2025/2026 Hybrid Powerunit speculation

[Tommy Cookers]

... the FIA always made a stop to it and improved rules and or spirit of the rules policing.

what's/where's the rule that does it ? .... (currently or 2025/6)

such a rule would be perverse and nonsensical (though that wouldn't stop the FIA having one)

[wuzak]

Well, apart from the fact that we are here talking about formula one and the FIA energy harvesting rules and not road going hybrids. Even the said RBPT engineer was of the opinion that driving the MGU-K with the engine will not be allowed. Which means no harvesting by the MGU-K other than under braking will be allowed for 2026 engine rules.

Note that the RRBT engineer is on the ICE program, not the hybrid system or the calibration side.

I noted that comment too, but then realised he is contradicted by:

5.14.5 The driver maximum torque demand may only be reduced at a maximum rate of 100kW in any 1s period and the power reduction will be limited to a maximum of 450kW.

At full demand the MGUK can only give 350kW, and the ICE will give its maximum. But allowing the power output to fall by 450kW strongly suggests that the ICE will be allowed to drive the MGUK to the tune of 100kW while the driver has his foot to the floor.

[wuzak]

also ... don't F1 drivers spend time with feet on both brake and accelerator pedals without deceleration ?

Well, yes. Their feet are on or near both pedals at all times. But that does not mean they are applying brake pressure while on the throttle.

I recall Williams asking Frentzen to lift his foot off the brakes in the Australian GP 1997, because he had some pressure applied, which would mean that the performance was lower and brake life could be compromised.

Also, the onboard shot of Danny Ric's pedals his year show him lift his foot completely off the pedal.

[saviour stivala]

Extremely hard to believe that an engineer of the caliber involved in the interview will contradict himself by the intended rules. The RBPT engineer involved who was of the opinion that ‘driving the MGU-K with the engine would not be allowed’ is an American mechanical engineer based in RBPT Milton Keynes as performance design team leader for formula one powertrain side of operation.

[AR3-GP]

If harvesting by the MGU-K without braking input was permitted (in addition to MGU-H), we would never observe clipping.

So my conclusion is that the RBPT engineer is probably correct and no one is actually doing this. But I could be wrong

[wuzak]

Extremely hard to believe that an engineer of the caliber involved in the interview will contradict himself by the intended rules. The RBPT engineer involved who was of the opinion that ‘driving the MGU-K with the engine would not be allowed’ is an American mechanical engineer based in RBPT Milton Keynes as performance design team leader for formula one powertrain side of operation.

He is involved with designing the ICE, not the ERS or the strategy of how to use the two together.

[wuzak]

If harvesting by the MGU-K without braking input was permitted (in addition to MGU-H), we would never observe clipping.

So my conclusion is that the RBPT engineer is probably correct and no one is actually doing this. But I could be wrong

What they are doing now and would they will be permitted to do in 2026 are not necessarily the same thing.

Clipping is when the MGUK stops deploying. That could be because the ES has run out of energy or because the energy strategy requires harvesting at that point. That could simply be that the MGUK is stopped deploying and the MGUH is sending its energy to the ES.

Energy is also recovered using lift-and-coast. The driver lifts off the throttle early and the MGUK helps slow the car before the brakes are applied.

[wuzak]

I'd like to point out that the MGUK power has increased by nearly 3 times, but the allowed energy recovery from the MGUK to the ES has increased 4.5 times.

Given that the braking times aren't going to increase that much, if at all, and that at most (all?) circuits the current cars cannot recover the allowed amount through braking alone, it is likely that using teh MGUK as a generator will be allowed.

[johnny comelately]

I'd like to point out that the MGUK power has increased by nearly 3 times, but the allowed energy recovery from the MGUK to the ES has increased 4.5 times.

Given that the braking times aren't going to increase that much, if at all, and that at most (all?) circuits the current cars cannot recover the allowed amount through braking alone, it is likely that using teh MGUK as a generator will be allowed.

What is the percentage of the rear braking that is mechanical now?

[saviour stivala]

‘’Energy is also recovered using lift and coast – The driver lifts off the throttle early and the MGU-K helps slow the car before the brakes are applied’’ oh dear that RBPT engineer involved in the RETECH interview must have been terribly wrong opinionizing that in his expert opinion running the MGU-K by the engine will not be allowed. It is a good thing having such eagle eyed expertise around here to pinpoint such so called expertise opinion slips pushed out by actual people involved with the F1 powertrain design.

[wuzak]

I'd like to point out that the MGUK power has increased by nearly 3 times, but the allowed energy recovery from the MGUK to the ES has increased 4.5 times.

Given that the braking times aren't going to increase that much, if at all, and that at most (all?) circuits the current cars cannot recover the allowed amount through braking alone, it is likely that using teh MGUK as a generator will be allowed.

What is the percentage of the rear braking that is mechanical now?

That depends on the particular braking zone.

Lighter braking zones would, potentially, have a higher percentage of MGUK braking. Heavier braking would have less.

Maximum braking power is ~2000kW, ~40% of that comes from the rear wheels. So that would mean 800kW from the rear wheels, which means currently the MGUK would have about 15% of the braking performance, but in 2026 it will be ~44%.

But not all braking events in F1 are maximum braking. And the amount of braking power varies with the speed of teh car - the power reduces as the car slows.

[johnny comelately]

I'd like to point out that the MGUK power has increased by nearly 3 times, but the allowed energy recovery from the MGUK to the ES has increased 4.5 times.

Given that the braking times aren't going to increase that much, if at all, and that at most (all?) circuits the current cars cannot recover the allowed amount through braking alone, it is likely that using teh MGUK as a generator will be allowed.

What is the percentage of the rear braking that is mechanical now?

That depends on the particular braking zone.

Lighter braking zones would, potentially, have a higher percentage of MGUK braking. Heavier braking would have less.

Maximum braking power is ~2000kW, ~40% of that comes from the rear wheels. So that would mean 800kW from the rear wheels, which means currently the MGUK would have about 15% of the braking performance, but in 2026 it will be ~44%.

But not all braking events in F1 are maximum braking. And the amount of braking power varies with the speed of teh car - the power reduces as the car slows.

Thank you, about what I expected.

[saviour stivala]

Brembo used to produce individual track braking data in the past. Up to some time ago nobody could see them deploying so much around a lap. The present MGU-K size used stayed at 120KW. At present harvesting possibilities by MGU-K and MGU-H combined they can deploy mostly all around the racing lap. What size will the 2026 MGU-K be?.

[AR3-GP]

Brembo used to produce individual track braking data in the past. Up to some time ago nobody could see them deploying so much around a lap. The present MGU-K size used stayed at 120KW. At present harvesting possibilities by MGU-K and MGU-H combined they can deploy mostly all around the racing lap. What size will the 2026 MGU-K be?.

3 times the current power output level.

[saviour stivala]

And what is the harvesting limit per lap?.