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Green GT's All-Electric Supercar Unveiled
Posted by
kdawson
on Tue May 26, 2009 02:46 PM
from the hoping-bugatti-picks-up-this-tech dept.
from the hoping-bugatti-picks-up-this-tech dept.
Mike writes "Swiss auto company Green GT recently released the first details on a svelte all-electric supercar that is being heralded as the most powerful electric race car ever built. Designed with the 2011 Le Mans race in mind, the Twenty-4 will boast a sleek carbon fiber chassis and twin 100-kw electric motors totaling 400 hp — enough to push the vehicle from 0-60 mph in 4 seconds flat, and to a top speed of 171 mph. GreenGT's head engineer Christophe Schwartz has stated that 'The GreenGT Twenty-4 design study could become our 2011 Le Mans Prototype electric racer, or it could even become an electric road-going supercar. There is a possibility to do both!'"
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Submission: Green GT's All-Electric Supercar Unveiled by Anonymous Coward
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24 hour charge?? (Score:5, Interesting)
According to their site, there's a large solar-powered charging station (100 square meters of photovoltaic surface) which can be used to charge the car between races, but unless they're seriously loading the thing with batteries, they're either going to need long pit stops for charging or the ability to swap out battery packs as fast as other cars can pit for fuel.
On the other hand, with their target date two years out and the rapidly evolving electric car scene, I wouldn't be surprised if there was some hot new prototype hitting the car show circuit around then that blew their doors off.
Re: (Score:2)
Re:24 hour charge?? (Score:5, Informative)
This is how it was done in SAE formula lightning. [wikipedia.org]
There is a video of the WVU team doing a pit practice here [youtube.com]. These are college kids, probably engineers and not mechanics. A real pit crew could do it in much less time.
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Re:24 hour charge?? (Score:4, Insightful)
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Re:24 hour charge?? (Score:5, Interesting)
Done right, I can see a mechanical battery change process... Much faster than gasoline fuel.
1. Pull up to red line.
2. 4 clamps grab wheels
3. car is left up in the air 2 ft, while spent batteries fall out, exit passenger side on conveyor belt.
4. new batteries come in at same time, put in proper position.
5. Car drops, latching in new batteries
6. clamps release wheels.
7. 0-60 in 4 seconds.
I could see a see a 4 second pit stop here.
Skip the 'lifting' process, and have them drop into a recess and you get rid of the GForce limitations on the driver. But you also make it so the system is embedded in the ground or the driver goes up/down a ramp.
Then again, remember how they want to shoot microwave power from space? Imagine if your power is beamed to you from the center of the track. (sounds dangerous)
And then instead of restrictor plates, you get resistor plates.
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Re:24 hour charge?? (Score:4, Insightful)
It's been a while since I watched that race, but from memory I think Le Mans pit stops aren't the 4-second in-n-out with four fresh tyres and a full tank that you get in Formula 1. They last a bit longer than that.
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Re:24 hour charge?? (Score:4, Interesting)
How much is "a bit longer"? Several pre-production cars have already demonstrated 10 minute charging, while BYD claims it on the production F3DM. If you have a really crazy cooling system and, say, a 250kW Aerovironment PosiCharge charger or 300kW Norvik MinitCharge charger, you should be able to do ~5 minutes per ~120 miles.
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Re:24 hour charge?? (Score:5, Informative)
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Re:24 hour charge?? (Score:4, Informative)
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Re:24 hour charge?? (Score:4, Informative)
Even racing supercars don't come close to running at 100% throttle nonstop -- and when they do slow down for turns, regen puts power back into the pack. Li-ion regen in the Roadster, for example, is around 65-70% efficient if I recall the numbers correctly. So you only lose 30-35% of the energy expended on an accel/decel cycle; the rest of your losses are primarily aero and rolling. Aero, which should be the primary loss mechanism, will depend heavily on how much downforce there is.
I agree, though, in that it's probably not practical for the race unless the pit stops are long.
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Re: (Score:3, Informative)
Most Formula 1 and Le Manns cars utilize Bernoulli tunnels under the car to produce significant downforce.
Re:24 hour charge?? (Score:4, Funny)
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Re:24 hour charge?? (Score:4, Interesting)
Electrics can and do kick serious but in drag racing, barely streetable Corvettes and Vipers getting hole-shotted of the line and their doors blown off in the traps by something that looks like what your Grandmother might drive to the grocery store make an impression too! Check out White Zombie [youtube.com] or 0 to 60 in under a second [youtube.com]
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Re:24 hour charge?? (Score:4, Interesting)
How about Supercapacitors [wikipedia.org]?
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That's still a lot of power... (Score:3, Insightful)
Even if you halve the power to 100kW (say the car only goes 50% power on average), those are quite big numbers. Who wants to be sitting in the car while 36MW flows into it?
The transfer is unlikely to be 100% efficient so there will be waste heat generated.
Re:That's still a lot of power... (Score:4, Informative)
Fail.
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Re: (Score:3, Informative)
well, it doesn't have to run for 24 hours on one charge, the other race cars are lucky to run 70 minutes on a tank of gas...
If it can make 150 miles, when they pull in to swap the tires, and jack it up, they could also drip the batteries from the under carrige and replace them en masse.
high performance charging system run on generators pit-site could bring those Li-Ti or Li-Su batteries to full charge in 30 minutes...
My concern is the 400HP total... most of it;s competition does 0-100 in about 8 seconds, a
Re:24 hour charge?? (Score:5, Informative)
Ahhh grasshopper. You are confusing horsepower with torque. A diesel engine with 100hp can create hundreds of pounds of torque. Horsepower doesn't tell the whole story and is not representative of how much torque the engine can produce, which varies with engine speed. A typical car has a torque curve that starts out gradually climbing and then reaching its maximum around 3000-4000 rpm (just an example here people) and begins to flatten and decline towards the red line, say at 6000 RPM. That means that this engine is only outputting peak torque at the maximum point in the curve. An electric engine has a purely linear torque scale. At 1 RPM it is generating 500lbs of torque. At 6000 RPM it is generating 500lbs of torque.
"The torque of an electric motor is independent of speed. It is rather a function of flux and armature current." - Wiki
Coupled with a continuously variable transmission (ala Prius) electric engines are both highly efficient and insanely powerful. If we can get past the hurdles of energy storage, which clearly dominates this discussion, then internal combustion engines will start to look as antique as the coal fired steam engine. I mean seriously. Which is more elegant, a giant motor, a shaft of metal surrounded by magnets and a coil of wire which is like 95% efficient or an insanely complex machine made of thousands of moving parts and components, which including a whole lot of small motors is only like 23% efficient at best? Never mind all the crap you had to go through to get the fuel that only yields 23% efficiency. Oh and forget about the terribly messy process of getting some black tar that was supposed to probably stay in the ground for a few million more years to cook down and refine into gasoline. (And people wonder why they haven't been building new refineries in the United States, maybe those people should have one in their backyard) I mean geez, solar panels are starting to exceed those kind of numbers already.... To hell with spending money on how to suck out the last few drops of oil from some sandy shoals. We should be spending all of our money on figuring out how to cleanly produce electricity. Our very future depends upon it in more ways than one.
Hmmmmmm....now where do we have a huge source of energy close by?
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Nice car (Score:5, Funny)
Looks like PDX's Plasma Boy Racing (Score:4, Informative)
Looks like Plasma Boy and his White Zombie [plasmaboyracing.com] have a competitor out there. (AFAIK, he uses hot-swappable battery packs as well, and only goes full out on the quarter mile).
2x100kW (Score:5, Informative)
Re: (Score:2)
Based on my almost non-existent understanding of French, it looks like each engine produces 2*100kW. Why it is reported this way, I do not know.
Re:2x100kW (Score:4, Informative)
It looks like a bad Google translation. The original French:
2 moteurs triphasés synchrones de 2 x 100 kW linéaires (2 synchronous tri-phase motors, each 2x100kW linear)
The Google translation:
2-phase synchronous motors of 100 kilowatts x 2 linear
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Who cares abou archaic measurements like hp anyway (Score:2)
I mean god, lets all get into the 19th century already people.
Also... It's The Torque Stupid
And 0-60 in 4 seconds is slow anyway...
HTH etc
Re:Who cares abou archaic measurements like hp any (Score:4, Interesting)
I can apply hundreds or thousands of foot pounds of torque by standing on a long lever. However, I cannot produce more than about .09 horsepower for any length of time. Uniform torque through the power band is important for good acceleration unless you have a continuously variable transmission, but other than that the maximum power and efficiency is what matters (and motors are far better at providing constant torque than internal combustion engines). 0-60 in 4s is rather slow for a supercar, but if it can maintain a higher efficiency by regenerative braking it may have a chance. Electric motors can usually handle 150-200% of their rated power for short bursts, like accelerating out of a turn using the energy regenerated from breaking coming into it.
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Re: (Score:3, Interesting)
I don't mean to nitpick, but it's possible for a human to produce a *lot* more than 0.09hp for quite a while. In the 1989 Tour de France final time trial [wikipedia.org] Greg LeMond produced roughly 2/3 horsepower continuously for just under an hour [mystrobl.de]. I'm not of that caliber but I can crank out just under a third of a horsepower for over two hours if I'm feeling really motivated, according to an on-bike dynamometer.
While I'm on the subject, humans have pretty good torque characteristics, similar in shape to a steam engine
Re:2x100kW (Score:5, Informative)
There is no actual conversion from kW to hp
Yes there are, but it's highly dependent on the context in which you use the term horsepower since it's not an SI unit.
One mechanical horsepower of 550 foot-pounds per second is equivalent to 745.7 watts
A metric horsepower of 75 kgf-m per second is equivalent to 735.499 watts
A boiler horsepower is used for rating steam boilers and is equivalent to 34.5 pounds of water evaporated per hour at 212 degrees Fahrenheit, or 9809.5 watts
One horsepower for rating electric motors is equal to 746 watts
http://en.wikipedia.org/wiki/Horsepower [wikipedia.org]
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Re:settled by Wolfram (Score:5, Insightful)
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Re:settled by Wolfram (Score:5, Informative)
hp = ft * lbs / min
W = N * m / sec
All of these units convert directly. I call your Wolfram and raise you a Google [google.co.uk].
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Re: (Score:3)
Taken from units.dat
# The horsepower is supposedly the power of one horse pulling. Obviously different people had different horses.
ushorsepower 550 foot pound force / sec # Invented by James Watt
metrichorsepower 75 kilogram force meter / sec # PS=Pferdestaerke in Germany
electrichorsepower 746 W
boilerhorsepower 9809.50 W
fwaterhorsepower 746.043 W
brhorsepower 745.70 W
donkeypower 250 W
chevalvapeur metrichorsepower
Seems pretty well defined to me.
Re: (Score:3, Informative)
2 x 100kW != 400 HP (Score:2, Informative)
Subject says it all, well almost.
100kW == 134HP
2 x100KW != 400HP (Score:3, Informative)
200KW ~= 268HP
400HP equivalent?
They need to explain that a bit better in the article and on the product website [green-gt.com]
more tech possible with electric (Score:2)
There are potential technology applications that could really enhance performance.
a) regenerative braking to store power would extend fuel performance even if regular fuel performance was identical to regular car. draw back would be battery cost. Best performance would be small quick draw thin film back to absorb curve braking and allow additional out of curve power spike
b) independent 4 wheel drive. a lot of electronics required but would be able to improve road grip and reduce tire wear
I don't see electro
Jack Bauer (Score:3, Informative)
Re: (Score:2)
Jack Bauer can go from zero to 60 in 0.1 seconds. He does not need a car to accomplish this.
Not that impressive (Score:2)
The hideous Eliica [wikipedia.org] already exists and blows it away, the Wrightspeed X1 [wikipedia.org] toasts it at least on accel (and the economy-canceled production model, the SR-71, was expected to be able to beat a Bugatti Veyron in 0-60), while Shelby Supercars [wikipedia.org] is working on the Ultimate Aero EV [shelbysupercars.com] which should blow them all away.
Old tech. (Score:2, Interesting)
This has been done among Universities for several years. If I remember Ohio State and Oklahoma won a lot of the races with these cars.
http://evri.ou.edu/lightning/specs.php
The races were short, it could only run for 8-10 minutes depending on the load without changing battery packs. A quick release mechanism was designed where all 32 batteries could be changed in 10-13 seconds.
Heat Problems? (Score:3, Interesting)
Why the big air scoops on this car? Do they have a heat problem? They almost look like they are placed for tire cooling more than anything else.
You would think that they would try to make this the sleekest wind-cheatingest car they could instead of grabbing huge chunks of air.
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Why the big air scoops on this car? Do they have a heat problem? They almost look like they are placed for tire cooling more than anything else.
You would think that they would try to make this the sleekest wind-cheatingest car they could instead of grabbing huge chunks of air.
Wind-cheating? The purpose of race car design isn't to reduce drag, the purpose is to generate maximum downforce.
Re: (Score:3, Insightful)
Which none of those scoops would do.....
So again I ask....?
Re:Heat Problems? (Score:4, Informative)
You hit it, the cooling is for breaks and tires, as well as down pressure.
Every once and a while in the NASCAR races they'll show you a camera view from inside the wheel well. You can see when the driver hits the breaks the rotors literally become red-hot from the friction of trying to slow the car down.
Now imagine that same situation, with wider tires and faster speeds on tracks with significantly more braking.
Odds are though, that the frame they are starting with is from some company that produces frames for indy or some other circuit cars. Just as the Tesla Roadster is actually a Lotus frame and body. So the cooling requirements will likely vary significantly from the function of the imaged vehicle.
-Rick
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171? (Score:3, Informative)
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Ummm ... doesn't the Tesla Roadster do it in sub 4 and its a consumer vehicle ... just a thought
Yeah -- the standard Roadster does 0-60 in 3.9 seconds, and the Sport version 3.7 seconds.
Re: (Score:3, Insightful)
Side note: 0-60 mph in 4 seconds flat. Ummm ... doesn't the Tesla Roadster do it in sub 4 and its a consumer vehicle ... just a thought
Yes, and the Wrightspeed X1, based on the Ariel Atom, does it in just over 3 sec.
Then again, straight acceleration isn't the most important thing in an endurance race. Audi has been cleaning up the big endurance races of late with their diesel engine, not by being the fastest, but by good team strategy and needing fewer pitstops for fillups.
Re: (Score:3, Insightful)
What would you call "an industrial scale"? I've been reading over market research on electric vehicle forecasts for a business, and they're all over the board. However, it's safe to say that almost everyone is calling for them to be in at least "sizable" numbers by 2015. The most extreme forecast I've come across is Wintergreen's, which is, if I recall the numbers correctly, 32.7 million shipped by 2015. I find that number a bit hard to believe, but on the other hand, when there's perhaps three dozen ma
Re:Racecars? (Score:4, Interesting)
Why not develop a car normal people will actually buy and use? This is interesting but I don't think we have the luxury of trickle-down innovation at this point
I disagree. We don't have the luxury of dumping millions of ill-thought out poorly designed cars on the market without adequate testing to ensure they won't all be clogging out junk yards with huge disposal problems of toxic battery components due to premature failure.
We do NOT have an electrical grid that can support all the new electric cars you would love to see. Sorry, its just not there, and not likely to be there for several decades.
We must go slowly on grid-charged cars until we can double our electrical generation capacity, and beef up the distribrution system.
Race technology has always lead the way in the automotive industry. How else can you get worst case scenario testing in the real world.
We DO NOT have to rush into deployment of half baked technology on a mass scale. We DO have the time to do this right. The end of the earth is NOT upon us.
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Re: (Score:3, Insightful)
Well, currently there's a lot of stigma about 100% electrical cars. Many people (potential customers) believe that completely electric vehicles must necessarily have at least one of the following weaknesses due to limitations with electric engines in cars:
A.) Too slow
B.) Incapable of driving very far
C.) Requiring too much time to refuel
D.) Too fragile
I would think that making one that can compete well at the 24 hours of Le Mans would go a long way toward changing those perceptions.
Re: (Score:3, Informative)
The acceleration is fine; most supercars do not have the best possible acceleration because it would interfere with top speed (e.g. gearing issues.) The top speed, however, is less than 200 mph, which is pretty much mandatory for a supercar today.
Re: (Score:3, Funny)
endurance racing challenge
Every 15 minutes the driver will have to announce whether or not they are there yet?