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

[saviour stivala]

“Could be for some reason all three of the original engine manufacturers where very clear to what RPM the engine shifted back to at 2014, 10500rpm, the same revs where max flow was beginning”. As explained earlier in the thread, they were ‘forced’ into designing for a max power speed of 10500rpm when the max RPM point at which the max flow was ‘added’ to the max fuel flow rate rule. Because it represented the max fuel flow volume (0.0528 grams) for each of the 31500 combustions per minute produced at that RPM. If that max RPM at which max fuel flow was to be reached wasn’t added on, the engine designers would have gone for a much lower max power speed.

[hollus]

stivala, I think you are making things confusing in a particular aspect, related to language.
Do we agree that the rules have a max fuel range, not point, between 10500 and 15000 rpm? That they are allowed the same fuel per second everywhere in that range?
And do we agree that the cars are driven back and forth over a range of about 1500rpm as they go up the gears?

I think talking of ranges, not points, would avoid a lot of misunderstandings.

Now back to IMHO: the engineering challenge was never to optimize PUs for a certain RPM, but for a range of about 1500 RPM. Back in 2014, for many teams, this range was about 2000rpm until they narrowed the gearing.

[Jolle]

stivala, I think you are making things confusing in a articular point.
Do we agree that the rules have a max fuel range, not point, between 10500 and 15000 rpm? That they are allowed the same fuel per second everywhere in that range?
And do we agree that the cars are driven back and forth over a range of about 1500rpm as they go up the gears?

I think talking of ranges, not points, would avoid a lot of misunderstandings.

Now back to IMHO: the engineering challenge was never to optimize PUs for a certain RPM, but for a range of about 1500 RPM. Back in 2014, for many teams, this range was about 2000rpm until they narrowed the gearing.

yes, yes and yes. and because all the manufactures use the 10.500 - 12.000 rpm at all times, without exception, suggest that they use 100kg/h all of the time. With the fuel flow per cycle at max at 10.500 this gives max torque at that precise point and despite all the theories, engine friction, heat management etc is at its best at as low rpm as possible, therefore max power is also at 10.500 rpm.

[hollus]

Truth be said, in practice they often are at 10300 after an upshift.
I have seen this umpteen times while collecting gearing data.
But talking of 10500 simplifies the discussion at hand.

[saviour stivala]

stivala, I think you are making things confusing in a articular point.
Do we agree that the rules have a max fuel range, not point, between 10500 and 15000 rpm? That they are allowed the same fuel per second everywhere in that range?
And do we agree that the cars are driven back and forth over a range of about 1500rpm as they go up the gears?

I think talking of ranges, not points, would avoid a lot of misunderstandings.

Now back to IMHO: the engineering challenge was never to optimize PUs for a certain RPM, but for a range of about 1500 RPM. Back in 2014, for many teams, this range was about 2000rpm until they narrowed the gearing.

yes, yes and yes. and because all the manufactures use the 10.500 - 12.000 rpm at all times, without exception, suggest that they use 100kg/h all of the time. With the fuel flow per cycle at max at 10.500 this gives max torque at that precise point and despite all the theories, engine friction, heat management etc is at its best at as low rpm as possible, therefore max power is also at 10.500 rpm.

It should be expressed as "with max fuel flow reached at 10500rpm it is the RPM at which combustion will peak/be the strongest (max power speed)". above that max power speed combustion can only weaken because while max fuel flow stays the same, the RPM increasing will increase the number of combustions each of which will have to share the same volume of fuel the leaser number of combustions did.

[Tommy Cookers]

Truth be said, in practice they often are at 10300 after an upshift.
I have seen this umpteen times while collecting gearing data.....

so (at 10300 rpm) a maximum of 98.2 kg/hr
this has somewhat reduced the notional mismatch (compared to an operating range starting at 10500 and 100 kg/hr)

and as has been said by others the rpm range of interest here has been reduced in recent years
partly as teams made the high gears closer than before
then more with 8 overall ratios fixed but cars giving increased corner speeds combined with decreased maximum speeds
is there still the permitted annual ratio change usually taken up after the Monaco GP ?

[saviour stivala]

Truth be said, in practice they often are at 10300 after an upshift.
I have seen this umpteen times while collecting gearing data.....

so (at 10300 rpm) a maximum of 98.2 kg/hr
this has somewhat reduced the notional mismatch (compared to an operating range starting at 10500 and 100 kg/hr)

and as has been said the rpm range has been reduced in recent years
with 8 overall ratios fixed but increased corner speeds combined with decreased maximum speeds
is there still the permitted annual ratio change usually taken up at the Monaco GP ?

Aren’t gear ratios in Monte Carlo to be the same as those at Monza or anywhere else according to the rules?

[hollus]

Yep, that is correct. Fixed for the year, the same for Monaco and Monza.

[63l8qrrfy6]

stivala, I think you are making things confusing in a articular point.
Do we agree that the rules have a max fuel range, not point, between 10500 and 15000 rpm? That they are allowed the same fuel per second everywhere in that range?
And do we agree that the cars are driven back and forth over a range of about 1500rpm as they go up the gears?

I think talking of ranges, not points, would avoid a lot of misunderstandings.

Now back to IMHO: the engineering challenge was never to optimize PUs for a certain RPM, but for a range of about 1500 RPM. Back in 2014, for many teams, this range was about 2000rpm until they narrowed the gearing.

yes, yes and yes. and because all the manufactures use the 10.500 - 12.000 rpm at all times, without exception, suggest that they use 100kg/h all of the time. With the fuel flow per cycle at max at 10.500 this gives max torque at that precise point and despite all the theories, engine friction, heat management etc is at its best at as low rpm as possible, therefore max power is also at 10.500 rpm.

It should be expressed as "with max fuel flow reached at 10500rpm it is the RPM at which combustion will peak/be the strongest (max power speed)". above that max power speed combustion can only weaken because while max fuel flow stays the same, the RPM increasing will increase the number of combustions each of which will have to share the same volume of fuel the leaser number of combustions did.

But you will have more smaller combustions in the same amount of time and as such the power will not drop.

[sosic2121]

But you will have more smaller combustions in the same amount of time and as such the power will not drop.

Would these "smaller combustions" (for example at 11k rpm) allow for higher CR to increase efficiency a little bit?
Maybe enough to offset the losses which increase with rpm?

Engine would be more efficient and create more power everywhere except 10500 rpm.

[Jolle]

yes, yes and yes. and because all the manufactures use the 10.500 - 12.000 rpm at all times, without exception, suggest that they use 100kg/h all of the time. With the fuel flow per cycle at max at 10.500 this gives max torque at that precise point and despite all the theories, engine friction, heat management etc is at its best at as low rpm as possible, therefore max power is also at 10.500 rpm.

It should be expressed as "with max fuel flow reached at 10500rpm it is the RPM at which combustion will peak/be the strongest (max power speed)". above that max power speed combustion can only weaken because while max fuel flow stays the same, the RPM increasing will increase the number of combustions each of which will have to share the same volume of fuel the leaser number of combustions did.

But you will have more smaller combustions in the same amount of time and as such the power will not drop.

Yes, a simplified theory.

In the simplified theory the amount of power is only dependent of the amount of fuel you burn in an amount of time. In theory it shouldn't matter if you have a 1 cylinder 500 cc with a big turbo or a 3l v12. Fuel has an amount of energy, burn that and you have power.
But in real life, you have to take in all the losses, which are greater with the rise of rpm.

So, this rule with a fuel flow instead of a max displacement to limit power, it's all about efficiency. Who can build the engine which can extract as much power out of the fuel by cutting the losses as much as possible. In the N/A days efficiency was not as important because fuel wasn't limited and before that, with re-fueling even more so.

Torque of course, is quite steady up to the 10.500 point and then drops, because every combustion has a smaller push. Up to that point the fuel is, with the formula they use, pretty steady per cycle.

[63l8qrrfy6]

Yes, a simplified theory.

In the simplified theory the amount of power is only dependent of the amount of fuel you burn in an amount of time. In theory it shouldn't matter if you have a 1 cylinder 500 cc with a big turbo or a 3l v12. Fuel has an amount of energy, burn that and you have power.
But in real life, you have to take in all the losses, which are greater with the rise of rpm.

I completely agree.
GG has already addressed the point that it is preferable to optimize for slightly lower peak power caused by such losses after 10500 rpm in exchange for a flatter power curve in the usual operating speed range.

[saviour stivala]

There will be a 13.21% decrease in fuel flow use in each combustion per minute between 10500rpm max fuel flow/max power speed and 12000RPM.

[hollus]

There will be a 13.21% decrease in fuel flow use in each combustion per minute between 10500rpm max fuel flow/max power speed and 12000RPM.

No one is disputing that.

At the same time, you'll have a 13.21% increase in the number of combustions per minute, which doesn't quite compensate, but is not too far from it.

The fact is that you have to accept being at 12000 just as many seconds as you are at 10500, it is the price to pay for upshifts. And the reason one might want to compromise. Even if you really have your peak at 10500 (the best possible peak power and the easiest thing to set-up), you will still run, quite a bit of time, at 12000, where you will be quite compromised. Your ICE will spend approximately the same amount of time at 10500 as at 10600, 10700 ...11000, 11100 ... 11900 and 12000 rpm.

The only way to avoid running at 12000rpm some of the time is running at 9000rpm some of the time, which is obviously much worse.

[henry]

There will be a 13.21% decrease in fuel flow use in each combustion per minute between 10500rpm max fuel flow/max power speed and 12000RPM.

No one is disputing that.

At the same time, you'll have a 13.21% increase in the number of combustions per minute, which doesn't quite compensate, but is not too far from it.

The fact is that you have to accept being at 12000 just as many seconds as you are at 10500, it is the price to pay for upshifts. And the reason one might want to compromise. Even if you really have your peak at 10500 (the best possible peak power and the easiest thing to set-up), you will still run, quite a bit of time, at 12000, where you will be quite compromised. Your ICE will spend approximately the same amount of time at 10500 as at 10600, 10700 ...11000, 11100 ... 11900 and 12000 rpm.

The only way to avoid running at 12000rpm some of the time is running at 9000rpm some of the time, which is obviously much worse.

Aerodynamic drag will mean that you spend more time at the higher revs since it causes acceleration to decrease and it takes longer for each 100rpm increment. Another reason to move peak power above 10500.

I could reverse the calculation process I used to establish the shape of the power curve for Vettel’s Ferrari at Singapore. Does anyone want to give me a shape starting with a peak at 10500?