2025/2026 Hybrid Powerunit speculation

[saviour stivala]

Struggling because of shortage of ballast.

[mzso]

Depends of fuel. It could be bioethanol or synthetic petrol.

Thus the limit is in MJ/h (coincidentally, it may have been how fuel flow was regulated back when Audi's Diesel was going against Porsche's petrol in LMP1).

Well, I expect them to go near the maximum allowed energy density, and expect they're close to it now. So more than a quarter less energy. They can only carry more fuel as weight goes, by using less energy dense fuel, which would only decrease performance with the extra weight.

[mzso]

Startup times where the main issue I was referring to. I’ve found a few papers discussing fast start up SOFC units (5mins) but they are tiny 10W cells.

Most of the commercially available units list starting times of Cold 24 hrs and Hot 2 hrs.

https://power.mhi.com/products/sofc/pdf/sofc_en.pdf

Just doesn’t seem very practical to me right now. Especially considering a 210kW unit is 33t (prolly half that when you remove all the turbine heat systems etc).

Ps for reference I used to manage a data centre with 3x 1.1MW 32ltr Cat Diesel generators that only weighed 6t each!

I would expect that those are monster sized cell stacks. I'm more optimistic about it. If they were to increase power density to be more suitable to F1, it would also decrease the mass and bulk of the fuel cell. At worst they could allow to pre-heat it.

[djos]

Startup times where the main issue I was referring to. I’ve found a few papers discussing fast start up SOFC units (5mins) but they are tiny 10W cells.

Most of the commercially available units list starting times of Cold 24 hrs and Hot 2 hrs.

https://power.mhi.com/products/sofc/pdf/sofc_en.pdf

Just doesn’t seem very practical to me right now. Especially considering a 210kW unit is 33t (prolly half that when you remove all the turbine heat systems etc).

Ps for reference I used to manage a data centre with 3x 1.1MW 32ltr Cat Diesel generators that only weighed 6t each!

I would expect that those are monster sized cell stacks. I'm more optimistic about it. If they were to increase power density to be more suitable to F1, it would also decrease the mass and bulk of the fuel cell. At worst they could allow to pre-heat it.

I’m going to remain pessimistic for now, imo the tech is just moving too slowly despite decades of development and billions invested.

[gruntguru]

Feels like the 1000hp power unit is just a marketing lie.

Very much so. Achieving 1000hp would be quite rare on a lap, as, to my mind, the electrical energy will be used mostly when the ICE isn't making much power.

Why limit ES and recovery at all, if they are pushing electrification. Makes no sense.

9MJ recovery seems like a stretch to me.

Will they be permitted to charge the ES direct using the ICE>GUK>ES path?

If so, 9 MJ would be straightforward. Efficiency would be high - operating the ICE near peak efficiency regardless of power required at the wheels. The turbo lag issue would disappear also.

[wuzak]

Feels like the 1000hp power unit is just a marketing lie.

Very much so. Achieving 1000hp would be quite rare on a lap, as, to my mind, the electrical energy will be used mostly when the ICE isn't making much power.

Why limit ES and recovery at all, if they are pushing electrification. Makes no sense.

9MJ recovery seems like a stretch to me.

Will they be permitted to charge the ES direct using the ICE>GUK>ES path?

If so, 9 MJ would be straightforward. Efficiency would be high - operating the ICE near peak efficiency regardless of power required at the wheels. The turbo lag issue would disappear also.

That is unclear.

It will also depend on the fuel allowed for a race.

[saviour stivala]

Charging ES direct by using the ICE > GUK > ES path will be most efficient indeed.

[BassVirolla]

Is there any possibility of using big turbos, possibly with some sort of flywheel or simply heavy turbine - compressor wheels?

While it will be slow to spin up to optimal speed at startup, it could keep spooled during the braking / cornering time, to minimize turbo lag when the driver applies the throttle another time.

Obviously, when the throttle is closed, you should vent the compressed air to the intake. Or not closing the throttle at all while at 0% throttle pedal. Only cutting fuel / spark and keeping the air flowing through the ICE.

[Holm86]

Is there any possibility of using big turbos, possibly with some sort of flywheel or simply heavy turbine - compressor wheels?

While it will be slow to spin up to optimal speed at startup, it could keep spooled during the braking / cornering time, to minimize turbo lag when the driver applies the throttle another time.

Obviously, when the throttle is closed, you should vent the compressed air to the intake. Or not closing the throttle at all while at 0% throttle pedal. Only cutting fuel / spark and keeping the air flowing through the ICE.

I've had the same thought.

And open throttle bodies at 0% throttle was something I suggested way back when the current engine regulations came through in 2014, as it would also minimize engine braking, letting the mgu-k harevst as much as possible

I wonder if heavier flywheels would be advantageous now? I know it has all been about less mass, but if there is going to be a lag, and longer 'coast' would it even out if the engine speed was kept up a little?

Don't think that would help much. As soon as you're off the throttle, and theres no combustion, the turbo RPM will drop off, no matter if the engine rpm drops slower due to a heavier flywheel.

But maybe if you had a flywheel on the turbo axle?

But I still think some sort of anti-lag system is more advantageous, and I doubt you would have to use much fuel for it

[Martin Keene]

The packaging of the turbocharger is going to be interesting. The regulations say it has to still on the centreline of the engine, and parallel with the crankshaft. Packaging that out the back of the engine will not be the most elegant solution, I wonder if there is potential for somebody to try hot-v, given that the inlet plenums will become simpler with the removal of variable geometry and it could give a nice airflow path from the roll bar into the turbo, out into side pods for charge cooling and into the inlet on the side of the engine, as well as the exhaust going straight out the back.

[djos]

Hot V configurations are currently banned so they’d have to change the regs.

[Holm86]

Hot V configurations are currently banned so they’d have to change the regs.

Yes

5.3.5 Engine exhaust gases may only exit the cylinder head through outlets outboard of the
cylinder bore centre line and not from within the “V” centre.

I really don't understand why they need to prescribe this, hot vee's are very common in the automotive world now.
These regulations are not at all visionary, and I have a very hard time understanding why they have to prescribe so much with the engine regulations, when there now is a budget cap so there won't be an spending war.

[djos]

Hot V configurations are currently banned so they’d have to change the regs.

Yes

5.3.5 Engine exhaust gases may only exit the cylinder head through outlets outboard of the
cylinder bore centre line and not from within the “V” centre.

I really don't understand why they need to prescribe this, hot vee's are very common in the automotive world now.
These regulations are not at all visionary, and I have a very hard time understanding why they have to prescribe so much with the engine regulations, when there now is a budget cap so there won't be an spending war.

I agree, there are far too many restrictions ATM. A budget cap on R&D and engine cost per unit (BoM) would be much better.

[Tommy Cookers]

.... if the engine rpm drops slower due to a heavier flywheel.....

increased ICE inertia would be bad news for the gearshifts up or down - increasing disruption and losses
(we have increased MGU-K inertia anyway - also bad news)

[Holm86]

.... if the engine rpm drops slower due to a heavier flywheel.....

increased ICE inertia would be bad news for the gearshifts up or down - increasing disruption and losses
(we have increased MGU-K inertia anyway - also bad news)

I know, I also said it would be a bad idea, and suggested at flywheel on the turbine axle to keep turbine rpm up when off throttle instead