2014-2020 Formula One 1.6l V6 turbo engine formula

[WhiteBlue]

If I understand it right we can assume 7% free net recovery in a situation where we have no increased boost, which is estimated at 2 bar absolute compressor pressure. This assumption was shown by analysing the Wright engine. But we have the option to add another bar compressor pressure and raise the crank power so that the turbine can "steal" the difference and give it to the MGU-H. That would be a deliberate "over boost" with the objective to increase back pressure and and further improve BSFC in compounded operation. That way we end up with the same engine power but perhaps another 15% "forced" recovery. The 15% is only an assumption at this point. But if we follow the assumption we have 22% total recovery power and all we have to do for it is over boosting to 3 or 3.5 bar which sounds like a manageable boost level. We would not saturate the MGU-K, but we would get another 143 ponies. If we assume some losses in the DC link about 130 bhp should still arrive at the crank shaft. So the compounding would be bringing us up to 780 bhp compounded power, which isn't such a bad power level at all. The big question is the gradient of power increase with increasing boost in the limited fuel flow scenario. Can we estimate that from the NACA report? If we have a gradient we could solidify the assumed values of 2.5 bar "over boost" and 15% "forced recovery".

[WhiteBlue]

The question of rpm use above 10.500 is most likely linked to the combustion process. The assumption here is that it is possible to run in stoichiometric mode with high compression ratios and that we inject in the compression phase. The higher the rpm the earlier we have to inject. The higher the boost the later we have to inject to prevent knocking. So there are two requirements that are running in the opposite direction, if I understand the injection and combustion process correctly.

If there is such a compromise to make I think I would rather go for higher boost than higher rpm as boost is was is giving us better BSFC. I may be wrong, but that is my view with my limited understanding of the situation.

I take a step back and look at the design fundamental principles and objectives:

• We have a power process with two machines that need optimizing for BSFC
• The ICE should run stoichiometric to achieve that
• There is a "free" level of recovery from the turbo compound at a low minimum boost with an initial BSFC1
• Increasing boost can improve BSFC1 to BSFC2 by raising the compounded output
• all design and operating parameters must be optimized with the aim of getting the highest BSFC2

In other words the ICE and the turbo cannot be designed to work with their best single efficiency but to get best combined efficiency. If there is a conflict between best compression ratio and best boost the compromise with the highest combined BSFC needs to be found. Same is true for boost and rpm. There is also the question of how much back pressure the turbine and the valves can withstand for their design life of 5.000 km. The manufacturers will be busy answering all these questions and there is scope to solve the problems for more power or more reliability. I think we can expect some nice competition for the first season.

[Tommy Cookers]

the NACA work shows that efficiency is maximised by the right amount of what I call backpressure running
the key aspect is that they are not raising induction/compressor pressure
they are raising exhaust pressure to exceed their fixed induction pressure ie to give a backpressure that maximises efficiency
maximal efficiency means for 2014 this method promises to maximise power (ie combined power)

it's an indulgence of mine (and of the FIA and their friends and fellow-travellers) to consider what we will call 'free' energy
this is a philosophical or aesthetic matter, not an engineering one, and should not impede our understanding of the engineering

backpressure appears to reduce the blowdown loss of exhaust KE/pressure, and increase relative exhaust pressure and turbine power
I'm hoping that others will express a view regarding the appropriate supercharge pressure for this degree of backpressure running

clearly there is a multi-faceted down-side to all this, in the ICE and the electrical side, and in relation to the car design
some say that Mr Newey has refused even to have the full permitted capacity in his existing KERS system

we know that the engine will have to run through a range of at least 10500-12300 rpm
the question I asked a year ago was what do we do regarding charging the cylinders when rpm increases without fuel increase
and my suggestion was backpressure (as less disadvantageous than the either of alternatives that you appear to expect ??)
now (although I recently said otherwise) they seem to be running much above this rpm
either they are 'sandbagging' or they intend to run significantly above the rpm I/we expected
and that question now seems crucial

[WhiteBlue]

I will quickly put some figures together what I think has been learned from the look at the air craft engines and what follows for the assumptions I made. Here are the base figures I use:

P0 = ICE base brake power at best rpm = 650 bhp = 485 kW
fuel flow f=m/t= 27.78 g/s
e = specific fuel energy = 46 MJ/kg
Free turbine excess power at low boost1 =7%
Forced turbine excess power at high boost2= 22%
P1 = free compounded brake power = 695.5 bhp = 518.6 kW
P2 = forced compounded brake power = 780 bhp = 582 kW

and this is what follows:

====>
BSFC0 = f/P0 = 57.3 g/kJ
BSFC1 = f/P1 = 53.6 g/kJ
BSFC2 = f/P2 = 47.7 g/kJ

======>
BTE0 = P0/e = 38 %
BTE1 = P1/e = 40.7%
BTE2 = P2/e = 45.7%

The target brake thermal efficiency of 45.7 % sounds pretty high but it is not an impossible target as other compounded power cycles have demonstrated. In electric power generation there are two stage gas/steam turbines used that reach 51% electric power efficiency. The comparable brake thermal efficiency is 52.6%. It would be interesting to look at the 1988 Honda turbo engine to compare what that delivered with limited boosting capability.

And these are the data for the 88 Honda RA168E engine in race trim:

Pr = 611 bhp = 455.6 kW
Fuel was 84% Toluene + 16% n-Heptane
e(TH-fuel) = 17.669 BTU/lb = 41.1 MJ/kg
BTE = 30.6%
===>
f (RA168E) = 36.22 g/s
=====>
BSFC (RA168E) = f (RA168E)/Pr = 79.5 g/kJ

If we wanted to express the corresponding BSFC for F1 fuel we can also find this.

Thermal power was 555.6 kW/0.306 = 1489 kW
Hypothetical petrol fuel flow would be 1489 kW/ 46 MJ/kg = 32.37 g/s (2% rich mixture reportedly)
BSFC (RA168E@petrol) = f (RA168E@petrol)/ Pr = 71.0 g/kJ

The RA168E was considerably less efficient from every aspect than I expect even the non compounded 2014 base ICE to come out.

[pgfpro]

FWIW I would now say 100kW (about 135 hp) typically ie much of the race time from the MGUH

we know the MGUH output will be driving the MGUK for much of the racetime, this saves on storage, efficiency and cooling
but I never knew how much recovery was possible with an SI engine, and how this improves efficiency (not power)
this 'backpressure operation' reduces the large loss of pressure and kinetic energies as the exhaust blows down from 8 bar
these losses are disproportionate as the great pressure and density difference causes supersonic flow and pressure drop

F1 CR will be much higher, but also mep/density will be higher so the blowdown losses are still high (unless we have backpressure)
as I see it, higher CR (although indisputably helping efficiency) means that the cylinder pressure is higher even at EV opening
unless the EV is opened later (though this seems possible)
with backpressure the blowdown may be from 9 bar Abs , but it's driving against a denser gas load now at maybe 2.7 bar Abs
which must be less lossy than eg N/A or 'no backpressure' blowdown from 8 bar Abs against maybe 1.05 bar Abs

FWIW it seems to me likely that the backpressure will be increased as rpm goes significantly above 10500
as it is the least bad option IMO for in-cylinder thermodynamics
and we now know that backpressure improves efficiency
yes there is an apparent obligation for electric power ie MGU-K motor action to be proportionate to ICE action
but that can be managed even with backpressure and recovery increasing at the high rpm end

WOW !!!!

My calculations are far from this. I guess back to the calculator for me. lol

What I find crazy is the fact that these recovery HP figures are massive. If true... why didn't anyone since put this technology into the modern day road car. The benefits would be through the roof in fuel savings and performance???

[WhiteBlue]

WOW !!!!
My calculations are far from this. I guess back to the calculator for me. lol
What I find crazy is the fact that these recovery HP figures are massive. If true... why didn't anyone since put this technology into the modern day road car. The benefits would be through the roof in fuel savings and performance???

I think there are big differences in road cars. They do not typically run on full throttle, so the power optimization is all wrong for them. The hybrid technology involved is quite expensive which may be the main reason. And finally have a look at engine life (Turbo and Valves). The F1 engine must cover 4.000-5.000 km while the road car engine is expected to do 200.000 km. I don't think you can do the huge back pressure for such a long time. Even the 7% recovery with stoichiometric combustion would probably be a hard job.

[dren]

If using the MGUH load for the backpressure increase past 10.5, you could get an increase in recovery to the redline. This would put the MGUH load at some percentage at 10.5k rpm, increasing to 100% at around redline. The powerband would increase even without added fuel, and you would gain with improvements in bsfc. The energy storage in the battery could be used in the lower revs.

So maybe 7% recovery at 10.5k rpm, then around as high as 20% at 15k rpm. 695hp to 780hp

I say this because I don't know how else to vary the backpressure other than loading the MGUH.

[Tommy Cookers]

The target brake thermal efficiency of 45.7 % sounds pretty high but it is not an impossible target as other compounded power cycles have demonstrated. In electric power generation there are two stage gas/steam turbines used that reach 51% electric power efficiency. The comparable brake thermal efficiency is 52.6%.

And these are the data for the 88 Honda RA168E engine in race trim:

the other compounded power cycles are totally different, because they use the sensible heat energy in the exhaust
that is the stuff that can be measured with a thermometer, not the stuff that can't
the stuff that a turbine cannot use
the stuff that is most of the energy in any exhaust
the stuff that caused another poster to refer us to (organic) Rankine cycle devices
Rankine cycle is what we call steam
the same cycle that has caused BMW to develop their Turbosteamer
do you dislike BMW ?
does the FIA dislike BMW ?
there's lots of recovery possible in new F1 via the Rankine cycle
but it's not allowed (and the minimum weight would need raising to maybe 800 kg)


IIRC the RA168E did not race 2% rich, it had to use 8% rich for response
this is somewhere in the SAE paper

[Tommy Cookers]

What I find crazy is the fact that these recovery HP figures are massive. If true... why didn't anyone since put this technology into the modern day road car. The benefits would be through the roof in fuel savings and performance???

the backpressure running ( -delta P) gives no gain in power
(beyond + delta P compounding as Wright publicised successfully in support of 10000 sales)
- delta P running gains only in fuel efficiency
so it only has better performance in a fuel-limited competition (where a - delta P engine would be different to a + delta P one)
even aviation customers don't want gains in fuel efficiency only, they would rather have a power gain, as Wright supplied

we can regard all the power recovered at + delta P as 'free' ie an increase in power
so the recovery % is a true measure of the benefits of this level of compounding
going beyond this level to - delta P running the recovery % is an optimistic measure of the benefits of - delta P running
because the increased recovery is just power diverted from the crankshaft
the real measure is the efficiency benefit , that is the gain in combined power that would occur running this way under fuel limit rules
under such rules both the ICE and the MGUH are drawing from a 'power pool' that is bigger with -delta P than with +delta P running
but the MGUH now draws a bigger share from the pool , ie it robs the crankshaft
so the MGUH benefit is bigger than the benefit in combined power
or .....
with + delta P working all MGUH generated power is recovered from waste exhaust
with - delta P working the MGUH generated power is increased, but the increase has not come from waste exhaust
and under fuel limiting there is more combined power because the - delta P working is more efficient

the price of this increase in combined power is the need for a bigger electrical system

IMO (sorry to dwell on this)

[dren]

You can vary the delta P with the MGUH, which it seems is a huge benefit here, especially when the fuel flow rate is constant in the upper revs. The increase in efficiency will show as a power gain.

Other than packaging/aero reasons, does anyone see any benefit to removing the intercooler?

[WhiteBlue]

The target brake thermal efficiency of 45.7 % sounds pretty high but it is not an impossible target as other compounded power cycles have demonstrated. In electric power generation there are two stage gas/steam turbines used that reach 51% electric power efficiency. The comparable brake thermal efficiency is 52.6%.

And these are the data for the 88 Honda RA168E engine in race trim:

IIRC the RA168E did not race 2% rich, it had to use 8% rich for response
this is somewhere in the SAE paper

!. I believe the figures I used are also from the SAE report:
http://www.grandprixengines.co.uk/Egs_6 ... _Honda.pdf

Rating .......................R...................Q
Both at IVP = 2.5 Bar & Peak Power Speed (NP) = 12,500RPM
Mixture strength (relative to Stoichiometric)
.................................+2%.................+15%
Peak Power (PP) BHP....... 611..................676 +10.5%
Specific Fuel Consumption (SFC) (Lb. Of fuel)/BHP. Hour
.................................0.467................0.523 ≈+12%

R rating is racing. Q rating is qualifying. So 2%+ seems correct.

2. I do not understand your comment about the efficiency target. Do you think it is doable or not?

[Tommy Cookers]

FWIW I don't think that it's doable
but there is a lot of publicity value for all who choose to involve themselves, and the true state of things will be unimportant
ever since I can remember we have had some or other engine or engine development is to change the world .......
the Wankel, later other rotaries eg the Sarich, turbocharging, the diesel (although we are told by the same class of people now that diesel particulates kill 60000/year in Germany and 30000/ year in the UK), the catalyst bs that ignores the 10%extra CO2 and consumption caused by 3-way catalysts needing a constant 2% rich mixture rather than the 2-way lean mixture
tonight we hear about the new nuclear fusion research ....... we've been doing that research for 60 years already !

most of the exhaust energy is sensible heat
this can be recovered with a vapour-phase cycle aka a steam engine
it was known 100 years ago (it was just waiting for the gas turbine to become as efficient as the steam turbine)
a successful combined cycle using sensible heat energy where there is a lot of sensible heat energy is no surprise
BMW appear to have this system ready for cars if the market develops ie is forced by legislation
as was the market for hybrids was forced entirely by politicians playing to an imaginary gallery

politicians/governments 'now earn their living'this way, and without this sort of thing would be discredited
people want to believe in something, to have a focus (eg now that there's no Cold War)
there's no room for the truth in this situation

as i have said before, we all should have smaller engines to save fuel, and we all know this and always did
but we don't want to be told so, we want to believe in some 'magic beans' design
and European governments in particular want this belief, to assist in selling complicated and expensive product
2014 F1 on these 'magic beans' lines has Govt. support (IMO even indirect financial support)

[ringo]

WOW !!!!

My calculations are far from this. I guess back to the calculator for me. lol

What I find crazy is the fact that these recovery HP figures are massive. If true... why didn't anyone since put this technology into the modern day road car. The benefits would be through the roof in fuel savings and performance???

Well, i'm very quiet on this, reason being i'm very cautious about apply those figures to an automotive engine and expect similar results. The aircraft operates in a very low pressure environment, with very low temperatures, maybe below zero at altitude and possibly steady speed. I wouldn't be so keen to apply the figures to a car that runs in a 1 atmosphere environment at normal temperatures.

Adding percentages, especially from the mechanical turbo-compound wont apply to the current system and the nature of operation of an F1 engine.
In my calculations if 120kw is given to the flywheel, you may expect a 6.99% improvement in BSFC
This is fairly consistent at most engines speeds.
However in theory if all the energy that can possibly be harvested was sent back to the flywheel there is a potential for 10.36% improvement at max engine speed of 15,000rpm. this ignoring losses in electrical equipment.

I think the physical properties and constraints of the system, as well as our gross simplification of adding percentages, is hiding the truth behind the turbo compound. Also as said early, these TC engines are low speed engines, moving at 1800 or 2600 rpm at fairly steady operation. There is a reason why they haven't implemented them in road going engines.

[ringo]

The target brake thermal efficiency of 45.7 % sounds pretty high but it is not an impossible target as other compounded power cycles have demonstrated. In electric power generation there are two stage gas/steam turbines used that reach 51% electric power efficiency. The comparable brake thermal efficiency is 52.6%. It would be interesting to look at the 1988 Honda turbo engine to compare what that delivered with limited boosting capability.

I wouldn't compare those two if i were you. COmpletety different engine cylce you are talking about. That is from a rankine cycle.
Don't confuse the word compound and apply it to different cycles. Those steam plants you are talking about are combined cycles and it's very wrong to put an otto cycle and a ranking under the umbrella of a "compound cycle". It doesn't exist.

It takes more than two stage turbines to get high efficiencies. In fact a steam turbine can have as many as 4 stages and you dont get the improvements you want. It's what you do with the cycle, like reheat and regeneration. Some terms i can't bother go into. But compounding as you understand it from the TC engine, shouldn't be applies to a power plant. haha
A steam turbine exhausts into almost absolute vacuum, a car does not. It doesn't need any more turbines than it has.
Most combined cycles are really two different plants, one smaller than the other, and one having use for heating water or absorption chilling or some other power use outside of main power generation.
It's not uncommon for a hi tech steam plant to see 60% efficiencies or more. Steam turbine is a different ball game than otto with brayton cycle.

[ringo]

If using the MGUH load for the backpressure increase past 10.5, you could get an increase in recovery to the redline. This would put the MGUH load at some percentage at 10.5k rpm, increasing to 100% at around redline. The powerband would increase even without added fuel, and you would gain with improvements in bsfc. The energy storage in the battery could be used in the lower revs.

So maybe 7% recovery at 10.5k rpm, then around as high as 20% at 15k rpm. 695hp to 780hp

I say this because I don't know how else to vary the backpressure other than loading the MGUH.

Not happening.

You cannot really control back pressure. Remember it's a result of a restriction in the exhaust system. Assuming we're not using waste gates, you cannot control back pressure. To intention increase it is also bad for the engine, it will reduce the crankshaft power, as the pumping losses will increase on the exhaust stroke, this increase friction power hence reducing brake power. It shouldn't be the goal to increase back pressure in the manifold. It should be the goal to increase boost pressure and reduce back pressure at turbine exit.
Remember you are doing this to increase pressure ratio of the turbine. That's what this whole back pressure thing is about. Pressure ratio is simply input pressure divided by exhaust pressure. In the Wright TC they were ultimately looking at that aspect.

Now that thing they call a waste gate.. nah! useless piece of equipment.