What is the KERS and how it works

[Scuderia Nuvolari]

if Williams is the only team using a flywheel and they can harness this power correctly, then I believe that nothing can stop them from being champs next year

[Scuderia Nuvolari]

Why would you use batteries if you lose15% in storage efficiency and have to drag around extra weight ? A flywheel turning at 50-100k should give you more power than any battery can put out. Does anyone have any comparable numbers?
The way that I understand it is that the vacuume is so good that it takes about 20 minutes of running time for two oxygen atoms to run into each other.

[Tommy Cookers]

you're up to speed with related posts in the big thread at the top of the list ?

[superdread]

Why would you use batteries if you lose15% in storage efficiency and have to drag around extra weight ? A flywheel turning at 50-100k should give you more power than any battery can put out. Does anyone have any comparable numbers?
The way that I understand it is that the vacuume is so good that it takes about 20 minutes of running time for two oxygen atoms to run into each other.

The Williams system uses the flywheel for storage of electrical energy, so they use an electronic coupling between the flywheel and the drivetrain. This also zaps power and increases weight. Also a battery gives greater freedom in shape, so with a flat array of batteries you get a lower CoG and can fit the whole thing easier under the fuel tank.

There are purely mechanical systems (flybrid) but they need a gearbox-like mechanism between them and the drivetrain. So there is no absolute holy grail for KERS (although a mechanically coupled flywheel is way cooler than some stupid batteries).

Flybrid states that they loose 2% stored energy per minute, but not for which of their systems this figure is meant.

And the figure of "about 20 minutes of running time for two oxygen atoms to run into each other" is a big load of BS, firstly this depends on what you define by "running into each other", secondly oxygen makes only about 20% of the air (and is a molecule) and thirdly is there no reference point to see if thats good or bad (this largely depends on my first point).
There is already an established scale to describe something like that and that is pressure (or spatial particle density).
(I'm kind of sorry, but such unscientific unhelpful "wow"-stuff gets on my nerves.)

[Scuderia Nuvolari]

Maybe I said that wrong
IT TAKES about twenty minutes of running time for two MOLECULES of air to collide.

[superdread]

Maybe I said that wrong
IT TAKES about twenty minutes of running time for two MOLECULES of air to collide.

That was not the nature of my complaint. This is not a tangible statement in any way, it doesn't convey any information besides "wow, they have very few gas particles in there",thus you can't compare it to other near-vacui.

The big problem is what is meant by collide. Molecules largely interact by bouncing of each others electron hulls and they don't have a maximal radius. You can have molecules hitting each other straight on, squeezing together and bouncing back, that's the easy case. But when they pass in a distance to each other, they change each others trajectory, the change is less for greater passing distances, so when is it small enough to don't count as a collision.

And, who is to say that gas particles of air at normal environmental conditions collide at a higher rate? (Can be much lower, when I count only strong interactions as collisions.)

(Also no volume was given, making the information uslesser.)

[bhall]

[...]

So there is no absolute holy grail for KERS (although a mechanically coupled flywheel is way cooler than some stupid batteries).

[...]

Oh, I don't know about that last bit.

Race car's carbon fiber frame also acts as a battery

(And to think, "they" laughed at me when I proposed a battery-floor as a possible design for the mythical Ferrari "Byrne floor" rumored during preseason testing.)

[Richard]

Let’s say for arguments sake that a perfect vacuum was possible. That isn’t much use if the resulting power train and packaging results in a less efficient system.

The real problem is the form factor, being able to squeeze the packaging into the smallest space. A smaller less efficient system would be preferable to a large efficient system. This is a function of physical volume and cooling demands. Of course cooling demand and heat output relate to efficiency

As an aside I do find it annoying when PR pull out abstract facts with no context, those facts become irrelevant. For example, why 2 molecules hitting every 20 mins? Is that over engineered? Why not 4 every 10 minutes? Is that better or worse than comparable systems? Does it give any performance advantage?

[Scuderia Nuvolari]

Rich, it's because I read it somewhere in one the many links that this forum has and it was stated by an engineer not by me. As a layman it helped me understand the concept of a flywheel and I actually got my first look at one.

[superdread]

Oh, I don't know about that last bit.

Race car's carbon fiber frame also acts as a battery

(And to think, "they" laughed at me when I proposed a battery-floor as a possible design for the mythical Ferrari "Byrne floor" rumored during preseason testing.)

Isn't that just making batteries structural? Like a gearbox?
As far as I know the Dyson-Lola tries to use the batteries as part of the front subframe. This improves packaging (and in LMP weight distribution) and weight (a little bit).

The real problem is the form factor, being able to squeeze the packaging into the smallest space. A smaller less efficient system would be preferable to a large efficient system. This is a function of physical volume and cooling demands. Of course cooling demand and heat output relate to efficiency

A big issue is density. For the sake of a lower CoG you want the KERS as dense and as flat as possible, and still be able to cool it properly. That's why Williams didn't went for it's own flywheel system, because the wheel has to be upright and that means a high CoG, also the surface area is not that big so cooling suffers. Batteries and supercapacitators are better in that respect, you can just make some holes in it and channel air through (high surface with high density) and you can mold them into a very flat shape.

For road cars on the other hand, flywheels are great. The, in my opinion, only worthwhile advantage of hybrids is regenerative braking and a flywheel system to reuse braking work for reaccelerating (60hp for5s or so) is small and light. Also in contrast to batteries a flywheel system lives longer and can be made mostly out of steel, making recycling easy.

As an aside I do find it annoying when PR pull out abstract facts with no context, those facts become irrelevant. For example, why 2 molecules hitting every 20 mins? Is that over engineered? Why not 4 every 10 minutes? Is that better or worse than comparable systems? Does it give any performance advantage?

Four molecules hitting each other (at the same time) is quite a rare occurence. Flybrid says that their racing system (either first or second generation) looses 2% a minute (seems just right), but not how efficient their CVT (quasi-CVT for second gen) is, so overall performance remains doubtful.

[Tommy Cookers]

surely there will be little or no change to the present KERS systems for 2013

and 2014 will have an MGUK and an MGUH, which will allow the total power to be 120 KW

clearly most of this electrical power will be consumed as generated (not stored), and storage innovation is less important ?

flywheel energy storage won't happen in F1 ?

[superdread]

clearly most of this electrical power will be consumed as generated (not stored), and storage innovation is less important ?

The other way around, isn't it? You have to store the energy or else it would make no sense to build the electric systems in (when starting to accelerate it makes little sense to take energy of the drivetrain to spool up the turbo if you can use stored engine, also slowing down the turbo to put the energy towards the drivetrain).

flywheel energy storage won't happen in F1 ?

Packaging and CoG makes it rather unfeasible.

[Tommy Cookers]

the turbo fans are confident that there's lots of waste exhaust energy recoverable to drive the turbine to generate electricity to drive the electric motors simultaneously, ie electric compounding (GUH energising MUK)
(control the GUH load on the turbine to control the turbo speed to control the boost to reduce over 10500 rpm to match the fixed fuel rate - I say the MGUH could be rather big, and there's advantage in having a high load/'back pressure')

this way there's no need to have storage sized for 120 KW electric drive (and the storage/recovery losses and cooling needs)

EDIT... as the rpm increases the air delivery per rev (charge) will be reduced to maintain near-stoichoimetric AFR

loading the turbine electrically via the GUH tends to reduce charge while keeping the boost relatively constant
(by reducing the pressure difference across the TC)

the engine would be designed to run (eg) between 10500 and 12200 rpm, with varying power fom GUH to MUK
(or be designed to run between 13900 and 15000, or be designed similarly to another rpm range)

........ such that the boost will be relatively constant
(because the (piston) compression/expansion ratio is dictated by the maximum charge, varying the boost with rpm (to control charge) means (wastefully) using a 'max charge' C/ER at lower charges)

controlled GUH operation (loading the turbine) .....

controls the charge (as rpm rise) by raising exhaust pressure, and minimises/avoids wastegating
and turns some genuine exhaust waste energy into electricity
(most exhaust pressure is lost on valve opening ie before the turbo/turbine, with more turbine loading of the exhaust (pressure) these losses are reduced)

IMO

[superdread]

the turbo fans are confident that there's lots of waste exhaust energy recoverable to drive the turbine to generate electricity to drive the electric motors simultaneously, ie electric compounding (GUH energising MUK)
(control the GUH load on the turbine to control the turbo speed to control the boost to reduce over 10500 rpm to match the fixed fuel rate - I say the MGUH could be rather big, and there's advantage in having a high load/'back pressure')

this way there's no need to have storage sized for 120 KW electric drive (and the storage/recovery losses and cooling needs)

I see what you mean. Having just noticed there is a draft of the rules for 2014 on the FIA-site and that they switch from a time-allotment for a lap to an energy-allotment this seems a logical thing to do. The limiting factor for shrinking the capacity is, I think, that stupid rule that they must drive under electric power in the pit straight.

[autogyro]

I think there will be more use of capacitors in balance with (possibly structural) batteries.