F1technical.net

If the KERS generator were attached to the front wheels, the ones most heavily loaded during braking
How much power could it gather? after a long straight with heavy braking
Supposing the rules don't limit its capacity

If KERS generators would be connected to both the front and rear wheels the maximum power can be estimated as:

Power [W] = mass of car [kg] x acceleration [m/s²] x speed [m/s]

For a F1 car in qualifying this would result in about
P ~ 645kg x 5 x 9,81m/s² x 92m/s = 2910627 W ~ 2,9 MW.

But as the acceleration is heavily dependent from speed, this could only be achieved for a very short moment of time. And imagine how big the generator would have to be to cope with such big powers!

This is in line with Brembo's numbers of 2000+ kW, but even if there were such generators, no battery could handle the charge.

http://formula1.brembo.com/en/home-en/b ... cards.html

Blanchimont wrote:If KERS generators would be connected to both the front and rear wheels the maximum power can be estimated as:

Power [W] = mass of car [kg] x acceleration [m/s²] x speed [m/s]

For a F1 car in qualifying this would result in about
P ~ 645kg x 5 x 9,81m/s² x 92m/s = 2910627 W ~ 2,9 MW.

But as the acceleration is heavily dependent from speed, this could only be achieved for a very short moment of time. And imagine how big the generator would have to be to cope with such big powers!

I think the speed in your equation needs to be (v1-v2)/2.

Also, as the speed falls, downforce is lost and braking effort becomes less.

xpensive wrote:This is in line with Brembo's numbers of 2000+ kW, but even if there were such generators, no battery could handle the charge.

http://formula1.brembo.com/en/home-en/b ... cards.html

That's assuming all the braking power was converted to electricity.

wuzak wrote: ...
I think the speed in your equation needs to be (v1-v2)/2.
...

I think Blanche is correct, we're talking about Power as in Force times Speed here where;

Force is Mass times Accelleration (Negative)

And

Speed is at when braking begins, or (v1+v2)/2 as the average over the braking sequence

However, I believe that 5 g is a bit much, 3-4 g is perhaps more realistic?

xpensive wrote:

wuzak wrote: ...
I think the speed in your equation needs to be (v1-v2)/2.
...

I think Blanche is correct, we're talking about Power as in Force times Speed here, where;

Force is Mass times Accelleration (Negative)

And

Speed is at when braking begins, or (v1+v2)/2 as the average over the braking sequence

However, I believe that 5 g is a bit much, 3-4 g is perhaps more realistic?

Surely that gives only the peak number, where the average is much more useful.

If you have 1000kW average over 5s you have 1000kJ of energy. But the 2000kW is only over 0.0000001s, so isn't significant in the scheme of things.

Was just looking at your link, and saw a peak braking number of 5.9g at the end of Monza's main straight (low downforce, remember), 5.98g at the end of the back straight in Montreal (leading into the final chicane) and 6.07g at the entry to turn 3 at Albert Park.

wuzak wrote: ...
Surely that gives only the peak number, where the average is much more useful.

If you have 1000kW average over 5s you have 1000kJ of energy. But the 2000kW is only over 0.0000001s, so isn't significant in the scheme of things.
...

Peak power number indeed, like the title of this very thread, and just like your peak deceleration number below?

wuzak wrote: ...
Was just looking at your link, and saw a peak braking number of 5.9g at the end of Monza's main straight (low downforce, remember), 5.98g at the end of the back straight in Montreal (leading into the final chicane) and 6.07g at the entry to turn 3 at Albert Park.

Isn't arguing for the sake of arguing great fun Wuz?

xpensive wrote:

wuzak wrote: ...
Surely that gives only the peak number, where the average is much more useful.

If you have 1000kW average over 5s you have 1000kJ of energy. But the 2000kW is only over 0.0000001s, so isn't significant in the scheme of things.
...

Peak power number indeed, like the title of this very thread

The title of the thread is "How much power if KERS recovered energy from the frontWheel" - which does not indicated peak power to me.

Also, I would suggest the energy recovered is a more useful number for KERS usage.

xpensive wrote:and just like your peak deceleration number below?

wuzak wrote: ...
Was just looking at your link, and saw a peak braking number of 5.9g at the end of Monza's main straight (low downforce, remember), 5.98g at the end of the back straight in Montreal (leading into the final chicane) and 6.07g at the entry to turn 3 at Albert Park.

Isn't arguing for the sake of arguing great fun Wuz?

I wasn't trying to argue. Just pointing that the peak number used by Blanchimont is not unusual.

the problem is not a need for a huge generator to access the brief high power peaks
with liquid cooling and modern materials it's not an issue (look at the MM MGUH)

the problem is the storage

we need an integrated unit that imports ICE power continuously (including exhaust), and power from braking
and exports power
with storage
the unit could be wholly mechanical or wholly electrical, or something other