2025/2026 Hybrid Powerunit speculation

[wuzak]

If we use Badger's diagram for Spa, and the maximum ramp down rate.

6s @ 350kW = 2,100MJ deployed
7s 350kW - 0kW = 1,225kJ deployed
5s 0kW to -250kW = 625KJ recovered
5s @ -250kW = 1,250KJ recovered

3,325kJ deployed
1,875kJ recovered

Net usage: 1,450kJ.

But, with this model will the car slow too much to make brake energy recovery negligible?

I didn't make the model to perfect scale on the time axle, I just wanted to roughly describe the different deployment phases I think we'll see.

- I think 6s @ 350 kW is probably a bit long, maybe 4 seconds? Think more "quick punch" out of the corner.
- Active braking might be 3-4 seconds with an average of 225 kW regen or something like that.

I based the 6s on acceleration estimates from 70km/h to 290km/h for current cars.

2026 cars should be similar, with similar power, less weight but less grip.

And won't they want to get to maximum speed as quickly as possible?

For that they will deploy maximum MGUK power for as long as possible.

Also, current braking for Les Combes at Spa is ~ 1.6s per Brembo. The speed only drops t ~ 170-170km/h.

[michl420]

You guys should not forget, that at 345 kph, the MGUK output is anyway 0 kw. The question will be how many kw are necessary for this speed (low drag mode) and how much from this can the ICE contribute.
Could it be possible, that after 10 sec MGUK assist, the ICE can drive the car with 340 kph alone?

[Badger]

If we use Badger's diagram for Spa, and the maximum ramp down rate.

6s @ 350kW = 2,100MJ deployed
7s 350kW - 0kW = 1,225kJ deployed
5s 0kW to -250kW = 625KJ recovered
5s @ -250kW = 1,250KJ recovered

3,325kJ deployed
1,875kJ recovered

Net usage: 1,450kJ.

But, with this model will the car slow too much to make brake energy recovery negligible?

I didn't make the model to perfect scale on the time axle, I just wanted to roughly describe the different deployment phases I think we'll see.

- I think 6s @ 350 kW is probably a bit long, maybe 4 seconds? Think more "quick punch" out of the corner.
- Active braking might be 3-4 seconds with an average of 225 kW regen or something like that.

I based the 6s on acceleration estimates from 70km/h to 290km/h for current cars.

2026 cars should be similar, with similar power, less weight but less grip.

And won't they want to get to maximum speed as quickly as possible?

For that they will deploy maximum MGUK power for as long as possible.

Also, current braking for Les Combes at Spa is ~ 1.6s per Brembo. The speed only drops t ~ 170-170km/h.

Consider 4 seconds of full deployment. Seconds 1-4 you have 1030 HP (more than we have now), second 5 you have 965 HP, second 6 you have 900 HP, second 7 you have 835 HP, second 8 you have 770 HP, etc. With the low drag mode and the lighter car you will accelerate plenty with these numbers, even when tapering those first few seconds.

Come to think of it 4 seconds of full deployment may be too much. 3 seconds may be more appropriate for a long straight. Especially when you consider that you will be traction limited early in the acceleration phase so you won't need full beans the first second probably.

[michl420]

Is it safe to say that, compared to this year's power units, a greater percentage of total fuel use per lap will be consumed at part-throttle and a lesser percentage consumed by full-throttle running? If so we could see results of part-throttle engine development.

Options for reducing power output:
-throttling of intake air + reducing fuel (typical)
-reducing fuel only while maintaining WOT (if feasible)
-cylinder cutting
-cylinder cutting + independent throttle body control (I see no stipulation that all six butterflies/barrels must move in unison)
-split throttling (use independent throttle body control to vary the a:f of any cylinder w respect to others)

I think part trottle will be less. Next year they must convert as much fuel as possible in propulsion (obvious) and electricity. They will try to run the ICE always with at least 350 kw output. (of course not in hard braking zones)

[wuzak]

Consider 4 seconds of full deployment. Seconds 1-4 you have 1030 HP (more than we have now), second 5 you have 965 HP, second 6 you have 900 HP, second 7 you have 835 HP, second 8 you have 770 HP, etc. With the low drag mode and the lighter car you will accelerate plenty with these numbers, even when tapering those first few seconds.

Come to think of it 4 seconds of full deployment may be too much. 3 seconds may be more appropriate for a long straight. Especially when you consider that you will be traction limited early in the acceleration phase so you won't need full beans the first second probably.

6s acceleration from 70km/h to 290km/h is a 220km/h increase.

4s acceleration would give you a bit more than 220*4/6 = 147km/h increase.

After 4s the speed would be 217km/h+.

But we know the acceleration is not constant, so it will probably be 240-250km/h, still a deficit of 50-40km/h.

It's going to take longer to get to 290km/h than 6s using lower power to accelerate, and the speed vs distance will be lower all along the straight.

We do not know what the current PUs produce, other than it is about 1,000hp. Which is similar to next year.

Assume 400kW for the ICE (often stated target, 48% TE).

First 4s total power 750kW, MGUK deployment 350kW = 1,400kJ

Your ramp rate seems to be 50kW/s, so 7s ramping to get to 0kW deployment.

7 * 350 / 2 = 1,225kJ.

Total energy deployed = 2,625kJ.

But you've deployed for 11s out of 23s. What do you do for the next 12s?

After 6s your scenario would have 100kW less power than my scenario. At 11s it would still be 100kW less, after 12s 50kW less and equal at 13s.

That is a big disadvantage in acceleration and speed along the straight.

[Badger]

Consider 4 seconds of full deployment. Seconds 1-4 you have 1030 HP (more than we have now), second 5 you have 965 HP, second 6 you have 900 HP, second 7 you have 835 HP, second 8 you have 770 HP, etc. With the low drag mode and the lighter car you will accelerate plenty with these numbers, even when tapering those first few seconds.

Come to think of it 4 seconds of full deployment may be too much. 3 seconds may be more appropriate for a long straight. Especially when you consider that you will be traction limited early in the acceleration phase so you won't need full beans the first second probably.

6s acceleration from 70km/h to 290km/h is a 220km/h increase.

4s acceleration would give you a bit more than 220*4/6 = 147km/h increase.

After 4s the speed would be 217km/h+.

But we know the acceleration is not constant, so it will probably be 240-250km/h, still a deficit of 50-40km/h.

It's going to take longer to get to 290km/h than 6s using lower power to accelerate, and the speed vs distance will be lower all along the straight.

We do not know what the current PUs produce, other than it is about 1,000hp. Which is similar to next year.

Assume 400kW for the ICE (often stated target, 48% TE).

First 4s total power 750kW, MGUK deployment 350kW = 1,400kJ

Your ramp rate seems to be 50kW/s, so 7s ramping to get to 0kW deployment.

7 * 350 / 2 = 1,225kJ.

Total energy deployed = 2,625kJ.

But you've deployed for 11s out of 23s. What do you do for the next 12s?

After 6s your scenario would have 100kW less power than my scenario. At 11s it would still be 100kW less, after 12s 50kW less and equal at 13s.

That is a big disadvantage in acceleration and speed along the straight.

Obviously. You deploy more energy on one straight you will go faster there, what about the rest of the lap? I'm suggesting the fastest way around the lap will be to mete out the deployment more evenly across several acceleration zones, especially on a track like Spa where you have more than one long straight.