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In stop and go driving, a hybrid makes sense.

At LeMans, not so much.

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I would think a hybrid system would be a huge advantage in racing for the same reason it's an advantage in stop and go driving. In a race you're either full on the throttle or full on the brake at all times. A system that can recover and discharge all that energy quickly would save on fuel (and thus pit-stop) time and weight. It seems like a perfect fit for a capasitor system since no long-duration energy storage is required.

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For NASCAR-style oval racing, a hybrid doesn't make much sense. For endurance racing with widely varying speeds and lots of advantage to be gained from braking? Hybrid technology makes sense.

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Maybe GM will bring a hybrid Vue. /sarcasm

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You'll NEVER store enough energy in a capacitor to make a difference.

However, if the rules at Le Mans are as skewed toward hybrids as they are toward Diesels, then Toyota will do very well. There's nothing superior about the R10 Diesel engine, it's just that the Le Mans rules allow it to carry more energy in its tank and have a motor 50% larger than a gas motor and a turbo with over twice the boost. If that wasn't enough, the air (power) restrictor is much larger and the minimum weight in the class was raised so that the Audi Diesel wouldn't be at as bad of a weight disadvantage against gas cars as it would have if the rules were not changed.

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I suspect Le Mans is a follow on race for their Supra GT with 400hp V8 with in-hub electric motors, super caps and regen braking. If it holds together, it will terrorize the other teams. See the following for more detail: http://www.greencarcongress.com/2007/07/toyota-hybrid-r.html#more

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Lascelles:
Honestly, I expect the capacitor is less because they want to put OUT a lot of torque as take it in.

What I'm saying is that a hybrid, a usual one is optimized for slow braking. That is, braking at say 0.2G. There is a rate at which the hybrid system can turn electrical energy into acceleration and it has the same limit at turning deceleration into electrical energy. So, if you brake hard in a normal hybrid, only a small amount of the energy is being turned into electricity, most of it is going into the brakes. If you can't capture that energy, you can't use it coming out of the corner.

I think Lad is spot on here. Toyota is probably not challenging in the prototype classes (the top classes of custom cars in Le Mans) and are probably instead planning on bringing their already-tested hybrid GT-class car to Le Mans. I would suspect they would have no difficulty getting an invite from the ACO for that car (Le Mans is invite only) and they would love the publicity and opportunity to measure their car up against some of the highest GT class cars.

I also predict that they'll get killed. They'd get absolutely slaughtered by the top runners in GT1. I can't quite be sure what would happen in GT2, but there sure are a lot of good cars and teams in GT2.

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@ why not the LS2/LS7?
I think you are mostly right. The capacitor is likely to be there to help to store energy more quickly from braking. However, Lascelles has a point, with that also comes with a ability of releasing large amounts of energy quickly. It acts as a buffer between the battery and the motor/generator, allowing higher performance without stressing the battery. So it kind of works both ways. The capacitor would be perfect for the quick charge/discharge required in Le Mans. However, alot rides on the implementation of the system, but that shouldn't be a problem with the engineers at toyota. I don't think we have ever really seen a hybrid proven in race conditions, it should be interesting.

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Let's look at the numbers:
A 1000 kg car going 50 m/s (about 110 mph) has 1250 kJ of kinetic energy. (1/2 * m * v^2).
3600 Joules is 1 Watt-hour so
1250 kJ = 350 Wh.

Current tech supercaps can hold ~6 Wh/kg, so you would need about 50 kg (80#) of caps to accelerate the car to 110 mph. Not bad really. (of course there's also weight in the control system, electric motor etc.)
But MIT have demonstrated 30 Wh/kg supercaps, which would weigh 12 kg, and EEStor claim 200 Wh/kg, which would weigh 2kg.

I don't really know enough about vehicle design to figure out the beark-even point for weight vs. efficiency, but in terms of energy storage they may soon be all set.

Discharging (or absorbing) that energy at 6 kW/kg, 50 kg of current tech supercaps could deliver 300 kW, or about 400 hp, which I would think would mean the problem is traction limited, not energy storage limited.

Anywho, this is certainly a very limited analysis, but I think it looks hopeful.

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