How will KERS affect racing

[xpensive]

How is that, please explain?

[xpensive]

Excuse me WB, but I am eagerly waiting for your explanation of how the flywheel storage is electrical?

[WhiteBlue]

Williams are the only team known to use a flywheel system. They reportedly use an electric motor/generator between the engine and the flywheel. It surprised me when I heard it. But it makes sense when you look at the road map of KERS. Soon they will have AWKERS and then you could not do it with one flywheel for both front and rear without an electrical conversion.

[xpensive]

Sounds intriguing, WB, please do not hesitate to elaborate on this and do explain how the power is stored electrically in the flywheel?

[xpensive]

He said something to the effect that one of the first things you learn when you study mechanical engineering, is that Friction force is Contact force times a friction coefficient, where the contact area has very little to do with it.

This is however not a totaly accurate anology, as said coefficient is not constant with the contact pressure, something which I am certain any trained engineer knows.

[xpensive]

Sounds intriguing, WB, please do not hesitate to elaborate on this and do explain how the power is stored if not in the flywheel?

[WhiteBlue]

http://www.williamshybridpower.com/

from this it seems that the electric machine is integrated in the flywheel.

Technology
Flywheels have been used to store and stabilise energy for hundreds of years. Early examples include the potter's wheel and spinning wheels. More recently advances in bearing technology, power electronics and vacuum enclosures have substantially improved their performance characteristics. The first modern flywheel systems were large stationary installations used to provide uninterruptible power supply and the production of very large pulses of electricity for scientific or industrial use.
Only in the last two decades has flywheel technology been seriously considered for use in mobile applications. It was held back by prohibitive weight and unwanted precession forces. Both of these characteristics are determined by the specific tensile strength (the ratio of the hoop stress to material density) of the flywheel. Advances in carbon fibre composite technology has allowed the specific tensile strength to be greatly improved leading to the development of light, high-speed flywheel systems. Test vehicles, particularly buses, have been produced using mechanical flywheel systems with a continuously variable transmission (CVT) to transfer power to and from the flywheel. The next evolution was electrically-driven flywheels which do not require a CVT system thus avoiding added weight and reduced efficiency. Electrically-driven flywheels have another important advantage over their mechanically driven relatives in that vacuum integrity is easier to maintain as no high speed mechanical seal is needed.
WHP has taken the electrically powered integral motor flywheel design and radically improved its performance characteristics by incorporating Magnetically Loaded Composite (MLC) technology. The MLC technology, which was developed in the nuclear industry by Urenco, incorporates the permanent magnets of the integral motor/generator into the composite structure of the flywheel itself by mixing magnetic powder into the resin matrix. In the event of a burst failure, the containment has to withstand only the crushing force of the composite material, which is far less than the load of discrete metallic fragments. The reduced containment requirement minimizes the overall weight of the system.
The magnetic particles in the composite are magnetised as a Halbach Array after the rotor is manufactured avoiding the need for backing iron to direct the flux. As the magnets in an MLC flywheel are comprised of tiny particles and there is no additional metal in the structure, the eddy current losses of the machine are significantly reduced. This can result in one-way efficiencies of up to 99%. The ultra-high efficiency means thermal management of the system is easier and it can be continuously cycled with no detriment to performance or reduction in life.

[Ciro Pabón]

Mosley said:

"We've finally found a serious engineering challenge for the teams in KERS. Some manufacturers have risen to this challenge, one manufacturer has produced electric systems which will astonish people when they appear, another team is working on a completely new technology which will also astonish people."

Completely new technology? Any ideas?

Back on thread:

"I think the teams will soon learn how to use and optimise KERS, but it won't help overtaking so much. It's a technology developed on road cars that will find a limited application in F1. The new aerodynamics regulations will be the biggest factor at changing racing by creating new overtaking opportunities." -- Geoff Willis --

With changes in aerodynamic regulations, change will come next year. Sad, this year was as close a championship as we'll see in our lives:

"We work 24 hours a day in the wind tunnel," said one team boss this week. "But we have hit a wall. We have only managed to find three percent more downforce this year. We just cannot find any more." http://www.grandprix.com/ns/ns20651.html

On the other hand, an opposing view:

"In comparison with the hybrid technology of production vehicles, the concepts for motor racing are considerably more powerful, and at the same time more compact. We are already holding discussions with many teams from various racing series."
-- Klaus Böttcher, director Bosch Motorsport --

Nice article on Bosch KERS: http://www.racecar-engineering.com/arti ... dular.html

Bosch four flywheel KERS. That's the energy storage unit, rated at 750 kilojoules: that's like 20 grams of gasoline give or take I estimate that over the course of the race, taking in account efficiency of ICE vs efficiency of electric motors, KERS should give you around 3-4 kilos of "extra gasoline"


I find this relevant for race strategy:

“A high charging rate means that you may also have very high cooling demands, batteries with a low charging rate may survive with forced air cooling, high charging rates will mean liquid cooling” Wildner (from Bosch) explains. “Mechanics will not be able to change cells trackside, though they they will be able to change the module. We won’t let them work directly with the cells as they are high voltage and low inner resistance and that could have safety implications.”

Are we going to see new inlets for KERS batteries? How will that affect the radiators and sidepods? Will batteries changed along the tyres if other manufacturers find how?

Another article by Racecar Engineering on the Magneti Marelli unit: http://www.racecar-engineering.com/news ... -kers.html

Magneti-Marelli liquid cooled unit


It says it's "single liquid cooled brushless direct current motor generator unit", "fairly conventional".

I find remarkable that you can get 80 hp from an 8 kg electric motor (that's what many car engines deliver from a 100 kilos or more ICE!). Many people has heard me saying that they're the future of racing. Check the Bosch motor, taken from here: http://www.greencarcongress.com/2008/11 ... lopin.html



Finally, long quote from Pedro Martínez de La Rosa:

Q: What does a 2009-spec car feel like to drive?
Pedro de la Rosa: It’s very different. Obviously, the slick tyres give you a lot more grip - so although we will be running with reduced downforce, the overall grip of the car won’t be that different to what we had. But it’s the balance front to rear that will change - the slick tyres have a very strong front-end going into the corners and they have very good traction coming out. Overall, to simplify things, I think the slick tyres will give us laptime in the low-speed corners and because of the reduced downforce we’ll be slower at high speeds.

Q: Do you think it will make overtaking easier?
Pedro de la Rosa: Yes, definitely. Considering this is Formula One - if people think the introduction of KERS and the reduction in downforce and slicks is going to transform Formula One, then forget it. It will still be a wide car, there will still be aerodynamic effect and offline will stay dirty. It will be easier, but it won’t be MotoGP. And people need to understand that.

The changes are headed in the right direction. The difficulty comes from having so many changes and a massive reduction in testing for next year. It will make fine-tuning your car between the races very difficult. It’s going to be very interesting - and there won’t be enough time to test everything.

http://www.formula1.com/news/features/2008/12/8754.html

[WhiteBlue]

One of the decisive features is water cooling which enables you to overload the IGPTs and motors. The other factor is the rapid progress of rare earth permanent magnets in the last 10 years. The wide spread use of AC servo drives in machine tools and robotics has pushed this development.

[G-Rock]

Thanks Ciro, that was a very thorough report.

[tarzoon]

are we missing something here? I thought the greatest advantage of motors (I will include both flywheels and kers here) is the high torque.

Now if the system is used when exiting a curve, the traction becomes increasingly relevant. On the other hand, the tyre wear will also increase considerably if the pilots are not careful with their right foot...

pls correct me if i'm wrong...

[WhiteBlue]

The way I understand it all KERS will have electric Motor/Generators. The difference between flywheel and the batterie systems will be the energy storage. Flywheel will be electro/mechanical. Batteries will be electro/chemical.

To adjust the breaking/accelerating torque of the KERS will require electronic adjustment. The AC servo Motor/Generator is controlled by the IGPTs of the inverter drive primarily. The inteligence of the drive is a common digital controller connected to the engine management and the SECU. I fail to see how you can design a binary push button for the driver without some modulation profile in the KERS controller.

So the question how smooth the decellerating and accelerating torque kicks in will be a function of that profiling. I reckon that there will be some fairly intensive head scratching between now and March to set up those profiles. They are no less complicated than the engine management profiles.

[tarzoon]

My point was that coming out of the curve may be tricky, even with very well tuned electronics. On the other hand, as cars have standard ECUs, how much can the teams adapt in KERS micro controller?

[mx_tifoso]

Corner-exit was of a concern to everyone when TC was removed, but as we could see throughout the 2008 season there weren't any significant problems with drivers losing control, tyre wear, etc, as had been predicted. So I doubt KERS will have any significant affect on corner-exit as well.

[WhiteBlue]

The way I see this working is a KERS acceleration profile that works proportional to the throttle position potentially with a bit of a ramp up. It will be launched by the driver button but will modulate the acceleration torque in a pre programmed way.

The breaking profile should take the clue from the braking pressure but will also need a shut down function. When the maximum load of the storage system is reached KERS must stop charging it. So from that point the KERS system must stop to work in braking mode until the storage is emptied.

Quite a bit of programming involved in that KERS controller. Drivers must be prepared to feel different corner exit response depending whether they use KERS or not. They will probably have even more of an adjustment to make to braking. I doubt that braking with KERS and without will feel the same.

One can only speculate which parts of the KERS control will be in the KERS subsystem and which part will be executed by the SECU.