2025/2026 Hybrid Powerunit speculation

[Tommy Cookers]

So from next year on, are they going to burn fuel to charge the battery?
Which is technologically the most efficient: burning fuel to charge the battery, or adding a front MGU with the disadvantage of extra weight?

F1 cars were 'burning fuel to charge the battery' from 1.1.2014
as did the Prius from 1996 or something

what's efficient ???
F1 races had 3 to 8 corners per 5km lap - now they have 18 corners (to stop 800 hp cars going fast)

if the WDC was on the circle track at Bonneville salt flats (other salt flats are available globally) .....
there would be no electrical recovery (under braking) because there would be no braking and ....
there would be no electrical 'boost' (under acceleration) because there would be (more or less) no acceleration ....
but the cars would be efficient

[karana]

Not sure what you are getting at there Wuzak. Is it the following?

My understanding is the power reduction rate limits only apply to "un-commanded" power reduction. So driver demand can reduce instantaneously if required and switching that surplus power to MGU-K recovery (genset mode) can also be instantaneous.

This power reduction rate is for full trottle recovery.
Question would be, if it isn't more lap time efficient to just go to part trottle an go immediatly to full harvest, or even have a button to start harvesting.
But such a button is most definitely forbidden by rules although the reduction would be technical be "driver demand".

But under partial throttle (well, technically it says partial load, but I'm relatively sure it means basically partial throttle) there is the rule that limits fuel flow, which will effectively limit recovery to at best around 200kW.

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

While I think it will be generally pre-programmed when the MGU-K starts harvesting, a button to start harvesting at 250kW under full throttle should probably still be allowed. There might be an argument such a button is disallowed by

C8.6.4 Accelerator Pedal
The only means by which the driver may control acceleration torque to the driven wheels is via a
single foot (accelerator) pedal mounted inside the Survival Cell.

but this rule also exists in the current (or rather old) regulations and "overtake buttons" that increase torque are currently allowed.

[wuzak]

Not sure what you are getting at there Wuzak. Is it the following?

My understanding is the power reduction rate limits only apply to "un-commanded" power reduction. So driver demand can reduce instantaneously if required and switching that surplus power to MGU-K recovery (genset mode) can also be instantaneous.

I'm asking if the statement "Unless the electrical DC power of the ERS-K is negative" means that the ramp down rate of 50kW/s or 100kW/s doesn't apply when the MGUK is recovering energy.

[karana]

Not sure what you are getting at there Wuzak. Is it the following?

My understanding is the power reduction rate limits only apply to "un-commanded" power reduction. So driver demand can reduce instantaneously if required and switching that surplus power to MGU-K recovery (genset mode) can also be instantaneous.

I'm asking if the statement "Unless the electrical DC power of the ERS-K is negative" means that the ramp down rate of 50kW/s or 100kW/s doesn't apply when the MGUK is recovering energy.

I mean, what else should it mean?

In other news, there has been an update for all 2026 regulations. One change I noticed: "Full throttle" was replaced by "power limited pending" or "power limited". The definition is sadly not included in the regulations.

C5.12.4 Except for conforming to Article C5.2.8, the driver maximum power demand cannot be reduced by
more than 150kW at the start of any (full Throttle) power limited pending period, and the power
reduction will remain fixed for a minimum of 1s. Further exceptions are permitted for specified
circuit sectors, subject to Article B7.2.1.
C5.12.5 The driver maximum power demand cannot be increased during any (full Throttle) power limited
pending or power limited period, except when the overtake mode, as specified in the Appendix to
the Regulations, is selected by the driver, or, subject to Article B7.2.1, when a reset of any power
reduction is permitted.

[michl420]

While I think it will be generally pre-programmed when the MGU-K starts harvesting, a button to start harvesting at 250kW under full throttle should probably still be allowed. There might be an argument such a button is disallowed by

C8.6.4 Accelerator Pedal
The only means by which the driver may control acceleration torque to the driven wheels is via a
single foot (accelerator) pedal mounted inside the Survival Cell.

but this rule also exists in the current (or rather old) regulations and "overtake buttons" that increase torque are currently allowed.

When such a button is allowed, wouldn`t the whole rampe down under full trottle just be theoretical, because I would think to harvest late, short, and maxiumum is the most lap time friendly way to do it?

[karana]

While I think it will be generally pre-programmed when the MGU-K starts harvesting, a button to start harvesting at 250kW under full throttle should probably still be allowed. There might be an argument such a button is disallowed by

C8.6.4 Accelerator Pedal
The only means by which the driver may control acceleration torque to the driven wheels is via a
single foot (accelerator) pedal mounted inside the Survival Cell.

but this rule also exists in the current (or rather old) regulations and "overtake buttons" that increase torque are currently allowed.

When such a button is allowed, wouldn`t the whole rampe down under full trottle just be theoretical, because I would think to harvest late, short, and maxiumum is the most lap time friendly way to do it?

Well, the rules regarding the ramp down and maximum power reduction still apply, whether the driver presses a button or not. The point is that when the MGU-K has already stopped deploying, you can switch to -250kW (but not -350kW!) immediately because of the "Unless the electrical DC power of the ERS-K is negative" part. This can happen without driver input as part of the deployment mode or (maybe?) with driver input because the driver wants to harvest more energy to prepare for an overtake.

Basically my guess is that the fastest way around the track is by staying at full throttle as long as possible and then braking as hard as possible (though maybe there are driving styles that require longer braking zones?)