2025/2026 Hybrid Powerunit speculation

[karana]

Why would they allow so much leeway on power on the ICE but a hard limit on electrical?

If I understand it correctly, there is actually no difference. Neither the ICE nor the MGU-K have a power limit, but rather an energy flow limit, for the ICE ~833kW and for the MGU-K 350kW. It's just that the MGU-K is extremely efficient and can get close to the 350kW.

[johnnycesup]

Show your calculations please.

I'm not the person you're replying to, but there's a 3000MJ/h limit to the fuel energy flow in the regulations. Now MJ/h (unit of mechanical work per unit of time) is obviously a unit of power, so 3000 MJ/h = 833 kW.

So considering the internal combustion engine can burn the fuel perfectly and nothing else is burned (so no oil burning shenanigans), a 470kW output is equivalent to 56,4% thermal efficiency. A bit optimistic IMO


EDIT:
Just to add to the previous discussion, using a common LHV for gasoline (44.3MJ/kg), the previous ruleset had a total fuel energy flow of 1230kW. If the 1000hp rumours are true, that would be a total thermal efficiency of 60,6%, which is pretty incredible.

Ok thank you. I see why you guys are wrong. Please have a look at the 2014 engine threads.

Engines do not work like that. You can't just pluck some numbers from the regulations and work backworks ( or rumours for that matter!).

You take numbers from a known physical engine or known physical/lab derived phenomena.

The previous rules had a fuel flow limit of 100kg/hr. This is equivalent to 4350 MJ/hr or 1230kW (note 4350 is higher than the 3000 number). The ICE engines (not the power unit!) as was calculated before by many forumers here is around 630kW. This smacks you sqaure at 52% thermal efficiency.

We know the combustion behaviour of these engines and we have estimated the MGUH and addition to efficiency and MGUK addition to output over 12 years of observation. So you use that and extrapolate. We do know that they were at limiting returns.

What you do, you see, is listen out when the season starts if you hear Mercedes shouting from the mountain tops of any record in thermal efficiency. They used to do this each year as the hybrid V6 developed because it was good for marketing their brand and the sport. And indeed those efficiency increases were genuine. With this new engine i am almost 100% sure that you will NOT hear any announcement on breaking any efficiency records.

Sorry, how are we wrong exactly?

The 1230 kW for the previous ruleset (2014-2025) was in my post before you replied and in the conditions I assumed (1000hp without need to use the battery), the thermal efficiency of the PU would absolutely be around 60,6%, and I stand by that number. If, as some people said here, the MGUH is only good for around 60kW, you'd get around 56% (probably closer to the truth), and if you want to completely disregard the electric part and say the ICE produces 630 kW, that corresponds to a efficiency of 51.2%, sure (I don't think that number tells the truth about that system).

Now in the current regulations (2026), a peak output of 470kW from the internal combustion engine would mean a thermal efficiency of at least 56% in that point, for sure. The only way it could be lower is if the incoming chemical energy into the system was higher than the number in the rules (so cheating).

I mean, if you think 470kW would mean an efficiency value (and without the MGUH that is not something with different interpretations) lower than 56% , would you please show your calculations?

[PlatinumZealot]

The 1230 kW for the previous ruleset (2014-2025) was in my post before you replied and in the conditions I assumed (1000hp without need to use the battery), the thermal efficiency of the PU would absolutely be around 60,6%, and I stand by that number. If, as some people said here, the MGUH is only good for around 60kW, you'd get around 56% (probably closer to the truth), and if you want to completely disregard the electric part and say the ICE produces 630 kW, that corresponds to a efficiency of 51.2%, sure (I don't think that number tells the truth about that system).

Now in the current regulations (2026), a peak output of 470kW from the internal combustion engine would mean a thermal efficiency of at least 56% in that point, for sure. The only way it could be lower is if the incoming chemical energy into the system was higher than the number in the rules (so cheating).

I mean, if you think 470kW would mean an efficiency value (and without the MGUH that is not something with different interpretations) lower than 56% , would you please show your calculations?

No no no.

The previous rule set is 100kg per hour of fuel flow maximum. (Or about 4350 MJ per hour of energy flow or 1620hp of fuel power) The previous power units made 1050hp or so with ICE plus Electric motor. 840hp plus 160hp.

The previous engines thermal efficiency is 840hp/1620hp. Or about 52% to 55%

These new engines will be stripped of two major efficiency boosters... The MGUH (heat recovery turbine) and 18:1 compression ratio down to 16:1. Their efficiency WILL GO DOWN. No matter how you slice it even without doing the numbers.


Now...
MGUK is now 350KW. Or 470hp.
This leaves 530hp for the ICE if the 1000hp rumour is true. (I doubt it based on reports).
Total fuel input power is 3000MJ/hr or 1,117hp
Efficiency is 530hp / 1117hp = 47%

So you see now? Thermal efficiency will be lower.

I think the real figure will be lower.

[johnnycesup]

No no no.

The previous rule set is 100kg per hour of fuel flow maximum. (Or about 4350 MJ per hour of energy flow or 1620hp of fuel power) The previous power units made 1050hp or so with ICE plus Electric motor. 840hp plus 160hp.

The previous engines thermal efficiency is 840hp/1620hp. Or about 52% to 55%

These new engines will be stripped of two major efficiency boosters... The MGUH (heat recovery turbine) and 18:1 compression ratio down to 16:1. Their efficiency WILL GO DOWN. No matter how you slice it even without doing the numbers.


Now...
MGUK is now 350KW. Or 470hp.
This leaves 530hp for the ICE if the 1000hp rumour is true. (I doubt it based on reports).
Total fuel input power is 3000MJ/hr or 1,117hp
Efficiency is 530hp / 1117hp = 47%

So you see now? Thermal efficiency will be lower.

I think the real figure will be lower.

Look, we are talking past each other. FW17 said that 470kW for the ICE in the 2026 regs would mean over 56% efficiency, which is true even in your calculations (just divide 470 kW = 630hp per 1117 hp).

Now I'm not saying that they will produce 470kW, I even said in the initial post that 56% was high ("A bit optimistic IMO"). Anything close to 400kW (48% efficiency) should be considered a major success IMO. And of course I know that the ICE only needs around 400kW for the whole system to have 1000hp peak power, not 470kW.

I mentioned the 1000hp thing to calculate the efficiency of the 2014-2025 engines (with MGUH), not 2026 ones.

We are not disagreeing at all.

[wuzak]

Tombazis said a while ago that the peak would be about 1,100hp, which would mean 470kW.

Renault said they had passed the initial power goal for the PU, which would have been about 400kW.

Before they abandoned the project, of course.

[saviour stivala]

Tombazis said a while ago that the peak would be about 1,100hp, which would mean 470kW.

Renault said they had passed the initial power goal for the PU, which would have been about 400kW.

Before they abandoned the project, of course.

Single seater director said ''The new PU will reach nearly 1100hp/820kw, about 100hp more than the current hybrid engines, shifting the balance of the power''. The 2026 ICE power is reduced to approximately 400kw/546hp. Electric power (MGU-K) is increased to 350kw/470hp, total power roughly 1100hp (combined power). Why the confusion?, Electric boost is often cited as a 470hp, therefore, the 470kw claim is correct, but describes the electrical component (MGU-K) rather than the ICE.

[FW17]

Efficiency is 530hp / 1117hp = 47%

So you see now? Thermal efficiency will be lower.

I think the real figure will be lower.

There is a Dongfeng 1.5L engine built for commercial use that is at 48%

[PlatinumZealot]

Efficiency is 530hp / 1117hp = 47%

So you see now? Thermal efficiency will be lower.

I think the real figure will be lower.

There is a Dongfeng 1.5L engine built for commercial use that is at 48%

https://encrypted-tbn0.gstatic.com/imag ... YZDSsMPA&s

You can do this using many techniques... The race car is different... High rpm.. Fast piston speed. Wide cylinders.. So it's more challenging with a race car.

The lean air fuel ratio... The rapid near homogenous combustion.. The MGUH.. The low friction materials. The extremely tight clearances. The high running temperatures.. The "designer" fuel are "tricks" the motorsport F1 people have to use.

I have no evidence obviously but I am gonna bet that we see a not so good thermal efficiency.

[TeamKoolGreen]

https://autoracer.it...rezza-alla-fia/



A source reveals that increasing the compression ratio is considerable: “It can reach +6/7% of the ICE power, +3/4% overall PU.
“We all have the skills to do it, it's not allowed. The FIA must be able to check it almost in real time” Binotto.

As already revealed by AutoRacer , Audi is the team pushing hardest to check Brixworth's engine , and Mattia Binotto made no secret of this during his presentation: "If what they're talking about were actually true, the performance gap would be significant ," he admitted bluntly. Significant is exactly the right word, a term also used by another engine specialist well before Binotto spoke in the past few hours. As we've already reported , moving from a compression ratio of 16 to 18 would guarantee an advantage of more than 40 hp, with further benefits for the Power Unit in terms of efficiency, energy recovery, and other values ​​that explain Binotto's strong concern. Audi Technical Director James Key also briefly commented on the matter. "I think it would be like bypassing the purpose of the regulations, which are somehow intended to control this area. We trust the FIA ​​because no one wants to go through a season where someone has a significant advantage and there's no solution, since the Power Unit is homologated. We hope the FIA ​​makes the right decision." With the FIA ​​likely to fail to intervene very soon, the teams would have no choice but to protest in Australia, moving from words to action. However, it's not that easy: "You can protest if you know what you're protesting against," Mattia Binotto stated.

[mzso]

By the way when will the PUs be homologated? Could one of the other manufacturers have rushed to create an expanding conrod, or piston or whatever since this first came out?

https://autoracer.it...rezza-alla-fia/

This is not a usable url.

[FW17]

Efficiency is 530hp / 1117hp = 47%

So you see now? Thermal efficiency will be lower.

I think the real figure will be lower.

There is a Dongfeng 1.5L engine built for commercial use that is at 48%

https://encrypted-tbn0.gstatic.com/imag ... YZDSsMPA&s

You can do this using many techniques...

I guess that is why we see all cars nowadays with 45% efficiency on the road

[wuzak]

At 17s, is that charging at a standing start?

[Badger]

At 17s, is that charging at a standing start?

How would it charge? It can only charge if the rear axle is rotating.

[Tommy Cookers]

... It can only charge if the rear axle is rotating.

fwiw I disagree ....
though of course the MGU-K torque is capped below c.6200 rpm equivalent

[Vappy]

At 17s, is that charging at a standing start?

I'm not sure if i've heard that exhaust-modulating sound for a launch. Up until last year, I have heard it mostly during off-throttle / braking. Mercedes had a pretty clean MGU-H energy recovery method up until the recent engine change, which while not as exciting as Honda's (personal opinion), it was still audibly prominent and consistent at races.

EDIT: I am mistaken. They did make that sound previously for launches.