2025/2026 Hybrid Powerunit speculation

[henry]

If the 2025 PUs are going to run on a carbon neutral fuel will they remove the fuel flow limit and use some other means of managing the power? After all fuel economy will only be relevant as a parameter in lap time optimisation.

Come to think of it why have KERS except in respect of the aforesaid lap time optimisation.

We might ask similar questions on race time optimisation and the race fuel quality allowance.

[gruntguru]

But airplanes for sure. There's just no credible alternative for electrified airplanes other than fuel cells.

Good luck with that. Fuel cells are at best 60% efficient, . . .

. . compared to jet engines at hmmm 40%?

[NL_Fer]

If the 2025 PUs are going to run on a carbon neutral fuel will they remove the fuel flow limit and use some other means of managing the power? After all fuel economy will only be relevant as a parameter in lap time optimisation.

Come to think of it why have KERS except in respect of the aforesaid lap time optimisation.

We might ask similar questions on race time optimisation and the race fuel quality allowance.

I see another potentially expensive fuel/combustion race if they keep the flow limiter. Personally i would prefer a torque curve limit on ICE and let them focus on the efficiency of the KERS.

[mzso]

You suspect wrong. Direct carbon fuel cells can go up to the 80-90% range. With decent power density. Hydrogen is not viable. Maybe HWBs sometime.
Takeoff is not a significant part of the whole flight, so the added weight should be modest.

Yes, carbon fuel cells are projected to operate in the 80% range. A little bit of reading, however, makes them not sound like the ideal power source for aircraft..... For ground electrical generating stations yes. From https://www.sciencedirect.com/science/a ... 5307003515

The direct carbon fuel cell (DCFC) employs a process by which carbon is converted to electricity, without the need for combustion or gasification. The operation of the DCFC is investigated with a variety of solid carbons from several sources including some derived from coal. The highly organized carbon form, graphite, is used as the benchmark because of its availability and stability. Another carbon form, which is produced at West Virginia University (WVU), uses different mixtures of solvent extracted carbon ore (SECO) and petroleum coke. The SECO is derived from coal and both this and the petroleum coke are low in ash, sulfur, and volatiles.

Actually I was mostly thinking of Solid-Oxyde fuel cells. Particularly influenced by this:
http://web.archive.org/web/202006102329 ... W-TOPS-120
https://ntts-prod.s3.amazonaws.com/t2p/ ... PS-120.pdf

As far as I know SOFCs can use alkanes up to butane, all of which can be bio-produced or synthesized.
(I'm quite sure SOFCs can also use hydrogen, if it ever becomes viable.)

[mzso]

But airplanes for sure. There's just no credible alternative for electrified airplanes other than fuel cells.

Good luck with that. Fuel cells are at best 60% efficient, . . .

. . compared to jet engines at hmmm 40%?

Apart from the 60% not being true I wonder if that's average efficiency or peak efficiency. And how often is a Turbofan jet near its peak efficiency. If only a high power during takeoff the average might be rather poor.

[mzso]

If the 2025 PUs are going to run on a carbon neutral fuel will they remove the fuel flow limit and use some other means of managing the power? After all fuel economy will only be relevant as a parameter in lap time optimisation.

Come to think of it why have KERS except in respect of the aforesaid lap time optimisation.

We might ask similar questions on race time optimisation and the race fuel quality allowance.

Why would they do that? They are and will continue to aim for maximum efficiency. Removing fuel flow limit and KERS promotes the opposite. Waste is still waste, even if it's carbon neutral waste.

I see another potentially expensive fuel/combustion race if they keep the flow limiter. Personally i would prefer a torque curve limit on ICE and let them focus on the efficiency of the KERS.

I don't think there is an "if". What they should have done is put a separate cap on engine development. (They can still do that, right?) So cost management is satisfied as well as efficiency goals.

[NL_Fer]

Maybe they will allow for some development in th first year, than freeze or limit it in 2027.

I remember it went that way in 2007.

2006 has introduced the new 2.4 V8. Than in 2007 the design would be frozen, unless for reliability upgrades. So the Renault was already reliable soon, Mercedes and Ferrari needed more upgrades, and by 2008 their “frozen” engines were much faster than Renault, Honda and Toyota.

They tried the token system in 2014, but that didn’t really work either.

[henry]

If the 2025 PUs are going to run on a carbon neutral fuel will they remove the fuel flow limit and use some other means of managing the power? After all fuel economy will only be relevant as a parameter in lap time optimisation.

Come to think of it why have KERS except in respect of the aforesaid lap time optimisation.

We might ask similar questions on race time optimisation and the race fuel quality allowance.

I see another potentially expensive fuel/combustion race if they keep the flow limiter. Personally i would prefer a torque curve limit on ICE and let them focus on the efficiency of the KERS.

Is not a fuel race the way F1 competition is supposed to accelerate development of these new fuels?

I would think the KERS system would be quite high efficiency and any gains would be small. But maybe the recent Ferrari and Honda news suggests that even very small gains are worthwhile.

[nzjrs]

I would think the KERS system would be quite high efficiency and any gains would be small. But maybe the recent Ferrari and Honda news suggests that even very small gains are worthwhile.

At least the Honda ones were attributed to battery / energy store upgrades, which I think gave greater scope for improvement here because of the crazy energy flows / duty cycles from the mguh and mguk being used simultaneously.

I think with just KERS and a simpler energy flow the scope for large improvements in the storage side might be smaller.

[NL_Fer]

In FE the improvement of the motor and driveline was pretty impressive, but they could also redesign the gearbox/diff and the ended up with a single gear setup. But with 400kw a few percent has more impact than 80kw KERS.

So who knows…

[henry]

I would think the KERS system would be quite high efficiency and any gains would be small. But maybe the recent Ferrari and Honda news suggests that even very small gains are worthwhile.

Currently the combined H & K flow rate is about 200 kW max. If the introduce 350 kW KERS that would be more of a challenge, particularly if the capacity of the ES is similar or even smaller. Currently the ES has to accommodate the losses from around 3 MJ per lap. Depending on what they do with flow limits in the regulations the flows are likely to bf similar or lower.

At least the Honda ones were attributed to battery / energy store upgrades, which I think gave greater scope for improvement here because of the crazy energy flows / duty cycles from the mguh and mguk being used simultaneously.

I think with just KERS and a simpler energy flow the scope for large improvements in the storage side might be smaller.

[JordanMugen]

Currently the combined H & K flow rate is about 200 kW max. If the introduce 350 kW KERS that would be more of a challenge, particularly if the capacity of the ES is similar or even smaller.

350 kW KERS would be more powerful than Formula E, wouldn't it? It says that Formula E plans 350 kW for qualifying on their next generation car, and 300 kW for racing.

(Currently, it's only ~160hp/110kW out of the battery pack, isn't it? So you are including the uncapped direct MGUH to MGUK energy flow in your 200 kW?)

Achieving 350 kW electric for a Grand Prix distance with only direct harvesting plus rear axle generation and a 20 kg battery (that's the current rule isn't it, albeit energy capacity is unlimited?) would be most impressive.

Of course, if that 350 kW is only available for 3-5 seconds per lap that would be quite the damp squib indeed.

Wouldn't it be sensible, instead, to increase the maximum battery weight from 20 kg to say 400kg so that 350 kW could be nearly always available for most of the Grand Prix?

IIRC Formula E battery weight is 250 kg, but their races are much, much shorter than 305km. A 400kg battery allowance (unlimited energy density to promote competition, of course) would make the F1 minimum weight about 1200kg, which would be great for road relevance as BEVs tend to be heavier than the similar ICE and it's important to reflect that and be road relevant.

---

Actually you could probably save about 50 (?), so it would be 1250 kg instead of 1300kg at a Grand Prix start, by reducing the combustion engine size to a 1L V4 turbo, and proportionally reducing the maximum liquid fuel allowance to 73 kg.

[henry]

Currently the combined H & K flow rate is about 200 kW max. If the introduce 350 kW KERS that would be more of a challenge, particularly if the capacity of the ES is similar or even smaller.

.

(Currently, it's only ~160hp/110kW out of the battery pack, isn't it? So you are including the uncapped direct MGUH to MGUK energy flow in your 200 kW?)

.

There are three circumstances in which the flow rate might be 200kW.

Anti -lag, when the H is spinning up the turbine . Very short duration.

Electric supercharge, when the ES supplies both the K driving the wheels and the H driving the compressor. Longer duration in qualifying than the race.

Forced recovery, when the ICE drives the K and the H is also charging the ES. This can be done at end of straight and used to be feasible in part throttle but the regulated that away.

Of course, if that 350 kW is only available for 3-5 seconds per lap that would be quite the damp squib indeed.



Wouldn't it be sensible, instead, to increase the maximum battery weight from 20 kg to say 400kg so that 350 kW could be nearly always available for most of the Grand Prix?

even with 400kg they might at very best get 20 seconds/lap from the battery and 10 to 15 seconds from braking. Even that’s not all the full throttle use. [/quote]

IIRC Formula E battery weight is 250 kg, but their races are much, much shorter than 305km. A 400kg battery allowance (unlimited energy density to promote competition, of course) would make the F1 minimum weight about 1200kg, which would be great for road relevance as BEVs tend to be heavier than the similar ICE and it's important to reflect that and be road relevant.

As proposals are currently framed in many countries domestic cars will be BEVs not hybrids.

Note that my numbers for power levels are speculative. Even after 7 years we know precious little about how they actually operate these PUs as opposed to how they might.

[NL_Fer]

With cars like the Rimac and the Tycan out there in production, i don’t see a custom 350kw battery as a big problem. But maybe recovery efficiency can be an interesting battle.

[wuzak]

With cars like the Rimac and the Tycan out there in production, i don’t see a custom 350kw battery as a big problem. But maybe recovery efficiency can be an interesting battle.

Average braking time for tracks in F1 is 10 - 15 seconds per lap. Not all of that will be capable of generating 350kW from the rear wheels.