2014-2020 Formula One 1.6l V6 turbo engine formula

[ringo]

From what I've heard and read. The current F1 engines are already more efficient than road cars. The problem comes with aerodynamic drag etc and the rpm they run at, I could be wrong but I heard somewhere that the engine as a unit is more efficient than a prius engine if you took away these factors. Someone will probably prove me wrong, though!

Current F1 V8 have 29% brake thermal efficiency (BTE) with petrol that is basically composed from the same ingredients as road car petrol. Historic turbo F1 cars have reached 30.6% BTE with fuel that was specially composed from n-heptane and

you've changed your tune there WB, i was saying 29% all allong, you were somewhere in the high 30's. I guess since you saw the 170kg in the article with tafin, you made an adjustment to your "facts". lol

[ringo]

"2014, we are with the engine an overall efficiency of 40, maybe achieve 45 percent something like And that sounds like a magic number to, as soon as the engine of a normal road cars we are a maximum of 30, 35 percent..."

My interpretation of that statement is that the output is crank-power plus MGU-H, which would mean the following;

a) 40% of 27.8 g/s at 46 kJ/g means a total of 511 kW (695 Hp).

b) 35% efficiency of the engine itself means 448 kW (610 Hp).

c) 511 - 448 = 63 kW (85 Hp) from the MGU-H.

Makes sense?

Yup. No magic smoke and mirrors there.

[ringo]

.......... exploited by the waste heat recovery system.

there is no waste heat recovery system in 2014 F1
despite the impression that you (and the FIA) are again trying to cultivate
the French have been spraying around the buzzword 'thermal' for over 50 years, eg for their special interest at Le Mans
they love to do this, it means nothing

the turbine recovers waste kinetic energy or waste pressure energy
as is shown by the energy recovery balance for the Wright T-C Fig 15 in the reference that I gave
a week ago you seemed to accept this

waste heat can only be recovered by eg adding the Rankine ('steam') cycle or the Stirling ('air') cycle
BMW seem (contrary to the impression you choose to give) to have done substantial 'Turbosteamer' work since 2006
now recovering from both exhaust and coolant heat

the waste heat in an SI engine exhaust is usually as large as the entire engine output power (car diesels similarly with coolant)
if turbines actually recovered this engines would long ago have in this way become conspicuously efficient
rather than still being conspicuously inefficient

No you are wrong there my friend. the temperature of the exhuast will drop when the generator is engaged.

[ringo]

Would hot stagnant air turn the turbine?

No, the energy quality would be too low. Remember the pressure difference is what drives the air. If the air is hot and stagnant that is telling you that the pressure gradient is to low. If the pressure before turbiner and after turbine are equal you wont get movement of air.
A turbine is mainly driven by pressure, and all this is tied to the specific gravity of the air, the internal energy, the temperature etc.

What i must say though is that any peak efficiency that we may be hearing out of the teams will be at one specific point, that wont be experienced on track.
I'll stick with an overall thermal efficiency of 39% if you consider storing the energy as useful as powering the flywheel, but an overall brake thermal efficiency of about 36%f if you look on the flywheel power itself.
Anywhere outside of that is some tailored in lab direct injection trickery, with disjointed manipulation of the different systems on the engine that won't be realized in race trim or race power.

40% is what i feel is acceptable, if we believe what they consider useful power includes storing energy. Being cognisant that definition of efficiency each team uses will vary and will have a say on what the % they state is.

For me that 40% is defined as ICE flywheel power + MGUK power + Flow of power to the ES.

The MGUK+ Flow of power to ES equal to MGUH unlimited draw from the turbo

[WhiteBlue]

From what I've heard and read. The current F1 engines are already more efficient than road cars. The problem comes with aerodynamic drag etc and the rpm they run at, I could be wrong but I heard somewhere that the engine as a unit is more efficient than a prius engine if you took away these factors. Someone will probably prove me wrong, though!

Current F1 V8 have 29% brake thermal efficiency (BTE) with petrol that is basically composed from the same ingredients as road car petrol. Historic turbo F1 cars have reached 30.6% BTE with fuel that was specially composed from n-heptane and

you've changed your tune there WB, i was saying 29% all allong, you were somewhere in the high 30's. I guess since you saw the 170kg in the article with tafin, you made an adjustment to your "facts". lol

I think you are mixing something up. The naked v6 turbo ICE was the engine with 35-38% BTE, not the V8. If You find a post where I put the v8 at 35 % I would like to know about it.

You are probably relating to this post!

Brake thermal efficiency
BTE0 = P0/E = 38 %
BTE1 = P1/E = 41%

what kind of heating values are you using?
Is this the value for the current V8?

You were quoting from my post about the BTE of the V6 on page 258 Link and asking for the heating values of the fuel. I confirmed that I use the same specific heat values for F1 fuel regardless of the engine, 46 MJ/kg.

[WhiteBlue]

The exhaust temperature should surely be measured after the turbine in a turbo engine right??

It depends what you want to achieve. Remember that Renault are now insulating the exhaust headers with shrouds in order to prevent exhaust energy being lost. That would be heat energy that will reduce the turbine energy if you would not insulate the headers. To provide proof you would have to measure the temperature at turbine entry or rely on computation.

[rjsa]

Would hot stagnant air turn the turbine?

We are talking points 4 => 5 here. I can't find a radial turbo-compressor turbine diagram, this will have to do. Both pressure and temperature decreasing inside the turbine during expansion.

I call that heat recovery. If there is another term please enlighten me, I studied this stuff almost 3 dacades ago and in portuguese.

[ringo]

It's not heat recovery in an ideal sense, but yeat the temp will drop through the turbine.
It's just that the internal energy of the air, the working fluid, is related to it's temperature; if we understand the concept of heat.
3 to 4 is when heat is added at constant pressure,
0 to 8 is the heat that is rejected from the turbine at exhaust pressure. Those isobars, or pressure lines diverge as you go to the right, so when u increase combustor temps point 4 will be further from point 8; increasing work output.
To increase work output you can also reduce Po to have a bigger gap between 4 and 8.

[rjsa]

It's not heat recovery in an ideal sense, but yeat the temp will drop through the turbine.
It's just that the internal energy of the air, the working fluid, is related to it's temperature; if we understand the concept of heat.
3 to 4 is when heat is added at constant pressure,
0 to 8 is the heat that is rejected from the turbine at exhaust pressure. Those isobars, or pressure lines diverge as you go to the right, so when u increase combustor temps point 4 will be further from point 8; increasing work output.
To increase work output you can also reduce Po to have a bigger gap between 4 and 8.

I know exctly what the brayton cycle is, what this diagram represents. Let's stick to 4=>5, which also representes the behaviour of the turbine section of a turbo-compressor.

When that turbine is connected to an alternator or dynamo, getting the wasted energy from the exhaust and charging a battery, how do you call that?

[ringo]

I know you know, but just for the other readers of the forum.

Well you can't use that diagram, reason being 3-4 cannot represent the engine.
you may have to use a broken cycle diagram. Gimme a sec to draw up something.

[ringo]

By the way, we don't have to pump up the power numbers to prove the efficiency,

Here is another example from my simulator:

ENGINE BRAKE POWER 563.41
brake thermal efficiency ηther 28.56%

brake thermal efficiency with MGUH
,+120kW MGUK 35.49%
improvement 6.93%

brake thermal efficiency with MGUH
MGUH unlimited 38.92%
improvement 10.36%

it works out pretty ok i guess because my equations are linked, i'm not pasting percentages here or there. just change certain conditions and things work out themselves. So even with my anemic 563hp the efficiency is pretty good.

The efficiency with MGUH is represented at 120kW going to the flywheel from the MGUh-MGUK, and the unlimited is assuming all what is generated is going to the flywheel. This is not the case, but i'm assuming the teams are using the storing rate of ES as part of their efficiency excuse.
This i feel is behind the Mercedes aim of 40%, if you notice i'm relatively close with 38.92.

[rjsa]

I know you know, but just for the other readers of the forum.

Well you can't use that diagram, reason being 3-4 cannot represent the engine.
you may have to use a broken cycle diagram. Gimme a sec to draw up something.

Ok, so for the sake of the readers that diagram represents what usually happens in a jet engine, where, you collect from atmosphere, compress adiabatically (without heat loss, fixed entropy S), heat at fixed pressure (burn the fuel) then expand the burnt mixture adiabatically again to then release the gases back to the atmosphere.

The 8=>0 segment occurs outside the system, since you collect and expel the air to the environment.

[Holm86]

The exhaust temperature should surely be measured after the turbine in a turbo engine right??

It depends what you want to achieve. Remember that Renault are now insulating the exhaust headers with shrouds in order to prevent exhaust energy being lost. That would be heat energy that will reduce the turbine energy if you would not insulate the headers. To provide proof you would have to measure the temperature at turbine entry or rely on computation.

Highest total efficiency is what we want to achieve. And if the thermal efficiency of an internal combustion engine is given by (T1-T2)/T1 then the T2 should be measured after the turbine in a turbo engine.

If you want the know the efficiency of the turbine you also need to measure the temperature before the turbine.

What I am getting at is should it matter if the exhaust temperature before the turbine gets higher if the temperature after stays the same??? Or would that just mean that the TE of the ICE becomes lower and the TE of the turbine gets higher??

Because I get the point of shrouding the exhaust to increase the efficiency of the turbine. But does that decrease the efficiency of the ICE at the same point??

[wuzak]

The exhaust temperature should surely be measured after the turbine in a turbo engine right??

It depends what you want to achieve. Remember that Renault are now insulating the exhaust headers with shrouds in order to prevent exhaust energy being lost. That would be heat energy that will reduce the turbine energy if you would not insulate the headers. To provide proof you would have to measure the temperature at turbine entry or rely on computation.

Highest total efficiency is what we want to achieve. And if the thermal efficiency of an internal combustion engine is given by (T1-T2)/T1 then the T2 should be measured after the turbine in a turbo engine.

If you want the know the efficiency of the turbine you also need to measure the temperature before the turbine.

What I am getting at is should it matter if the exhaust temperature before the turbine gets higher if the temperature after stays the same??? Or would that just mean that the TE of the ICE becomes lower and the TE of the turbine gets higher??

Because I get the point of shrouding the exhaust to increase the efficiency of the turbine. But does that decrease the efficiency of the ICE at the same point??

For the record, in my previous explanation I understod that the "exhaust temperature" as described by WB was after the turbine.

And having a quick calculation I can now see that you can still get a gain in efficiency if both the engine temperature and exhaust temperature rise if the latter is smaller than the former, but not always (depends on the relative change of Temperatures).

Back to my example:
Engine at 1000K, exhaust at 650K - TE = 35%
Engine up to 1100K (+100K), exhaust 700K (+50K) - TE = 36%
Engine 1100K (+100K), exhaust 725K (+75K) - TE = 34%

Note that increased temperatures in teh combustion chamber can be bad for the combustion processes.

I would also think that given the same turbine, it does not necessarily follow that an increase in temperature before the turbine will lead to greater energy recover. It may just lead to hotter exhaust.

[WhiteBlue]

The system from the exhaust valves to the exit of the turbine is closed. So any increase in temperature will lead to a higher pressure of the gas. That means that the engine may see a reduction of the work it can extract. But because I have a second working engine in the chain it does not worry me. The delta p of the turbine is not fixed. It is the exit pressure and temperature that is typically fixed. So an increase in temperature and pressure between exhaust valves and turbine entry is generally good for my total efficiency if I can handle the thermal load on the turbine and the valves with my design.