2025/2026 Hybrid Powerunit speculation

[wuzak]

So the RBPT engineer was of the opinion that driving the MGUK with the ICE would not be allowed.

That leaves braking zones to recover energy - braking and lift-and-coast.

Though the regulations that allow power output to reduce by up to 450kW at 100kW/s would suggest otherwise.

[saviour stivala]

‘’ So RBPT engineer was of the opinion that driving the MGU-K with the engine would not be allowed’’. That is the same as at present rules, because driving the MGU-K with the engine to harvest means using fuel to harvest. And. As at present rules, lift and coast will neither harvest. Harvest by the MGU-K only takes place when driver hits the brakes. Lift and coast is at present only good to save fuel and brakes, because brakes are not being activated, they are letting the air absorbs some of the energy that the brakes would have if driver had hit the brakes.

[AR3-GP]

‘’ So RBPT engineer was of the opinion that driving the MGU-K with the engine would not be allowed’’. That is the same as at present rules, because driving the MGU-K with the engine to harvest means using fuel to harvest. And. As at present rules, lift and coast will neither harvest. Harvest by the MGU-K only takes place when driver hits the brakes. Lift and coast is at present only good to save fuel and brakes, because brakes are not being activated, they are letting the air absorbs some of the energy that the brakes would have if driver had hit the brakes.

Driving the MGU-K with the engine isn't allowed for all practical purposes because there are regulations surrounding the vehicle response to throttle and braking input to prevent things like traction control and other traction driver aids.

So basically, the only way the MGU-K can cause retardation against the engine is if the driver pushes the brake pedal while accelerating. If the driver is not pushing the brake pedal, then any retardation from the MGU-K beyond the inherent mechanical losses of the rotating elements could be devised as a form of traction control.

[saviour stivala]

No doubt that driving the MGU-K with the engine would if it had been allowed opened a can of worms. and so if it will be allowed for the new engine formula that can of worms will be splashed open. And that is why I always argued out on here that the brake pedal is the only triggering switch for the MGU-K to harvest, and that when driver lifts and coast There is no harvesting being done.

[henry]

‘’ So RBPT engineer was of the opinion that driving the MGU-K with the engine would not be allowed’’. That is the same as at present rules, because driving the MGU-K with the engine to harvest means using fuel to harvest. And. As at present rules, lift and coast will neither harvest. Harvest by the MGU-K only takes place when driver hits the brakes. Lift and coast is at present only good to save fuel and brakes, because brakes are not being activated, they are letting the air absorbs some of the energy that the brakes would have if driver had hit the brakes.

Driving the MGU-K with the engine isn't allowed for all practical purposes because there are regulations surrounding the vehicle response to throttle and braking input to prevent things like traction control and other traction driver aids.

So basically, the only way the MGU-K can cause retardation against the engine is if the driver pushes the brake pedal while accelerating. If the driver is not pushing the brake pedal, then any retardation from the MGU-K beyond the inherent mechanical losses of the rotating elements could be devised as a form of traction control.

This is not the case.

At part throttle the ECU can mix ICU and MGU-K to match the driver torque demand. This is a little more restricted now than it was initially by restrictions on fuel flow versus power.

At max torque demand the ECU decides on the power output by mixing max ICU and K in several discrete steps; in decreasing order of power, Esupercharge, self sustain plus, self sustain, ICU only, ICU minus k. There are a couple of others which Honda used which cycled the K at something like 20 to 40Hz.

Even when braking it is legal, and may have been deployed, to drive with the ICU when the K saturates the available rear axle traction, last year this was at about 120kph. This year I don’t know the speed but might be a little higher if this years cars generate less low speed downforce c

[AR3-GP]

‘’ So RBPT engineer was of the opinion that driving the MGU-K with the engine would not be allowed’’. That is the same as at present rules, because driving the MGU-K with the engine to harvest means using fuel to harvest. And. As at present rules, lift and coast will neither harvest. Harvest by the MGU-K only takes place when driver hits the brakes. Lift and coast is at present only good to save fuel and brakes, because brakes are not being activated, they are letting the air absorbs some of the energy that the brakes would have if driver had hit the brakes.

Driving the MGU-K with the engine isn't allowed for all practical purposes because there are regulations surrounding the vehicle response to throttle and braking input to prevent things like traction control and other traction driver aids.

So basically, the only way the MGU-K can cause retardation against the engine is if the driver pushes the brake pedal while accelerating. If the driver is not pushing the brake pedal, then any retardation from the MGU-K beyond the inherent mechanical losses of the rotating elements could be devised as a form of traction control.

This is not the case.

At part throttle the ECU can mix ICU and MGU-K to match the driver torque demand. This is a little more restricted now than it was initially by restrictions on fuel flow versus power.

At max torque demand the ECU decides on the power output by mixing max ICU and K in several discrete steps; in decreasing order of power, Esupercharge, self sustain plus, self sustain, ICU only, ICU minus k. There are a couple of others which Honda used which cycled the K at something like 20 to 40Hz.

Even when braking it is legal, and may have been deployed, to drive with the ICU when the K saturates the available rear axle traction, last year this was at about 120kph. This year I don’t know the speed but might be a little higher if this years cars generate less low speed downforce c

I don't think we are discussing the same thing. There's no restriction in the regulation about mixing ICE and MGU-K to meet the torque demand from the throttle pedal as long as the throttle pedal can produce the same torque response, turbo lag aside to avoid suspicion of traction control.

The problem is using the MGU-K as a form of retardation on the drivetrain (i.e trying to harvest with the MGU-K in the absence of a braking input). I don't see how this is not traction control (even if a team were to pretend it's not the main function), which is banned.

[Tommy Cookers]

Driving the MGU-K with the engine isn't allowed for all practical purposes because there are regulations surrounding the vehicle response to throttle and braking input to prevent things like traction control and other traction driver aids.
So basically, the only way the MGU-K can cause retardation against the engine is if the driver pushes the brake pedal while accelerating. If the driver is not pushing the brake pedal, then any retardation from the MGU-K beyond the inherent mechanical losses of the rotating elements could be devised as a form of traction control.

generation without braking seems entirely to be allowed as long as the resulting PU output is within the mapping rules ..
ie it will be consistent from lap to lap

we have seen it with the Honda in magazine-published test telemetry c.2017

the FIA has a definition of what constitutes traction control eg use of wheel rpm measurement
limits on mapping were introduced (pre-hybrid/ERS F1) after traction control was so defined and banned
mapping is within these limits a permissible help to the driver - so the FIA doesn't call it a driver aid

[henry]

Driving the MGU-K with the engine isn't allowed for all practical purposes because there are regulations surrounding the vehicle response to throttle and braking input to prevent things like traction control and other traction driver aids.

So basically, the only way the MGU-K can cause retardation against the engine is if the driver pushes the brake pedal while accelerating. If the driver is not pushing the brake pedal, then any retardation from the MGU-K beyond the inherent mechanical losses of the rotating elements could be devised as a form of traction control.

This is not the case.

At part throttle the ECU can mix ICU and MGU-K to match the driver torque demand. This is a little more restricted now than it was initially by restrictions on fuel flow versus power.

At max torque demand the ECU decides on the power output by mixing max ICU and K in several discrete steps; in decreasing order of power, Esupercharge, self sustain plus, self sustain, ICU only, ICU minus k. There are a couple of others which Honda used which cycled the K at something like 20 to 40Hz.

Even when braking it is legal, and may have been deployed, to drive with the ICU when the K saturates the available rear axle traction, last year this was at about 120kph. This year I don’t know the speed but might be a little higher if this years cars generate less low speed downforce c

I don't think we are discussing the same thing. There's no restriction in the regulation about mixing ICE and MGU-K to meet the torque demand from the throttle pedal as long as the throttle pedal can produce the same torque response, turbo lag aside to avoid suspicion of traction control.

The problem is using the MGU-K as a form of retardation on the drivetrain (i.e trying to harvest with the MGU-K in the absence of a braking input). I don't see how this is not traction control (even if a team were to pretend it's not the main function), which is banned.

We are discussing exactly the same thing. There is no requirement to use the brake pedal to have the K harvest. During every upshift the K harvests to help drop the ICU revs. The K is wholly under software control and can drive or harvest at will so long as the rules on driver input to torque output are met, as @Tommy Cookers says the control must not take into account road speed.

At one point in the history of this engine formula Honda deployed “extra harvest” where with the ICU at full power the K harvested at between 20 to 40hz sending its output to the ES via the H. No brakes involved and wholly legal.

[AR3-GP]

I stand corrected. I just didn't understand how such a mechanism could not be abused as traction control even if the wheel speeds were not being fed into the software that controls it.

[aleks_ader]

No but would that be bad thing really? i would argue doesnt get more road relevant like that.

[Tommy Cookers]

I stand corrected. I just didn't understand how such a mechanism could not be abused as traction control even if the wheel speeds were not being fed into the software that controls it.

yes the FIA can see what at all times the software is telling the MG to do ....
but conceivably the MG might not at all times actually do what the software is telling it to do ....
eg sudden wheelspin might cause pole slipping, tending to kill wheelspin ....
on braking sudden wheel under-rotation might cause pole jumping, tending to kill wheel under-rotation/locking

the FIA might or might not highlight this as being traction control or ABS-type driver aids ...
and it's possible the system could do or appear to do suspect things even without any ulterior design

[AR3-GP]

I stand corrected. I just didn't understand how such a mechanism could not be abused as traction control even if the wheel speeds were not being fed into the software that controls it.

yes the FIA can see what at all times the software is telling the MG to do ....
but conceivably the MG might not at all times actually do what the software is telling it to do ....
eg sudden wheelspin might cause pole slipping, tending to kill wheelspin ....
on braking sudden wheel under-rotation might cause pole jumping, tending to kill wheel under-rotation/locking

the FIA might or might not highlight this as being traction control or ABS-type driver aids ...
and it's possible the system could do or appear to do suspect things even without any ulterior design

Well we can be sure that if there are any benefits for traction, the engineers have designed the latencies in such a way that it's making it easier to drive, not harder

[saviour stivala]

‘’The problem (at hand) is using the MGU-K as a form of retardation on drivetrain. i.e trying to harvest with MGU-K in absence of braking input’’. As is usual a lot of things that are not being discussed is promptly pushed out. A question here for other things that are claimed to have been happening. Are those claimed things (attempts at harvesting when the brakes are not being used, so MGU-K is powered by engine) is still being used/allowed to be used?. A note to moderation. Hope moderation will allow this time.

[Tommy Cookers]

Are those claimed things (attempts at harvesting when the brakes are not being used, so MGU-K is powered by engine) is still being used/allowed to be used?.

why not ? .... isn't fuel-limited hybrid F1 fuel-limited hybrid F1 ?

aren't about 50 million hybrid road cars being used that way ?
doesn't their (fuel consumption and emissions) certification depend on it ?
controlling PU power by throttling wastes fuel
controlling PU power without throttling doesn't

also ... don't F1 drivers spend time with feet on both brake and accelerator pedals without deceleration ?
also ... below c.70 mph the 'electric-braking' term (modifying the rear brake line pressure) becomes zero

[saviour stivala]

Well, apart from the fact that we are here talking about formula one and the FIA energy harvesting rules and not road going hybrids. Even the said RBPT engineer was of the opinion that driving the MGU-K with the engine will not be allowed. Which means no harvesting by the MGU-K other than under braking will be allowed for 2026 engine rules. Which also means harvesting by MGU-K will be the same as for the present formula. I am not saying that like in most other things in formula one rules, the rules weren't interpreted otherwise, but when that happened the FIA always made a stop to it and improved rules and or spirit of the rules policing. They did add or improved on MGU-K IN-OUT sensors at one time. I know for a fact that drivers use both brake and throttle at the same time sometimes to help top-up ES (harvest), and that means and proves that no harvesting takes place without brake pedal input.