Question about KERS

[Azmio]

Anyone can verify the energy dissipated in braking an F1 car from 300km/h to 80km/h. Is it as high as 2000 kJ?

Out of this 2000 kJ, how much can be recovered by KERS assuming that there is no limitation by FIA?

 

[SomptingGuy]

Rough figures.

For those speeds the car sheds c. 5.3kJ/kg. With a weight limit of about 600kg, that's 3.2MJ. The limit for teams this year is 0.4MJ.

This is a quote from Max Moseley's recent letter to FOTA on the subject

Formula One would benefit from systems with more capacity than the present 400KJ, 60KW, (for example maxima of: 2MJ stored, 150KW in, 100KW out) but still very small and very light, as is essential in Formula One. These figures are theoretically possible with mechanical devices, but not feasible in the foreseeable future using batteries and/or capacitors.

So Moseley's advisors think it's possible to grab 2/3 of the available kinetic energy, assuming it's all grabbed from a single braking event. But not using existing technology.

- Steve

 

[Azmio]

phew, 400kJ out of 3200kJ is not that much. That 400 kJ is the maximum energy recovered per lap or per braking/discharge?

I wonder if the KERS system is really worth it considering the extra weight that it carries. moreover the gyroscopic affect introduce by the rotating disc causes some car handling problem. Not to mention the power transmission losses from the KERS to the wheel.

This year races are going to be interesting!!

 

[GregLocock]

"This year races are going to be interesting!!"

Well, here's hoping. I doubt it tho.

Cheers

Greg Locock

SIGlease see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[Azmio]

i am placing my bet on car not equipped with no KERS at least in the first few races. That 400 kJ cap is really an anti climax. With that 400 kJ limit, I have a feeling that the penalty will surpass the benefits.

 

[SomptingGuy]

5.2 Other means of propulsion :
5.2.1 The use of any device, other than the 2.4 litre, four stroke engine described in 5.1 above and one KERS, to power the car, is not permitted.
5.2.2 With the exception of one fully charged KERS, the total amount of recoverable energy stored on the car must not exceed 300kJ. Any which may be recovered at a rate greater than 2kW must not exceed 20kJ.
5.2.3 The maximum power, in or out, of any KERS must not exceed 60kW.
Energy released from the KERS may not exceed 400kJ in any one lap.
Measurements will be taken at the connection to the rear wheel drivetrain.
5.2.4 The amount of stored energy in any KERS may not be increased whilst the car is stationary during a race pit stop.
Release of power from any such system must remain under the complete control of the driver at all times the car is on the track.
5.2.5 Cars must be fitted with homologated sensors which provide all necessary signals to the SDR in order to verify the requirements above are being respected.

The extra weight of the KERS just means less flexibility to place balast where it's best used in order to bring the car up to its minimum weight.



- Steve

 

[PedroCG]

from 300kph to 80kph a 600kg car would need to loose 1,94MJ in kinetic energy, the air and roling resistance times the time to decelarete (litle i guess) would also need to be subtracted to this energy, the braking is not going to be done by the kers alone (its only acting on the rear wheels rigth?), finaly you need to take in consideration the efficiency of the generator etc (90%?). 400KJ seems very good given all the loses.

 

[SomptingGuy]

... I read it as 380km/h to 80km/h, oops. It is a Friday.

- Steve

 

[Azmio]

steve,

having to shift away the ballast from the original point will significantly increase the lap time. Moreover, the KERS has to be placed at the back of the car.

 

[SomptingGuy]

Err, that's what I said. No "extra" weight, just the same overall weight but forced to be in the wrong places.

I too doubt if many of the starting cars will have it. If you believe what you read, Ferrari may not. I wonder how long it'll take for all teams to have to adopt the same policy (whatever that is) in order to be competitive? Different approaches to solving the same problem just don't cut it in F1.

- Steve

 

[globi5]

At least capacitors can be placed almost anywhere.

http://www.greencarcongress.com/2009/01/bmw-rolls-out-b.html#more

Different approaches to solving the same problem often lead to boring races, because one team managed to obtain a significant advantage.

We'll see.

 

[SomptingGuy]

Exactly. Like when there was a choice between NA and T/C.

- Steve

 

[Nico3d3]

Maybe different approaches lead to boring races, but at least, it enable us to see what Formula 1 has always been in the past. It was a place to see the state of the art of automobile technology. Now with all the rules, it's almost impossible to bring real innovation in Formula 1.

 

[patprimmer]

I believe that F1 shold be a class to reward inovatio.

The way to interesting racing is via restritions to aerodynamics.

I know there is some contradiction in my two comments. Who said life was meant to be easy.

Regards
Pat
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[crysta1c1ear]

Out of this 2000 kJ, how much can be recovered by KERS assuming that there is no limitation by FIA?

What do you mean by recovered?

You can recover as much energy as you like within the limits of what is available: time spent braking, (eg 15 seconds per lap) and a maximum allowed recovery rate of 60kW, (eg maybe 900KJ per lap), but it would be circuit dependent.

You can extract 400kJ per lap from the KERS system, that is the real limitation imposed in the rules.
So that could be for example a 50% efficient system taking 800kJ per lap of braking and giving 400kJ back usefully, and wasting the other half!