Years ago, when KERS was new, I was told by an insider that SECU's base programming (the part "fixed" that teams have no access to) allows KERS to be used as motor only when throttle pedal is at 100% (and speed is above 100km/h) and as generator only when throttle is at 0%.
He told me that was exactly to prevent KERS being used to mimic TC/LC, in part throttle phases KERS just is out of the game, no transfer of energy can happen between MGU and drivetrain.
Remember also that other rules require that the throttle has to be WO when pedal is at 100% and that when throttle is at 100% the engine must produce the max torque it's capable of (discussed at length in the aftermath of the Germany 2012 and the Red Bull maps case).
To tell the truth I've never heard about these KERS/throttle limitations from other sources, so I can't swear these do exist, but certain things seem to confirm it, like the message we sometimes hear from pitwall telling drivers to not overlap throttle and brake (I remember once some races ago it was specifically mentioned it prevented KERS harvesting, not sure which race it was though, was before summer so possibly Germany or UK, will check recordings when I've the time), or the fact that whenever FOM graphics shows KERS energy release active, it's always when the throttle bar is full. (not that it would make sense to waste hardly recovered energy for when ICE alone can already cause wheelspin, but if it was helpful in term of traction management we would see it done).
autogyro wrote:
During the Japanese Grand Prix on at least one occasion a Red Bull engineer was heard over the radio telling the driver to use Kers coming out of a slow corner, chicane or hairpin.
Should be quite obvious that "out of the corner" hasn't to be taken literally or as "right at the apex", it's just meant to give the driver a reference of the places where he needs to use it, and it implies "as soon as you can use it", which is when he can go full throttle.
Laptime wise the advantage from a given amount of energy (whatever the source is) is the highest the lowest the speed at which you can use it, for two reasons essentially; first because kinetic energy grows with square of speed (so the lower the speed, the more speed you gain for given amount of energy), second because when you are at low speed you are also more distant from next braking point, so whatever speed gain you get is used for more time, contributing more to the increment of average speed.
That's why the best strategy to use limited KERS energy, for laptime, is in short bursts out of various corners, only up to a certain speed, conveniently distributed, giving precedence to the corners with slow exit speed and followed by the longest distance to next braking (for example, in Monza KERS is best used out of first chicane but not out of second, because, while in term of speed Roggia's exit would be a good place, it's so close to Lesmo 1 braking that using energy there would be a waste, whatever speed gain you get is nullified few seconds later; better to use the remaining juice out of Lesmo 2, which has lot higher exit speed, so is not ideal in that sense, but is still preferable due to the long run to the next braking point).
Naturally that always implies that the lowest speed is the speed at which you can have enough grip to use full ICE + max KERS.
A F1 car though generates enough downforce to apply full ICE power + KERS from somewhere between 120-150 km/h (depending by aero trim, tyres conditions, lateral acceleration in that specific corner etc), and, bar very few exceptions, even the "slow" corners are already at 70-80km/h or more, meaning that it takes very little time to get to speed, hence grip, high enough for full throttle + KERS, in not many meters out of corner exit it's doable.
For example, this is a plot of two Webber's Suzuka laps (speed from engine noise and throttle captured from FOM graphics), pole position and start of race:
As you can see even with high fuel load at start of the race he can go full throttle very quickly after the local minimum of speed.
Or, another example, Singapore's pole lap for Vettel, here also with indication of areas where KERS is used (which you can see is always at full throttle):
So, yeah, KERS is used out of slow corners, because that's where it helps the most, but only when grip is high enough.
Naturally, if your car can benefit from more grip at corner exit, then you can go on throttle earlier AND using KERS earlier, which doubles the advantage.
In that sense Red Bull is very well placed, but it's not like they go on KERS earlier because they use KERS for traction management, it's the opposite, they have more traction so can go full throttle, and consequently on KERS, earlier.
