Why is KERS restricted?

[autogyro]

There is absolutely no reason to drive the front wheels.
The rear wheels of regulation size give sufficient traction to be equally if not as efficient as any four wheel drive system and without the added weight and complication.
Four wheeled drive on tarmac is for Chelsea tractor posers, not drivers.
It is sensible to replace front wheel braking with energy harvesting using a generator however.

[Richard]

Four wheeled drive on tarmac is for Chelsea tractor posers, not drivers.

What about the Audi Quattro, I thought that was for improved performance on tarmac? They are certainly not off road vehicles.

[xxChrisxx]

Four wheeled drive on tarmac is for Chelsea tractor posers, not drivers.

What about the Audi Quattro, I thought that was for improved performance on tarmac? They are certainly not off road vehicles.

Generally rear drive is best where grip is not an issue. 4WD never used to be used on tarmac becuase the weight penalty used to offset and marginal gain in grip. In lower grip conditions, or where 1 wheel is more likely to slip say on braking or turn in thats where 4WD gats the advantage.

[autogyro]

Four wheeled drive on tarmac is for Chelsea tractor posers, not drivers.

What about the Audi Quattro, I thought that was for improved performance on tarmac? They are certainly not off road vehicles.

Generally rear drive is best where grip is not an issue. 4WD never used to be used on tarmac becuase the weight penalty used to offset and marginal gain in grip. In lower grip conditions, or where 1 wheel is more likely to slip say on braking or turn in thats where 4WD gats the advantage.

4WD also compromises the design of the front suspension,steering and tire design.
On a tarmac stage similar to an F1 track it would be a simple matter to beat a 4WD Quatro with a redesigned rear wheel drive version with the same power and weight.

[xxChrisxx]

4WD also compromises the design of the front suspension,steering and tire design.
On a tarmac stage similar to an F1 track it would be a simple matter to beat a 4WD Quatro with a redesigned rear wheel drive version with the same power and weight.

Aye, there is that too.

[machin]

I though the 4wd rule died a while ago when the teams didnt agree to the budget cap?

Yep, That's how I see it too. The 2010 rules are basically the same as the 2009 rules... so all the low budget incentives have been removed.

[alexbarwell]

Can't really agree with autogyro - drive at the front on a track car is an advantage; rather than the situation of the rear wheels about to lose traction on hard acceleration, with the fronts doing nothing, if the fronts can also provide accelerative effort then the car will get going a good bit more. Granted there is not the weight transfer onto the fronts. Additionally, if alternators/generators are used on the front to recover energy, if they were intrinsic to the wheel carriers then there is less of a weight penalty, but if the system is bi-directional using the generators as motors when necessary as in KERS at the moment then even more effective use is made for a small weight consideration.

[Richard]

In lower grip conditions, or where 1 wheel is more likely to slip say on braking or turn in thats where 4WD gats the advantage.

So the Quattro is of advantage on a normal road (with bumps, drain covers, leaves and mud) but not on a smooth clean circuit?

[autogyro]

Can't really agree with autogyro - drive at the front on a track car is an advantage; rather than the situation of the rear wheels about to lose traction on hard acceleration, with the fronts doing nothing, if the fronts can also provide accelerative effort then the car will get going a good bit more. Granted there is not the weight transfer onto the fronts. Additionally, if alternators/generators are used on the front to recover energy, if they were intrinsic to the wheel carriers then there is less of a weight penalty, but if the system is bi-directional using the generators as motors when necessary as in KERS at the moment then even more effective use is made for a small weight consideration.

On smooth tarmac there is to much of a trade off in the front end changes needed to gain anything from FWD.
Agreed, with the addition of a central front generator for energy harvesting, using the generator as a motor becomes partly viable.
It may be possible (if in the regulations of course), to apply some torque to the front wheels to increase acceleration. I would be more interested in usng this limited torque to improve cornering and rear traction without compromising the front tires and front design to deal with the application of to much torque.
An interesting development direction completely dependent on beating Fota and re establishing Kers at a sensible power output.

[riff_raff]

For some types of race circuits, I would agree with autogyro: 4WD may not be beneficial over a rear 2WD system.

I once talked to an old timer that worked for Lotus back in the late 60's. He explained that the 1968 Lotus 56 turbine powered, 4WD Indy car performed worse than a conventional rear-driven 2WD chassis would have, due to the lack of traction that the front tires normally had. He claimed they got better performance putting all of the power through the rear tires, since any power diverted to the unloaded, less-grippy fronts mostly resulted in tire spin.

Of course in those days, they didn't have the sophisticated front/rear or side/side torque biasing, limited slip diffs like we have now. And the late 60's Indy roadster chassis had no aero downforce devices to load the front tires. So it may not still be the case.

The F1 regulations now prohibit 4WD, or even 2WD of the fronts. But I do remember some cars using a front end differential system for braking torque transfer:

http://www.racecar-engineering.com/alla ... ealed.html

Regards,
Terry

[xpensive]

Perhaps the question of this topic should begin with what is the potential energy recovery for KERS anyway?
I have amused myself with some numbers as follows, a most simplified xample;

Car is 700 kg, lap is 80 seconds, 60 of those are on full throttle, 500 kW (680 Hp), and 20 on the brakes, going from 260 km/h to 100 six times over the lap. Conclusively, engine produces 30 000 kJ and brakes are wasting 10 000 kJ (m*v^2/2).

In other words, one third of what has been produced, engine efficiency not counted, is converted into heat by the brakes. Gone.

10 000 kJ of braking energy over 20 s is also an average of 500 kW, why conventional brakes have to be replaced by some form of 500 kW generative devices, preferably 125 kW at each wheel of the car. Doesn't sound too far out, does it?
But how to store the energy, a 10 000 kJ battery?
No, the 1600 kJ stored before the corner should be discharged immedietely after the same, like 160 kW for ten seconds.

Mr Todt, bring the manufacturers back and let them have a go at that. Unlimited budgets please!

[autogyro]

Perhaps the question of this topic should begin with what is the potential energy recovery for KERS anyway?
I have amused myself with some numbers as follows, a most simplified xample;

Car is 700 kg, lap is 80 seconds, 60 of those are on full throttle, 500 kW (680 Hp), and 20 on the brakes, going from 260 km/h to 100 six times over the lap. Conclusively, engine produces 30 000 kJ and brakes are wasting 10 000 kJ (m*v^2/2).

In other words, one third of what has been produced, engine efficiency not counted, is converted into heat by the brakes. Gone.

10 000 kJ of braking energy over 20 s is also an average of 500 kW, why conventional brakes have to be replaced by some form of 500 kW generative devices, preferably 125 kW at each wheel of the car. Doesn't sound too far out, does it?
But how to store the energy, a 10 000 kJ battery?
No, the 1600 kJ stored before the corner should be discharged immedietely after the same, like 160 kW for ten seconds.

Mr Todt, bring the manufacturers back and let them have a go at that. Unlimited budgets please!

Now you are getting close to my thinking and IMO the way road vehicle development has to go. Kers is essential for the future of F1 and opposition marks out those destroying the sport.

[machin]

Running some more numbers:-

If a 400kJ per lap / 60kW KERS system weighs 50kg (Race Tech Magazine), and the car accelerates from 70mph to 150mph 10 times per lap the energy required to accelerate that weight is 883kJ.... i.e more than the energy they're currently allowed to recover......!!!!

If teams didn't have to build to a minimum weight then the KERS in its current form reduces car performance.....

[machin]

... and that's not even thinking about the erngy required due to additional drag that results from running KERS(due to additional crossectional area of the car and cooling).......

[machin]

FYI; I like KERS, I just hate the 400kJ per lap rule..... it should be unrestricted and used as often as possible (i.e. after each corner, so storage doesn't have to be too big).