Capacity of F1 fuel injectors.

[Bandit1216]

13:1 (lambda 0.88) is not "lean as hell". For many modern engines that is best performance AFR.
Time to re-visit the Honda RA 168e paper.https://www.scribd.com/document/1237322 ... 68E-Engine Page 6. Max power AFR at equivalence ratio of 1.15 (lambda 0.87) and that was a turbocharged engine.

the RA168E was designed to be limited to 2.5 bar abs and iirc 150 litres of 84% toluene/16% heptane fuel
presumably earlier engines using high boost and no formal fuel quantity restriction would have been run richer

Best power mixture for the RA168e was 0.87 and would have been similar for other (conventional) fuel of equal knock resistance. Richer mixtures would cost power. The lost power (and some) might be recovered by increasing boost, CR or spark advance due to the improved knock resistance and thermal stress offered by richer mix. (Of course the rules did not permit more boost and a richer mix would have increased fuel consumption which was also regulated)

aero engines were run eg 60% rich at maximum boost the Wright Turbocompound paper has a takeoff energy balance diagram showing AFR used rich mixture (Mr Heron said) lowers flame temperature and (I say) chemically opposes dissociation and increases benefits of any TEL or similar additives

Again the rich mixture is not increasing power - it is enabling higher boost and ensuring durability. Any leaning of the Wright TC under takeoff conditions would increase power. It might need higher octane fuel and it might reduce engine durability, but it would increase power.

Just thinking out load. Wouldn't old aero engines lean themselves out by having a lot of ram air in flight, by the nature off them, resulting in rich mixture during takeoff an standstill?

[Tommy Cookers]

Again the rich mixture is not increasing power - it is enabling higher boost and ensuring durability. Any leaning of the Wright TC under takeoff conditions would increase power. It might need higher octane fuel and it might reduce engine durability, but it would increase power.

it might appear to increase power if the boost was fixed (necessarily at a lower level than was used with rich mixture) but this also ignores the reduction with rich mixture of CO2 dissociation (this presumably greater in a low rpm engine)

Not sure what you are getting at here? ("appear to increase power") The dynamometer doesn't lie.

and the 'Rankine power' of the surplus fuel boiling during the power stroke

I remember doing the calculations for the so called "Rankine" effect for water injection. It doesn't exist - the heat consumed in vaporising the water would do more work if used to heat the combustion gases. No doubt the same applies for vaporising excess fuel.

in the Wright ....
it wouldn't increase power as it would increase peak temperature then cause detonation then pre-ignition then failure
the engine can't be operated at takeoff boost without a very rich mixture
'Rankine' power is an attributable benefit as without boiling (of fuel or WI) the temp peaks would be too high to survive
most Wright 3350s had WI not DI - though btw later Wright TCs had DI starting after bdc

LATER EDIT Charles Fayette Taylor's book shows knock-limited mep peaking at around 70% rich
this ASTM test and subsequent global PN test use a mandated CR and variable boost (from a reservoir)
ASTM shows with isooctane KLmep is 60% higher (relative to stoichiometric) when at 70% rich
PN shows the effect with rich avgas use relative to stoichiometric isooctane use - it doubles the KLmep
(the real engine power doesn't double as the higher boost costs a lot of crankshaft power)
Taylor's book states that typically 70% rich was used at takeoff
but Heron wrote that RR and Allison treated 115/145 PN fuel as if it was 145/145 PN
implying that they didn't need a rich mixture at takeoff etc - and wrote that RR used the rich mixture for cooling
the RR and Allison were originally designed around 80/87 PN fuel - the Wright 3350 was designed around 115/145 PN
(early) Wrights used 10:1 AFR at takeoff bte 22.3% and 17.9 AFR at cruise bte 32.6% (TC but not counting exhaust thrust)
later versions had 7.2 CR and gave best sea level bsfc 0.35 lb/hp-hr (not counting exhaust thrust)
(takeoff fuel power is 16170 hp - almost half of this is dumped as unburnt CO, CH4, and H2 in the exhaust)


nowhere have I said or implied that major richening increases power of all engines eg the Honda and NA aircraft engines
I have even said how it is possible to operate a light aircraft engine so rich that the power is reduced

@ Bandit
there is quite a lot of ram when running at takeoff power even when the aircraft is stationary
the biggest outside effect on mixture strength is variation of air density with altitude
in light aircraft the mixture system is uncalibrated and users may adjust mixture wrt EGT gauges or empirically or not

[Bandit1216]

Oké.

I have some experience with tuning a turbo engine for my own car. It was an 1.5 8v with approx 225 bhp on 1,5 Bar boost. Quite much for a small street car back in 2000. I do know it ran good at 0.85 lambda, but I set it on 0,7 for good measure to cool it. No increase or decrease to be noticed between 0.85 and 0.7, just some flames now and then. Of course I didn't have a dyno and had to use on road tuning.

[Tommy Cookers]

bumped
LATER EDIT Charles Fayette Taylor's book shows knock-limited mep peaking at around 70% rich
this ASTM test and subsequent global PN test use a mandated CR and variable boost (from a reservoir)
ASTM shows with isooctane KLmep is 60% higher (relative to stoichiometric) when at 70% rich
PN shows the effect with rich avgas use relative to stoichiometric isooctane use - it doubles the KLmep
(the real engine power doesn't double as the higher boost costs a lot of crankshaft power)
Taylor's book states that richness as great as 180% of stoichiometric was used at takeoff
but Heron wrote that RR and Allison treated 115/145 PN fuel as if it was 145/145 PN
implying that they didn't need a rich mixture at takeoff etc - and wrote that RR used the rich mixture for cooling
the RR and Allison were originally designed around 80/87 PN fuel - the Wright 3350 was designed around 115/145 PN
(early) Wrights used 10:1 AFR at takeoff bte 22.3% and 17.9 AFR at cruise bte 32.6% (TC but not counting exhaust thrust)
later versions had 7.2 CR and gave best sea level bsfc 0.35 lb/hp-hr (not counting exhaust thrust)
(takeoff fuel power is 16170 hp - almost half of this is dumped as unburnt CO, CH4, and H2 in the exhaust)

nowhere have I said or implied that major richening increases power of all engines eg the Honda and NA aircraft engines
I have even said how it is possible to operate a light aircraft engine so rich that the power is reduced