2014-2020 Formula One 1.6l V6 turbo engine formula

[ppj13]

FWIW I think the penalty of a temporary 250 hp ES and motor drive capability is a lot more than 3 kg

Motors, motor controllers, motor wiring and mechanical design is not affected. MGUK will deliver 160HP and MGUH will deliver 60-80HP or so, definitively not more than what it is needed to help spin the turbo, and not more that what it is designed to harvest.

"Only" special thing are the batteries and battery control unit. Is it 3 extra kg or 30? I don't know.

[Tommy Cookers]

the NACA report 822 is what I had in mind
its tabulated results show that raising the exhaust pressure moves power from crankshaft to turbine roughly 1:1
power remains roughly constant, but efficiency is greatly improved
and the focus of the work is these large BSFC gains from raised exhaust pressure

Google NACA UK Archive 1945
or NACA report 822
(its in the archive at Cranfield)
or naca.larc.nasa.gov/

http://www.enginehistory.org/Wright?TC%20Facts.pdf
should get the Wright brochure that covers the rather different position of the version they sold to airlines in the 50s
they sold engines with high power and reasonable bsfc, not engines with high bsfc and reasonable power

Google this
turbo compounding the rotary
it should get Join aircraft rotary engine newsletter
which has loads incl Fig 15 recovery energy balance from 1954 SAE Transactions 'Development of the R-3350 Turbo Compound Engine'
Paul Lamar points out the large pressure loss at the exhaust valve
this inspires him - see his upload to Youtube

at leanish cruise the Wright TC has 2655 hp sensible exhaust energy
of which 1735 hp is unusable by any expander
an expander (eg turbine) can only use the KE (920 hp available)
of this 525 hp is dumped bt the exhaust going from cylinder to exhaust port
the net recovery after all losses is 160 hp
and the combined output is 1840 hp

BTW both the production TurboCompound engines and the 500,000 ? so-called turbocharged engines the USA made in WW2 always had mechanically driven superchargers, categorised in the papers referenced above as auxiliary superchargers
(so the turbocharger was always in any production engine a second stage of supercharging)

bumped for link to the only SI turbocompound engine ever in production

[pgfpro]

I found another good read about a company making a turbo compounding setup.
http://vandynesuperturbo.com/index.html

[Holm86]

New video. Though doesn't give any new knowledge.

[tok-tokkie]

I posted a screen grab from that video in the WO5 thread. It shows even more clearly the doubled up crankpins for each of the three throws of the crankshaft. Discussed earlier and only three simple throws are permitted.

[Blackout]

Made a (ugly) Paint drawing showing how the Merc layout is IMO (for the charge air)
(Black: the intercooler is above the angine / Green: the intercooler is in the sidepod)
http://i57.servimg.com/u/f57/14/79/55/26/122_me12.jpg

[JNF]

Some thoughts about boost pressure.

As it seems to be calculated here several times, the needed pressure for burning the fuel in stoichiometric conditions at 10500 is about 2,25 bars absolute. I've seen in many occasions to be said that the maximum boost is 3,5 bars based on apparently info released be Renault. This got me wondering are they pulling a leg and having a laugh at ignorant journalists or is there some benefit in extra boost.

I got told that with direct injection the air fuel mixture usually isn't homogenic. If that's true, then calculations based on stoichiometric mixture no longer apply. In one scenario they might try to get rich mixture in the middle and some extra air around close to the cylinder walls which would insulate and lessen the heat losses. Since the mixture is in different layers, the mean ratio would be way more lean than in homogenic mixture.

Any thoughts? I'm no engineer and this is my first time. Please be gentle.

[David1976]

Made a (ugly) Paint drawing showing how the Merc layout is IMO (for the charge air)
(Black: the intercooler is above the angine / Green: the intercooler is in the sidepod)
http://i57.servimg.com/u/f57/14/79/55/26/122_me12.jpg

That is exactly how I understand it.
I do wonder whether the longer rotor shaft will present it's own problems with the RPM it will be spinning at?

If Merc's powertrain is orientated as speculated it is indeed a clever design that could offer benefits to road cars at a later date.

[Tommy Cookers]

.....stoichiometric conditions at 10500 is about 2,25 bars absolute. I've seen in many occasions to be said that the maximum boost is 3,5 bars based on apparently info released be Renault. This got me wondering are they pulling a leg and having a laugh at ignorant journalists or is there some benefit in extra boost.
I got told that with direct injection the air fuel mixture usually isn't homogenic. If that's true, then calculations based on stoichiometric mixture no longer apply. In one scenario they might try to get rich mixture in the middle and some extra air around close to the cylinder walls which would insulate and lessen the heat losses. Since the mixture is in different layers, the mean ratio would be way more lean than in homogenic mixture.

FWIW ......
I think we all know Renault mean 3.5 abs not 3.5 + 1 abs (and 3.5 abs is a wind-up ?)
maddeningly to us oldies, since the turbo era everyone (outside the USA) calls abs 'boost'
eg if you check the 1988 so-called 2.5 bar boost limit was actually 2.5 bar abs (interesting to think over the practicalities)

if even 3.5 abs is to be believed, it's interesting as it implies a high exhaust pressure or even an actual backpressure

is some insulation benefit from DIs initial stratification realisable without significant mean leaning beyond stoich ?
significant mean leaning because means pumping more air at higher pressure through the engine than is otherwise needed
(though some of that loss would be recovered by the turbine)
and it would need more charge cooling


@ppj13
regarding the temporary power benefits of wasting the exhaust and motoring the compressor
does it take substantial power to simultaneously motor the turbine at the same 100,000+ rpm ? (or do they have declutching ?)

[David1976]

I wonder if Merc's speculated powertrain installation advantage is not only in having the high pressure air adjacent to where you want the components that need the most cooling, but in theory all the heated components are located together which could benefit aero when the hot air is exited?

[mrluke]

I think we all know Renault mean 3.5 abs not 3.5 + 1 abs (and 3.5 abs is a wind-up ?)
maddeningly to us oldies, since the turbo era everyone (outside the USA) calls abs 'boost'
eg if you check eg 1988 so-called 2.5 bar boost limit was actually 2.5 bar abs (interesting to think over the practicalities)

This is not and cannot be correct.

Nearly all production turbo cars run between 0.5 and 1.5 bar boost. They even have boost gauges which demonstrate this. None of these engines are running at below atmospheric pressure.

Boost is air pressure extra over atmospheric, or to be more literal, a boost in the air pressure/density ingested by the engine.

[ringo]

The boost pressure Renault quoted was much lower down in rpm. It's not at 10,500.
At the end of the day, you want to run boost to match the amount of fuel you need to burn. More boost than you need is simply a waste of energy.
All engines should run about the same amount, unless they have drastically different compression ratios.

[JNF]

If I got this correct the boost isn't much higher in the lower revs. This is based on fuel flow formula 0,009*rpm+5,5 given in the rules and air-to-fuel ratio 14,7:1 which remains constant throughout the rev range. I doubt they would rev the engine lower in any situation other than idling in the pits.

So it seems to me they are just throwing out some random numbers.

[Abarth]

@JNF
Thanks for the graph, saved me time to do it for myself, as I was wondering how the needed pressure would be at lower revs.
What charge air temperature are aou assuming with these pressure levels?

Thank you.

[ppj13]

Sorry for my ignorance:

Why is the boost higher (if only a little) at lower revs? Isn't it true that injection time is almost constant below 10500 due to fuel flow limit? Shouldn't the boost be flat also?

Edit: don't bother. The injection time is a little bit bigger as the rpms go lower. The same amount than the boost.