KERS How does it acutally work?

[racshot65]

Hey guys,
Could someone explain how the KERS that teams like BMW are developing acutally work, how can you take heat for example from the brakes and power the car? Also, how much power is actually generated enough for 1 lap or more?


Hmmm... actually reading that back Kinetic energy recovery system I guess that suggests it not the heat there using so what actually is it?


Thanks

[tomislavp4]

No, they´re not using the heat, kinetic energy is something else...
Take a look at theese:
http://en.wikipedia.org/wiki/Kinetic_energy
http://en.wikipedia.org/wiki/Regenerative_braking

Hope it helps

[alexbarwell]

Assuming the heart of it is using some pretty old-fashioned principles, a traditional DC motor with permanent(now high power ceramic) magnets obviously outputs a torque for a given input current, but will also output a current for a given input torque, faster revolutions make for greater outputs, a greater number of windings produces a greater voltage, again increasing with speed, so braking from top speed stands to produce some massive outputs reducing to virtually nil at slow speeds. In braking the charge action is engaged that results in an equivalent braking effort - more charge rate akin to jumping hard on the brakes. When accelerating the process can reverse pumping the battery current into the (wheel-mounted?) motor/generators giving a power boost in addition to the normal engine drive. If fitted to the front wheels, rules permiting, as most braking effort is applied here, most charging would come from here and if the energy was re-applied to the front wheels during acceleration you would conceptually have a quasi- (yurgh!) 4 wheel drive system with the front end helping to power out of a bend with the possibility of a tighter exit line. The discharge issues from KERS encountered might be from design approaches of high voltages instead of high current which has battery and cabling issues - flash-chargable batteries are a work in progress, so ultra-capacitors may be playing their part.

[pipex]

Hi!,
maybe they are using voltage source approaches instead of current source because the size of the dc link components? just a thought or maybe they are trying to use Matrix Converters? they are pretty good at energy density i think.

best regards

[alexbarwell]

Well, actually looking at the current open-ness of KERS which is basically a limited permission to recover kinetic energy any system that provides the function (and isn't lethal) could count. One system mentioned involved flywheels with coupling rollers and a variety of transmission fluid, but to a point keeping it compact and simple with few moving parts is a safe bet particularly for the smaller teams. Magnets now can be very small, light and viciously strong and aluminium windings reduce weight at the expense of conductivity. We could go for electrostatics and have the drivers rubbing against a nylon carpet lined cockpit to go faster

[pipex]

We could go for electrostatics and have the drivers rubbing against a nylon carpet lined cockpit to go faster

LOL!

best regards

[pgj]

We could go for electrostatics and have the drivers rubbing against a nylon carpet lined cockpit to go faster

LOL!

best regards

Men in tights? lol

Great information alex, thank you.

[riff_raff]

The cheapest, lightest and most effective type of KERS is a smooth driver. It's the old adage about "the driver that carries the most speed through a corner will always be the fastest".

Kinetic energy that is not lost to braking, downshifting or sliding, does not need to be recovered. Smooth is fast. Just like Jim Clark, Alain Prost and Rick Mears.

[alexbarwell]

Riff-raff, very true, but seeing as how the rules have been tweaked to reduce cornering sppeds a bit (grooved tyres, limitations on downforce designs - '79 brabham with the windmill?) then the best bet is to get cornering speeds well sorted and then make sure you can store and re-deliver that energy that would otherwise be lost. On the greeny-cars-for-the-road front, I'm wondering why they don't fit a solar panel as the main part of the roof - if you run out of juice, park up and wait a while (in daylight) and magically the 'fuel tank' will fill itself...how green can you get?

[freedom_honda]

seems like Honda is testing their KERS next week in Jerez.

Ross Brawn, Team Principal:
"There will be very few technical changes to the cars but the downforce levels will be quite different. Singapore is a high downforce track and there will be a range of downforce levels for the remaining tracks thereafter. We are testing in Jerez next week for four days but the focus there will be on projects for the 2009 car and in particular the KERS system."

that would be their second on-track test with their KERS. (they already tried KERS once with their old car).
it would be interesting to see how they go with their KERS at race speed.

[bazanaius]

Hey guys, just wondering what people thought about the application of the rules for kers...

- how is the output controlled? Is it a 'push once per lap' thing, or is the output power just a max per lap that you can use however you want?
- If this is that case, how is that controlled? Is the power out measured over a lap to ensure it doesn't break the limit? How does this relate to the rate at which energy is captured?
- i.e. obv the energy isn't all captured at once, but if I'm using random amounts throughout a lap, what stops me 'topping up' as I go. Or can I only capture a certain amount a lap?
- Is the actual storage mechanism (whatever method is used) controlled so it can only hold the regulated amount - how does this stop the 'topping up' method?

I guess a single reply of 'they can only press it once a lap' answers the question, but I was just having a think about how I'd try to gin an advantage if I was doing this

[mx_tifoso]

Read the thread (link below) on regenerative systems, there are 24 pages at the moment, and I would go as far as saying that most, if not all, of your questions can be answered by reading them. A lot of discussion, some videos, many links, etc., are featured, enjoy.

F1Technical- Regenerative systems

And if the thread linked above does not do the job for you, there are a few more threads floating around with the same or similar subject, so do a few searches and you'll get more information.

[pipex]

Hi!,
I'll try to answer per point from what i know, maybe it's wrong .

- how is the output controlled? Is it a 'push once per lap' thing, or is the output power just a max per lap that you can use however you want?
- If this is that case, how is that controlled? Is the power out measured over a lap to ensure it doesn't break the limit? How does this relate to the rate at which energy is captured?
- i.e. obv the energy isn't all captured at once, but if I'm using random amounts throughout a lap, what stops me 'topping up' as I go. Or can I only capture a certain amount a lap?
- Is the actual storage mechanism (whatever method is used) controlled so it can only hold the regulated amount - how does this stop the 'topping up' method?

- the output is a max per lap... 400kJ of energy per lap
- there is a limit of the rate of energy capture it is specified in the regulations...
- i think this is related to the the energy limit per lap and the limits of the rate of charging
- i don't know exactly how this will be done, but i think for the case of mechanical flywheel based systems this could be done with a clutch/CVT trans (i'm no mech eng.) and in the electrical KERS with an inverter switch off (inverter is the thing that controls power flow between the batteries/supercapacitor/electric flywheel and the motor/generator).

I have another question, how the system will synchronize the engagement of the classic brakes?? i think this is pretty involved... maybe i should ask in the other thread, but i don't know

best regards

Edit: Just to add a new idea (don't burn energy when you can control its flow instead)