Flywheel or Battery KERS?

[CHT]

Which KERS system do you think will be the winner?

Here is a video of Williams Flywheel type,
http://www.youtube.com/watch?v=4PcIt0FPvWQ

Here is a video of Ferrari (Battery) KERS
http://www.youtube.com/watch?v=0pqK6UeCSKo

[WhiteBlue]

Here is a video of Williams Flywheel type,
http://www.youtube.com/watch?v=4PcIt0FPvWQ

That isn't the Williams system! It is Torotrac's! Williams do not use a CVT but a flywheel with integrated motor/generator.

[scarbs]

It think that electric batteries will win, largely due to their numeracy and the teams that run them. Ferrari\ToroRosso, Renault\Red Bull, Toyota, BMW, McLaren\FIndia are all running a Li-ion battery set up. Then Williams are running a flywheel\electric system (by Williams Hybrid power). While the pure flywheel solution as presented by Flybrid (using torotraks CVT) is not expected to reach the gird, but was earmarked for Honda before their pull out. Brawn are expected to run without KERS.

Personally I think;
• Batteries are not a mature enough technology for the high charge rates needed in F1, they are difficult to package, heavy and have some (but solvable) issues regards safety. but electric battery development is what is needed to get roadcars closer to lower emissions.

• Pure flywheel is the simplest and most compact, which is good for car packaging, but is hindered where the unit can be placed. It also has some road vehicle applicability.

• Curiously flywheel\electric seems the best compromise in F1, the systems compact MGU\flywheel can be placed in the front of the car which is good for packaging. From a road car perspective, it offers little to the industry and hence is a bit of a dead end outside motorsport.

I guess it depends how long term we are looking, for now I would head for a flywheel or flywheel\electric in F1, if I was sponsored by a major motor manufacturer it would have to electric.

[Scania]

I think both of them can be use is the best on road car, & flywheel will win in F1

battery can store energy long time, but it need so much time to finish chemical reaction. flywheel work very fast but the energy can't store very long time.

in F1, the energy no need to store so much time, so flywheel will win.

in road car, flywheel can be a cushion between motor & battery. while the car barking, many power will build up from the motor to the battery in short time, normal battery can't take all over & waste them by heat. so we can transfer the power to flywheel temporary, after barking, if the car speed up, we can use the power in the flywheel first & only take power from battery after while the flywheel stop.

if the car stop, the flywheel can keep rota & transmit the power to battery slowly, so the efficiency will better than transfer the battery directly.

[Steven]

More info on both systems:
http://www.f1technical.net/features/11805

I believe the flywheel (at least Williams' design) is the safer and most interesting system in F1. I also believe that if the FIA would push on for a standard design, than the flywheel will have the advantage, simply because they can easily last one season, while batteries have to be replaced every single race (due to their degradation).

[ISLAMATRON]

yes the longevity of the flywheel makes it much more attractive.

[Ciro Pabón]

The excellent article at this site sums up most of what can be said about KERS.

I would only add that lithium ion batteries lost 20% of their charge capacity per year, even if you don't use them. I don't think this is good for regular cars. Besides, recycling them is a ugly task.

On the other hand, batteries, using nanotechnology, have a better prospect to increase energy density.

As Tomba explains, battery and flywheels probably will follow the path they've already taken: when you need to charge the thing quickly, you use a flywheel. When you can wait several hours for a charge, then you use a battery. Flywheels can store less energy, batteries can store less power during its lifetime. Flywheels have a long life, batteries last 5 years tops.

I think those are the reasons why stop-and-go trucks, like UPS trucks, use a flywheel, while most regular car hybrids use a battery.

The first kind of vehicles are designed to save gasoline because of their typical pattern of use: they have a lot of "reusable" energy being wasted today. The hybrids save gasoline because they can use the ICE to charge the batteries at a constant, optimal RPM.

Finally, I don't know if the economics of the KERS will influence its development and use among the public: right now few people has had to change the battery pack of their hybrids, but they cost several thousand dollars to replace... Flywheels don't have this disadvantage, but their ability to store a full day worth of energy is limited.

[safeaschuck]

I like the idea that the Williams flywheel could (on a road car scale) be plugged into the mains and charged like batteries or topped up by solar panels on the roof.
Probably still not the right answer for road cars though.

Would the flywheel system maintain it's advantage i.e. slightly more compact for a given power output, when scaled up far enough to make a lightweight road car complete a journey? For instance if you took all the batteries out of a Tesla and replaced them with flywheels?????

[PlatinumZealot]

I think the Williams Hybrid system is the best but it is too expensive for road use.

The Li ion is similar to what present day road cars are using.

The pure mechanical Flywheel system could be the cheapest to adapt. But with friction acting How long can it rotate without stopping? A day, two days? i wonder..

[timbo]

I think the Williams Hybrid system is the best but it is too expensive for road use.

I think it is cheaper than LiIon. Actual chemical processes required for manufacturing of the battery is quite expensive and hazardous.
Problem with flywheel is that it stores energy for a limited periods of time. You won't expect flywheel to hold power over night, right?
I believe he best solution is flywheel/battery combo with flywheel acting as short time buffer.

[scarbs]

I think the Williams Hybrid system is the best but it is too expensive for road use.

The Li ion is similar to what present day road cars are using.

The pure mechanical Flywheel system could be the cheapest to adapt. But with friction acting How long can it rotate without stopping? A day, two days? i wonder..

The Flybrid flywheel setup would spin for about 40mins according to Jon Hilton its designer. Weighing just 25kg, 12 cm x 20cm, costing a few thousand on top of the car and nearly lasting as long as the car without servicing, the 80 or so horsepower boost, would certainly be a good option for most cars. Obviously around town it would be of limited benefit, but on open A and B roads it would be great!

[xpensive]

To my mind, the interesting challenge is the eficiency of kinetic energy recovery, when in theory stopping a 1000 kg car from 102 km/h is exactly 400 kJ,
which as we all know can be used to produce those 80 Hp for 6.8 seconds.

How do you go about stopping the cars without conventional breaks, while storing said kinetic energy at basically the same 60 kW-rate as at release, with a minimum of losses?

[Chaparral]

Why not a flywheel/capacitor arrangement then?

[timbo]

Why not a flywheel/capacitor arrangement then?

I believe batteries are more convenient. Capacitors may generate huge current on discharge that potentially is more dangerous.

[ISLAMATRON]

The Flybrid flywheel setup would spin for about 40mins according to Jon Hilton its designer. Weighing just 25kg, 12 cm x 20cm, costing a few thousand on top of the car and nearly lasting as long as the car without servicing, the 80 or so horsepower boost, would certainly be a good option for most cars. Obviously around town it would be of limited benefit, but on open A and B roads it would be great!

As a boost it would have to be on open roads/highways... but if the motor(MGU) was directly connected to the wheels than it would be ideal for putting around in the city stop & go, the main gas engine wouldnt even have to run until about 20mph or so, as modern hybrids are designed to do.

To my mind, the interesting challenge is the eficiency of kinetic energy recovery, when in theory stopping a 1000 kg car from 102 km/h is exactly 400 kJ,
which as we all know can be used to produce those 80 Hp for 6.8 seconds.

How do you go about stopping the cars without conventional breaks, while storing said kinetic energy at basically the same 60 kW-rate as at release, with a minimum of losses?

The efficiency of the MGU coupled with a flywheel or battery storage unit is higher than the ICE, and higher still when compounded with Regen braking. It seems the flywheels can absorb energy at a higher rate (specific power) than the batteries. The regen braking system would be capable of stopping the car but braking distances would probably increase. In any such case the drive and braking would have to be on all 4 wheels to attain maximum efficiency.