MGU-K(brakes) will need extra MGU-H(exhaust) input.
One side effect of 2017’s F1 aero/tyres overhaul is that more power will be needed to propel cars that will be 26kg heavier, produce around 20 percent more downforce, and generate extra drag due to Pirelli’s 25 percent wider tyres.
Although new-spec cars will be faster on corner exit, they will go slower on a straight line, resulting in a lower speed differential. Theoretically, there should be less acceleration phases and less braking.
All-in-all that means more downforce, more grip and therefore faster lap times. The apex speed will be increased as well as the air drag. Therefore harvesting of energy recovery will be changed. The car will have a lower top speed, but can brake later due to the higher downforce.
The braking distance therefore becomes shorter, which has an impact on the energy recovery. There needs to be different driving profiles and strategies in order to pick up the limited energy of 2 MJ on the MGU-K.”
F1 batteries can receive up to 2MJ per lap from the MGU-K, it recovers that energy under braking. Like a bicycle dynamo, the generator slows down the vehicle – either instead of the brakes or in conjunction with them – by acting on the drive shaft.
With the maximum output of the energy recovery systems (ERS) still limited at 120kW, the amount of energy recovered depends on the time spent under braking. In other words, shorter braking distances will equate to a smaller energy harvest.
In 2016, drivers were braking for 1.1s (according to figures released by brake supplier Brembo) to decelerate from 330kph to 120kph on the approach to Turn 1 at Circuit de Barcelona-Catalunya. Overall, pilots spent 18 percent of the lap on the brakes. That figure is bound to decrease this year, with cars travelling faster through curves but slower on a straight line.
According to some reports, the braking time for Turn 1 in Barcelona could go from 1.1s down to 0.8s, which would affect the other seven braking areas at the Spanish Grand Prix venue. Some existing corners are even expected to become straights (i.e. be taken flat-out) in 2017, meaning even fewer opportunities to recover energy under braking.
Meanwhile, cars will spend more time on straights due to the increase in drag, so energy demands on these portions will be potentially higher.
There might be venues on the F1 calendar where the overall braking time is not enough to get 2MJ per lap. In that case, the MGU-H would need to complement the MGU-K in harvesting more energy at the exhaust, which is feasible in theory given the longer periods of full-throttle expected.
This will call for a proficient MGU-H and above all a powerful, yet efficient, ICE. One may surmise then that engine manufacturers have factored in these new constraints and revised the dimensions of their turbocharger and MGU-H accordingly.
So rather than just looking at improved 1.6 turbo performance who is going to get the new balance of recovery systems optimised?