2025/2026 Hybrid Powerunit speculation

[Tommy Cookers]

Just add a spec MGUH already...🙄

and a (so-called) CU-MGUH
the (so-called) CU isn't just equivalent to a fuel pump - it's the equivalent of the cylinder head and everything above it
and the MGUH being a 125000 rpm machine, the CU-MGUH is very different to the CU-MGUK

running leaner that current F1 (so needing more compressor work) and better at converting cylinder heat into work ....
the 2026 ICE will have relatively less exhaust energy available for MGUH recovery

[mzso]

So now maximum power of MGUK (350kW) can be only used up to 290kph rather than 300kph.

Maximum MGUK power at 340kph has changed from 150kW to 100kW.

MGUK power can be 200kW above 340kph in override mode, reducing to 0kW at 355kph.

Maximum recharge while driver is at full throttle is now set to 100kW. Previously it could be higher if the full 350kW MGUK output wasn't used during the full throttle period.

So more energy starvation...
They pretty much guarantee that the engine will be running during braking and turning on most circuits, to generate power.

[saviour stivala]

So "They will be running the engine 'up' against the MGU during braking and cornering phase'' instead of against a closed throttle (no fueling). All this is being assumed while forgetting that they have to use 30% less fuel load during a race.

[wuzak]

So now maximum power of MGUK (350kW) can be only used up to 290kph rather than 300kph.

Maximum MGUK power at 340kph has changed from 150kW to 100kW.

MGUK power can be 200kW above 340kph in override mode, reducing to 0kW at 355kph.

Maximum recharge while driver is at full throttle is now set to 100kW. Previously it could be higher if the full 350kW MGUK output wasn't used during the full throttle period.

So more energy starvation...
They pretty much guarantee that the engine will be running during braking and turning on most circuits, to generate power.

It makes sure that they won't be getting to the end of the straight with less than 300kW (ICE power - 100kW) of power.

[Tommy Cookers]

So more energy starvation...
They pretty much guarantee that the engine will be running during braking and turning on most circuits, to generate power.

It makes sure that they won't be getting to the end of the straight with less than 300kW (ICE power - 100kW) of power.

not more 'energy starvation' ....

because the 'energy gap' has been somewhat closed ....
the permitted 'lap-expenditure' of electrical energy having been reduced (typically by 1 MJ)

the rules have correspondingly borne down on conspicuous odd behaviours

[mzso]

So "They will be running the engine 'up' against the MGU during braking and cornering phase'' instead of against a closed throttle (no fueling). All this is being assumed while forgetting that they have to use 30% less fuel load during a race.

They're never using the full allowance now anyway. (Maybe in Monza) But in anyways, they'll need power to be fast.

[saviour stivala]

Having to start a race with no more than 70kg of fuel instead of a 100kg of fuel while using the same engine capacity will drastically reduce if not completely eliminate their ability to start the race like they do with less than their 100kg of allocated fuel at present. At present their ability to start a race with less than their minimum fuel load allocated is an attempt that results in more efficient use of the car, On the contrary using fuel to running the engine against MGU while braking will drastically reduce car running efficiency.

[Tommy Cookers]

So "They will be running the engine 'up' against the MGU during braking and cornering phase'' instead of against a closed throttle (no fueling). All this is being assumed while forgetting that they have to use 30% less fuel load during a race.

when driving needs only partial ICE powers 'running the engine against the MGU' saves fuel
because at partial ICE powers (however obtained) the ICE is less efficient

at present throttling is minimally used as ICE power is controlled in part by boost control via MGU-H rpm control
from 2026 more throttling will be needed - unless there's ample 'running the engine against the MGU'

[saviour stivala]

''When driving only needs partial ICE power 'running the engine against the MGU saves fuel because at partial ICE power (however) the ICE is less efficient''. When driving only needs partial power running the engine against the MGU or any other power consumer for that matter, will result in burning more fuel and not less.

[Tommy Cookers]

''When driving only needs partial ICE power 'running the engine against the MGU saves fuel because at partial ICE power (however) the ICE is less efficient''. When driving only needs partial power running the engine against the MGU or any other power consumer for that matter, will result in burning more fuel and not less.

no
the ICE partial power to the wheels costs less fuel as ICE efficiency increases by adding the ICE power to the MG

yes the extra ICE power has its own fuel cost (this also at the increased ICE efficiency) but ....
the 2 powers simultaneously cost less fuel than the two powers would separately and then ....

after this generated electrical energy is spent where high energy spending is most advantageous to race progress ....
there has been less fuel burn than would otherwise be needed for that amount of race progress ....
ie this is a fuel saving

[chaoticflounder]

''When driving only needs partial ICE power 'running the engine against the MGU saves fuel because at partial ICE power (however) the ICE is less efficient''. When driving only needs partial power running the engine against the MGU or any other power consumer for that matter, will result in burning more fuel and not less.

Would challenge you to do some research on this. It is the core concept that hybrid vehicles are built around. Specifically look at a brake specific fuel consumption chart (BSFC). Ideally, hybrids are first meant to harvest the excess energy to keep the engine at optimum BSFC and then turn the engine off at any other operating location and run on the harvested energy outside of that.

[saviour stivala]

When the ICE is run 'against' the MGU the ICE efficiency digresses and not increases as it is using more fuel. more so under braking. When the ICE is run against the MGU, under braking or not, there is only ICE power to the rear wheels and not 2 powers, and when done under braking it is most negative fuel use. When the 2 powers are separate, it means the rear wheels are being provided with ICE + MGU power which means less fuel.

[saviour stivala]

''When driving only needs partial ICE power 'running the engine against the MGU saves fuel because at partial ICE power (however) the ICE is less efficient''. When driving only needs partial power running the engine against the MGU or any other power consumer for that matter, will result in burning more fuel and not less.

Would challenge you to do some research on this. It is the core concept that hybrid vehicles are built around. Specifically look at a brake specific fuel consumption chart (BSFC). Ideally, hybrids are first meant to harvest the excess energy to keep the engine at optimum BSFC and then turn the engine off at any other operating location and run on the harvested energy outside of that.

When running the engine against the MGU under braking the fuel consumption goes up. (burning fuel to charge ES).

[wuzak]

''When driving only needs partial ICE power 'running the engine against the MGU saves fuel because at partial ICE power (however) the ICE is less efficient''. When driving only needs partial power running the engine against the MGU or any other power consumer for that matter, will result in burning more fuel and not less.

Would challenge you to do some research on this. It is the core concept that hybrid vehicles are built around. Specifically look at a brake specific fuel consumption chart (BSFC). Ideally, hybrids are first meant to harvest the excess energy to keep the engine at optimum BSFC and then turn the engine off at any other operating location and run on the harvested energy outside of that.

When running the engine against the MGU under braking the fuel consumption goes up. (burning fuel to charge ES).

This new rule might limit the amount of fuel the ICE can burn to recharge the battery:

5.4.5 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

[saviour stivala]

Would challenge you to do some research on this. It is the core concept that hybrid vehicles are built around. Specifically look at a brake specific fuel consumption chart (BSFC). Ideally, hybrids are first meant to harvest the excess energy to keep the engine at optimum BSFC and then turn the engine off at any other operating location and run on the harvested energy outside of that.

When running the engine against the MGU under braking the fuel consumption goes up. (burning fuel to charge ES).

This new rule might limit the amount of fuel the ICE can burn to recharge the battery:

5.4.5 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

Agree that 5.4.5 seems to might limit the amount of fuel the ICE can burn to recharge the ES. But by agreeing/saying that ''running the engine against the MGU'', the original said "under braking", the ICE would be burning 'EXTRA' fuel to charge ES, WE are risking another down-vote by those that doesn't think so.