gruntguru wrote: ↑
Thu May 16, 2019 6:14 am
The numbers are different to your gut feel unfortunately. Using a low rotational inertia for the engine plus MGUK of 0.05 kg.m^2 and a rpm change on upshift from 12,000 to 10,500 we get a change in kinetic energy of 18 kJ. (To achieve this in 1 second would require a braking power of 18 kW). The MGUK has a power limit of 120 kW so it will slow the engine from 12,000 to 10,500 in 0.15 sec (150 ms). That is way too slow for a gearshift. If the shift was say 15 ms, the braking power required to slow the engine would be 1200 kW.
18 kJ (actually something less) per gearshift would not destroy the clutch over the course of a race.
For the gearchanges that happen when consistent traction is useful to the driver, in and around corners, I think it would be useful to maintain constant power. Assuming in qualification the power from the PU prior to the shift is 660kW then the PU could be switched off for 27msec, during which the 18kJ of inertial energy could provide the 660kW, and then the PU could pick up where it left off.
Obviously that’s not what happens but a combination of reduced or even negative PU, plus some clutch slip to vary the gear ratio and extend the change time might be useful to achieve constant power, if that is a useful goal.
An implication might be that change time would be different for each power output level the PU is targeting.
Another implication is that it might be useful to arrange the power curve so that the output is the same before and after gearchanges. When I looked at Ferrari’s power curve a couple of years ago that is roughly what I saw.
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