F1 Energy store density for 2026 and hot swap batteries

[diffuser]

It's unclear to me whether the ICE is allowed to run at high power to generate when the power pedal is not pressed. I've heard it both ways and the rules keep changing as well.

The rules have a clause that limits the fuel flow under part throttle.

Notably they define the fuel flow in terms of the engine power, not power demand.

The rule specifies a flat fuel flow rate for power below -50kW and a proportional flow rate above -50kW.

With no throttle at all, the cars will either be braking or lift and coasting.

Don't think those cars will ever coast. Makes more sense to have the MGU-K engaged and being on the throttle, if the rules prevent some automatic control of that. Nothing prevents a driver from having one foot on the throttle and the other on the brake at the same time.

[mzso]

It's unclear to me whether the ICE is allowed to run at high power to generate when the power pedal is not pressed. I've heard it both ways and the rules keep changing as well.

The rules have a clause that limits the fuel flow under part throttle.

Notably they define the fuel flow in terms of the engine power, not power demand.

The rule specifies a flat fuel flow rate for power below -50kW and a proportional flow rate above -50kW.

With no throttle at all, the cars will either be braking or lift and coasting.

Don't think those cars will ever coast. Makes more sense to have the MGU-K engaged and being on the throttle, if the rules prevent some automatic control of that. Nothing prevents a driver from having one foot on the throttle and the other on the brake at the same time.

Power pedal input corresponds to output power AFAIK. So pressing both would be just wasteful. Unless they can do it in neutral or such.

[diffuser]

The rules have a clause that limits the fuel flow under part throttle.

Notably they define the fuel flow in terms of the engine power, not power demand.

The rule specifies a flat fuel flow rate for power below -50kW and a proportional flow rate above -50kW.

With no throttle at all, the cars will either be braking or lift and coasting.

Don't think those cars will ever coast. Makes more sense to have the MGU-K engaged and being on the throttle, if the rules prevent some automatic control of that. Nothing prevents a driver from having one foot on the throttle and the other on the brake at the same time.

Power pedal input corresponds to output power AFAIK. So pressing both would be just wasteful. Unless they can do it in neutral or such.

Engaging the clutch would be the easiest way to do that. I don't think it's necessary though. Why wouldn't they set it up that the MGU-K is either generating power or charging the battery. Until the ICE is at max power the MGU-K is always in generations mode. Once more power is required, it slowly eases off the MGU-H harvesting demand and transitions to power delivery from the MGU-K.

Isn't that what electric cars do with regenerative braking in one peddle mode? You apply the brakes only when you need more braking power than going off throttle gives you.

[Cold Fussion]

Engaging the clutch would be the easiest way to do that. I don't think it's necessary though. Why wouldn't they set it up that the MGU-K is either generating power or charging the battery. Until the ICE is at max power the MGU-K is always in generations mode. Once more power is required, it slowly eases off the MGU-H harvesting demand and transitions to power delivery from the MGU-K.

Isn't that what electric cars do with regenerative braking in one peddle mode? You apply the brakes only when you need more braking power than going off throttle gives you.

I'll preface this with saying I haven't studied the regulations, but doesn't doing this almost necessitate an active feedback loop, which is surely akin to traction control? If you were to set it up without feedback, and map the throttle to account for a potential -350KW offset from the MGU-K generating, what would happen if the battery was full and you could no longer provide that -350KW offset?

[gruntguru]

Engaging the clutch would be the easiest way to do that. I don't think it's necessary though. Why wouldn't they set it up that the MGU-K is either generating power or charging the battery. Until the ICE is at max power the MGU-K is always in generations mode. Once more power is required, it slowly eases off the MGU-H harvesting demand and transitions to power delivery from the MGU-K.

Isn't that what electric cars do with regenerative braking in one peddle mode? You apply the brakes only when you need more braking power than going off throttle gives you.

I'll preface this with saying I haven't studied the regulations, but doesn't doing this almost necessitate an active feedback loop, which is surely akin to traction control?

As long as the effort applied at the tyres has always the same relationship to throttle (and/or brake) pedal position - it is not traction control.

Meaning to say - if the "active feedback loop" has tractive effort (or some proxy) as its sole input (not wheel speed etc) it has the same effect as an old fashioned mechanical throttle.

[gruntguru]

If you were to set it up without feedback, and map the throttle to account for a potential -350KW offset from the MGU-K generating, what would happen if the battery was full and you could no longer provide that -350KW offset?

One would assume they have long been using some sort of electronic control of the braking force to compensate for the variable nature of the MGUK harvesting.

[Tommy Cookers]

I'll preface this with saying I haven't studied the regulations, but doesn't doing this almost necessitate an active feedback loop, which is surely akin to traction control?

As long as the effort applied at the tyres has always the same relationship to throttle (and/or brake) pedal position - it is not traction control.
Meaning to say - if the "active feedback loop" has tractive effort (or some proxy) as its sole input (not wheel speed etc) it has the same effect as an old fashioned mechanical throttle.

the MGU-K 'control electronics' receive a timing of every revolution (of the MGU-K) - ie hundreds of times per second
so the CE acts like a synthetic 'active camshaft' (pulsing MG excitations in synchrony with instantaneous rotor position)
it's intelligent (in effect the 'magic' velocity-control/ torque-control combo that people seem to envisage) ....
and so knows all about changes in rotational velocity (of the crankshaft that drives the rear wheels)

but continuity of this synchrony isn't guaranteed - or even compelled
ie momentary pole slip (or pole skip) can amount to TC (or ABS)
however the 2026 PU will have response slower than that current (because the MGU-K inertia is higher relatively)
so the 2026 car will be less inclined to wheel spin and slip

as with the 2014 rules it's almost as if the rule-makers know what they are doing