and back is your baseline, you need to be able to rotate them 90 degrees in either direction, which may be the source of your error.

    If it isn't intuitively clear, it may help to draw a diagram. If you have a 90 degree forward arc (45 degrees right and 45 degrees left), and then reflect that around a line perpendicular to your forward axis to represent the area available with reverse, you'll have a 90 degree forward arc and a 90 degree reverse arc representing the directions you can go, and two 90 degree side arcs representing directions you cannot go.

    Expand the forward arc to 180 degrees, and when you reflect it you can go anywhere.
  • Re:water (Score:3, Informative)

    by DragonWriter (970822) on Tuesday June 19, 2007 @05:26PM (#19571833)

    Technically in a perfect world, even gas combusts into water vapor.


    Even with complete combustion, gasoline (or any hydrocarbon) combusts to CO2 plus water vapor, not only water vapor, which was what the GP was asking. The only way something can combust to just water vapor, even assuming complete combustion, is if it doesn't start out with any elements other than hydrogen and oxygen in the reactants.

    (The wikipedia article you quote makes this clear, too, but your statement here seems to have overlooked that rather basic fact.)
  • The c,mm,n (Score:2, Informative)

    by hcgpragt (968424) on Tuesday June 19, 2007 @05:36PM (#19571955)
    In Holland an environmentalists group actually build a environment friendly car and showed it of at the annual, national car show. It was put together in a combined effort with three universities in a few months. Made the big brands look pritty silly I can tell you!. It's called the c,mm,n (pronounced: common). at it is open-source no-less :) here [www.snm.nl] is a local item on it. It's in dutch, but it got neeat pictures showing that this is no vapor-ware. It actually sits on someone's driveway ....

    The technology is there. It's proven. I guess its the investments in factories putting the big guys off?

    p.s. found the homepage [autoindetoekomst.nl] to the project:

  • Re:Simple (Score:2, Informative)

    by drinkypoo (153816) <martin.espinoza@gmail.com> on Tuesday June 19, 2007 @05:38PM (#19571991) Homepage Journal

    You could then probably got cross country with the car if you wanted not depending on solar power because you have 250 miles of battery power available. It would at least be easy out here in the south west.

    It's a 3,000 mile trip across the country (approx.) and most of it is not in the southwest.

    What are you smoking, and where do I get some?

  • by Shivetya (243324) on Tuesday June 19, 2007 @05:39PM (#19571993) Homepage Journal
    Mostly has been discounted.

    #1. There were not enough people that wanted the car, yeah a lot of them with it but many didn't want to pay for it.
    #2. Blame the government. Laws requiring replacement parts and service over reasonably expected lifetimes meant GM would be subsidizing the ownership of the cars
    #3. Can't attest to that, GM did get rid of theirs for money reasons
    #4. Repeat of #1
    #5. States should not be allowed to create rules that affect other states adversely. Also, California for all its so called environmentalism was one of the primary reasons diesels died here, yet Europe seems them as a solution
    #6. Laughable
    #7. Not true. Electric cars require different skills and with limited applicability with the low numbers of them they could not create enough interest in people training for it
    8. There were not enough people who wanted them.

    the problem with the EV and related cars is they did not fit the lives of the majority of drivers. They were inconveinent and not practical.

  • Re:Crash tested? (Score:3, Informative)

    by nutshell42 (557890) on Tuesday June 19, 2007 @05:43PM (#19572035) Journal
    If that's true, sign me up.

    Robert Kubica crashed [youtube.com] into a wall at 280km/h and walked away (well, "was cut out of the car") with a sprained ankle and a mild concussion.

  • by pavon (30274) on Tuesday June 19, 2007 @06:06PM (#19572301)
    I think the drug prohibition is an absolutely unjustifiable assault on civil liberties that has done nothing but promote violence both domestically and in South America. But this constant mindless promotion of hemp is just silly.

    Hemp is not a great biodiesel crop. It is better than corn, but that is just because nearly every conceivable crop is better than corn. Here is a decent approximation of vegetable oil crop yields [journeytoforever.org] for various plants.

    In reality biomass fuel from any traditional crop is not a sustainable substitute for petroleum - we use too much of it. There isn't enough arable land, and there are already concerns about top soil depletion just with food crops. That isn't to say it isn't a good supplement (especially if the oil is a byproduct that would go to waste otherwise), but we need to figure out something else, like algae or hydroponic crops with sustainable fertilizers, if were are to produce enough biomass to have a significant impact on petroleum use.
  • Yeah, but.... (Score:3, Informative)

    by DRAGONWEEZEL (125809) on Tuesday June 19, 2007 @06:10PM (#19572361) Homepage
    Capacitor Tech is increasing!
  • by drgruney (1077007) on Tuesday June 19, 2007 @06:42PM (#19572661)
    No mass-market innovation will EVER come out of the government. Superficially, the Internet appears to be an exception to his rule... You sir are an idiot. I can't believe you're being modded as insightful. What about polarized sunglasses, insulation, cordless power tools, the smoke detector, LEDs, infra-red thermometers, better golf balls, and that's just the space program. If you want military let's include jet engines, rockets, GPS, satellite communications, mature broadcast communications. The list goes on and on and on.
  • Re:Simple (Score:2, Informative)

    by Solandri (704621) on Tuesday June 19, 2007 @07:47PM (#19573347)

    The AC on an average passenger car can consume as much as 5HP and is horribly unlikely to consume less than 3. that's 2.2 to 3.7 kilowatts.
    A friend and I were discussing this. 3.7 kW is more than a one-ton central air conditioning unit [wikipedia.org]. In a electrically powered AC, that's enough to cool a 600-700 square foot apartment/room. A car is typically 100 sq ft or less. Why the heck does it need so much cooling? Yes a large portion of its perimeter is windows, but houses and apartments have much larger windows. Car windows are probably less than 4 m^2 when measured perpendicular to a single direction. Sunlight is about 800 W/m^2 on a sunny day at noon, so at most the sun is pumping in 3200 Watts into your car. A heat pump like an AC should be able to handle that easily while consuming less power. (And remember, this is a worst case estimate.)

    Our guess was that a lot of the energy in a car AC is wasted. A car normally doesn't have much electrical energy available. So power-hungry systems like the AC are run via other means. The AC is run off vacuum pressure drawn from the engine. It's not the most efficient way to harness energy, but it takes advantage of energy that would otherwise be wasted. So our guess was that between the HP generated at the shaft, transferring to vacuum pressure, then to mechanical energy running the compressor for the AC, you're losing a lot of energy. This inflates the AC's energy consumption up to 5 HP.

    Assuming we're right, the whole picture changes with electric or hybrid vehicles. They'll be able to provide large amounts of electric power. Room and central ACs already run off electrical power, and we know they can be pretty darn efficient. So an electric vehicle could conceivably air condition your car with much less power than a gasoline or diesel car requires.

  • by Dare nMc (468959) on Tuesday June 19, 2007 @07:48PM (#19573357)

    assume the small motors inside the wheels are gear free.

    actually almost certainly false. I haven't actually seen any electric motors, of the size fit for vehicles, that make anywhere near the torque of a gas/diesel at low rpm's at the motor shaft. For instance we (company I work for) make both electric, and mechanical drive trucks behind 2000+ HP diesiels. The electric Truck has a fixed 50:1 gearing reduction where the mechanical drive is around 35:1 in first gear.

    It only makes sense, electric motors are well known for making even torque across a wide RPM range, hence no need for multiple gear ratio. Since torque*distance=power (or torque*rpm with fixed gearing), a electric motor of the same HP as a gas motor is going to have a-lott lower peak torque than a lower RPM turning diesel (assuming the electric turns at higher RPM.)

    As for no need for brakes, in the Generator world, torque=current, voltage=speed, so at low speeds you can't run the brakes in generator mode any where near peak torque, so you would have to run it in power mode to plug brake to a stop. Otherwise you have to run insane current, (is your motor to be made of super conductors?) at extremely low voltage, or change winding configurations dynamically.

    similar to brake mode, you need insane current to get extreme torque, and since power = torque*rpm at 0 rpm you got 0 efficiency so you really get your motors extremely hot if you run them at (or near) stall RPMs for any length of time. So although it may makes good (maybe 60% of peak) torque at stall, you can't use it for long.

  • by Ungrounded Lightning (62228) on Tuesday June 19, 2007 @07:59PM (#19573433) Journal
    The radical new design of the Scuderi power plant splits the cylinders of an internal-combustion engine in two, compressing air in one chamber, then shooting it into a combustion chamber where it's mixed with gas and ignited....

    This technology already exists in a sense. It is called a "turbo" or a "super-charger", and has been in use for years.


    Actually, it's older than that. It's the "brayton" cycle - as opposed to the "otto" cycle where it's all done in one cylinder in four strokes.

    The FIRST patent on automobiles was the Seldon patent (No. 549,160 - November 5, 1895) - where he patented cars as a side-effect of patenting a particular design for a brayton engine. That little piece of IP - sold to an early auto company which turned into a patent troll operation - ended up with him collecting royalties on all cars made by all early automakers until Henry Ford got his dander up and refused to pay. After a long and expensive battle the courts agreed with Ford, because Ford used the otto cycle and the patent specified the brayton cycle.
  • Re:Simple (Score:1, Informative)

    by Anonymous Coward on Tuesday June 19, 2007 @08:27PM (#19573653)
    >Am I a looney who wants them to legalize marijuana? Sure!
    >But there's greater uses than smoking it.

    I come from an area where the large-scale cultivation of hemp failed badly. It's truely an invasive weed that's difficult to manage. About the only thing I know it's good for is the control of erosion in ditches.

  • Re:Simple (Score:5, Informative)

    by adolf (21054) <flodadolf@gmail.com> on Tuesday June 19, 2007 @10:37PM (#19574473) Journal
    Er. Uh. WTF?

    Automotive air conditioner compressors are not powered by vacuum[1].

    Instead, they are driven by a belt which is connected to the crank shaft by means of two or more pulleys and an electric clutch (which is used to disengage the compressor when not needed, or conditions dictate[2]).

    The reason the air conditioner seems so overbuilt in a car is because it -is- overbuilt, because the demands upon it are huge. Peope don't treat them the same as they do in their homes. You don't leave your glass house to sit in an unshaded parking lot for 8 hours and then expect its AC to cool it off from 100+ degrees to something tolerable in just a few minutes, do you?

    But you do expect the car's AC to do just that, and cool the air as instantaneously as possible. And remember, it doesn't just have to keep up with the sunlight streaming through the windows, but it also has to remove heat from a few hundred pounds of plastic and sheet metal in the interrior, plus offset the heat generated by its warm-blooded occupants. A pre-heated car with 5 people in it on a hot, sunny day requires a lot of cooling capacity to catch up, let alone keep up, and I'm sure that a lot of folks in such a situation might feel that it's nowhere near overbuilt enough. (The profound lack of meaningful thermal insulation doesn't help much, either.)

    So, yeah. It's inefficient and wasteful. But then, so is anything else that involves a piston engine.

    [1]: Yeah, sure. The controls in the passenger compartment may be vacuum-operated, but they're just setting the position of various flaps and valves inside the maze of ducts inside the dashboard. There have been various vacuum-operated accessories in cars in the past (things like convertable tops, windshield wipers) as well as in the present (power-assisted brakes), but they're all pretty small things. To suggest that the vacuum of a small gasoline engine is adequate to run a multi-kilowatt compressor load is laughable, at best: Even if you did get it to work, the engine would be uncontrollable at low-to-idle throttle due to presense of copious amounts of air in the cylinders where there would normally be a partial vacuum. Fuel input would have to be increased to match, or else there would be detonation due to the lean mixture (which is every bit as bad as it sounds). This combination of increased air and increased fuel will result in, you guessed it, increased engine speed. Which is not exactly something you want happening just because you switch on the AC, and reeks of "lawsuit waiting to happen." And never mind the efficiency of this hypothetical clusterfuck.

    [2]: The compressor may turn off and on depending on pressures (too high, or too low), engine load, throttle position, temperature inside or outside or both, or whatever else the car's designers had in mind.

  • Re:water (Score:5, Informative)

    by fractoid (1076465) on Tuesday June 19, 2007 @10:47PM (#19574529) Homepage
    You're missing a vital point. Regardless of overall efficiency, an electric vehicle can be powered by any form of electricity generation. Nuclear, using an Integral Fast Reactor [wikipedia.org], is 'as good as it gets' in terms of power generation. Carbon neutral, no long-term radioactive waste output, inherently safe, and very efficient in terms of uranium usage (99.5% energy recovered as compared with ~1% in a standard nuclear reactor). In terms of CO2 output, switching to electric vehicles has no immediate negative impact and long term very positive impact.

    According to this [memagazine.org], the most efficient well-to-wheels technology is a hybrid drive burning a petrol/methane mix. However, hybrids still require fossil fuels which ultimately lead to carbon emissions, and they are orders of magnitude more complex to build than battery electrics, which are currently expensive only due to companies trying to recoup R&D investment costs, rather than inherent manufacturing expense.
  • Re:Simple (Score:4, Informative)

    by Squalish (542159) <Squalish AT hotmail DOT com> on Wednesday June 20, 2007 @12:17AM (#19574995) Journal
    The processing into vegetable oil is a completely mature, low-energy process: simple mechanical pressing, ultrasonic agitation, and miner solvents are all used.

    Transesterification of the vegetable oil is likewise a well-understood process, though it takes significant amounts (something like 10% of the energy content, IIRC) of alchohols, and is relatively slow. I've seen at least half a dozen new catalysts for transesterification which drastically speed the reaction, paper launch from the lab in the last year - metal oxides and high-surface-area nanoreactors.

    Vegetable oil can be used as a pure fuel source in diesel engines, if it's preheated significantly and doesn't have to deal with cold weather. Transesterification into biodiesel brings the gel point and viscosity most of the way to diesel territory, though extreme-low-temperature performance can be an issue.

    All this has been accomplished on an industrial level, but it's a very young industry, very private, and very tentative. If oil goes back to $20/barrel, the entire industry collapses overnight, like the one that formed after the last oil crash.

    Soybeans are infact a horrible substance to make biodiesel out of - Rapeseed(canola) is the nearest comparable crop that's used, and it achieves 3x the yield per acre. Soya biodiesel is a huge PR project and a baseline demand load for the soya industry (see fuel ethanol coming from France's wine glut). Since Japan started buying whole soybeans instead of protein isolates a while ago, it's an unnecessary one.

    Algae is promised to POTENTIALLY achieve 5000-20000 gallons per acre-year (Soybeans, 50, Rapeseed, 150) by the underfunded + now deceased Aquatic Species Program initiated after the first oilshock. This is a HIGHLY optimistic range, but even at 1/10 the lower bound, it's competitive with oil palms. Aquaculture of the ideal monocrop/ecosystem for maximal fatty-acid storage from photosynthesis in the easy-to-contaminate, hard-to-isolate micro-realm, on the other hand, is a work in process. We have tens of thousands of years of agricultural experience, and there are still agricultural science theses coming out.

    http://en.wikipedia.org/wiki/Biodiesel_production [wikipedia.org]
  • by cdn-programmer (468978) <terr AT terralogic DOT net> on Wednesday June 20, 2007 @03:22AM (#19576007)
    Most batteries wear out faster than tires!

    Some of the best and most expensive batteries currently available are good for only about 3000 cycles with about a 2/3 draw down. The batteries in the Toyota Prius are drawn down about 25% and are good for only about 3000 cycles at this level. This is with the best battery management we can conceive.

    If I calculate the amount of energy the battery will furnish at the best possible management of the battery system what I come up with is that they are at best marginal. Now Toyota has much better usage data than I have and perhaps the physics of the battery system is that they get many more cycles at lower draw downs and at draw down/recharge cycles which are quite short. I don't have the data. Maybe others do. If so then it would be great to put up a website with a consolidated explanation of the care and feeding of battery systems.

    Nevertheless, having invested bux in RailPower (TSE:P) after doing the engineering and concluding their systems would not work... I conclude now that I was foolish to have relied on their engineers. The short of it is that their systems didn't work! They ended up selling hybred locomotives and then buying them back for about 1.5x what they sold them for in order to avoid litigation - litigation presumably for fraud.

    Toyota and Nissan are playing this game now and I suspect they are banking on developments in battery technology IN THE NEAR FUTURE to bail them out when their present battery systems start to fail.

    Perhaps this is what GM faced. I suspect they would have clicked their heels and screamed "Yahoo!" if the battery systems in the EV* autos were standing up. They seem to have done pretty much every thing else right. Of course the owners loved the car. We just need batteries that work.

    Last I looked, the best batteries cost about $10,000 and could convert a Prius into a true EV with gas assist as required. I think this is an excellent way to go. But even with these batteries we are looking at 3,000 cycles.

    The short of it is that most batteries wear out faster than tires.

    ----------------

    What we are looking for is a way to store energy or to buffer energy.

    Toyota and Nissan designed their current hybrids to buffer energy.

    Its a small step as people have noted to buffer from the wall outlet to the office and call it an EV.

    There are nuclear alternatives. Alpha emitters can be used to create a small to large and continuous energy flow which can _slowly_ recharge batteries. These are totally safe. But they provide no surge ability. In this hypothetical senerio if when you get home you forget to plug your car in then what does the car do with its extra juice once the batteries are full? One option: make lotsa noise then run a big toaster and finally if that fails catch on fire?

    What of a high pressure air tank?

    What of phase change?

    Here is a funny idea: Lets use CO2. In liquid form its at 800 PSI at say room temperature. When compressed it can provide quite a lot of energy. We could expand it through a normal motor and run the low pressure gas into a bag. For regenerative braking we could take the low pressure gas and re-compress it. The problem is the size of the bag. To do anything useful the bag for a Prius sized auto might have to be about the size of a city bus. We could put this on a trailer - like a boat trailer of course and tow it behind the car.

    This system would have virtually unlimited cycles and I guess when the car wears out we could trade in the car and keep the old bag and trailer system.

    Obviously I write this tongue in cheek. I wish to illustrate the problem.

    How do we store or buffer the energy?

    If we can solve this problem the rest of the problem is simply a matter of good engineering and even GM showed they have very good engineers available.

  • Re:Simple (Score:3, Informative)

    by drinkypoo (153816) <martin.espinoza@gmail.com> on Wednesday June 20, 2007 @10:43AM (#19580929) Homepage Journal

    My 5200BTU Panasonic window air conditioner pulls about 400 watts, I've hooked up an amp-meter myself to look. I doubt a small car or truck would need that much more cooling then it takes to cool off an old, uninsulated, and poorly sealed bedroom.

    That's where you're wrong. Here's why:

    You say "uninsulated" by have you ever taken apart a car? The outer skin of the vehicle (and in any modern [unibody] vehicle, the whole car is structural) is a piece of sheet metal. Inside of that there may be at best a half-inch layer of this crappy felt "insulation" which is there more to reduce noise than to keep you insulated. It probably has less thermal benefit than a sheet of plywood. Inside of that is either cloth, cloth over cardboard, plastic, or cloth over plastic. Truly snazzy cars have leather, which also do little to mitigate heat effects.

    What there is almost none of in this equation is airspace, because there is immense pressure to maximize usable interior volume.

    The floor of the car typically also has a thin asphalt coating, maybe a quarter inch in a big heavy luxury car, probably quite a bit less in anything else. This is also there primarily to retard noise, it's quite dense and does little to prevent heat from passing through it. I know this because I have a 240SX with no carpet and the asphalt doesn't accomplish much of anything. In that car, it's got barely over 1/8" of asphalt, and it's got spotty coverage to begin with.

    Anyway, cars also have a lot more glass than the average house, per square foot of area. So we have a metal egg with very little insulation with no airspace and a ton of glass permitting sunlight to enter as compared to your big box, with MANY more cubic feet of space, with walls with two fairly thick layers of material (and the outer layer is almost certainly a composite itself, perhaps involving one or more composite layers at that) and with substantial airspace between them, almost always over three inches on both interior and exterior walls.

    Naturally, this is going to involve a lot more insolation and a lot less insulation per cubic foot than your bedroom.

    Anyway, I took two years of auto body and paint classes and am ASE certified in automotive heating/cooling and air conditioning systems...

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