1361 replies to this topic

[Melbourne Park]

I had thought (suspected) that the key for F1 at the moment would be weight, and braking feel. But if the system charges so quickly, then one could use the KERS braking only at high speed, where lock ups do not happen. Tht's interesting. I presume therefor that McLaren have a wand or button somewhere, that only allows the KERS to work above for example, 160KPH. I guess brake feel is not an issue with KERS afterall.

Since next year the KERS power allowed will be twice as much, does that mean more batteries and capacitors, or does it mean flywheels will make an appearance?

Edited by Melbourne Park, 04 May 2009 - 00:43.

[gruntguru]

I had thought (suspected) that the key for F1 at the moment would be weight, and braking feel. But if the system charges so quickly, then one could use the KERS braking only at high speed, where lock ups do not happen. Tht's interesting. I presume therefor that McLaren have a wand or button somewhere, that only allows the KERS to work above for example, 160KPH. I guess brake feel is not an issue with KERS afterall.

Since next year the KERS power allowed will be twice as much, does that mean more batteries and capacitors, or does it mean flywheels will make an appearance?

I'm not sure why they would use such a high charge rate, since there is plenty of opportunity during a lap to accumulate the energy limit specified. The electric motor only needs to be 60 kW. To be rated at 500+ kW when charging sounds strange

[Wuzak]

I'm not sure why they would use such a high charge rate, since there is plenty of opportunity during a lap to accumulate the energy limit specified. The electric motor only needs to be 60 kW. To be rated at 500+ kW when charging sounds strange

I was under the impression that the KERS system charge rate was limited to 60kW, and that future KERS would be something like charge 150kW/discharge 100kW.

[J. Edlund]

I was under the impression that the KERS system charge rate was limited to 60kW, and that future KERS would be something like charge 150kW/discharge 100kW.

5.2.3 The maximum power, in or out, of any KERS must not exceed 60kW.

So, it seems impossible that they are able to charge the KERS in half a second without exceeding the 60 kW maximum charge/discharge rate. This maximum rate is probably also why most teams have selected batteries as energy storage. Supercaps can handle higher charge/discharge rates, but since this rate is limited by the regs to 60 kW, and supercaps have a much lower energy density batteries should be the better (lighter) choice. Flywheels also offer higher charge/discharge rates but also a higher energy density, and when the maximum allowed charge/discharge rate is increased perhaps more teams will select flywheels. The long life of flywheels, and that they can be built with non toxic materials and easily be recycled at end of life, sure makes them the envoronmetally friendly choice.

[Greg Locock]

5.2.3 The maximum power, in or out, of any KERS must not exceed 60kW.

So, it seems impossible that they are able to charge the KERS in half a second without exceeding the 60 kW maximum charge/discharge rate. This maximum rate is probably also why most teams have selected batteries as energy storage. Supercaps can handle higher charge/discharge rates, but since this rate is limited by the regs to 60 kW, and supercaps have a much lower energy density batteries should be the better (lighter) choice. Flywheels also offer higher charge/discharge rates but also a higher energy density, and when the maximum allowed charge/discharge rate is increased perhaps more teams will select flywheels. The long life of flywheels, and that they can be built with non toxic materials and easily be recycled at end of life, sure makes them the envoronmetally friendly choice.

A flywheel based system which can absorb 60 kW will need a 100 hp electric motor. That is not going to be light.

[gruntguru]

A flywheel based system which can absorb 60 kW will need a 100 hp electric motor. That is not going to be light.

The system I have seen is mechanically connected using a CVT (toroidal).

Edited by gruntguru, 06 May 2009 - 05:04.

[J. Edlund]

A flywheel based system which can absorb 60 kW will need a 100 hp electric motor. That is not going to be light.

If the KERS is going to absorb 60 kW a motor with slightly less than a 60 kW rating is required to spin up the flywheel as the measurement is done at the connection to the rear wheel drivetrain (there are losses between the rear wheel drivetrain and the flywheel). But the rotor of the electric motor will also serve as the flywheel, so it's partly useful weight. Bosch currently offers flywheels (in pairs), with built in motor generators which can store 380 kJ, these have a weight of 18 kg.

The weight of a 60 kW electric motor is around 5 kg. Out of a total mass of 25 kg for the KERS system, the majority, around 18 kg or so is the batteries.

The 60 kW motor generator unit connected to the engine will be the same unit as used in battery based systems.

The lifetime of a flywheel based energy storage solution is also about 10000 times longer than that of battery storage solution, in other words, the same system can be used for a whole season in F1.

Edited by J. Edlund, 05 May 2009 - 16:05.

[J. Edlund]

Regarding the motor generator unit (MGU), does anyone know if any team has chosen to use the MGU as a replacement for the conventional permanent magnet alternator?

[scolbourne]

This may be a system we will see many teams using next year.

http://www.bosch-mot...2/html/3766.htm

"Hybrid systems by Bosch Motorsport always comprise a battery, the electric motor, and the KERS controller. This contains the power electronic, the battery management, and the management system for hybrid and engine functions. A lithium-ion battery with scalable capacity or a flywheel energy storage device is used for storing energy. The latter stores up to 750 kilojoules of energy. The electric motors weigh between four and eight kilograms with a maximum power level of 60 kilowatts. Thanks to its modular structure, KERS from Bosch can be put together individually in terms of weight, robustness, and performance to suit the requirements of the respective race series."

[Demo.]

I know the rules state that the use of KERs has to be under the control of the driver but it still surprises me that no team has looked at using it as a form of long term low power boost (driver switches the power to a low output mode and gets more time to drain his maximum allowed 400kJ (and he still needs to press the button to use the boost even in lower power mode)) especially on tracks like Monaco where it would appear to make far more sense to have an extra 2 to 5 HP for 15-30 seconds Approx than the 6.5 seconds most have at present.
After all the rules only state the maximum power output not the maximum duration.
Does anyone know if any of the teams done such studies after all in Monaco very shortly after you have applied KERs you are then needing to scrub off the extra speed therefore by using less over a longer time (out of 6 or 7 corners or all the way up the hill) means you have the benefit of the extra power for longer all be it at lower levels?
OR are they limited by the electronics/programming in the SECU?
The typical scenario i am on about would be one where a car in front is trying to pull away or a car in clear air is trying to catch up rather than as an overtaking measure after all the driver could always switch back to a 'normal' power output to be able to use it to overtake.

[Kalmake]

...it would appear to make far more sense to have an extra 2 to 5 HP for 15-30 seconds Approx than the 6.5 seconds most have at present.

The most efficient way is max power couple of times per lap. I think it was explained in earlier posts.

In Monaco KERS was of little benefit, but on the other hand the weight balance wasn't an issue there.

FOTA teams voted to not run KERS next year. So unless there is a breakaway, no team will have it.

[desmo]

The fact that the only options the FIA can apparently ideate are either to have KERS mandatory or banned outright is I think emblematic of everything that has gone wrong with F1.