Max power, at 10500RPM or higher than 10500RPM?

[Jolle]

SS, before 2014 there was no fuel flow limit at any RPM. Why then did the manufacturers run the engines at such high RPM if it only took them further from the so-called max power RPM (ie. max grams/CE) you are describing?

I don't think you understand the principle of how you get power. Burning fuel get you power, burn more fuel, get more power. To burn more fuel you need more air (the oxygen you need), so, in N/A engines, higher RPM means more air and that means more power. Max fuel flow is at max rpm, by definition.

For turbo engines it's the same, more fuel is more power and for that you need more air. Because you don't need to suck the air in with the pistons, but push it in with the turbo, rpm or even displacement is irrelevant. In turbo engines boost is the dominating factor. more boost is more air is more fuel is more power.

With N/A engines air intake was regulated with the displacement at first, making that all manufactures were searching for even higher rpm's, until they really caped this off with a rpm limit.

With turbo engines of any discplacement and/or rpm with unregulated boost, power is in theory unlimited (remember, boost=power)

so, in other series they choose to limit air intake by restrictors to prevent unlimited power and have weird engines but opted for a fuel limit. Also because rpm is in theory also unrelevent, they have set a value that still sounds like more or less a racing engine and that is that 10.500 rpm. A value that is easy to manage with current tech, without any trouble of blowing up engines or the need of next get technology.

[PlatinumZealot]

For turbo charger in V6 hybrid fuel saving its a bit tricky.

Reliability (strength of parts versus weight)
Fuel efficiency
Turbo lag
Cooler size

Will also come into play in limting the horsepower.

We saw mercedese run a tight power limiting chassis design on hot tracks this year.

[MarcJ]

SS, before 2014 there was no fuel flow limit at any RPM. Why then did the manufacturers run the engines at such high RPM if it only took them further from the so-called max power RPM (ie. max grams/CE) you are describing?

I don't think you understand the principle of how you get power. Burning fuel get you power, burn more fuel, get more power. To burn more fuel you need more air (the oxygen you need), so, in N/A engines, higher RPM means more air and that means more power. Max fuel flow is at max rpm, by definition.

For turbo engines it's the same, more fuel is more power and for that you need more air. Because you don't need to suck the air in with the pistons, but push it in with the turbo, rpm or even displacement is irrelevant. In turbo engines boost is the dominating factor. more boost is more air is more fuel is more power.

With N/A engines air intake was regulated with the displacement at first, making that all manufactures were searching for even higher rpm's, until they really caped this off with a rpm limit.

With turbo engines of any discplacement and/or rpm with unregulated boost, power is in theory unlimited (remember, boost=power)

so, in other series they choose to limit air intake by restrictors to prevent unlimited power and have weird engines but opted for a fuel limit. Also because rpm is in theory also unrelevent, they have set a value that still sounds like more or less a racing engine and that is that 10.500 rpm. A value that is easy to manage with current tech, without any trouble of blowing up engines or the need of next get technology.

I don't think you understand chemical kinetics, the chemical reactions the fuel goes through in a lean environment, according to Prof Heinz Pitch the major reaction is the production of hydroxyl radical how fast you produce OH radicals that rip hydrogen off. It's the rate coefficients that define this that gives the fuel burning rate.

Let's say the fuel is optimised for lambda 1.45. Tommy Cookers was more right than my guess of 1.6.

[MatsNorway]

Back to the original question.
I do think they optimize it for 10.5k. They can not afford to loose power and they can not afford to run less efficiency than possible. That is extra weight, fatter rads and then a fatter car with more drag or less downforce. Extra wear too.

Like GG have said they lose power due to friction all the way up to the shift point. And with a flat fuel flow these things have the flattest power curve any F1 car have ever had most likely. Well within what a driver would find troublesome when being flat out.

[henry]

Back to the original question.
I do think they optimize it for 10.5k. They can not afford to loose power and they can not afford to run less efficiency than possible. That is extra weight, fatter rads and then a fatter car with more drag or less downforce. Extra wear too.

Like GG have said they lose power due to friction all the way up to the shift point. And with a flat fuel flow these things have the flattest power curve any F1 car have ever had most likely. Well within what a driver would find troublesome when being flat out.

At most circuits they run most of the race above 10500. If they optimise for 10500 they will spend most of the race below the optimum power. I don’t think they do that. In fact I’ve measured it and I’m convinced that at Singapore last year Ferrari optimised for around 11200 rpm.

[MatsNorway]

At most circuits they run most of the race above 10500. If they optimise for 10500 they will spend most of the race below the optimum power. I don’t think they do that. In fact I’ve measured it and I’m convinced that at Singapore last year Ferrari optimised for around 11200 rpm.

Yeah you would never run below 10.5 even if optimized for 10.5k. My thinking is that they will taper of from whatever they are optimum at anyway due to rpm increase. So why not go as low as possible for the highest average. The highest average across the rpm they use would be from 10.5 to whatever, then next gear chance takes them to 10.5 again..

Do you claim that from you can see they chance gear "late" so that the engine never goes as low as 10.5?

Thinking about it, i guess one early shift could be more loss in time than one late.
so you have a fair point in that they are humans not machines so staying above 10.5k might be more important than getting the absolute maximum.

However, that does not mean the engine should not be optimized for its maximum potential. On the straights they would probably try to hit so they are on the 10.5 and up.

Also.. gotta watch Mercedes man They have the best engine. haha

[gruntguru]

If you want to maximise average power across the finite range required for a multi-ratio gearbox (and you do) and power peak is at a single rpm (and it is), the maximum power rpm will lie somewhere between the upper and lower rpm limits of that range.

In other words the power peak will be above 10,500 rpm.

[saviour stivala]

Where will the additional fuel flow rate above that mandated by the rules comes from for a max power speed above 10500 RPM?.

[hollus]

No extra fuel needed. The fuel amount is the same. The available energy is the same. Friction is only one of a lot of factors that influence power output. And while one probably cannot optimize for minimum friction above 10500, one can probably optimize for maximums of many other things around 11000rpm. Namely timings, AFR, details of gas flow, swirl, etc., etc., which would influence the amount of fuel burned (never 100%) and the amount of heat rejected to the cylinders, etc, etc.
Friction (which favors 10500, true) is only one factor between many.

By the way, we shouldn't be having the same conversation from pages 1 and 2 in this same thread again, should we?

[saviour stivala]

No extra fuel needed. The fuel amount is the same. The available energy is the same. Friction is only one of a lot of factors that influence power output. And while one probably cannot optimize for minimum friction above 10500, one can probably optimize for maximums of many other things around 11000rpm. Namely timings, AFR, details of gas flow, swirl, etc., etc., which would influence the amount of fuel burned (never 100%) and the amount of heat rejected to the cylinders, etc, etc.
Friction (which favors 10500, true) is only one factor between many.

By the way, we shouldn't be having the same conversation from pages 1 and 2 in this same thread again, should we?

“Where will the additional fuel flow rate above that mandated by the rules comes from for max power speed above 10500 RPM?”. “No extra fuel is needed”. At 10500 RPM the engine is producing 5250 combustions per minute and consuming 1.666 kg/min of fuel. At 11000 RPM the engine will be producing an additional 250 combustions per minute (5500 combustions per minute) which will have to share the same 1.666 kg/min of fuel. Which means that maximum power speed is set/dictated by the mandated maximum 100 kg/h fuel flow rate.
Agree. ‘WE’ shouldn’t have had to go through the same conversation from pages 1 and 2.

[MatsNorway]

Allright i agree or see it now.

10.5 to 11ish sounds ideal due to practical reasons ala. human errors. That must be why they do it correct?

But in theory if a machine chanced gears surely you would make it peak as low as possible.

Either way.. Flat fuel flow is the best and ideal scenario for the future. You get more power, a more road relevant engine, a challenge for the engineers and a better sounding engine as it does not run oh so lean and gentle (far below its limits) until it hits the peak.

[hollus]

...At 11000 RPM the engine will be producing an additional 250 combustions per minute ... which will have to share the same 1.666 kg/min of fuel...

It is fuel burned per minute, not per combustion event that powers the car. Power = Energy / Time.

[saviour stivala]

...At 11000 RPM the engine will be producing an additional 250 combustions per minute ... which will have to share the same 1.666 kg/min of fuel...

It is fuel burned per minute, not per combustion event that powers the car. Power = Energy / Time.

The allowed maximum fuel burned per minute is 1.666 kg/min at 10500 RPM, at which RPM the engine is producing 5250 combustions per minute. At 11000 RPM the engine is producing 5500 combustions per minute with each added combustion having to share the same maximum amount of fuel which will result in less powerful combustions because there is less fuel per combustion. More power needs More fuel.

[subcritical71]

...At 11000 RPM the engine will be producing an additional 250 combustions per minute ... which will have to share the same 1.666 kg/min of fuel...

It is fuel burned per minute, not per combustion event that powers the car. Power = Energy / Time.

The allowed maximum fuel burned per minute is 1.666 kg/min at 10500 RPM, at which RPM the engine is producing 5250 combustions per minute. At 11000 RPM the engine is producing 5500 combustions per minute with each added combustion having to share the same maximum amount of fuel which will result in less powerful combustions because there is less fuel per combustion. More power needs More fuel.

With this reasoning the maximum power per combustion would then be at the lowest possible RPM (ie. as close to 0 RPM as possible). Even with the reduction of fuel flow below 10,500 RPM there is more fuel available per CE the lower in RPM you go...

For example...
10,500 RPM = 5,250 CE = 0.317460317 g/CE (baseline)
10,000 RPM = 5,000 CE = 0.318333333 g/CE = 0.275% more fuel available per CE
5,000 RPM = 2,500 CE = 0.333333333 g/CE = 6.05% more fuel available per CE
1,000 RPM = 500 CE = 0.483333333 g/CE = 52.25% more fuel available per CE....

This is why power (energy over time) instead of events needs to be considered.

[gruntguru]

More power needs More fuel.

Crankshaft power = fuel chemical power x conversion efficiency.

More crankshaft power needs:
- more fuel . . . OR . . .
- better conversion efficiency.

If you consider the rpm range from 10,500 to 15,000 - fuel chemical power is constant and conversion efficiency is a parameter that depends on rpm and a number of engine design choices. Friction will normally dictate best conversion efficiency at the lowest rpm (10,500) but there are a number of design parameters that allow the designer to move the peak conversion efficiency to some higher rpm - say 11,000 - at some small cost to the ultimate value of conversion efficiency (and therefore peak power). I refer you again to the following chart where the orange curve outperforms the blue curve for a gearbox with 15% ratio spacings (I don't recall the actual ratios used in current F1 cars). The shift points for max acceleration would utilise an operating range of approximately 10,400 - 12,000.