Tommy Cookers wrote: ↑
Mon Jun 05, 2017 7:32 pm
well your paragraph headed 'firstly' is wrong
unless you are suggesting (without so saying) that for qually only the braking is entirely friction/'mechanical' ?
the tyres don't know the source/sources of the retarding torque transmitted through them, so their behaviour isn't variable ... and
rear brake cooling is designed down to a level that relies on regenerative braking - ie the brakes overheat if the regeneration has tripped out
the constant power regenerative characteristic (having a torque-response time of tens of millisec) should help braking, acting as weak rear ABS
Sorry Tommy, I didn't see your post until now (someone gave it a plaudit).
To take things in turn:
Craigy wrote: Firstly - the cars are generally going to charge under braking.
In this state, the car has to shed energy anyway - so it makes sense to do this here
Hopefully we can agree on the first part of my post, that I've quoted above.
Craigy wrote: and there are limited circumstances where one would want to not do this - related to better control of braking over bumps
Teams have different brake bias (front:rear) settings corner to corner. This is something we hear them talking about and seeing from cockpit video quite a bit. Teams also adjust their BBW brake bias from corner to corner, especially in quali. I'd be interested to know your thoughts on this - do you think that teams are only adjusting the hydraulic brake bias, or do you agree that they are doing both a modulation of the ERS-K and the hydraulic brakes from corner to corner?
Craigy wrote:heating the rear tyres, or something like that, where you only want the mechanical braking to work.
F1 teams use the rear brake disk temperatures to heat or cool the rear wheels and consequently the bulk of the rear tyres.
This can be adjusted using the BBW balance (the more regen you're doing with the ERS-K, the less energy ends up in the rear brake disks, and the cooler they become, and vice-versa).
I wasn't suggesting that the tyre "knows" where the braking torque is coming from. I was suggesting that the ERS-K settings have an effect on rear brake disk temperatures (circa 120kw for 33s per lap up for grabs - that's a lot of heat into the brake disks and rims, then consequently on rear tyre temperatures).
I think we know that when the ERS-K isn't harvesting, the rear brake temperatures can go so high they can stop a car from finishing a race (eg. Hamilton, Canada 2014), even when the bias is as forward as the drivers feel able to deal with.