2025/2026 Hybrid Powerunit speculation

[Juzh]

Verstappen on the 2026 rules
“If you go flat-out on the straight at Monza, and I don't know what it is, like four or five hundred [metres] before the end of the straight, you have to downshift flat-out because that's faster.

Christian Horner

"Plus, with the characteristics of these engines, that the combustion engine just doesn't become a generator to recharge a battery."

So full throttle battery charging is more or less confirmed with this, is it not? We can finally disregard that red bull PU engineer saying it's not allowed?

[hardingfv32]

Is there any fundamental reason that the IC unit (engine) will be that much different than the current engines under the new rules. I do not think the basic engineering needs to be any different. This assumes that new design efficiencies have not been discovered.

Brian

[vorticism]

So full throttle battery charging is more or less confirmed with this, is it not? We can finally disregard that red bull PU engineer saying it's not allowed?

I read VES as just commenting on aero drag build up requiring a downshift to keep the engine from bogging down.

Is there any fundamental reason that the IC unit (engine) will be that much different than the current engines under the new rules. I do not think the basic engineering needs to be any different. This assumes that new design efficiencies have not been discovered.

Brian

They'll be burning ~1/3 less fuel and presumably needing less air from the compressor unless they're going for even more extreme dilution. So, less heat, less peak combustion pressure, less power, so the internals could become lighter (although probably won't considering weight regs).

If 2014 was doubling down on all the mistakes of 2009, 2026 seems to be tripling down. Good job F1/FIA; you'll skewer the windmill of climate change one of these decades.

[saviour stivala]

The 2026 'K' power which will nearly triple from 161-to-469 hp means increased regenerative braking energy that would otherwise goes to waste. This increased regenerative braking will nearly eliminate friction brakes.

[wuzak]

So full throttle battery charging is more or less confirmed with this, is it not? We can finally disregard that red bull PU engineer saying it's not allowed?

I read VES as just commenting on aero drag build up requiring a downshift to keep the engine from bogging down.

That was aimed at the statement by Horner:

"Plus, with the characteristics of these engines, that the combustion engine just doesn't become a generator to recharge a battery."

[vorticism]

I read VES as just commenting on aero drag build up requiring a downshift to keep the engine from bogging down.

That was aimed at the statement by Horner:

"Plus, with the characteristics of these engines, that the combustion engine just doesn't become a generator to recharge a battery."

That's what I'm trying to clarify. Seems like he's just talking about aero, but if what Horner says is true then he could be saying end of straight aero+harvest(i.e. WOT harvest) requires a downshift.

[wuzak]

I read VES as just commenting on aero drag build up requiring a downshift to keep the engine from bogging down.

That was aimed at the statement by Horner:

"Plus, with the characteristics of these engines, that the combustion engine just doesn't become a generator to recharge a battery."

That's what I'm trying to clarify. Seems like he's just talking about aero, but if what Horner says is true then he could be saying end of straight aero+harvest(i.e. WOT harvest) requires a downshift.

He is talking about running out of battery, which means going from a maximum of 750kW at the start of the straight, to probably 550kW for most of the straight to 400kW when the battery runs out, and down to 300kW if they are recharging at WOT.

The aero aspect of it is that if the power is reduced the speed can't be maintained, and to keep the engine in the best power band, ~10k - 12k, they would have to downshift.

It might be that they are at the early stages of developing their energy management strategies, and at the moment they don't work well.

[wuzak]

The example Max gives is Monza's main straight.

The issue is that there is only 9.5s of braking at Monza according to Brembo.
https://www.brembo.com/en/company/news/ ... mbo-brakes

Assuming 350kW can be recovered for all the braking time, that is 3.325MJ, well short of the allowed 9MJ.

If the remainder is recovered at WOT at a rate of 100kW, that would require 56.75 seconds! Leaving approximately 13.75s to deploy (assuming 80s lap).

It may be that a track like Monza will not use the full 9MJ recovery allowed.

[saviour stivala]

The 2026 'K' will produce three times the recovery power then the present 'K' does at present, and that includes on all tracks.

[NL_Fer]

I think Redbull very much know what they are doing. Probably to push the FIA in finalizing any active aero rules early, so that Redbull can start integrating both aero and powerunit strategies.

Probably they are pushing for a DRS like system to compensate the loss of torque after the battery runs out on the straight. I feel sorry for any team which is less integrated with the engine department.

[wuzak]

The example Max gives is Monza's main straight.

The issue is that there is only 9.5s of braking at Monza according to Brembo.
https://www.brembo.com/en/company/news/ ... mbo-brakes

Assuming 350kW can be recovered for all the braking time, that is 3.325MJ, well short of the allowed 9MJ.

If the remainder is recovered at WOT at a rate of 100kW, that would require 56.75 seconds! Leaving approximately 13.75s to deploy (assuming 80s lap).

It may be that a track like Monza will not use the full 9MJ recovery allowed.

For comparison, if the MGUH can recover 60kW on average at full throttle, and Monza has 75% full throttle then the MGUH can recover:

75% * 80s * 60kW = 3,600kJ = 3.6MJ.

Plus we have braking recovery from MGUK.

9.5s * 120kW = 1,140KJ = 1.14MJ.

So current PU could recover as much as 4.7MJ.

[wuzak]

I think Redbull very much know what they are doing. Probably to push the FIA in finalizing any active aero rules early, so that Redbull can start integrating both aero and powerunit strategies.

Probably they are pushing for a DRS like system to compensate the loss of torque after the battery runs out on the straight. I feel sorry for any team which is less integrated with the engine department.

You would think that the simulations would not be very good considering the FIA have not yet published the chassis and aero rules.

Maybe the FIA have done their own simulations and have found it difficult to get aero rules that give the performance required.

[wuzak]

The 2026 'K' will produce three times the recovery power then the present 'K' does at present, and that includes on all tracks.

Thanks for that, I would never have worked that out by myself!

So, 2023 PU MGUK recovers 1.14MJ in braking at Monza.
2026 PU MGUK recovers 3.325MJ in braking at Monza.

3.325MJ is lower than the 9MJ that is allowed to be recovered per lap. So they will have to do something else to maximise the recovery and deployment per lap.

[Cs98]

The example Max gives is Monza's main straight.

The issue is that there is only 9.5s of braking at Monza according to Brembo.
https://www.brembo.com/en/company/news/ ... mbo-brakes

Assuming 350kW can be recovered for all the braking time, that is 3.325MJ, well short of the allowed 9MJ.

If the remainder is recovered at WOT at a rate of 100kW, that would require 56.75 seconds! Leaving approximately 13.75s to deploy (assuming 80s lap).

It may be that a track like Monza will not use the full 9MJ recovery allowed.

For comparison, if the MGUH can recover 60kW on average at full throttle, and Monza has 75% full throttle then the MGUH can recover:

75% * 80s * 60kW = 3,600kJ = 3.6MJ.

Plus we have braking recovery from MGUK.

9.5s * 120kW = 1,140KJ - 1.14MJ.

So current PU could recover as much as 4.7MJ.

Yeah. I don't think some realize that the brake harvesting is by far the less efficient regeneration tool on these current cars. The MGU-H is the key to why they have good deployment, they don't even reach their 2MJ limit on brake harvesting on nearly all tracks. Getting rid of exhaust gas regen for 2026 is going to make this so much worse.

If you assume F1 cars are full throttle around 70% of the lap, brake for 10-15% of the lap, and are off throttle/partial throttle for the remaining part, this 350kW regeneration will not be nearly enough (even if you assume perfect regen in the braking zones). A further problem is that on current gen cars they can divert energy to the ES in partial throttle corners because they have over 800HP in the ICE. So if you only need 600HP or less you can recharge the ES with the full 120kW. But when the ICE is only 350kW and the MGU-K is also 350kW, that becomes a much less useful tool in the corners.

This all sets up for a lift and regenerate formula where they will be coasting for a few seconds before every corner just running the ICE as a 350kW generator, then the braking starts and they get a bit more regeneration, and then you get a bit of deployment out of the corner that quickly tapers down before you run out again. Rinse and repeat.

[mzso]

The 2026 'K' power which will nearly triple from 161-to-469 hp means increased regenerative braking energy that would otherwise goes to waste. This increased regenerative braking will nearly eliminate friction brakes.

No. The rear brakes are mainly there for backup already. You can't get much power from there. And the front brakes the more important ones are still unutilized.
Besides all the braking together wouldn't be nearly enough to regenerate enough energy. Most energy is wasted by drag and friction, which helps when it comes to breaking. They go full power for much longer than they brake.