Green GT's All-Electric Supercar Unveiled

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!'"

Comments

24 hour charge??

[gbulmash]

What interests me is how they'll power the car in a 24-hour race. There don't seem to be details on that.

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:24 hour charge??

[alta]

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.

Re:24 hour charge??

[Yvan256]

How about Supercapacitors?

Re:24 hour charge??

[fiannaFailMan]

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.

Re:24 hour charge??

[Rei]

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.

Re:24 hour charge??

[dk90406]

20-30 seconds for tire change. About a minute if the car needs refueling as well. They are not allowed to change the tires while fuel is being pumped.

Re:24 hour charge??

[Rei]

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.

Re:24 hour charge??

[caffeineboy]

This is how it was done in SAE formula lightning.

There is a video of the WVU team doing a pit practice here. These are college kids, probably engineers and not mechanics. A real pit crew could do it in much less time.

Re:24 hour charge??

[Tanktalus]

Well, not against gas-powered cars, but in an all-electric race, perhaps... (if anything gets electric cars kick-started in the public consciousness, it'd be an all-electric indy or something)

Re:24 hour charge??

[ckthorp]

Audi took almost a 1 hour stop for maintenance and still took 3rd.

Re:24 hour charge??

[LandDolphin]

They should really make a race where you can enter any stock car. But what would you call such a race?

Re:24 hour charge??

[budgenator]

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 or 0 to 60 in under a second

Re:24 hour charge??

[ZosX]

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?

Nice car

[PPH]

Pity about that short extension cord.

Looks like PDX's Plasma Boy Racing

[Marxist Hacker 42]

Looks like Plasma Boy and his White Zombie have a competitor out there. (AFAIK, he uses hot-swappable battery packs as well, and only goes full out on the quarter mile).

2x100kW

[Marcika]

Just to point out: TFA must be erroneous or don't know what they are talking about. Two 100kW engines add up to a total of 200kW, i.e. 268hp - far short of the claimed 400hp.

Re:2x100kW

[dmatos]

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

Re:2x100kW

[harryandthehenderson]

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

Re:Heat Problems?

[RingDev]

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

Re:Racecars?

[icebike]

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.

Re:settled by Wolfram

[xZgf6xHx2uhoAj9D]

WTF are you on about?

Re:settled by Wolfram

[Marcika]

To reiterate MyLongNick:

hp = ft * lbs / min

W = N * m / sec

All of these units convert directly. I call your Wolfram and raise you a Google.

Re:Who cares abou archaic measurements like hp any

[DamnStupidElf]

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.

171?

[spoop]

171 mph top speed jumps out at me as very uncompetitive at Le Mans. The Circuit de la Sarthe is a long track with a lot of straights, especially the Mulsanne Straight. Last year, the cars in the GT2 class which I assume this will compete in (the slowest class) topped out at 182-186mph for the most part. Source: http://auto-racing.speedtv.com/article/le-mans-radar-trap-speeds-and-corners-speeds/

Re:That's still a lot of power...

[Jeffrey Baker]

1) Kilowatts is energy, not power.

Fail.