2025/2026 Hybrid Powerunit speculation

[saviour stivala]

With the removal of the MGU-H in 2026, the energy recovery system will no longer recover energy from the turbocharger's heat. This will put exclusive reliance on breaking as the only source of energy recovery, recovery will be from kinetic energy captured by MGU-K during braking.

The MGUK recovers energy by braking the ICE, but that does not mean it is braking the car, or that the driver is braking.

The MGUK can be used to control the output of the PU to match the driver's demand.

The MGU-K recovers energy by braking the ICE and that means it will be decelerating the car, for that to happen the driver would have lifted off throttle and is using the brake pedal. Yes, the MGU-K will be crucial for balancing and managing the ICE output, the MGU-K's power will be significantly increased to 350 kw, which is almost triple the current output, to compensate for the reduced power from the ICE. The MGU-K main roles will be to provide extra power for acceleration, particularly out of corners, and ensure a more balanced 50/50 spilt between electrical and ICE power. The current power unit split, is 80% ICE/20% electrical. In short in 2026 the MGU-K will be the primary source of power with its deployment potentially limited by factors like car speed. To recover energy, the MGU-K will continue to recover kinetic energy from braking and cornering to store in battery.

[dren]

With the removal of the MGU-H in 2026, the energy recovery system will no longer recover energy from the turbocharger's heat. This will put exclusive reliance on breaking as the only source of energy recovery, recovery will be from kinetic energy captured by MGU-K during braking.

The MGUK recovers energy by braking the ICE, but that does not mean it is braking the car, or that the driver is braking.

The MGUK can be used to control the output of the PU to match the driver's demand.

The MGU-K recovers energy by braking the ICE and that means it will be decelerating the car, for that to happen the driver would have lifted off throttle and is using the brake pedal. Yes, the MGU-K will be crucial for balancing and managing the ICE output, the MGU-K's power will be significantly increased to 350 kw, which is almost triple the current output, to compensate for the reduced power from the ICE. The MGU-K main roles will be to provide extra power for acceleration, particularly out of corners, and ensure a more balanced 50/50 spilt between electrical and ICE power. The current power unit split, is 80% ICE/20% electrical. In short in 2026 the MGU-K will be the primary source of power with its deployment potentially limited by factors like car speed. To recover energy, the MGU-K will continue to recover kinetic energy from braking and cornering to store in battery.

What happens when the ICE puts out 400kw and the MGUK brakes the ICE with 150kw?

[saviour stivala]

The MGUK recovers energy by braking the ICE, but that does not mean it is braking the car, or that the driver is braking.

The MGUK can be used to control the output of the PU to match the driver's demand.

The MGU-K recovers energy by braking the ICE and that means it will be decelerating the car, for that to happen the driver would have lifted off throttle and is using the brake pedal. Yes, the MGU-K will be crucial for balancing and managing the ICE output, the MGU-K's power will be significantly increased to 350 kw, which is almost triple the current output, to compensate for the reduced power from the ICE. The MGU-K main roles will be to provide extra power for acceleration, particularly out of corners, and ensure a more balanced 50/50 spilt between electrical and ICE power. The current power unit split, is 80% ICE/20% electrical. In short in 2026 the MGU-K will be the primary source of power with its deployment potentially limited by factors like car speed. To recover energy, the MGU-K will continue to recover kinetic energy from braking and cornering to store in battery.

What happens when the ICE puts out 400kw and the MGUK brakes the ICE with 150kw?

The MGU-K will not ''brakes'' the ICE with 150kw when the ICE is putting out 400kw.

[wuzak]

With the removal of the MGU-H in 2026, the energy recovery system will no longer recover energy from the turbocharger's heat. This will put exclusive reliance on breaking as the only source of energy recovery, recovery will be from kinetic energy captured by MGU-K during braking.

The MGUK recovers energy by braking the ICE, but that does not mean it is braking the car, or that the driver is braking.

The MGUK can be used to control the output of the PU to match the driver's demand.

The MGU-K recovers energy by braking the ICE and that means it will be decelerating the car, for that to happen the driver would have lifted off throttle and is using the brake pedal. Yes, the MGU-K will be crucial for balancing and managing the ICE output, the MGU-K's power will be significantly increased to 350 kw, which is almost triple the current output, to compensate for the reduced power from the ICE. The MGU-K main roles will be to provide extra power for acceleration, particularly out of corners, and ensure a more balanced 50/50 spilt between electrical and ICE power. The current power unit split, is 80% ICE/20% electrical. In short in 2026 the MGU-K will be the primary source of power with its deployment potentially limited by factors like car speed. To recover energy, the MGU-K will continue to recover kinetic energy from braking and cornering to store in battery.

Under your system, recovery will be about 1 - 1.25 times the battery capacity at most circuits, whereas teh allowable is a bit over 2 times the battery capacity.

I would think, therefore, that any time the ICE is capable of producing more power than the driver demands (ie part throttle) the MGUK will be generating.

Similar to what dren posted, if the driver demads 350kW but the ICE can produce 400kW, the ICE will produce the 400kW and the MGUK will recover 50kW to meet the driver's demand.

Also, as I have shown many times, the rules specify that the MGUK output can be reduced from +350kW to -250kW when the driver is at full throttle.

When the driver demand is above the potential ICE output, the MGUK will have to deploy, even at part throttle, subject to battery state of charge and speed ramp down rules.

[saviour stivala]

The MGUK recovers energy by braking the ICE, but that does not mean it is braking the car, or that the driver is braking.

The MGUK can be used to control the output of the PU to match the driver's demand.

The MGU-K recovers energy by braking the ICE and that means it will be decelerating the car, for that to happen the driver would have lifted off throttle and is using the brake pedal. Yes, the MGU-K will be crucial for balancing and managing the ICE output, the MGU-K's power will be significantly increased to 350 kw, which is almost triple the current output, to compensate for the reduced power from the ICE. The MGU-K main roles will be to provide extra power for acceleration, particularly out of corners, and ensure a more balanced 50/50 spilt between electrical and ICE power. The current power unit split, is 80% ICE/20% electrical. In short in 2026 the MGU-K will be the primary source of power with its deployment potentially limited by factors like car speed. To recover energy, the MGU-K will continue to recover kinetic energy from braking and cornering to store in battery.

Under your system, recovery will be about 1 - 1.25 times the battery capacity at most circuits, whereas teh allowable is a bit over 2 times the battery capacity.

I would think, therefore, that any time the ICE is capable of producing more power than the driver demands (ie part throttle) the MGUK will be generating.

Similar to what dren posted, if the driver demads 350kW but the ICE can produce 400kW, the ICE will produce the 400kW and the MGUK will recover 50kW to meet the driver's demand.

Also, as I have shown many times, the rules specify that the MGUK output can be reduced from +350kW to -250kW when the driver is at full throttle.

When the driver demand is above the potential ICE output, the MGUK will have to deploy, even at part throttle, subject to battery state of charge and speed ramp down rules.

No, the driver will not be at full throttle while the MGU-K switches from deployment to harvesting.
The ICE and MGU-K as a power unite will produce what the driver demands through his command of throttle pedal, This demanded output will be as a 'split' between the ICE and MGU-K, provided the battery (ES) can supply the split part asked out of it by the MGU-K.

[mzso]

Braking will be the only way to recover energy in 2026. The battery (ES) can only be charged by braking. But the brakes will not be the only way to slow down the car.

Why do keep repeating this when its been shown by many to be complete horseshit!

The car can harvest electrical energy without the brake pedal being touched. The teams do it now, this from Honda:

Looking at MGU-K and MGU-H usage by driving situation, the MGU-K is fully used during deceleration to recover kinetic energy, while the MGU-H is used to recover energy at the same time. What this specifically means is that exhaust temperature is intentionally allowed to increase when off-throttle to allow recovery of the heat energy from the exhaust gas and storage in the ES. The team developing this control technology have termed it Additional Harvest Power, or AHP.

Under partial throttle when starting to exit a corner, a different control technology called partial recovery is employed. It is used to generate electricity by diverting excess output to the MGU-K after the engine generates enough output to meet the driver’s needs. Both AHP and partial recovery consume extra fuel, but this control technology was planned and implemented because increasing energy recovery and storing it in the ES to increase the amount of energy used for MGU-K assist achieves a greater performance gain than what could be achieved through fuel consumption alone.

https://global.honda/en/tech/motorsport ... train_ESS/

Great posts by wuzak and diffuser explain it very well...

Maybe I just don't have the ear for it, but shouldn't this be evident in the engine noise?
Well, it should be far more noticeable next year.

[saviour stivala]

Braking will be the only way to recover energy in 2026. The battery (ES) can only be charged by braking. But the brakes will not be the only way to slow down the car.

Why do keep repeating this when its been shown by many to be complete horseshit!

The car can harvest electrical energy without the brake pedal being touched. The teams do it now, this from Honda:

Looking at MGU-K and MGU-H usage by driving situation, the MGU-K is fully used during deceleration to recover kinetic energy, while the MGU-H is used to recover energy at the same time. What this specifically means is that exhaust temperature is intentionally allowed to increase when off-throttle to allow recovery of the heat energy from the exhaust gas and storage in the ES. The team developing this control technology have termed it Additional Harvest Power, or AHP.

Under partial throttle when starting to exit a corner, a different control technology called partial recovery is employed. It is used to generate electricity by diverting excess output to the MGU-K after the engine generates enough output to meet the driver’s needs. Both AHP and partial recovery consume extra fuel, but this control technology was planned and implemented because increasing energy recovery and storing it in the ES to increase the amount of energy used for MGU-K assist achieves a greater performance gain than what could be achieved through fuel consumption alone.

https://global.honda/en/tech/motorsport ... train_ESS/

Great posts by wuzak and diffuser explain it very well...

Maybe I just don't have the ear for it, but shouldn't this be evident in the engine noise?
Well, it should be far more noticeable next year.

We have been talking about the 2026 PU when Mattchu dropped in and declared what I was saying as complete horseshit, and making a fool of yourself giving as an example the present use of the MGU-H to harvest energy while driver is under throttle. MGU-H will be gone in 2026. But than I could not blame you coming over and repeating yourself, while you could not read my reply to your first post, something which is out of my control. The same situation stands for the two others in discussion,

[Tommy Cookers]

Doubling the amount of energy that can be recovered per lap to 8.5 megajoules, this will require drivers to use new braking strategies to efficiently charge the battery, as the system will have a higher power output of up to 350 kw.

what 'new braking strategies' ??

at speed ....
350 kW is about 1 g deceleration - this uses less than 30% of the rear tyre grip
so the brakes add another 3 g' deceleration - this uses the rest of the tyre grip
the 2-state aero will select the high DF/high drag state on braking

'efficiently charging the battery' would cap deceleration at 1 g (prolonging the braking to prolong the generation)
that would give us a weird battery-charging contest instead of a motor race

the 2014 rules turned out to be commendably ingenious - and so will the 2026 rules

[saviour stivala]

Sounds like the coffee was strong.

[diffuser]

Braking will be the only way to recover energy in 2026. The battery (ES) can only be charged by braking. But the brakes will not be the only way to slow down the car.

Why do keep repeating this when its been shown by many to be complete horseshit!

The car can harvest electrical energy without the brake pedal being touched. The teams do it now, this from Honda:

Looking at MGU-K and MGU-H usage by driving situation, the MGU-K is fully used during deceleration to recover kinetic energy, while the MGU-H is used to recover energy at the same time. What this specifically means is that exhaust temperature is intentionally allowed to increase when off-throttle to allow recovery of the heat energy from the exhaust gas and storage in the ES. The team developing this control technology have termed it Additional Harvest Power, or AHP.

Under partial throttle when starting to exit a corner, a different control technology called partial recovery is employed. It is used to generate electricity by diverting excess output to the MGU-K after the engine generates enough output to meet the driver’s needs. Both AHP and partial recovery consume extra fuel, but this control technology was planned and implemented because increasing energy recovery and storing it in the ES to increase the amount of energy used for MGU-K assist achieves a greater performance gain than what could be achieved through fuel consumption alone.

https://global.honda/en/tech/motorsport ... train_ESS/

Great posts by wuzak and diffuser explain it very well...

Maybe I just don't have the ear for it, but shouldn't this be evident in the engine noise?
Well, it should be far more noticeable next year.

That just sounds to me like, in that situation, they're not allowing any of the exhaust to by pass the turbo for the first paragraph.

In the second paragraph they're just leaving the MGU-K in generate mode till the power requirements exceeds what the ICE can deploy without the MGU-K.

[saviour stivala]

After 5 years into this discussion forum (The 2025/2026 hybrid powerunit) with around 8 posts into the thread, (Speculation) having been added to the title, some are still confusing what the present powerunit formula can do with what the new for 2026 powerunit formula would be able to do without use of the MGU-H.

[vorticism]

I see no references to injection and spark events in Issue 13. Number permissible per cycle or their occurrence with respect to any cycle. Have I missed it? That might open the door for anti-lag. On the other hand, with MGUK harvesting, the ICE will still be producing heightened exhaust pressure & temperature even when off-throttle and part-throttle (accelerator pedal position). How often will the ICE not only drop below 10k in revs, but even drop meaningfully below peak BMEP? Will we get anti-lag sounds in addition to part-throttle engine notes at corner approach?

Separately: if the MGUK is weaker than the ICE it can never fully arrest full-throttle ICE power. So what percentage of MGUK recovery will be from part-throttle ICE fueling and how will this affect efficiency? Will it even be part-throttle or just extra, extra lean burn in that scenario? i.e. to achieve less-than-peak ICE output for MGUK genset’ing.

[BassVirolla]

I see no references to injection and spark events in Issue 13. Number permissible per cycle or their occurrence with respect to any cycle. Have I missed it? That might open the door for anti-lag. On the other hand, with MGUK harvesting, the ICE will still be producing heightened exhaust pressure & temperature even when off-throttle and part-throttle (accelerator pedal position). How often will the ICE not only drop below 10k in revs, but even drop meaningfully below peak BMEP? Will we get anti-lag sounds in addition to part-throttle engine notes at corner approach?

Separately: if the MGUK is weaker than the ICE it can never fully arrest full-throttle ICE power. So what percentage of MGUK recovery will be from part-throttle ICE fueling and how will this affect efficiency? Will it even be part-throttle or just extra, extra lean burn in that scenario? i.e. to achieve less-than-peak ICE output for MGUK genset’ing.

There are rules, discussed a few pages ago, that link pedal position to fuel flow.

As such, there is a limited maximum recovery possible when of throttle but not applying e-brake beyond what the ICE is outputting (case of lift & coast with still some ICE power).

Also, this link between pedal position ("torque demand") and fuel flow limits what is achievable at part throttle.

Nevertheless, while limited, not forbidden.

[Tommy Cookers]

... if the MGUK is weaker than the ICE it can never fully arrest full-throttle ICE power...
... MGUK recovery ... Will it even be part-throttle or just extra, extra lean burn in that scenario? ....

the MGU-K can increase its current (torque) for full power at rpms below 10500 (2014-25 caps this torque at 5775 rpm)
2026 caps WOT generation at 250 kW - so much reducing ICE arrest scope

increased lean burn seems imo unlikely as they have dumped the 10% ethanol and have instead 3% methanol only

[vorticism]

Thanks both. How is ICE thermal efficiency affected when producing below peak ICE power? F.e. in the part-throttle charging regimes, when the engine is producing 100 or 200 hp or whatever to be absorbed by the MGUK, how reduced is the TE of the ICE compared to the peak power it was primarily designed to make? And in these low power output modes can they utilize leaning of the a:f ratio, in addition to, or in replacement of, use the ITBs to limit power output. Tommy, you are suggesting we might have seen peak dilution ratios in the current formula. Unless there is still development potential in the realms of CI, wave front ignition (whatever it's called), stratification, etc., within the limits of the injector, ignition, and fuel tech imposed by the regulations.