2025/2026 Hybrid Powerunit speculation

[mzso]

https://www.auto-motor-und-sport.de/for ... in-hybrid/

High revs even in the curves
So the battery is not only filled when the driver is on the brakes. Instead, gasoline is converted into electrical energy: "We had to come up with something. The engine switches to full load mode when braking and cornering to produce additional energy, which we feed directly into the battery. So the engine takes over the task of a generator in parts of a lap."

So I guess we will also lose the glorious down shift sounds next year ...

Fits my expectations from the first time I read about this formula. But instead of "lost glory", I think it will be just really jarring (and maybe confusing) to watch cars slowing and turning while the engine is continues to howl.
I also expect lots of driver complaints, maybe continuously.

For those who had hoped that the volume would go up overall without the MGU-H in the exhaust system, Thomas has bad news: "The sound will only change a bit. This is not necessarily due to the expansion of the MGU-H, but rather to the changes to the turbo. The back pressure is reduced because the turbo does not have to drive the electric motor. This results in a little more sound. On the other hand, however, only three-quarters of the amount of fuel that goes into the engine is still available. On the test bench, we found a similar volume level as before."

And as suspected, the volume won't really change because of the lower amount of fuel in these engines ...

I think most people are more disappointed by the timbre, rather than the volume, even if they don't realize it. Though I don't think that will become more appealing either.

I think this is the most unifying regulations by the FIA ever. Pretty much no-one likes it at all...

[mzso]

Very unlikely power reduction would be "instantaneous". Even if not regulated by the FIA, engineering teams would not allow such instability to be built into the operating envelope.

I was thinking not all circumstances can be predicted. And it might happen that they run out of usable charge at the end of the lap in the start/finish straight. What else can they do? Using more energy is an instant DSQ, right?

[karana]

Very unlikely power reduction would be "instantaneous". Even if not regulated by the FIA, engineering teams would not allow such instability to be built into the operating envelope.

I was thinking not all circumstances can be predicted. And it might happen that they run out of usable charge at the end of the lap in the start/finish straight. What else can they do? Using more energy is an instant DSQ, right?

There is no direct limit on deployment, so I don't think this can happen. The control unit will reduce the output before the battery runs out of charge.

[Holm86]

Very unlikely power reduction would be "instantaneous". Even if not regulated by the FIA, engineering teams would not allow such instability to be built into the operating envelope.

I was thinking not all circumstances can be predicted. And it might happen that they run out of usable charge at the end of the lap in the start/finish straight. What else can they do? Using more energy is an instant DSQ, right?

There is no direct limit on deployment, so I don't think this can happen. The control unit will reduce the output before the battery runs out of charge.

Watch the video, they speak of the power reduction regulations from the 4.20 minute mark

[karana]

I was thinking not all circumstances can be predicted. And it might happen that they run out of usable charge at the end of the lap in the start/finish straight. What else can they do? Using more energy is an instant DSQ, right?

There is no direct limit on deployment, so I don't think this can happen. The control unit will reduce the output before the battery runs out of charge.

Watch the video, they speak of the power reduction regulations from the 4.20 minute mark

https://youtu.be/WVxJPNXpsLg?si=I4j1moYrFfqfw8MT

Yes, I wasn't referring to those limits, the way I wrote it is obviously false. I meant there is no direct limit on how much energy can be deployed per lap. Of course, due to the harvest limit of 8.5 MJ you can deploy at most 12.5 MJ per lap.
My understanding of what mzso was getting at is that cars might be reaching a certain limit on deployment before reaching the finish line and in order to avoid a DSQ having to reduce the output from 350 kW to 0 kW immediately. But the only limit is the SOC of the battery, which is predictable by the control unit.

[Holm86]

There is no direct limit on deployment, so I don't think this can happen. The control unit will reduce the output before the battery runs out of charge.

Watch the video, they speak of the power reduction regulations from the 4.20 minute mark

https://youtu.be/WVxJPNXpsLg?si=I4j1moYrFfqfw8MT

Yes, I wasn't referring to those limits, the way I wrote it is obviously false. I meant there is no direct limit on how much energy can be deployed per lap. Of course, due to the harvest limit of 8.5 MJ you can deploy at most 12.5 MJ per lap.
My understanding of what mzso was getting at is that cars might be reaching a certain limit on deployment before reaching the finish line and in order to avoid a DSQ having to reduce the output from 350 kW to 0 kW immediately. But the only limit is the SOC of the battery, which is predictable by the control unit.

Yes if you have a fully charged battery entering the lap, you can spend 12.5MJ(9.5MJ at some tracks) during that lap, as the maximum state of charge is 4MJ, and maximum allowed harvest during the lap is is 8.5 MJ(5MJ at some tracks), so as you say, that limit is given by the regulations in that way.

If you look at the 6.10 minute mark of the video they explain the ramp down of deployment, so no it is not legal to go from full 350kw to 0kw in an instant, it has to happen gradually ...
Or else I'm completely misunderstanding what you are talking about.

[Holm86]

https://www.autosport.com/f1/news/whats ... /10744935/

In response to drivers’ early misgivings, the FIA has adjusted the technical regulations to embrace a so-called ‘turn-down ramp rate’ which will taper the power delivery before the available charge runs out at tracks with high energy requirements. The sporting regulations also now enshrine a sliding scale of permitted energy harvesting depending on the venue, rather than the fixed amount of 8.5MJ per lap.

This latter tweak came in response to fears that at tracks with low demand for braking, the only way to harvest 8.5MJ over a lap would be to brake or lift-and-coast on the straights – a ridiculous spectacle as well as a potential safety issue. The cap will now be as low as 5MJ at some venues.

But to me that just looks like they will be even slower at high speed tracks, as less braking zones means less allowed harvested MJ, and the ´turn-down ramp rate´bleeds off the power on the straights ...

[karana]

Watch the video, they speak of the power reduction regulations from the 4.20 minute mark

Yes, I wasn't referring to those limits, the way I wrote it is obviously false. I meant there is no direct limit on how much energy can be deployed per lap. Of course, due to the harvest limit of 8.5 MJ you can deploy at most 12.5 MJ per lap.
My understanding of what mzso was getting at is that cars might be reaching a certain limit on deployment before reaching the finish line and in order to avoid a DSQ having to reduce the output from 350 kW to 0 kW immediately. But the only limit is the SOC of the battery, which is predictable by the control unit.

Yes if you have a fully charged battery entering the lap, you can spend 12.5MJ during that lap, as the maximum state of charge is 4MJ, and maximum allowed harvest during the lap is is 8.5 MJ, so as you say, that limit is given by the regulations in that way.

If you look at the 6.10 minute mark of the video they explain the ramp down of deployment, so no it is not legal to go from full 350kw to 0kw in an instant, it has to happen gradually ...
Or else I'm completely misunderstanding what you are talking about.

Yeah, we're not disagreeing, my post was in response to mzso, who argued that there might be scenarios where it's not possible to respect this ramp down of deployment without possibly deploying to much energy per lap (at least this was my understanding of mzso's post). I don't think such scenarios exist.

[Holm86]

Yes, I wasn't referring to those limits, the way I wrote it is obviously false. I meant there is no direct limit on how much energy can be deployed per lap. Of course, due to the harvest limit of 8.5 MJ you can deploy at most 12.5 MJ per lap.
My understanding of what mzso was getting at is that cars might be reaching a certain limit on deployment before reaching the finish line and in order to avoid a DSQ having to reduce the output from 350 kW to 0 kW immediately. But the only limit is the SOC of the battery, which is predictable by the control unit.

Yes if you have a fully charged battery entering the lap, you can spend 12.5MJ during that lap, as the maximum state of charge is 4MJ, and maximum allowed harvest during the lap is is 8.5 MJ, so as you say, that limit is given by the regulations in that way.

If you look at the 6.10 minute mark of the video they explain the ramp down of deployment, so no it is not legal to go from full 350kw to 0kw in an instant, it has to happen gradually ...
Or else I'm completely misunderstanding what you are talking about.

Yeah, we're not disagreeing, my post was in response to mzso, who argued that there might be scenarios where it's not possible to respect this ramp down of deployment without possibly deploying to much energy per lap (at least this was my understanding of mzso's post). I don't think such scenarios exist.

Okay we totally agree then, such a situation should not be possible. It would be easy to program this down-rate into the ECU so you never go from 350kw to 0kw in an instant ...

[mzso]

I don't think such scenarios exist.

Great then. One less problem to think about.

[karana]

The regulations have been updated. One change that caught my eye is that the total power reduction limit of 450 kW was raised to 600 kW even for the races, not just for qualifying as before.

One thing I was wondering about this for quite some time is if this can be in a way circumvented by the driver by lifting to maybe ~10% power demand and have the ICE running at full power with the ERS-K at -350kW.

Especially as the rule

Designs which allow specific points along the accelerator pedal travel range to be identified by the
driver or assist the driver to hold a position are not permitted.

was removed in the previous version of the regulations

[mzso]

One thing I was wondering about this for quite some time is if this can be in a way circumvented by the driver by lifting to maybe ~10% power demand and have the ICE running at full power with the ERS-K at -350kW.

Circumvent what? Isn't this to allow them to save (more) energy. Isn't it something they need to do rather than want to do? Or am I misunderstanding something? You're talkin about output power reduction, and not power for regen, right?

[karana]

One thing I was wondering about this for quite some time is if this can be in a way circumvented by the driver by lifting to maybe ~10% power demand and have the ICE running at full power with the ERS-K at -350kW.

Circumvent what? Isn't this to allow them to save (more) energy. Isn't it something they need to do rather than want to do? Or am I misunderstanding something? You're talkin about output power reduction, and not power for regen, right?

I meant the regen limit of -250kW. My guess is you would rather harvest at the full -350kW at the end of straights instead of only -250kW, for the same reason this limit was raised from the original -100kW in the first place.

Let's assume the ICE can deliver 400kW. Let us also assume we want to harvest 0.5MJ before the braking zone. As the rules are now written, the PU must stay above 150kW under full throttle at the end of straights, so this would take 2 seconds. But my thinking is, if the driver can reduce the power demand to 50kW and the ECU can achieve this by running the ICE at full power and the ERS-K at -350kW, you would only need ~1.4 seconds to harvest 0.5MJ. This should be more laptime efficient.

Due to C.5.12.f below I think this only really works when you already stopped deploying, because only then the ERS-K can go from 0kW to -350kW in an instant without reducing ICE power (though I'm not 100% sure I understand this rule correctly), but I can imagine this happening, especially on long straights.

C.5.12.f: The electrical DC power of the ERS‐K may not be reduced at rates greater than those specified in Article C5.12.6, unless:
• the theoretical MGUK power resulting from reduction at rates equal to those specified in Article C5.12.6 is negative;
• the ICE power is negative and the ERS-K power needs to be reduced further to achieve the driver demand;
• the ERS-K power needs to be reduced further to achieve the maximum power permitted by Article C5. 2.8;
• the driver power demand is negative;
• a gearshift is in progress.
• car speed is below 210kph.

I think what this rule does is actually prevent the driver from circumventing the ramp down of deployment by reducing power demand by 350kW in order for the ERS-K to go from 350kW to 0kW in an instant. If the driver does it the power reduction has to come from the ICE. But my proposed scenario should be possible due to the first bullet point.

[mzso]

Just thought of something. Is it possible to replace the MGU-H with a flywheel, maybe even a mechanical one?
Do the regulations ban this?
Going further, is using the exhaust this way to store and deploy power banned?

By the way. What did they add to the regs to ban so called "split turbos"? How long can turbos be?

[gruntguru]

Just thought of something. Is it possible to replace the MGU-H with a flywheel, maybe even a mechanical one?
Do the regulations ban this?
Going further, is using the exhaust this way to store and deploy power banned?

By the way. What did they add to the regs to ban so called "split turbos"? How long can turbos be?

Flywheel has been done in the early days of regen. Don't know if the current regs permit but it wouldn't compete with MGUK plus Li battery on energy density.