2025/2026 Hybrid Powerunit speculation

[dren]

Kinetic energy from braking will not get the allowed amount of recovery per lap.

They will use the engine to generate electricity.

He's right semantically, recovery is only through braking since otherwise that's "lost" to heat. But, energy will also be converted/stored in the batteries through burning gas and using the motor as a generator. He knows that and I'm sure has read the many pages of posts by you and others in this thread.

Even more, the ruleset states about torque demand from the power unit. They can (and I think they will) put a MGUK load against engine torque, outputting a net zero (or so) PU output. I strongly think that the lift and coast will be massive and will sound funny.

Oh yeah, revving engines through the bends. It'll be interesting sounding for sure!

[wuzak]

He's right semantically, recovery is only through braking since otherwise that's "lost" to heat. But, energy will also be converted/stored in the batteries through burning gas and using the motor as a generator. He knows that and I'm sure has read the many pages of posts by you and others in this thread.

Even more, the ruleset states about torque demand from the power unit. They can (and I think they will) put a MGUK load against engine torque, outputting a net zero (or so) PU output. I strongly think that the lift and coast will be massive and will sound funny.

Oh yeah, revving engines through the bends. It'll be interesting sounding for sure!

The rpm is constrained by the gearing.

At the hairpin at Monaco, for instance, the engine speed can dip as low as 5-6,000rpm. This will still be the case.

What will change is that the ICE will be making power and the MGUK recovers, more or less, the same power, matching the driver's power demand of approximately 0kW.

[BassVirolla]

Even more, the ruleset states about torque demand from the power unit. They can (and I think they will) put a MGUK load against engine torque, outputting a net zero (or so) PU output. I strongly think that the lift and coast will be massive and will sound funny.

Oh yeah, revving engines through the bends. It'll be interesting sounding for sure!

The rpm is constrained by the gearing.

At the hairpin at Monaco, for instance, the engine speed can dip as low as 5-6,000rpm. This will still be the case.

What will change is that the ICE will be making power and the MGUK recovers, more or less, the same power, matching the driver's power demand of approximately 0kW.

I don't remember the numbers, but the fuel flow is also restricted to throttle pedal position. Some time ago I did some calculations and the amount of recovery through this is not a lot, but not negligible.

[saviour stivala]

With no MGU-H, the only way to harvest energy and rechacharge the battery will be through the motor generator unit - kinetic during braking.

[saviour stivala]

When I say that the only way to charge the battery is through the motor generator - kinetic when under braking, I don't mean that the motor generator cannot be made to charge by other means, it is my personal opinion that the rules will not allow the batteries to be charged by any other means.

[wuzak]

When I say that the only way to charge the battery is through the motor generator - kinetic when under braking, I don't mean that the motor generator cannot be made to charge by other means, it is my personal opinion that the rules will not allow the batteries to be charged by any other means.

The rules do not link energy recovery to braking.

They do specify where, or how much, the MGUK can recover under full power demand and has extra limits on fuel flow at part throttle.

[wuzak]

Oh yeah, revving engines through the bends. It'll be interesting sounding for sure!

The rpm is constrained by the gearing.

At the hairpin at Monaco, for instance, the engine speed can dip as low as 5-6,000rpm. This will still be the case.

What will change is that the ICE will be making power and the MGUK recovers, more or less, the same power, matching the driver's power demand of approximately 0kW.

I don't remember the numbers, but the fuel flow is also restricted to throttle pedal position. Some time ago I did some calculations and the amount of recovery through this is not a lot, but not negligible.

Fuel flow is regulated by:
C5.2.3 Fuel energy flow must not exceed 3000MJ/h.
C5.2.4 Below 10500rpm the fuel energy flow must not exceed EF(MJ/h)=0.27*N(rpm)+ 165
C5.2.5 At partial load, the fuel energy flow must not exceed the limit curve defined below:
EF (MJ/h) = 380 when the engine power is equal to or below −50kW
EF (MJ/h) = 9.78 x engine power (kW) + 869 when the engine power is above −50kW

At 5,000rpm, the fuel flow defined by 5.2.4 is 1,515MJ/h, just over half the maximum. Or ~202kW, assuming 48% TE.

I think 5.2.5 may refer to the PU output, since the ICE doesn't really produce negative power.

At 0kW PU, the fuel flow allows ~116kW power from the ICE, assuming 48% TE.

Under braking, where the PU is recovering more than 50kW, the ICE makes about 51kW.

At 100kW output, the ICE can make ~246kW.

At the hairpin at Monaco, the recovery will be limited by 5.2.5 (~116kW at 0 power demand) rather than 5.2.4 (202kW @ 5,000rpm).

[saviour stivala]

When I say that the only way to charge the battery is through the motor generator - kinetic when under braking, I don't mean that the motor generator cannot be made to charge by other means, it is my personal opinion that the rules will not allow the batteries to be charged by any other means.

The rules do not link energy recovery to braking.

They do specify where, or how much, the MGUK can recover under full power demand and has extra limits on fuel flow at part throttle.

Yes, formula 1 rules 'explicitly' link energy recovery to braking.
No formula 1 rules do not allow for energu recovery under full power demand.

[wuzak]

When I say that the only way to charge the battery is through the motor generator - kinetic when under braking, I don't mean that the motor generator cannot be made to charge by other means, it is my personal opinion that the rules will not allow the batteries to be charged by any other means.

The rules do not link energy recovery to braking.

They do specify where, or how much, the MGUK can recover under full power demand and has extra limits on fuel flow at part throttle.

Yes, formula 1 rules 'explicitly' link energy recovery to braking.
No formula 1 rules do not allow for energu recovery under full power demand.

Can you quote the regulation that explicitly links energy recovery to braking?

As to allowing energy recovery under full power demand:

C5.12.6 The driver maximum power demand must not be reduced at any greater than the rates defined below:
a. 50kW in any 1s period at Competitions where the FIA determines that the power limited distance exceeds 3500m. These Competitions and the vehicle fundamentals used for the calculation of the power limited distance may be found in the document FIA-F1-DOC-Cxxx.
b. 100kW in any 1s period at all other Competitions.
Furthermore, the total power reduction is limited to a maximum of 600kW and the resulting electrical DC power of the ERS-K must remain above −250kW.

-250kW seems like energy recovery/generation to me.

[Mattchu]

You need to clarify if when you use the term "braking", do you account for engine braking or has the brake pedal got to be pressed for it to be considered "braking"?