2014-2020 Formula One 1.6l V6 turbo engine formula

[321apex]

BMEP=IMEP-FMEP
BMEP -> torque at the crank
IMEP -> mechanical potential from combustion
FMEP -> all frictional losses, pumping, mechanical
The higher the engine speed with limited fuel, the higher are the friction losses (FMEP)... and LESS brake POWER. So ideal power peak is at 10500 RPM, however you must factor in the RPM spread for the gearing, which will force you to rev the engine in a zone of DIMINISHING FUEL efficiency [BSFC].
Engine speed of 15k RPM is the worst possible option. IMHO
Think about this:
- Will an engine make more power at 11k or at 10k?
- How much less power will you make at 15k vs 11k? What will be your BSFC at 15k?

whilst I agree that the engine will not work well over the whole 10500-15000 rpm range (I said so 18 months ago) ...
the friction losses will rise slower with increased rpm than the supercharging work will fall
12500-14500 rpm running could work very well in 2014 (partly because fuel is still freely available at rpm below this (to 10500)
but has no future as it's not compatible with backpressure operation of the turbine
which will be needed when fuel allocation is reduced in the future

btw your Raijput doesn't understand the Wright Turbo-Compound, or more importantly, the magneto

I disagree that fuel is "freely available" since you pay the weight penalty of carrying it on board. Just imagine, that you could have 10% lower average BSFC per lap, which means you could start a race with 90 kg of fuel, saving up to 10 kg in vehicle mass over at least some early portion of a race distance.

The "free " turbine work you are hoping to harness IS NOT FREE, it still comes from the fuel tank. If you want to energize MGU-H, you must burn fuel.... and rather inefficiently at that. Conventional, easy ways to spool up turbos is to retard spark timing. But while doing that you increase thermal load on the engine/cooling system and your BSFC takes a hit.

Running engine should not be viewed as an MGU-H propulsion system. MGU-H is of nice benefit as a by-product to reclaim what would be lost in hot exhaust. But compromising engine performance to gain in MGU-H is bunk engineering and a dead end street.
IMHO of course

[langwadt]

BMEP=IMEP-FMEP
BMEP -> torque at the crank
IMEP -> mechanical potential from combustion
FMEP -> all frictional losses, pumping, mechanical
The higher the engine speed with limited fuel, the higher are the friction losses (FMEP)... and LESS brake POWER. So ideal power peak is at 10500 RPM, however you must factor in the RPM spread for the gearing, which will force you to rev the engine in a zone of DIMINISHING FUEL efficiency [BSFC].
Engine speed of 15k RPM is the worst possible option. IMHO
Think about this:
- Will an engine make more power at 11k or at 10k?
- How much less power will you make at 15k vs 11k? What will be your BSFC at 15k?

whilst I agree that the engine will not work well over the whole 10500-15000 rpm range (I said so 18 months ago) ...
the friction losses will rise slower with increased rpm than the supercharging work will fall
12500-14500 rpm running could work very well in 2014 (partly because fuel is still freely available at rpm below this (to 10500)
but has no future as it's not compatible with backpressure operation of the turbine
which will be needed when fuel allocation is reduced in the future

btw your Raijput doesn't understand the Wright Turbo-Compound, or more importantly, the magneto

I disagree that fuel is "freely available" since you pay the weight penalty of carrying it on board. Just imagine, that you could have 10% lower average BSFC per lap, which means you could start a race with 90 kg of fuel, saving up to 10 kg in vehicle mass over at least some early portion of a race distance.

The "free " turbine work you are hoping to harness IS NOT FREE, it still comes from the fuel tank. If you want to energize MGU-H, you must burn fuel.... and rather inefficiently at that. Conventional, easy ways to spool up turbos is to retard spark timing. But while doing that you increase thermal load on the engine/cooling system and your BSFC takes a hit.

Running engine should not be viewed as an MGU-H propulsion system. MGU-H is of nice benefit as a by-product to reclaim what would be lost in hot exhaust. But compromising engine performance to gain in MGU-H is bunk engineering and a dead end street.
IMHO of course

If you gain more from the MGU-H than you lose because of back pressure it is a win and free, if it wasn't a win they
would all just have a dummy MGU-H

[321apex]

If you gain more from the MGU-H than you lose because of back pressure it is a win and free, if it wasn't a win they
would all just have a dummy MGU-H

Clearly, when you use "if" you speak for all of us, who at this stage of the game are not privi to know the relative efficiencies/deficiencies to make the call. But as I wrote in my previous post, the electricity generated in MGU-H comes from the fuel tank and it is not free. Treating it as a bonus which would otherwise be wasted is more rational.

The MGU-H has to be run because there is no other way to stall the exhaust turbine in order to control boost in absence of traditional wastegate.
The MGU-H has dual roles. Controlling boost and generating electricity.

If something was to fail (hypothetically), which of these functions is more important and needs to be preserved to finish the race?
It's an academic question, because in my view, when you answer it you begin to sway any compromises of it's design towards it's most important function. In my view the most important function is a reliable boost control. Without it you may cook the engine and fail to reach the finish line. It must be said of course, that MGU-H has to get rid of the electricity while it reliably controls boost.

2014 is the first taste engineers get with MGU-H and as such will approach it carefully with a lot of safe margins, which means that we will have to wait 1-2 years for "skin of teeth" efficiencies to be squeezed out.

[321apex]

But, Apex, the original point you made was:
"What that means is that the power peak and torque become "cast in stone" as an event in rev range. By adding or subtracting boost you may move these peaks up or down in value but not much in RPM."

What I am arguing is that for a 2014 F1 turbo engine, that is definitely not true. In fact the opposite: fuel flow limits the power; you can't change the power at all (except minor efficiency changes). But you can operate almost at any rpm you want from 10500 to 15000.

Of course, efficiency (and therefore power) may be a little better at some rpm values than others, but according to the Cosworth simulations, the self-sustaining mode power is pretty flat from 11000 to 13000. If you had the Cosworth engine, this is the range you would like to use in qualifying.

For best efficiency (which is what matters in the race during times you are saving fuel), there could be a reason to go below 11000 rpm if:
1. the ICE has higher efficiency there (probably the case)
and
2. you do not need much MGU-H energy because you almost fully recharge the energy store under braking (probably not).

Otherwise, you want to run where the total efficiency (including MGU-H) is highest: 11000 to 13000 rpm (in the Cosworth case).

I think you are totally overlooking the importance of MGU-H power.

Electric motors can generate constant torque from zero to max rotating speed, and as such can have a linear power output. ICE engines don't have that luxury and have to be engineered to deliver needed power or torque properties.

I've said it before, but sure can repeat it, that if you could make the power you need at lower RPM, then you should do exactly that and... go have a beer . All critical internal engine loads go up with the square of engine speed. Pistons, rods, valve gear have to be made STRONGER in order to be able to run at 15k than if it had to run to 12k. Stronger means larger mass, more inertia, more friction and less efficiency from burned fuel.

Does the car you drive rev to 12k? Why not?

[langwadt]

If you gain more from the MGU-H than you lose because of back pressure it is a win and free, if it wasn't a win they
would all just have a dummy MGU-H

Clearly, when you use "if" you speak for all of us, who at this stage of the game are not privi to know the relative efficiencies/deficiencies to make the call. But as I wrote in my previous post, the electricity generated in MGU-H comes from the fuel tank and it is not free. Treating it as a bonus which would otherwise be wasted is more rational.

The MGU-H has to be run because there is no other way to stall the exhaust turbine in order to control boost in absence of traditional wastegate.
The MGU-H has dual roles. Controlling boost and generating electricity.

If something was to fail (hypothetically), which of these functions is more important and needs to be preserved to finish the race?
It's an academic question, because in my view, when you answer it you begin to sway any compromises of it's design towards it's most important function. In my view the most important function is a reliable boost control. Without it you may cook the engine and fail to reach the finish line. It must be said of course, that MGU-H has to get rid of the electricity while it reliably controls boost.

2014 is the first taste engineers get with MGU-H and as such will approach it carefully with a lot of safe margins, which means that we will have to wait 1-2 years for "skin of teeth" efficiencies to be squeezed out.

if the energy out of the MGU-H comes from exhaust energy otherwise wasted I'd call it free

They are free to have a waste gate if they want and at least some teams do, but it only a safety feature
dumping exhast energy with a waste gate is wasting precious energy

[olefud]

As you know engines are air limited pumps. "Choked flow" sets the limit to ingest air.
http://en.wikipedia.org/wiki/Choked_flow.

If I understand this statement IMHO you’re mischaracterizing choked flow as “the” limiting factor in VE. Choked or supersonic flow is indeed a limit. However, in the intake, it usually comes into play at the curtain area during low valve lift. For the most part flow is compromised by inertia, turbulence, channelizing, direction change poor pressure recover (a form of turbulence) and such. I suppose that a boosted engine could in theory have pressure differences that would induce choked flow in a poor port design. But if you look at jet intake design, particularly ramjets, you will find designs that minimize choked flow.

[wuzak]

If you gain more from the MGU-H than you lose because of back pressure it is a win and free, if it wasn't a win they would all just have a dummy MGU-H

Thy don't have to have an MGU-H at all - it is not mandatory.

[321apex]

if the energy out of the MGU-H comes from exhaust energy otherwise wasted I'd call it free

That was not my argument at all. I supported all along the positive benefit of MGU-H's role of preserving energy.
There were suggestions, that the engine itself should be used as a "propulsion system" for MGU-H, and I disagree with that approach. So you are right - what MGU-H delivers is of benefit and it is free AND we get the functionality of boost control on top of that, which may indeed pose soem challenges in itself.
But in my view the BSFC of the engine itself must be viewed as paramount entity to be optimized.

They are free to have a waste gate if they want and at least some teams do, but it only a safety feature
dumping exhast energy with a waste gate is wasting precious energy

Please realize that you are using incorrect definition of a "wastegate". Wastegate as shown in this picture is one of a combination of two such parts on the Cosworth Indy engine shown. It is a part located near the lower edge of this photo.


It is constructed of a "can" which contains a diaphragm in a chamber connected to a stem of a valve. This valve is actively controlled to move along it's axis and release excess exhaust gas pressure contained between the engine and the turbine housing. There are several different modes of controlling the wastegate. The diaphragm in the can effectively divides it in to two pressure chambers. Tapped access into each chamber allows pneumatic control to be applied to exert valve movement based upon some targeted logic. The spring shown goes in the "top can" although I have seen wastegates having different arrangements.


In it's day, the 2.65L, 45inHga Indy turbo engine would use just 35% of the exhaust gas to drive the turbocharger and make 800HP with steel valve springs and steel connecting rods. Releasing the rest to the atmosphere. Towards the end of CART, the 37.5Hga engines were revving to 18k with steel valve springs making around 900HP. At that point even less exhaust was used to drive the turbo.

What you are speaking of is more like an overboost blow off valve, which is either fully closed or fully open. Wastegate is an important and precise pressure modulating device.

[wuzak]

The rules allow the following fuel flow:
9500 - 91 kg/h
10000 - 96
10500 - 100 = <<<-------GOLDEN POINT

The higher the engine speed with limited fuel, the higher are the friction losses (FMEP)... and LESS brake POWER. So ideal power peak is at 10500 RPM, however you must factor in the RPM spread for the gearing, which will force you to rev the engine in a zone of DIMINISHING FUEL efficiency [BSFC].

In theory - not necessarily in practice.

As we have theorised before, in turbo-compound mode the peak power will be moved up the rpm range.

The reason for this that the constant fuel flow from 10,500rpm dictates a constant mass air flow from the turbo and a falling boost requirement. The exhaust energy doesn't fall as much as the boost, so there is more power to use for the MGU-H. And that the increased MGU-H power more than offsets the increased friction.

The Cosworth graphs seem to confirm a 1000rpm+ shift for peak power to higher rpm.

[321apex]

As you know engines are air limited pumps. "Choked flow" sets the limit to ingest air.
http://en.wikipedia.org/wiki/Choked_flow.

If I understand this statement IMHO you’re mischaracterizing choked flow as “the” limiting factor in VE. Choked or supersonic flow is indeed a limit. However, in the intake, it usually comes into play at the curtain area during low valve lift.

When we deal with racing engines, we are typically interested in "maximums". As such we are interested what is happening at the limit and why.
Here you have a typical power curve, where following a power peak, it tails off. Why is that? Well simply put, with the incremental RPM there isn't equal incremental air going into the combustion chambers to make the power go up.


Why is it not going in? Well something is preventing it I guess and choked flow is one of the key factors.

For the most part flow is compromised by inertia, turbulence, channelizing, direction change poor pressure recover (a form of turbulence) and such. I suppose that a boosted engine could in theory have pressure differences that would induce choked flow in a poor port design. But if you look at jet intake design, particularly ramjets, you will find designs that minimize choked flow.

Racing engine's ports and valves and seats are optimized for FLOW and not for swirl, tumble and all that nice stuff good for emissions. You make a point however with inertial aspects of flow dynamics, which has it's solution in the lengths of ducts themselves.
Ramjet is a supersonic device used in aerospace and while I am not really on the topic I have a feel, that nice and steady state condition of flight may serve very well such an engineering configuration. However inside of a port of an engine we have CHAOS changing every 0.0001 sec. into something else, which isn't exactly steady state. IMHO

[langwadt]

if the energy out of the MGU-H comes from exhaust energy otherwise wasted I'd call it free

That was not my argument at all. I supported all along the positive benefit of MGU-H's role of preserving energy.
There were suggestions, that the engine itself should be used as a "propulsion system" for MGU-H, and I disagree with that approach. So you are right - what MGU-H delivers is of benefit and it is free AND we get the functionality of boost control on top of that, which may indeed pose soem challenges in itself.
But in my view the BSFC of the engine itself must be viewed as paramount entity to be optimized.

They are free to have a waste gate if they want and at least some teams do, but it only a safety feature
dumping exhast energy with a waste gate is wasting precious energy

Please realize that you are using incorrect definition of a "wastegate". Wastegate as shown in this picture is one of a combination of two such parts on the Cosworth Indy engine shown. It is a part located near the lower edge of this photo.
snip
What you are speaking of is more like an overboost blow off valve, which is either fully closed or fully open. Wastegate is an important and precise pressure modulating device.

I know what a waste gate is and Renault say they have a wastegate in case the MGU-H fails or can't reach quick enough

top left corner?
http://img4.auto-motor-und-sport.de/Ren ... 663800.jpg

[chip engineer]

...
Here you have a typical power curve, where following a power peak, it tails off. Why is that? Well simply put, with the incremental RPM there isn't equal incremental air going into the combustion chambers to make the power go up.

https://lh6.googleusercontent.com/-mKvX ... +curve.png
Why is it not going in? Well something is preventing it I guess and choked flow is one of the key factors.
...

The air is not going in because there is not enough pressure differential to give enough airflow in a NA engine at that rpm.
Using airflow limits in NA engine to make a point about a boosted engine makes no sense. Also, with the fuel flow limit, there is no air flow increase needed at high rpm.

[321apex]

...
Here you have a typical power curve, where following a power peak, it tails off. Why is that? Well simply put, with the incremental RPM there isn't equal incremental air going into the combustion chambers to make the power go up.

https://lh6.googleusercontent.com/-mKvX ... +curve.png
Why is it not going in? Well something is preventing it I guess and choked flow is one of the key factors.
...

The air is not going in because there is not enough pressure differential to give enough airflow in a NA engine at that rpm.

I must respectfully say that "you ain't right" on this one . When the flow is "choked" you can not bring any additional flow thru pressure differential increase. It is STUCK! at the level it is.

What would "uncork it"? Cam change, YES YES YES. Now you may ponder the question what does cam change do?

Using airflow limits in NA engine to make a point about a boosted engine makes no sense.

Rest assured, that I am not a pioneer in using analogies drawn from one area of science to explain others. In this case, the NA analogy with Turbo is quite nearly identical if you understand the subject. If my argument makes little sense to you, then you should review in detail the information I provided along until you understand it. What I share here with you is something that was never given to me on a platter. You are getting the gist and are not liking it.

Also, with the fuel flow limit, there is no air flow increase needed at high rpm.

Since when??? Are you inventing new principles of Otto cycle engine operation? Maybe you can provide some citations from technical literature to support this.

Although some measure of charge stratification is possible with direct fuel injection, however what you are expecting isn't supported by any thermodynamic principles.

[Holm86]

Also, with the fuel flow limit, there is no air flow increase needed at high rpm.

Since when??? Are you inventing new principles of Otto cycle engine operation? Maybe you can provide some citations from technical literature to support this.

Although some measure of charge stratification is possible with direct fuel injection, however what you are expecting isn't supported by any thermodynamic principles.

The fuel flow is completely flat from 10500 rpm to 15000. So the airflow will also be completely flat. Thats why the boost pressure needs to drop from 10500 rpm to 15000 rpm.

[Abarth]

[[...]Rest assured, that I am not a pioneer in using analogies drawn from one area of science to explain others. In this case, the NA analogy with Turbo is quite nearly identical if you understand the subject. If my argument makes little sense to you, then you should review in detail the information I provided along until you understand it. What I share here with you is something that was never given to me on a platter. You are getting the gist and are not liking it. [...]

What about continue learning instead of throwing tons of theory together and missing the whole picture?

Why should a configuation which peaks at say 15'000 in N/A not be able to peak at 10'500 when overcharged? Ever heard of overboost mapping, decreasing the boost arbitrarily?

Hint, as Holm86 already pointed out: You need to decrease boost going from 10'500 to 15'000 in these fuel flow restricted engines.
Unless you deliberately are "choking" them earlier, needing to rise the boost again. Not THAT efficient in terms of pumping losses though.... .