2025/2026 Hybrid Powerunit speculation

[vorticism]

How about: traverse the entire crankshaft fore or aft slightly along the crank axis, causing all six of the connecting rods big ends to fall away or toward the cylinder centers. +/- Xmm to achieve center when the engine is running to get the extra travel at TDC. Design the crank throw journals and/or bearings with crown such that they are spherical. Might get away with using a typical cylindrical wrist pin and live with the piston itself being angled slightly within the bore during the test. At rest (incl when turned slowly for test), the conrods would be slightly angled, when running the conrods are straight with the big ends aligned with the cylinder centers.

I guess this could be achieved with TE; a static plastic disc pushing on a thrust bearing that contacts the crankshaft f.e. Or by oil pressure or some other means. At operating speeds would centrifugal forces be sufficient to take over and assure alignment? Or would the device always be receiving thrust/axial loads from the conrods trying to push off-axis. In which case how bad would frictional losses to thrust bearings be.

Edit: while this could alter piston stroke sufficiently at rest during a it would require significant displacement of the crankshaft, over 5mm axially to alter the piston TDC locations by ~0.4mm. Conrods would be tilted about 5* off center so spherical journals would be be need on both ends of the conrod which conflicts with the wrist pin needing to be 18-19 mm in diameter i.e. a sphere section fitted to that would be too narrow. It also may conflict with the engine cubic capacity which must be 1600cc +0/-10.

In general it may be good to keep that 10cc tolerance in mind. We have been talking about a 2cc/cylinder alteration of the TDC CC volume, which would be 12cc across 6 cylinders. This has implications for the true amount of compression ratio change available and for what the actual total cubic displacement of the engine would be. I doubt the FIA inspects the cubic capacity of the finished engines but if CAD shows it would be outside of that tolerance window then it would be a non-starter.

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Sidenote: the previous 18:1 CR was not inspected for (afaict). This new one will be and there are only so many ways to do that. I’m assuming it is an optical or contact measurement of the piston face performed through the spark plug hole, or with the cylinder heads removed. Obviously running temperatures would not be convenient to achieve in that scenario, short of heating the engine in an oven, removing it, and performing all of the measurements within a certain amount of time as it cools down. Why is a CAD inspection not sufficient? Presumably that is what was done over preceding decade. Why does the FIA now want to measure this instead of infer it?

[Farnborough]

Of interest to the discussion, if not seen before.



More in depth overview of the last generation PU.

[diffuser]

Of interest to the discussion, if not seen before.



More in depth overview of the last generation PU.

Interesting. Most interesting is they have in cylinder pressure sensors.....

[BassVirolla]

How about: traverse the entire crankshaft fore or aft slightly along the crank axis, causing all six of the connecting rods big ends to fall away or toward the cylinder centers. +/- Xmm to achieve center when the engine is running to get the extra travel at TDC. Design the crank throw journals and/or bearings with crown such that they are spherical. Might get away with using a typical cylindrical wrist pin and live with the piston itself being angled slightly within the bore during the test. We're only talking about half millimeters and fractions of degrees here. At rest (incl when turned slowly for test), the conrods are slightly angled, when running the conrods are straight with the big ends aligned with the cylinder centers.

I guess this could be achieved with TE; a static plastic disc pushing on a thrust bearing that contacts the crankshaft f.e. Or by oil pressure or some other means. At operating speeds would centrifugal forces be sufficient to take over and assure alignment? Or would the device always be receiving thrust/axial loads from the conrods trying to push off-axis. In which case how bad would frictional losses to thrust bearings be.

Note the previous 18:1 CR was not inspected for (afaict). This new one will be and there are only so many ways to do that. I’m assuming it is an optical or contact measurement of the piston face performed through the spark plug hole, or with the cylinder heads removed. Obviously running temperatures would not be convenient to achieve in that scenario, short of heating the engine in an oven, removing it, and performing all of the measurements within a certain amount of time as it cools down. Why is a CAD inspection not sufficient? Presumably that is what was done over preceding decade. Why does the FIA now want to measure this instead of infer it?

Angled pistons are a neat receipt for a fast piston and cylinder failure, it's why is important for the rods to not being twisted nor bent.

Nevertheless, I can understand why you talk about spherical throws (and piston pin!) to angle the rod, but I still cannot figure how you get the throw from offset to centered.

[vorticism]

Interesting. Most interesting is they have in cylinder pressure sensors.....

Timestamp? I ask because the new regs seem to imply such sensors may not always be in place. My post on the previous page regarding dismountable components.

[diffuser]

Interesting. Most interesting is they have in cylinder pressure sensors.....

Timestamp? I ask because the new regs seem to imply such sensors may not always be in place. My post on the previous page regarding dismountable components.

I'd have to go back and watch it but it was the 2nd question in Q&A section at the end.

I thought it was interesting cause I figured they can use that for compression ratio testing?

[Snorked]

Interesting. Most interesting is they have in cylinder pressure sensors.....

Timestamp? I ask because the new regs seem to imply such sensors may not always be in place. My post on the previous page regarding dismountable components.

Around 37mins 20 secs. He later says they may get rid of them for the 2026 regulations on cost grounds as the sensors are expensive.

[vorticism]

Is 16:1 less about limiting compression and more about limiting IVO:EVO duration ratios (i.e. turbocharger contribution)? If they were using Miller cycle previously then 18:1 may also have been about that. Since the IVO duration would have been somewhat free if Miller cycle was the norm. I suppose the dev path otherwise would have been ever longer IVO durations along with higher boost pressures but not necessarily higher in-cylinder compression.

Interesting. Most interesting is they have in cylinder pressure sensors.....

Timestamp? I ask because the new regs seem to imply such sensors may not always be in place. My post on the previous page regarding dismountable components.

Around 37mins 20 secs. He later says they may get rid of them for the 2026 regulations on cost grounds as the sensors are expensive.

Thanks for that. The 'dismountable components' list for the combustion chamber includes a 'component' to replace a pressure sensor, but not a pressure sensor itself. Maybe they're used for breaking in the engine, then plugged for use in competition. Reinserted for diagnostics between FP, Q, & races.

The plug is of free geometry (beyond diameter) & material (afaict) so could be another magic TE device to guess at. A plunger filled with wax or plastic and voila, TE based CR effector. Seems a bit too on the nose, though. FIA: "What is that?"

[mzso]

Mercedes PU sounds completely different to there previous gen PU

https://x.com/mercedesamgf1/status/2001 ... 10261?s=46

You forgot the scare quotes. It has a slightly deeper timbre, and that's it.

[mzso]

Will we be seeing silicon carbide batteries in F1 power pack?

It is sad F1 has restricted battery packs to placed within the monocoque, could have been better if they were left free to teams.

https://www.youtube.com/watch?v=cwJpkfWWcsc&t=38s

It's silicon-carbon, not carbide. They've been talking about silicon this and that in the anode for many years. It never really came to pass. Best I remember is Tesla adding some silicon.
In any way a proper solid-state battery is better. It has neither silicon nor carbon, just lithium metal.

[scuderiabrandon]

Will we be seeing silicon carbide batteries in F1 power pack?

It is sad F1 has restricted battery packs to placed within the monocoque, could have been better if they were left free to teams.

https://www.youtube.com/watch?v=cwJpkfWWcsc&t=38s

It's silicon-carbon, not carbide. They've been talking about silicon this and that in the anode for many years. It never really came to pass. Best I remember is Tesla adding some silicon.
In any way a proper solid-state battery is better. It has neither silicon nor carbon, just lithium metal.

Are SSB's anywhere near advanced enough to be considered for use in F1? I believe Mercedes, who are the only relevant manu here that has also conducted real life prototyping and testing, say they are at least still 4 years away, from producing EVs using SSB'S. I believe it was developed in-house, in conjunction with HPP.

[diffuser]

Will we be seeing silicon carbide batteries in F1 power pack?

It is sad F1 has restricted battery packs to placed within the monocoque, could have been better if they were left free to teams.

https://www.youtube.com/watch?v=cwJpkfWWcsc&t=38s

It's silicon-carbon, not carbide. They've been talking about silicon this and that in the anode for many years. It never really came to pass. Best I remember is Tesla adding some silicon.
In any way a proper solid-state battery is better. It has neither silicon nor carbon, just lithium metal.

Are SSB's anywhere near advanced enough to be considered for use in F1? I believe Mercedes, who are the only relevant manu here that has also conducted real life prototyping and testing, say they are at least still 4 years away, from producing EVs using SSB'S. I believe it was developed in-house, in conjunction with HPP.

I initially misunderstood the requirements. The battery duty cycle in Formula 1 is fundamentally different from that of an EV. An F1 battery may alternate between charge and discharge on the order of 50 times per lap, which demands extremely high C-rates and rapid transient response. I don’t recall the exact regulation, but F1 is limited to roughly three energy storage systems per season.

This is in stark contrast to EV batteries, which typically experience a few charge cycles per week, followed by relatively slow, continuous discharge. EV battery design prioritizes long-term degradation resistance and calendar life, often with warranties extending to around 200,000 km.

[gruntguru]

EV charge and discharge rates can be quite high and frequent. There are plenty of examples with:
- 500+KW discharge from a ~100KW.hr battery ~5C
- 20%-80% recharge in 20 minutes ~1.8C
- regen braking @ 500KW? ~5C

I recognise that is not the common operation but they are capable - no doubt with reduced life.

[BorisTheBlade]

AMuS more or less confirmed what I mentioned a couple of days ago: Being in Slipstream of another car might be preferable in many race situations over being in clean air.

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

Some sepculation about how this all might influence racecraft:

At most circuits, they will not be able to recover the maximum allowed energy per lap by braking and partial throttle alone. In order to achieve that - and to maximize the usage of the "boost mode" - it will be required to make significant use of "super-clipping". Think of around 10s on a track such as Barcelona, to be spread over several "ends-of-straights".

This quite likely means, that in order to optimize lap-time, they will have to sacrifice top speed on certain straights when in clean air.
So when a driver comes under pressure from behind, he might be forced to reduce his "super-clipping" in order to stay in front. But that in turn will allow the following driver to build an ever increasing energy differential, allowing him to use more "boost mode" and/or the "overtake mode".

I think, this will allow for more overtakes, as the base-performance differential between two cars can be lower than today. Or the tire differential.
It is even possible, that situations arise, where the leading car might let itself get overtaken and stay behind for some laps, in order to gain an advantage later on.

Either way: This will add new strategical layers. In order to not confuse viewers, some visualizations will be needed. At least the current ES SOC and indicators for recovery as well as deployment for dog-fighting cars will be needed. And this can also spark additional excitement, seing how the following car builds up its ES SOC differential.

[venkyhere]

what does all this really mean, from a 30k ft overview perspective ?

- new 2026 era regulations, by increasing the share of battery power from 20% to 50% while keeping total power the same are anyway going to make the cars slower - we can say this without doing any complex analysis and without reading a giant document describing the regulations. because the track layouts are going to remain the same. IF we are to see same/similar laptimes (given the overall weight reduction from previous era isn't huge), it points to an impossible 'IF', because :
(a) weight penalty of battery is prohibitive
&
(b) the opportunities to refill the battery with electrically recovered mechanical energy aren't numerous/long enough, neither efficient enough, to compensate for the electrical energy that would get 'used up' for even a decently paced race stint lap.

For example, lets say the 'PU system' is capable of 1000 units over a qualifying lap, lets see how much is possible over a race stint lap -
2014 to 2025 : 700(ICE)+100(battery) to the wheels, 100(ICE)+50(braking) to restore 100 units to the battery via MGU_K, ie to maintain electrical energy equilibrium while fuel supply is availabe 'unrestricted'
2026 onwards : 300(ICE)+200(battery) to the wheels, 200(ICE)+50(braking) to restore 200 units to the battery via MGU_K, ie to maintain electrical energy equilibrium while fuel supply is availabe 'unrestricted'.
Even though this example generously assumes the new MGU-K is going to be much superior in terms of efficiency in recharge mode (200/250 = 0.8 is an improvement over 100/150 = 0.66), we can clearly see that only 500 is sent to the wheels while 800 was sent to the wheels in the previous era. The cars are going to be ridiculosuly slower(this is without even considering the fact that MGU-H a.k.a free energy, is completely gone now) or may be 'considerably slower' (severity reduced from 'ridiculous' owing to overall less heavy cars), over a race stint. Qualifying laps maybe faster , since there is no need to recharge the battery and the higher share of the 'faster source of energy' may be put to use.

In other words, it all boils down to the simple undergrad-level concept :
- energy density.
We can't yet match (forget surpass) the energy density of fossil fuel via an ion exchange system because, while both systems are essentially extracting energy from chemical bonds, the battery system needs to store all contributing chemicals, while the fuel system gets a portion of the 'chemical' from oxygen in air that comes 'free' without any storage required. Given the high energy conversion efficiency of super-optimized ICE used in F1, this 'energy density penalty' becomes really stark.