Offset cylinder explained.

[gruntguru]

Peak HP on a current F1 engine is crankshaft power plus turbine power minus compressor power. It is possible that the best output comes with exhaust back pressure significantly higher than intake manifold pressure hence my original comment.

. . . But I will repeat (my disagreement) 'Because the F1 engine (ICE) is turbocharged, shooting for peak power, the lower the turbine pressure the better. In short, if a compressor can reach full boost with less turbine exhaust gas pressure the more the peak HP output.

Correct - however the turbine (MGUH) power will be reduced and the compressor power might be increased. The optimum level of exhaust back pressure is the one that maximises self-sustaining power (crank+turbine-compressor)

[saviour stivala]

That the turbocharged ICE peak power is crankshaft power I already said that I am in agreement. further things were forced upon me because you did not stop at crankshaft power, you involved other things on which I did not agree.

[saviour stivala]

Peak HP on a current F1 engine is crankshaft power plus turbine power minus compressor power. It is possible that the best output comes with exhaust back pressure significantly higher than intake manifold pressure hence my original comment.

. . . But I will repeat (my disagreement) 'Because the F1 engine (ICE) is turbocharged, shooting for peak power, the lower the turbine pressure the better. In short, if a compressor can reach full boost with less turbine exhaust gas pressure the more the peak HP output.

Correct - however the turbine (MGUH) power will be reduced and the compressor power might be increased. The optimum level of exhaust back pressure is the one that maximises self-sustaining power (crank+turbine-compressor)

So it is ok than to go talking beyond ICE crank power. SO, "However the turbine (MGU-H) power will be reduced'' Agreed. And yes, The trick is to find the optimum back pressure, the least possible the better. Although Turbine-MGU-H power has it's importance as to recovery, we were talking about ICE crank peak power. When MGU-H is being turbine powered, Crank cannot produce peak power. Whichever way one looks at it, without having good crank peak power one will be a sitting duck.

[wuzak]

. . . But I will repeat (my disagreement) 'Because the F1 engine (ICE) is turbocharged, shooting for peak power, the lower the turbine pressure the better. In short, if a compressor can reach full boost with less turbine exhaust gas pressure the more the peak HP output.

Correct - however the turbine (MGUH) power will be reduced and the compressor power might be increased. The optimum level of exhaust back pressure is the one that maximises self-sustaining power (crank+turbine-compressor)

So it is ok than to go talking beyond ICE crank power. SO, "However the turbine (MGU-H) power will be reduced'' Agreed. And yes, The trick is to find the optimum back pressure, the least possible the better. Although Turbine-MGU-H power has it's importance as to recovery, we were talking about ICE crank peak power. When MGU-H is being turbine powered, Crank cannot produce peak power. Whichever way one looks at it, without having good crank peak power one will be a sitting duck.

The ICE by itself could make more power itself than it does in self-sustaining mode, but the compounded power is more than the ICE could make by itself.

The peak power is the maximum of the compound engine.

An example from WW2 is the Allison V-1710-127 (-E27).

The base engine, a 2 stage supercharged V-12, could produce 2,200hp.

The V-1710-127 had an extra turbine at the back, connected by a shaft to the engine. With the turbine, the compound engine could produce nearly 3,000hp.

For the F1 PU, the ICE may produce 850hp without any assistance from the ERS and the MGUH not recovering energy.

In self-sustaining mode the ICE may only produce 800hp, but the MGUH is recovering 80hp from the turbo and sending it to the MGUK, and then transferring the power to the crankshaft. So the output is 880hp.

(Power values illustrative only.)

It seems that you are arguing that the peak power is 850hp, not 880hp. If I have misread your posts, I apologize.

[saviour stivala]

"It seems that you are arguing that peak power is example 850, not 880. If I have misread your post, I apologize". Whatever your reading was, be assured that there is no need for any apologizing, not at all. These things happen and are normal in a technical forum because different people keeps pushing/pulling/adding/subtracting things to the subject proper that can rightly influence said subject. Just to make clear and simple my personal opinion as to the different levels of power outputs possible from the formula one power unit. The peak power output/s of a formula one power unit can be divided into four levels of outputs. (1) turbocharged ICE. (2) Turbocharged ICE + ES electrical power. (3) Turbocharged ICE + turbine driven 'H' supplying electrical power through "K". (4) ICE in electric supercharging mode, with both 'H' and 'K' sharing ES power, in this mode no exhaust is involved with the turbine. It should be noted that the only (1) turbocharged ICE (by itself), is actually capable of a continues flow of power output all around a lap, In all other levels the combined ICE + electrical power outputs (maximum allowed) are time limited around a lap.

[Hoffman900]

This paper might provide some insight. It was co-authored by Ferrari and published in 2021:

https://sciprofiles.com/publication/vie ... 39734f7f18

Time-Optimal Low-Level Control and Gearshift Strategies for the Formula 1 Hybrid Electric Powertrain

Today, Formula 1 race cars are equipped with complex hybrid electric powertrains that display significant cross-couplings between the internal combustion engine and the electrical energy recovery system. Given that a large number of these phenomena are strongly engine-speed dependent, not only the energy management but also the gearshift strategy significantly influence the achievable lap time for a given fuel and battery budget. Therefore, in this paper we propose a detailed low-level mathematical model of the Formula 1 powertrain suited for numerical optimization, and solve the time-optimal control problem in a computationally efficient way. First, we describe the powertrain dynamics by means of first principle modeling approaches and neural network techniques, with a strong focus on the low-level actuation of the internal combustion engine and its coupling with the energy recovery system. Next, we relax the integer decision variable related to the gearbox by applying outer convexification and solve the resulting optimization problem. Our results show that the energy consumption budgets not only influence the fuel mass flow and electric boosting operation, but also the gearshift strategy and the low-level engine operation, e.g., the intake manifold pressure evolution, the air-to-fuel ratio or the turbine waste-gate position.

[gruntguru]

. . . But I will repeat (my disagreement) 'Because the F1 engine (ICE) is turbocharged, shooting for peak power, the lower the turbine pressure the better. In short, if a compressor can reach full boost with less turbine exhaust gas pressure the more the peak HP output.

Correct - however the turbine (MGUH) power will be reduced and the compressor power might be increased. The optimum level of exhaust back pressure is the one that maximises self-sustaining power (crank+turbine-compressor)

. . Although Turbine-MGU-H power has it's importance as to recovery, we were talking about ICE crank peak power.

Not "we".
One of us (I) was talking about self-sustaining PU power which is the power output of the heat engine when fuel is the only energy input. The engine teams are targeting self-sustaining power, not crankshaft power.

[vorticism]

I wonder if they considered geared compounding as an option before deciding no compounding, period, in the new formula.

[Hoffman900]

From that paper:

For the battery recharge case, however, the trade-off between the engine power and the MGU-H recuperation is more pronounced. The fact of not shifting into the 8th gear keeps the engine speed high and therefore the pressure in the intake manifold lower (compared to the battery discharge case). As a consequence, the compressor power is lower and more power can be recuperated by the MGU-H. The power unit control around the upshifts occurs each time in a similar manner: the MGU-H recuperates less to accelerate the turbocharger shaft, whilst the throttle valve is operated to achieve the optimal fuel-to-air ratio value. The battery recharge target also influences the waste-gate operation. In conventional gasoline turbocharged engines, the waste-gate is operated to diminish the turbine power and thereby controls the intake manifold pressure [79]. By contrast, for the considered high-performance power unit the waste-gate is used to increase the engine power by diminishing the exhaust manifold pressure. The turbine power extraction is reduced and therefore the MGU-H power recuperation goes roughly to zero (when no upshift is taking place). The intake manifold pressure is not affected, the engine pumping power increases and so does the overall engine power. In addition to that, the MGU-K operation is also influenced by the battery availability. Not only the MGU-K cut occurs later on the straight if more battery energy can be deployed, but also the slope is different

…

The battery recharge target has an influence on the time interval the waste-gate is kept open, and therefore directly influences the resulting engine pumping power. The latter is shown to have the largest impact on the overall engine power, since the sum of the engine combustion and friction power are, on average, constant for all the battery budgets (for the considered fuel consumption target). Opening the waste-gate comes at the expense of a lower MGU-H recuperation: in fact, the average MGU-H recuperation (on straight) is roughly zero if the waste-gate is kept always open. A similar trend is observed for the MGU-K operation, whose average value becomes larger if more battery energy can be depleted. Overall, the power drawn from the battery, i.e., the sum of the MGU-K and MGU-H powers, becomes very small in magnitude if an aggressive battery recharge target has to be met: The power recuperated from the extra enthalpy contained in the hot exhaust gases is directly fed from the MGU-H to the MGU-K.

[wuzak]

Correct - however the turbine (MGUH) power will be reduced and the compressor power might be increased. The optimum level of exhaust back pressure is the one that maximises self-sustaining power (crank+turbine-compressor)

. . Although Turbine-MGU-H power has it's importance as to recovery, we were talking about ICE crank peak power.

Not "we".
One of us (I) was talking about self-sustaining PU power which is the power output of the heat engine when fuel is the only energy input. The engine teams are targeting self-sustaining power, not crankshaft power.

It could still be considered "crankshaft power" since the MGUK connects only to the crankshaft.

Unlike in LMh or LMdh hypercars, where the MGUK is connected to the front wheels.

[gruntguru]

From that paper:

. . . By contrast, for the considered high-performance power unit the waste-gate is used to increase the engine power by diminishing the exhaust manifold pressure. The turbine power extraction is reduced and therefore the MGU-H power recuperation goes roughly to zero (when no upshift is taking place). The intake manifold pressure is not affected, the engine pumping power increases and so does the overall engine power. . . .

…

. . . . Opening the waste-gate comes at the expense of a lower MGU-H recuperation: in fact, the average MGU-H recuperation (on straight) is roughly zero if the waste-gate is kept always open. . . .

These two quotes suggest that the turbine is still developing significant power in "electric supercharging" mode. In fact if "the average MGU-H recuperation (on straight) is roughly zero" is correct, the MGUH power required to run the compressor is zero.

[Hoffman900]

From that paper:

. . . By contrast, for the considered high-performance power unit the waste-gate is used to increase the engine power by diminishing the exhaust manifold pressure. The turbine power extraction is reduced and therefore the MGU-H power recuperation goes roughly to zero (when no upshift is taking place). The intake manifold pressure is not affected, the engine pumping power increases and so does the overall engine power. . . .

…

. . . . Opening the waste-gate comes at the expense of a lower MGU-H recuperation: in fact, the average MGU-H recuperation (on straight) is roughly zero if the waste-gate is kept always open. . . .

These two quotes suggest that the turbine is still developing significant power in "electric supercharging" mode. In fact if "the average MGU-H recuperation (on straight) is roughly zero" is correct the MGUH power required to run the compressor is zero.

That's how I interpreted it, but it's not necessarily making more boost, it's just removed pumping losses, but I'll need to re-read with fresher eyes later. It has figures with turbine mass flow, exhaust temperature, etc. of modeled and measured (from Ferrari) data. It’s a free download.

Funny enough, I was looking for combustion traces from a NASCAR engine at lunch today when I found this and a few other papers from the same authors. One goes into how Ferrari detects pre-ignition and knock on their engine circa 2017.

[saviour stivala]

How can an exhaust turbine still be developing significant power in electric supercharging mode with waste-gate open and exhaust gasses by-passing the turbine?.

[saviour stivala]

Correct - however the turbine (MGUH) power will be reduced and the compressor power might be increased. The optimum level of exhaust back pressure is the one that maximises self-sustaining power (crank+turbine-compressor)

. . Although Turbine-MGU-H power has it's importance as to recovery, we were talking about ICE crank peak power.

Not "we".
One of us (I) was talking about self-sustaining PU power which is the power output of the heat engine when fuel is the only energy input. The engine teams are targeting self-sustaining power, not crankshaft power.

Yes. As I already told you, you was actually talking or intending too, about the peak power of the ICE/heat engine. But at the same time you was also adding/contributing to that other things that can add power or effect the peak power output. As to ''sustained power'' It is only now that you have changed the wording from ''peak power'' to ''sustained power''. Arguing a technical subject using these subjects adding/subtracting tactics intended or not can only result in confusion and not clarity of the subject at hand.

[vorticism]

From that paper:

. . . By contrast, for the considered high-performance power unit the waste-gate is used to increase the engine power by diminishing the exhaust manifold pressure. The turbine power extraction is reduced and therefore the MGU-H power recuperation goes roughly to zero (when no upshift is taking place). The intake manifold pressure is not affected, the engine pumping power increases and so does the overall engine power. . . .

…

. . . . Opening the waste-gate comes at the expense of a lower MGU-H recuperation: in fact, the average MGU-H recuperation (on straight) is roughly zero if the waste-gate is kept always open. . . .

These two quotes suggest that the turbine is still developing significant power in "electric supercharging" mode. In fact if "the average MGU-H recuperation (on straight) is roughly zero" is correct the MGUH power required to run the compressor is zero.

It depends on what they mean by "turbine power extraction." Whether we take that to mean compounding only or combined compounding and compressor drive power.

In the early days the Ferrari wastegate was almost as large as the main exhaust. Which might suggest effectively a total loss of turbine power when in use.

Need to solve for these potential regimes:

Compressor: driven by MGUH alone
Compressor: driven by turbine alone
Turbine: driving MGUH and compressor
Turbine: driving compressor only
Turbine: driving nothing