2014-2020 Formula One 1.6l V6 turbo engine formula

[johnny comelately]

@ johnny c

afaik
the forum consensus says induction pressure ('boost') is 4 bar and so the mean AFR will be 2 lambda

this is heat dilution ie the heat is spread over 2x the traditional amount of air without real stratification
so the temp in-cylinder is much lower so the heat taken by coolant is very much lower
so the heat remaining in-cylinder (in the much greater gas mass) is much higher

this is a recipe that is giving F1 and some NG-fuelled stationary engines unprecedented (for SI) efficiency
by maintaining the combustion efficiency of this lean mixture via a prechamber firing non-lean mixture
and providing the compressor and turbine are outstandingly efficient


this used by gg on P864 Honda thread to derive a peak pressure before ignition of 220 bar and temp of OMG degrees
I guess he assumed 4:1 compressor action and 18:1 in-cylinder compression (I haven't tried to check assumptions)
of course we know that in-cylinder compression starts with IV closure

MY POINT ?
what if F1 uses late IV closure ?? (ie Atkinson emulation as Prius does) - or even early IV closure ?
the assumptions about 2x lambda AFR don't hold

Tommy, the first part I get : for about 700bhp you need 495 litres per second or 640 grams per second of air, which means inlet pressure of 4 bar (3 boost +1 free)
At 12:1 AFR (bio content etc) = 53 grams fuel per second.....

Could you explain more of your thinking from there please.
Regarding: a) 2x lambda (b) charge temperature and how it relates to the heat dilution you speak about.
I do understand generating the maximum heat and the keeping of that heat in the cylinder.
I really hope we are not on different planets as I really want to learn about this.

[Tommy Cookers]

@ godl

we seem to agree that globally there's hundreds of refineries producing gasoline (ie before any brand-related 'additives')
each of those refineries gasolines has about 'natural' 1000 constituents which won't be exactly the same as any other refineries
FIA rules can't stop any of 10000+ total known constituents of gasoline being used in unnatural proportions (within limits)
eg to name only one - 'Triptane' is a natural constituent of crude oil and so a natural constituent of gasoline
many of these constituents have never been isolated and tested (as uneconomic and pointless for everyday fuel)
people sometimes like to imagine that gasoline is one substance - so-called Iso-Octane (correctly 2,2,4-trimethyl pentane)
Triptane is correctly 2,2,3-trimethyl butane
it is a good fuel and (unlike gasoline) very responsive to organometallic octane boosters eg tetraethyl lead or nickel carbonyl
so-called '200 octane' aviation fuel was triptane+avgas+TEL (or '300 octane' if pure triptane+TEL)
these numbers are really PN eg a rich-mixture turbo engine could be boosted enough to give 200% or 300% of NA power
in F1 its enabling of high compression and boost could increase power for eg 100 kg fuel by increasing efficiency
(NB though of course if F1 uses partial CI eg spark controlled CI or full CI then very high octane may be undesirable)

why do you think that there's no upper limit of Octane Number ????????
and no limit on mass-specific energy

ok some fuel companies may have made a sincere attempt at rules that limit the scope of a fuel war
but we would say the same about the engine rules - and some think some engine companies have been tricked by another


@ johnnyc

max fuel rate is 100 kg/hr = 27.77 gm/sec

4 bar implies a certain air rate (depending on assumptions about EV via tuned lengths and valve timing etc)
we know bio is butanol or isobutanol (or others even closer in stoichiometric mass to gasoline)
we know they use TJI or similar

all this implies say 1.5 - 2 lambda ie well beyond the normal design of lean-running
so combustion heat is diluted by this greater air mass (not as conventional by lambda air mass or similar/less air mass)
so temperature in-cylinder is lower and so heat taken necessarily to coolant is much lower
so energy available for useful work is higher (more gas not more temperature)
and some would say exhaust energy available for useful work is higher
how else are they getting an SI engine close to 50% bte ?

TJI/prechamber is used in turbo (uncompounded) natural gas fuelled stationary and marine SI engines at eg 4 lambda

[johnny comelately]

@ godl

we seem to agree that globally there's hundreds of refineries producing gasoline (ie before any brand-related 'additives')
each of those refineries gasolines has about 'natural' 1000 constituents which won't be exactly the same as any other refineries
FIA rules can't stop any of 10000+ total known constituents of gasoline being used in unnatural proportions (within limits)
eg to name only one - 'Triptane' is a natural constituent of crude oil and so a natural constituent of gasoline
many of these constituents have never been isolated and tested (as uneconomic and pointless for everyday fuel)
people sometimes like to imagine that gasoline is one substance - so-called Iso-Octane (correctly 2,2,4-trimethyl pentane)
Triptane is correctly 2,2,3-trimethyl butane
it is a good fuel and (unlike gasoline) very responsive to organometallic octane boosters eg tetraethyl lead or nickel carbonyl
so-called '200 octane' aviation fuel was triptane+avgas+TEL (or '300 octane' if pure triptane+TEL)
these numbers are really PN eg a rich-mixture turbo engine could be boosted enough to give 200% or 300% of NA power
(in our case it's enabling of high compression and boost could increase power for eg 100 kg fuel by increasing efficiency)

why do you think that there's no upper limit of Octane Number ????????
and no limit on mass-specific energy

ok some fuel companies may have made a sincere attempt at rules that limit the scope of a fuel war
but we would say the same about the engine rules - and some think some engine companies have been tricked by another


@ johnnyc

max fuel rate is 100 kg/hr = 27.77 gm/sec

4 bar implies a certain air rate (depending on assumptions about EV via tuned lengths and valve timing etc)
we know bio is butanol or isobutanol (or others even closer in stoichiometric mass to gasoline)
we know they use TJI or similar

all this implies say 1.5 - 2 lambda ie well beyond the normal design of lean-running
so combustion heat is diluted by this greater air mass (not as conventional by lambda air mass or similar/less air mass)
so temperature in-cylinder is lower and so heat taken necessarily to coolant is much lower
so energy available for useful work is higher (more gas not more temperature)
and some would say exhaust energy available for useful work is higher
how else are they getting an SI engine close to 50% bte ?

TJI has established it's use in turbo (uncompounded) gas-fuelled stationary and marine SI engines at eg 4 lambda

Thanks Tommy, I dont know if my head can handle the amount of scratching required to unlearn so much regarding lambda 2 running.
Combined with extremely high compression pressure.
This level of performance then is fuel enabled? regarding knock.
Looking at the specs I see there is no max octane rating, but they do say commercially available, but you reckon that is covered by the natural occurrence of 'enhancing' elements?
Have you come to these conclusions from deduction of the facts we are given? (mothers maiden name Holmes) or 'inside' knowledge
I read till my eyes get sick and havent come across this, so thank you for the Aha moment.
One of our key enablers has been twin flame ignition (where do they get turbo from in TJI?) which has pulled back timing to 9 degrees BTDC.
This brings up so many questions like ignition timing, and max compression pressures, they must have destroyed some engines working out these fuel limits.
anyway, thank you for this.

[johnny comelately]

What would the injection strategy be to cause acceleration (transition) if your max flow rate is 29 grams a second?

[Tommy Cookers]

to be entitled to 100 kg/hr (= 27.77 gm/sec) they must be doing 10500 rpm
the fuel rate is capped at this 27.77 above 10500
fwiw I have suggested both ....
inherent legal fuel accumulation due to fuel compression and other compliance at permitted 500 bar injection pressure
and using less than 27.77 at 10500 but 27.77 somewhere over 10500

TJI is turbulent jet ignition - Mahle's name for their 'prechamber'

in these heat dilution engines the work done on the compression stroke etc is unusually high
so novel crankshafts arrangements often appear in patents and posts here
high temperature at TDC is useful given that temperature fall thereafter tends to be greater
fuel is presumably heated to help combustion

physical thermodynamics says that more air helps efficiency (air standard efficiency vs real cycles and all that)
chemical thermodynamics says temperatures should be low enough to avoid dissociation ie CO2>C0 then CO>CO2
but the fuel must be burnt in the combustion chamber
since we don't have hydrogen or methane fuel we can't go so lean as they can
the single stage compressor and turbine are borderline in efficiency for purposes of compression combined with recovery
ie recovery doesn't seem to improve with higher boost

your best bet might be to call up all gruntguru's posts

but we still don't know the actual AFR as we don't know VE re novel valve timing and tuned length effects

[johnny comelately]

to be entitled to 100 kg/hr (= 27.77 gm/sec) they must be doing 10500 rpm
the fuel rate is capped at this 27.77 above 10500
fwiw I have suggested both ....
inherent legal fuel accumulation due to fuel compression and other compliance at permitted 500 bar injection pressure
and using less than 27.77 at 10500 but 27.77 somewhere over 10500

TJI is turbulent jet ignition - Mahle's name for their 'prechamber'

in these heat dilution engines the work done on the compression stroke etc is unusually high
so novel crankshafts arrangements appear in patents
high temperature at TDC is useful given that temperature fall thereafter tends to be greater
fuel is presumably heated to help combustion

Thanks Tommy. I will have to go for a slow ride on a horse to think about all this

[johnny comelately]

I have done a bit of a search regarding BSFC and there doesnt seem to be much mention of it the lasy few years, does anyone know what it is for these current engines?
It has got to be better than 170g/kw/hr (le mans numbers i think)

[gruntguru]

I have done a bit of a search regarding BSFC and there doesnt seem to be much mention of it the lasy few years, does anyone know what it is for these current engines?
It has got to be better than 170g/kw/hr (le mans numbers i think)

Probably better than 160. All the evidence points to thermal efficiency > 50% for Mercedes. The trouble with BSFC is it depends also on the heating value of the fuel.
https://en.wikipedia.org/wiki/Brake_spe ... onsumption Scroll down to the table which shows BSFC and Thermal Efficiency.

[johnny comelately]

I have done a bit of a search regarding BSFC and there doesnt seem to be much mention of it the lasy few years, does anyone know what it is for these current engines?
It has got to be better than 170g/kw/hr (le mans numbers i think)

Probably better than 160. All the evidence points to thermal efficiency > 50% for Mercedes. The trouble with BSFC is it depends also on the heating value of the fuel.
https://en.wikipedia.org/wiki/Brake_spe ... onsumption Scroll down to the table which shows BSFC and Thermal Efficiency.

Yes, that is why I was after a known figure (or educated guess) to help work out the energy content in relation to the horsepower and mandated fuel flow etc etc. Things are not adding up in this little head of mine

[godlameroso]

I always wondered, say there's 50MJ/kg of fuel, a kg of fuel is enough for 100 seconds of running, in those 100 seconds, you will harness say 5MJ of that energy, so your combustion engine will use maybe 20MJ/100 seconds(out of the potential 50) + 5 MJ that you harvested along those 100 seconds. 25MJ/kg worth of energy used for the fuel which has a theoretical 50MJ/kg of energy. When they say 50% TE do they mean this?

[johnny comelately]

I always wondered, say there's 50MJ/kg of fuel, a kg of fuel is enough for 100 seconds of running, in those 100 seconds, you will harness say 5MJ of that energy, so your combustion engine will use maybe 20MJ/100 seconds(out of the potential 50) + 5 MJ that you harvested along those 100 seconds. 25MJ/kg worth of energy used for the fuel which has a theoretical 50MJ/kg of energy. When they say 50% TE do they mean this?

i think you are somewhere along the right line of thinking. Tommy Cookers thoughts about fuel properties is very thought provoking, the only confusing thing is the wording "commercially available" talk about 50 shades of grey.
An interesting thing is a test done by Ferrari with ALonso where they used two fuels and compared laptimes, its on you tube I think. obviously it was a few years ago and can you trust it for all sorts of reasons....the quest for truth continues

[johnny comelately]

PR video re fuels: https://www.youtube.com/watch?v=H5jei8Y19vI
probably not relevant enough to todays engines as it is 2011

[johnny comelately]

Are there any numbers for (pollutant) emissions for these current formula engines, in particular NOx ?

[godlameroso]

Apparently lots of NOx that would put the eq ratio around .6 or .7, probably ~2,200K+ combustion temps.

On an unrelated note, the only consequense of adding oil to the air fuel mixture would be lower octane rating would it not(lower than the 87 oct limit by the regulations)? A small amount of oil could change the reactivity of a fuel.

[J.A.W.]

Apparently lots of NOx that would put the eq ratio around .6 or .7, probably ~2,200K+ combustion temps.

On an unrelated note, the only consequense of adding oil to the air fuel mixture would be lower octane rating would it not(lower than the 87 oct limit by the regulations)? A small amount of oil could change the reactivity of a fuel.

Somehow G, I doubt the knowingly calculated addition of 'lubricant' - as a performance additive would have been allowed to significantly 'degrade' the 'performance number' of the fuel, likely the opposite, if anything.

Fuel/oil companies did have of course, for many years previously - experience with Grand Prix racing 2T
motorcycles, which also consumed a similar fraction of lube mixed with the fuel.

& although in that case, the lube being added was of primary tribological value, you can bet that it was
also formulated to ensure fuel performance was maintained, esp' after high TEL race-gas was banned.