Electric Le Mans Concept Car "Updated"

[Pebb]

Source: AutoCar

A Swiss company has unveiled the electric Green GT racing car, which it hopes to race at Le Mans in 2011.

Designed by Frenchman Thomas Clavet, the Green GT design study is powered by two 100kW water-cooled electric motors. The company claims this equates to the around 350-400bhp and, more impressively, 1475lb ft of torque up to 100mph and then 590lb ft.

The car weighs 860kg, which the car's builders claim means the car will have a 0-62mph time of under four seconds and a top speed of 171mph.

Although the Green GT would run in its own category for electric cars, for comparison last year's winning Audi R10 has around 700bhp, weighs 925kg and takes about 3.5sec to go from 0-62mph. The Audi R10 hit a top speed of 204mph at last year's Le Mans.

Details of the battery pack are sketchy, but the car uses lithium ion batteries, while solar panels help power the ancillary electronic systems. How these would work during night racing conditions is unclear.

The car's builders say they plan to have two Green GTs at Le Mans in 2011, and will be building 22 road-going version over the next three years.

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More info about the batteries - PistonHeads

Power comes from two lithium-ion batteries, topped-up by solar panels which just might be useful for approximately half of the French endurance classic.

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Extra Images

 

[Bram Turismo]

Awesome

Audi and Peugeot need to take a look at this concept of it works out if they want to be greener. I hope this car would do good, the thing looks stunning!

 

[Northstar]

So what happens when the battery dies?
Do they just swap the old one out with a fully charged one?

Seems flawed.

 

[Stevisiov]

I think its a great test for electric cars. Not only do you have to be fast to win an endurance race (and this isn't to bad) not LMP standards, but its quick. It also has to have good range and quick refuelling, which has been a huge problem for electric cars.

 

[ROAD_DOGG33J]

I hope Batman gets to race this thing.

 

[Duphman]

So what happens when the battery dies?
Do they just swap the old one out with a fully charged one?

Seems flawed.

Hopefully it lasts through the whole race. However Team Joest has swapped a whole transmission, so a T-shaped lithium battery being swapped in a couple of minutes is not out of the question for these teams. The pit crew has to be ready for anything.

It will likely be much slower than the LMP1 cars whether they be privateer or factory backed.

 

[Eric.]

There's no way it can manage the whole race on one battery, that is a ton of energy. If that kind of power was this easily available we would be seeing them being considered for electric road cars. I could be wrong and the cost could be the only reason they aren't being used, but I would think that at least somebody like Tesla would have talked about something like that.

 

[Radracing]

They should just mount a generator that runs on either Hydrogen or biofuel to run the electric motors. Didn't Chevy do something like this with a gaint flywheel to run a generator.

 

[Bram Turismo]

I was thinking about the KERS system used in Formula 1. Couldn't this car use some kind of device that stores energy in the battery under braking, which is then used under acceleration?

 

[ExigeEvan]

Get back to me when this thing is in the slightest bit feasible.

 

[Pebb]

I posted up extra info about this car, earlier on.

 

[Stevisiov]

The only way in which I can see it being feasible is by having a changeable battery at every stop.

Solar panels though? Seriously?

 

[semilife]

It probably would be pushing it at the momentto run the whole race on a single battery, the most likely solution is maybe a battery change with a freshly charged battery after each stint, or a pre-desiginated period. Would Le Mans regaulations allow such an arrangement? Arent electric engines caplable of more tourque than any conventional mechanical engine?

I think we shouldnt just write this off as purely a gimmick I think it potentially shows promise. Going slightly off topic, think back to when diesel engines were first proposed for racing, nobody gave them a chance, however they have proved to be potentially quite ambitious. Well that my two bits worth anyway.

 

[Radracing]

Think if they did start this type of racing series it would further advance battery developement much faster. You figure the amount of money F1 teams pour into R&D just to win. If they did that with an electric racing series and the money that they would go through you think we would have all kinds of grass roots teams that would build electric race cars with very low maintenance with regards to electric motors and battery companies sponsoring for their brand batteries.

 

[Radracing]

On second thought how about getting all those rich guys that bought the Tesla's and start a racing series. That should put the other guys on notice.

 

[Peter]

thats the sexiest thing i have ever seen on 4 wheels.

 

[MinoltaMan89]

thats the sexiest thing i have ever seen on 4 wheels.

Take a look at my avatar.

 

[Eric.]

It probably would be pushing it at the momentto run the whole race on a single battery, the most likely solution is maybe a battery change with a freshly charged battery after each stint, or a pre-desiginated period. Would Le Mans regaulations allow such an arrangement? Arent electric engines caplable of more tourque than any conventional mechanical engine?

I think we shouldnt just write this off as purely a gimmick I think it potentially shows promise. Going slightly off topic, think back to when diesel engines were first proposed for racing, nobody gave them a chance, however they have proved to be potentially quite ambitious. Well that my two bits worth anyway.

They make more torque, but only at a few RPM. Once it winds out its not making a whole lot. Max torque is created the moment it starts turning, and then it drops exponentially.

 

[kikie]

This experiment is very good for the automobile sector, which is trying to develop green cars.

 

[-ultraflow-]

1475lb ft of torque !!!!

It's a nice electric car concept, but dont forget this cars have a major pollution in the manufacture of their batteries.

 

[-ultraflow-]

1475lb ft of torque up to 100mph

I perfectly agree with the development of electrics cars.

But despite being green cars, we always have to keep in mind that the manufacture of the batteries of these cars, are always a big problem because they contain very harmful chemical and parts that pollute the environment more than CO2 emissions.

 

[ExigeEvan]

They make more torque, but only at a few RPM. Once it winds out its not making a whole lot. Max torque is created the moment it starts turning, and then it drops exponentially.

Not true, the Tesla is known for it's extremely linear torque range.

Maximum torque is 200 ft-lbf (270 Nm), obtained at 0 rpm and almost constant up to 6,000 rpm, a common feature of electric motors and one of the biggest differences (from the performance point of view) with internal combustion engines

Will find further sources if needed, wikipedia was just easiest.

 

[Eric.]

Not true, the Tesla is known for it's extremely linear torque range.


Will find further sources if needed, wikipedia was just easiest.

That may be the result of some sort of controller increasing the amperage as it spins faster. I've always saw horsepower charts for electric motors that drop exponentially. I'll see if I can find anything about that.

Edit: Here's something like what I had saw before.

That's from a Tesla. And like I said, the torque drops sharply. I think the torque is managed somehow to stay constant up to 8000rpm, after that it starts dropping like a rock. And of course horsepower climbs while the torque is constant, as power is the rate that work is done.

I don't know how high the Tesla's motor will spin though, so it might not drop in that application.

 

[JCE]

It may be fast, but it cannot outrun ugly.

 

[Metar]

Let's see. Are the solar panels any use? Nay. Will the batteries last an hour at race-speeds (stints at Le Mans are usually an hour long)? Nay. Powerful engine? Nay. Good chassis with proven handling dynamics? Nay. Are the aerodynamics refined? Nay (they're downright terrible - it'd be naive to think this thing will be fast).

This looks like a kiddy's well-rendered imagination.

That may be the result of some sort of controller increasing the amperage as it spins faster. I've always saw horsepower charts for electric motors that drop exponentially. I'll see if I can find anything about that.

Edit: Here's something like what I had saw before.

That's from a Tesla. And like I said, the torque drops sharply. I think the torque is managed somehow to stay constant up to 8000rpm, after that it starts dropping like a rock. And of course horsepower climbs while the torque is constant, as power is the rate that work is done.

That's not exponential, it's quite perfectly linear..

 

[ExigeEvan]

Eric, you've just proven yourself wrong....

They make more torque, but only at a few RPM. Once it winds out its not making a whole lot. Max torque is created the moment it starts turning, and then it drops exponentially.

Clearly, from that diagram you can see linear torque upto 6000 rpm.
That's neither a "few" RPM, and neither does it drop exponentionally.

I've always saw horsepower charts for electric motors that drop exponentially. I'll see if I can find anything about that.

Again, that's a pretty linear, but moderate gradient, line. It does drop off, but no different to any gasoline engine.

And, FYI, and exponential is a distinct curve, not a line of gradient.

 

[Jim Prower]

Well, how about Tractive effort?

This is the curve from a Diesel Electric locomotive. as you can see, it follows an exponential curve after the voltage limit (Where the motor can draw fewer volts without problem) and falls off until the top speed is hit, or the locomotive can offer no further current. Same with the Tesla's "Torque Curve," which I'm willing to bet Tesla smoothed to make theirs seem more advantageous on the chart. (and they also compared their engine with a much less powerful engine)

In a locomotive, "tractive effort" roughly equates to Torque, as it's the effort directly taken from the wheels, which, in turn, are being directly driven by the electric motors. It is the linear force produced by the torque applied to the wheels, which in turn, produce a force upon the rails.

This is explained a bit further by this voltage/current curve from a 3000HP locomotive.

As one can see, the Volt/Amp curve and the T.E. curve closely correlate in shape and size. It should be similar in the Tesla...which is why I think it's either on a controller instead of letting the motor decide how much current it draws, or that Tesla's chart is a bit shaky.

 

[ExigeEvan]

That's an exponential decay curve mostly, yes.

Now is that for the Tesla or something else?

 

[Jim Prower]

The curves above are for a Diesel Locomotive, so, not for the Tesla. However, they're how the Tesla's torque curve SHOULD act.

It helps to think of it like a turbine hooked to a fixed source of pressure. Say you've got a massive turbine, and it's hooked up to an air tank. The air at first can't get past the impellers (it's also sealed perfectly) and your line pressure is the same as your tank. Soon, it starts to move, and pressure drop is negligible for a little while, because your air is moving slowly. but soon you reach a point where the pressure of the air in the line is far less than the air in the tank, because the air is moving so much faster through it and the turbine. Pressure = force, and force in a rotary system = torque.

In the case of an electric motor, or an "Electron Turbine," Voltage is the Pressure forcing electrons through the system, and Amperage is the speed of your electron flow. It follows that as the motor goes faster, there will be less torque.

The sudden drop off comes from the fact that your power supply can only give out so much voltage. So everything stays constant until you hit the point on that exponential curve where voltage starts to drop as Amperage increases. It causes a very sudden and distinct drop, which is noticeable, particularly in a heavy-haul situation, like trying to start a train up a hill. You can get the wheels moving, but you hit a wall, typically at 10-15 mi/h. An old adage from the transition era went...

"A steam locomotive will pull a train it can't start. A Diesel will start a train it can't pull."

Of course, the Diesel engine is running at constant (usually maximum) RPM in the case of a heavy pull, so the traction motors are drawing maximum juice. With a running start, a Steamer might...MIGHT...be able to surpass the pulling power of a diesel on a long grade with the same train. It's the same with other reciprocating engines, too.

Now, I don't know how Tesla plays with their motor's torque curve: the only thing I can figure is that they have the motor on a controller that boosts the voltage at high speed and flattens the drop off.

 

[Eric.]

Yeah, so I think what I said still stands...I'm sure I have saw things elsewhere with max torque from 0rpm and then dropping sharply afterwards, whether exponentially or linearly I'm not sure.