2025/2026 Hybrid Powerunit speculation

[henry]

Currently :

At part throttle they can mix power from the ICE and MGU-K so long as the resultant power output matches the driver’s demand. Originally the only restriction was the part throttle fuel flow requirement, more recently they also provide a fuel flow to power demand requirement. So if demand is 400kW you can make it with 450kW ICE and regen 50kW with the K.

At full throttle the contribution of the K to the power output is wholly under software control. So at the beginning of the straight it can be 600kW ICE and +120kW from the K and at the end 600 ICE and -120 K.

There was NEVER EVER a requirement to link the K regen to the brake pedal. They CAN, and do, use the K for braking but there is no regulation that says they MUST.

What they will do in 2026 I don’t know. They seem to have dropped the fuel flow to power restriction on part throttle so maybe they expect part throttle regen to try to make up for the shortfall, versus the current state, caused by removing the MGU-H.

[saviour stivala]

''there was never a rquirement to link the 'K' regeneration to the brake pedal''. Gereration is linked to thebrake pedal and deployment is linked to the throttle pedal. 'K' regenerates under braking an energy that would otherwise have gone to waste. ''extra recovery'' such as ICE-TO-MGU-K is not permitted and will not be permitted in 2026.

[mzso]

There was NEVER EVER a requirement to link the K regen to the brake pedal. They CAN, and do, use the K for braking but there is no regulation that says they MUST.

What they will do in 2026 I don’t know. They seem to have dropped the fuel flow to power restriction on part throttle so maybe they expect part throttle regen to try to make up for the shortfall, versus the current state, caused by removing the MGU-H.

Okay, I had it mixed up a bit.
So I guess it will be possible to regen without power demand, and enough brake demand on the rear wheel? Running the engine purely for regen?

[henry]

There was NEVER EVER a requirement to link the K regen to the brake pedal. They CAN, and do, use the K for braking but there is no regulation that says they MUST.

What they will do in 2026 I don’t know. They seem to have dropped the fuel flow to power restriction on part throttle so maybe they expect part throttle regen to try to make up for the shortfall, versus the current state, caused by removing the MGU-H.

Okay, I had it mixed up a bit.
So I guess it will be possible to regen without power demand, and enough brake demand on the rear wheel? Running the engine purely for regen?

I certainly think this is a possibility. With current aero the 350kW will likely exceed the required braking power on the rear axle at any speed below 180kph (very approximately). The BBW system could reasonably use the ICE to drive the K to keep its regen level higher than the brakes alone.

I believe this is also a possibility currently where the 120kW K exceeds the rear axle traction at about 120kph. But I don’t think it is used. I went looking for it a few years ago, and at Monza I noted LeClerc using throttle at the entry to the first chicane which would have had this effect, likewise I thought the Alpha Tauris might have been doing so under software control, but the available telemetry was not convincing.

Currently there is only a very small recovery available and it would mean running the ICE at its least fuel efficient range, so I doubt the complexity is worth it. In 2026 on the other hand the recovery duration will be longer and the ICE will operate much further up its power curve, so it may be worth it, particularly in qualifying when fuel quantity is not an issue.

[mzso]

There was NEVER EVER a requirement to link the K regen to the brake pedal. They CAN, and do, use the K for braking but there is no regulation that says they MUST.

What they will do in 2026 I don’t know. They seem to have dropped the fuel flow to power restriction on part throttle so maybe they expect part throttle regen to try to make up for the shortfall, versus the current state, caused by removing the MGU-H.

Okay, I had it mixed up a bit.
So I guess it will be possible to regen without power demand, and enough brake demand on the rear wheel? Running the engine purely for regen?

I certainly think this is a possibility. With current aero the 350kW will likely exceed the required braking power on the rear axle at any speed below 180kph (very approximately). The BBW system could reasonably use the ICE to drive the K to keep its regen level higher than the brakes alone.

I believe this is also a possibility currently where the 120kW K exceeds the rear axle traction at about 120kph. But I don’t think it is used. I went looking for it a few years ago, and at Monza I noted LeClerc using throttle at the entry to the first chicane which would have had this effect, likewise I thought the Alpha Tauris might have been doing so under software control, but the available telemetry was not convincing.

Currently there is only a very small recovery available and it would mean running the ICE at its least fuel efficient range, so I doubt the complexity is worth it. In 2026 on the other hand the recovery duration will be longer and the ICE will operate much further up its power curve, so it may be worth it, particularly in qualifying when fuel quantity is not an issue.

It will sound weird on some circuits when the engines will newer go below 350kw of power.

[saviour stivala]

"There was NEVER EVER a requirement to link 'K' regen to brake pedal. They CAN and DO use 'K' for braking but, there is no regulation that says there MUST''. Yes indeed there was no REQUIREMENT and no MUST, as in the first place the spirit of the 2014 ERS rules where it concerns 'k' regen was "To harvest energy under braking that would otherwise goes to waste''. Further explanations as to how the new ERS will work not only linked 'K' to brake pedal, but also it's deployment to the throttle pedal. And that is why that RBPT power unit for 2026 team leader engineer said 'ICE- TO- K' is not allowed and that it will also not be allowed for 2026. On a different note, some on here also attributes 'extra' harvesting by the 'k' to when lift and coast is used, but this is also out of the question as apart of it being 'extra harvesting' which in itself is not allowed, when driver lifts and coast, he is neither using the brake pedal nor the throttle pedal. There were times that 'extra harvesting attempts were made, But those attempts were eliminated by the introduction of the second in-out of 'k' policing sensor. There is only one way known to regen/harvest by 'k' under power - ICE -TO - 'K'. which the rules cannot do anything about, that is when driver uses both brake and throttle pedals at the same time.

[karana]

In this video you can see the SOC on the steering wheel, and it seems to suggest that there is regen happening midcorner and even while accelerating. In turn 10 you can see the SOC increasing from 65% at the apex to 68/69% until it goes down again. It looks to me, that at least in 2020 it was possible to run the MGU-K against the ICE.

https://www.youtube.com/watch?v=g9nYB57MLJY

[AR3-GP]

"There was NEVER EVER a requirement to link 'K' regen to brake pedal. They CAN and DO use 'K' for braking but, there is no regulation that says there MUST''. Yes indeed there was no REQUIREMENT and no MUST, as in the first place the spirit of the 2014 ERS rules where it concerns 'k' regen was "To harvest energy under braking that would otherwise goes to waste''. Further explanations as to how the new ERS will work not only linked 'K' to brake pedal, but also it's deployment to the throttle pedal. And that is why that RBPT power unit for 2026 team leader engineer said 'ICE- TO- K' is not allowed and that it will also not be allowed for 2026. On a different note, some on here also attributes 'extra' harvesting by the 'k' to when lift and coast is used, but this is also out of the question as apart of it being 'extra harvesting' which in itself is not allowed, when driver lifts and coast, he is neither using the brake pedal nor the throttle pedal. There were times that 'extra harvesting attempts were made, But those attempts were eliminated by the introduction of the second in-out of 'k' policing sensor. There is only one way known to regen/harvest by 'k' under power - ICE -TO - 'K'. which the rules cannot do anything about, that is when driver uses both brake and throttle pedals at the same time.

I noticed in Bahrain quite a few times the harvesting lights coming on in the T5/T6/T7 complex when the driver would have been on full throttle. It was not in the brake zone.

[saviour stivala]

Which 'harvesting lights' and were ware they positioned on the car that you were noticing please.

[AR3-GP]

Which 'harvesting lights' and were ware they positioned on the car that you were noticing please.

The lights on the rear wing endplate.

Exit of T4 in Hamilton Alonso battle. The driver should have been full throttle before T5 but the lights are flashing on the rear wing. They will naturally lift in T5/T6, but this is too early to be lifting. Look how early the lights come on Alonso's car. Alonso is nowhere near T5 when the harvesting lights come on.

[saviour stivala]

Flashing lights on rear wing endplates in dry conditions. It is incorrect to say that rear wing endplates flashing lights denotes harvesting by 'K'. Thos lights will flash when the car is no longer deploying electrical energy, ie. the car is down 120kw, so will not be accelerating at the same rate (de-rating) = the electrical part is no longer supplying power. Also When driver lifts of the gas pedal = The driver is slowing down but not really braking.

[saviour stivala]

In this video you can see the SOC on the steering wheel, and it seems to suggest that there is regen happening midcorner and even while accelerating. In turn 10 you can see the SOC increasing from 65% at the apex to 68/69% until it goes down again. It looks to me, that at least in 2020 it was possible to run the MGU-K against the ICE.

https://www.youtube.com/watch?v=g9nYB57MLJY

''There is regen happening mid-corner and even while accelerating. In turn 10 you can see the SOC increasing from 65% to 68/69%'' Quite possible harvesting by the 'H'.

[AR3-GP]

Flashing lights on rear wing endplates in dry conditions. It is incorrect to say that rear wing endplates flashing lights denotes harvesting by 'K'. Thos lights will flash when the car is no longer deploying electrical energy, ie. the car is down 120kw, so will not be accelerating at the same rate (de-rating) = the electrical part is no longer supplying power. Also When driver lifts of the gas pedal = The driver is slowing down but not really braking.

Hmm. Well I learned something new. I didn't know this was the case.

[mzso]

"There was NEVER EVER a requirement to link 'K' regen to brake pedal. They CAN and DO use 'K' for braking but, there is no regulation that says there MUST''. Yes indeed there was no REQUIREMENT and no MUST, as in the first place the spirit of the 2014 ERS rules where it concerns 'k' regen was "To harvest energy under braking that would otherwise goes to waste''. Further explanations as to how the new ERS will work not only linked 'K' to brake pedal, but also it's deployment to the throttle pedal. And that is why that RBPT power unit for 2026 team leader engineer said 'ICE- TO- K' is not allowed and that it will also not be allowed for 2026. On a different note, some on here also attributes 'extra' harvesting by the 'k' to when lift and coast is used, but this is also out of the question as apart of it being 'extra harvesting' which in itself is not allowed, when driver lifts and coast, he is neither using the brake pedal nor the throttle pedal. There were times that 'extra harvesting attempts were made, But those attempts were eliminated by the introduction of the second in-out of 'k' policing sensor. There is only one way known to regen/harvest by 'k' under power - ICE -TO - 'K'. which the rules cannot do anything about, that is when driver uses both brake and throttle pedals at the same time.

Your comment is a bit all over the place. But the points I gather is that brake pedal needs to pressed for regen, and throttle for deployment to happen?
(And some awkwardly phrased rant about using K not being mandatory. For some reason.)

So how on earth will they charge the batteries? Getting the drivers to break while on full power. And learning to do so by only the amount the K max power, via some visual display?
Seems obnoxious.

[saviour stivala]

Stra8ght-2-d-point and lets keep it simple by leaving potential added confusion out. The gist of the subject = 'K' Harvesting (harvest energy under braking that would otherwise have gone to waste) meaning 'K' harvesting is linked to brake pedal. Any other additional/extra harvesting by the "K' is not allowed. 'K' Deployment = meaning 'K' Deployment is linked to throttle pedal.