2014-2020 Formula One 1.6l V6 turbo engine formula

[dren]

Yes, similar to the steam turbines (although they are axial) here at work in the high pressure, non pulse reguard. Once the pressure is exausted in the first pass, the steam receives a reheat treatment and passes through another section of the turbine (both share the same shaft). They only rotate at 3600rpm steady state, so I don't see the reheat pass as being of benefit to an F1 PU. The high pressure operation is certainly similar, though. It typically drops from around 2000psi to around 500psi, temp drop is 1050F to 700F. I don't know what kind of pressure you are looking at in the exhaust of a SI ICE. I'm guessing we can assume a similar % of pressure and temp drops, thus energy available. There are six control valves where blowdown loss would take place, but they are positioned circumferentially around the blades (buckets) in close proximity to the nozzles. The tube exhaust certainly would help with higher back pressure and blowdown loss as you state TC.

[Pierce89]

[...]

I wonder what that would bring in terms of turbo efficiency. Because in that case the advantage could be threefold: more efficient packaging, less heat into the side pod, and increased turbo efficiency.

It's my understanding that the log-style manifold isn't nearly as efficient as a tubular manifold. I think the advantage is purely one of packaging. (If I tried to explain why, you'd know less about it than when you started. So, I'll leave that to someone more qualified.)

That is also what I understood, that you want to go for equal lenght. But on the other hand I also understand that you can gain efficiency from a turbine from increasing the inlet temperature. Basically you're throwing away potential work by allowing the gas to cool.

From the arrangement it is pretty clear that the Mercedes turbine is running at higher temperatures. For the log the radiating/convecting surface is simply much less. And from the materials and the way they apply them, I have a pretty clear indication that they are trying keep the gas hot.

What I don't know is whether the thermal efficiency gain would offset the loss from not having equal length headers, or even give an overall gain. For that it would be nice if someone more knowledgable could chip in.

Erveryone uses exotic coatings to keep the exhast heat in the pipes. I agree with Ringo about Merc having a larger turbine that allows them to harvest more energy. I think Renault and Ferrari compromised between turbo response and energy recovery, whereas Merc went for max energy recovery, which gives them more than enough extra juice to electronically avoid lag.

[Edax]

Erveryone uses exotic coatings to keep the exhast heat in the pipes. I agree with Ringo about Merc having a larger turbine that allows them to harvest more energy. I think Renault and Ferrari compromised between turbo response and energy recovery, whereas Merc went for max energy recovery, which gives them more than enough extra juice to electronically avoid lag.

If so I would very interested to know what coatings. The tubes are clearly not coated on the outside. It would very much surprise me if the tubes are coated on the inside. From a thermal viewpoint it doesn't matter whether you aply a TBC on the inside or the outside of a tube. However from a practical viewpoint you want to put it on the outside.

Reason is that the methods to inside coat a tube, like suspension coatings usually deliver inferior quality, and also pose a higher risk: The coatings offer lower thermal resistance, are more likely to fail and if it does spall then it ends up downstream in the system (in this case the rotor).

The only reason why inside coatings are sometimes considered is because of temperature limitations. I do know some examples from automotive. If (for a production engine) you want to keep temperatures up in an exhaust manifold, you may consider coating the inside instead of the outside, because this means you can stay with cheap casting alloys instead of going to expensive high temperature alloys.

For F1 it is no problem to go to a superalloy like Alloy 600 or 718, and they can run over 1000C, provided that they are not (cycle)stressed too much. I could be mistaken but I don't think the exhaust gasses run so hot that they run into material limitations.

[Skippon]

Zircotec

http://www.zircotec.com

Check it out!!!!

[Edax]

Zircotec

http://www.zircotec.com

Check it out!!!!

Zircotec (YSZ) is indeed one of the best thermal barrier coatings out there, weight/performance wise. And it would be my first choice for coating, but on the outside. This is normally applied by plasma spraying, HVOF spraying or similar. The problem is you can not run a spraying nozzle through the entire length of the header. For the outside its no problem.

here you can see the difficulty.
https://www.youtube.com/watch?v=pvm4R2wBjvA

Extremely cool process by the way. I

[langwadt]

Erveryone uses exotic coatings to keep the exhast heat in the pipes. I agree with Ringo about Merc having a larger turbine that allows them to harvest more energy. I think Renault and Ferrari compromised between turbo response and energy recovery, whereas Merc went for max energy recovery, which gives them more than enough extra juice to electronically avoid lag.

If so I would very interested to know what coatings. The tubes are clearly not coated on the outside. It would very much surprise me if the tubes are coated on the inside. From a thermal viewpoint it doesn't matter whether you aply a TBC on the inside or the outside of a tube. However from a practical viewpoint you want to put it on the outside.

Reason is that the methods to inside coat a tube, like suspension coatings usually deliver inferior quality, and also pose a higher risk: The coatings offer lower thermal resistance, are more likely to fail and if it does spall then it ends up downstream in the system (in this case the rotor).

The only reason why inside coatings are sometimes considered is because of temperature limitations. I do know some examples from automotive. If (for a production engine) you want to keep temperatures up in an exhaust manifold, you may consider coating the inside instead of the outside, because this means you can stay with cheap casting alloys instead of going to expensive high temperature alloys.

For F1 it is no problem to go to a superalloy like Alloy 600 or 718, and they can run over 1000C, provided that they are not (cycle)stressed too much. I could be mistaken but I don't think the exhaust gasses run so hot that they run into material limitations.

I agree coating the inside would be an unnecessary risk in case something chips off and ruins the turbine, and I would expect valves, seats, pistons etc. to become a problem before hitting the limit of an inconel exhaust

[wuzak]

Yes, similar to the steam turbines (although they are axial) here at work in the high pressure, non pulse reguard. Once the pressure is exausted in the first pass, the steam receives a reheat treatment and passes through another section of the turbine (both share the same shaft). They only rotate at 3600rpm steady state, so I don't see the reheat pass as being of benefit to an F1 PU. The high pressure operation is certainly similar, though. It typically drops from around 2000psi to around 500psi, temp drop is 1050F to 700F. I don't know what kind of pressure you are looking at in the exhaust of a SI ICE. I'm guessing we can assume a similar % of pressure and temp drops, thus energy available. There are six control valves where blowdown loss would take place, but they are positioned circumferentially around the blades (buckets) in close proximity to the nozzles. The tube exhaust certainly would help with higher back pressure and blowdown loss as you state TC.

Reheat won't work for F1 PUs because they are only allowed one turbine stage. Maybe for Le Mans, but where are they getting reheat from - more fuel?

[Holm86]

Is this the most we have seen of any engine so far??
https://twitter.com/gianluca_medeot/sta ... 7338624000

[riff_raff]

I agree coating the inside would be an unnecessary risk in case something chips off and ruins the turbine, and I would expect valves, seats, pistons etc. to become a problem before hitting the limit of an inconel exhaust

That's a great point. Even a tiny flake of ceramic coating breaking loose from the inside of an exhaust pipe and impacting the turbocharger's turbine wheel would cause significant damage due to the extremely high velocity the turbine wheel operates at.

Coating the exhaust pipes with a thermal barrier does not help as much as you would imagine. There is only heat transfer from the exhaust gas to the exhaust pipe wall at the thin boundary layer flow. There is little heat transfer from the core flow. And the heat transfer rate is also limited when the relative delta T between the exhaust gas boundary layer and the red hot inner pipe wall grows smaller.

The parts of the engine that experience the greatest heat transfer are the exhaust valve and seat edges.

[Tommy Cookers]

...... The 1.6 turbo has ample breathing to burn the available fuel - if the charge isn't dense enough, turn up the boost! Less intercooling means hotter exhaust and more energy available to be recovered by the MGU-H ie more power from the same fuel flow. The limiting factor here will probably be thermal stress on the combustion chamber components. This however could be reduced by running more boost and a leaner AFR. DI technology (read stratified charge) makes lean mixtures very do-able and I am sure all the engines are running leaner than stoich' (>14.7:1).

The next bottleneck is turbine inlet temperature. This can also be alleviated by leaner mixture (the energy lost in reduced exhaust temperature is gained in higher mass flow) but will probably be a limiting factor in the end. .......

will the thermal stress on the combustion chamber components be reduced by leaner running ?
because the heat liberated eg at 27.78 gm/sec of fuel is the same at any AFR at or above your example 14.7
2014 F1 AFR above 14.7 needs air added to the stoichiometric air mass (not fuel reduced/fixed air mass as we might in a road car)
requiring disproportionately more work on the charge by the supercharger (eg 20% flow increase takes about 40% pressure increase)
and more work would then be done on that charge by the piston
more work on the charge air means more heat in the combustion chamber
(and of course all this extra work, less the part that naturally useably emerges elsewhere, costs crankshaft power)

IMO we won't see significantly lean mixtures (at WOT) in 2014 ......
DI is inherently stratified charge but most DI benefits are obtainable running a (mean) AFR near to stoichiometric ie .....
core (ie initial) AFR is rich, so combustion starts more rapidly and more consistently than with stoichiometric or leaner mixture
eg according to the paper (once linked in this thread) on Ferrari N/A F1 tests (why N/A F1 always gave the driver the rich option)
also HUCR is higher (due to core richness)
running DI this way has almost all the benefits of rich running
without as with rich PI (ie a rich mean mixture) the wasted weight and bulk of excess (unburnable) fuel
this surely was the reason for DI in many WW2 aircraft engines and some postwar
(they could still gain the in-cylinder cooling benefits if selecting rich mean mixture, but not the benefits to supercharging)
Ferrari won in the 1964 F1 V8 with DI (using less fuel ??) even after Lucas PI was available (though went Lucas in the 1965 F1 flat 12)

DI running lean mean AFR delivers less of its heat near the cylinder and chamber walls
this reduces losses to coolant (and allows higher CR ?)
but there remains extra losses to crankshaft power as mentioned above
my guess is that we won't see lean mean AFR until the fuel allocation/rate is reduced
and only then because there is a minimum capacity (1590 cc ?) and minimum (5730 ?) rpm due to the MGU-K torque limit

[Powerslide]

Isn't part of direct injection fundamentals also in its ability to provide concentrated fuel around the centre of combustion chamber? it would be rather nice if stoichiometric is at peak efficiency central of combustion chamber yet have some fuel saved as the outer portion are learner on lighter engine loads. Can we assume lean mixture to be beneficial to Formula One strategy when operating below maximum power and save some fuel for peak power, replacement strategy?

[FW17]

Is this the most we have seen of any engine so far??

I guess 2 of these are mounted vertically within the V

[Dragonfly]

I think only one. On the lower photo one can see the edge of the second tube of the twin manifold which is clearly seen on the first photo.

[piston]

...... The 1.6 turbo has ample breathing to burn the available fuel - if the charge isn't dense enough, turn up the boost! Less intercooling means hotter exhaust and more energy available to be recovered by the MGU-H ie more power from the same fuel flow. The limiting factor here will probably be thermal stress on the combustion chamber components. This however could be reduced by running more boost and a leaner AFR. DI technology (read stratified charge) makes lean mixtures very do-able and I am sure all the engines are running leaner than stoich' (>14.7:1).

The next bottleneck is turbine inlet temperature. This can also be alleviated by leaner mixture (the energy lost in reduced exhaust temperature is gained in higher mass flow) but will probably be a limiting factor in the end. .......

will the thermal stress on the combustion chamber components be reduced by leaner running ?
because the heat liberated eg at 27.78 gm/sec of fuel is the same at any AFR at or above your example 14.7
2014 F1 AFR above 14.7 needs air added to the stoichiometric air mass (not fuel reduced/fixed air mass as we might in a road car)
requiring disproportionately more work on the charge by the supercharger (eg 20% flow increase takes about 40% pressure increase)
and more work would then be done on that charge by the piston
more work on the charge air means more heat in the combustion chamber
(and of course all this extra work, less the part that naturally useably emerges elsewhere, costs crankshaft power)

@TommyCookers: What about Q = m * c * delta T?!
The heat may be the same, but for a leaner mixture you have a higher mass (specific heat capacity will change only slightly). Therefore your temperature will go down with leaner mixtures due to the higher mass.
But I agree with you, that less intercooling (with leaner mixture due to higher boost) will lead to a higher temperature:
- Compressor efficiency < 1
- Higher pressure without intercooling means higher temperature at start of combustion
- therefore even with a higher mass the temperature would be higher during combustion
And higher temperature leads to knocking. Therefore less compression ratio in the ICE has to be used (which is less efficient).

DI running lean mean AFR delivers less of its heat near the cylinder and chamber walls
this reduces losses to coolant (and allows higher CR ?)
but there remains extra losses to crankshaft power as mentioned above
my guess is that we won't see lean mean AFR until the fuel allocation/rate is reduced
and only then because there is a minimum capacity (1590 cc ?) and minimum (5730 ?) rpm due to the MGU-K torque limit

with the "mentioned above" you mean the "work done on more charge by the piston"?
- The higher work will be gained back at expansion.
- There may be more heat, but also more mass. The temperature at the end of compression will just depend on the temperature at start of compression, the CR and the isentropic coefficient (which will be slightly higher for lean mixtures, but just a very small amount). So I would assume the same temperature at end of combustion, but due to the higher mass less temperature during combustion. This prevents knock, giving the possibility of a higher CR and leading to higher efficiency.

In my opinion it will be a compromise because the engine is not operated just at one speed and there is a certain operating range for turbine and compressor. Therefore the AFR will change with the engine speed to have the best overall efficiency. So they will have done a lot of simulations and dyno tests to decide which speed range they want to use and what AFR gives them the best efficiency in the combination with different turbines and compressors (not to mention the combination with the MGU-K, MGU-H, ... ).
If we take this into account, the development could have taken quite some time...
And perhaps there is no big deal about the Mercedes engine but they just got the best compromise. Who knows.

[Tommy Cookers]

thanks piston ! .... and a +1 for the clarification
(about 80% of the extra piston work done to compress extra air for leaning will be returned ie 10% is lost up 10% down as friction ?)

do we know what 'boost' (for clarity, really absolute induction pressure) anyone is actually using ?

Ferrari and Renault have exhaust systems that can give by NA cylinder filling equivalent to 1920 cc of air at atmospheric pressure
at stoichiometric mixture they only need boost of 0.7 bar at 10500 rpm to match the fuel rate of 27.78 gm/sec ? (less at higher rpm)
ie they only need very light boost, by F1 standards the power taken by the compressor is small (superficially, good for recovery)

do people appreciate how much more compressor power is needed to increase this air massflow by eg 20% ? (for leaning)
the biggest downside is the need for much more intercooling
(a useful proportion of this extra compressor power is 'recovered' to the crankshaft, and a lesser proportion to the mgu-h)

(in principle independent of leaning) there is potential in allowing exhaust pressure to rise (demanding more compressor power)
MB have apparently chosen this route

though if the peak combustion temperature can be better managed by leaning this may help by reducing dissociation
(high temperature causing temporary reversion of CO2 to CO, delaying heat release)
the complex injection strategies now available anyway seem able to manage peak temperature etc, ie without needing leaning

DI is very useful even without a lean mean mixture (when not banned as in recent NA F1)
because the core 'richness' gives more consistent and more rapid start to combustion
(the reason why NA F1 used rich mixture, according to the paper on F1 Ferrari engine tests once linked in this thread)
DI with mean stoichiometric mixture gives most of the advantages of rich running without the disadvantages

we should not assume that they are generally running a lean mean mixture just because DI has potential to facilitate this
there seems to be quite a lot of running at low rpm, presumably as an efficient means of getting partial powers
recovery should be possible in some of this running ?
and mean lean mixture would extend the envelope of this, by allowing more WOT at partial power ?
cylinder cutting (as an alternative to partial power lean running) appears to give less scope for recovery, but is still used ??