2014-2020 Formula One 1.6l V6 turbo engine formula

[gruntguru]

in what engine is it thermodynamically advantageous to not have charge cooling? in an engine that has too low a CR charge cooling increases HUCR

Sure there is a knock trade off - which I indicated in the post you are responding to. However, for a given CR, the thermal efficiency will be higher without intercooling.

Raising CR produces diminishing BTE returns. I doubt that increases beyond 11.0:1 would produce significant improvements.

Think back to the Honda RA168E.
- 26 year old technology, PFI.
- 2.5 bar MAP
- 0.98 AFR
- 70*C CAT
- 9.6:1 CR

Current F1. Fuel knock resistance? - probably similar to 1988 F1?
- Latest technology. DI, stratified charge?
- 3.5 bar MAP
- 1.4 AFR
- 80*C+ CAT ie moderate intercooling
- 11:1 CR

All very feasible IMHO.

or in an engine that has too high a turbine PR and so gives more electrical power than can be used
and less crankshaft power than the other cars in the race

No, higher Charge Air Temperature will mostly benefit turbine energy so there would be no point if the MGUK was already maxed out.

OTOH there is no limit on MGUH harvesting. You have indicated MM unit has 80kW limit. Are all the teams using MM? I would expect MB to use Bosch or Siemens technology. MB supposedly run a "larger turbine". That would suggest a higher capacity MGUH to go with it.

btw ..... why worry about dissociation ? not only does (consistent) dissociation raise HUCR but, in your lean engine, reassociation would occur in the exhaust manifold and so increase turbine power though there could be a protest over this

1. For best efficiency, heat needs to be added at the highest pressure/temperature in the cycle, ie immediately after TDC. Adding heat later in the power stroke is bad for efficiency and adding it in the exhaust header is worse still.
2. At very lean mixtures and consequent potentially moderate exhaust temperatures, reassociation may not occur in the exhaust.
3. Increasing CR at the expense of leaving fuel unburnt? That is a very poor tradeoff. Besides, Stoichiometry is not the ideal place to be if high CR is the goal. Far better to be at 1.2 or more.

[gruntguru]

. . . . I actually wouldn't be surprised if F1 teams pass the fuel through a heat exchanger to preheat the fuel. TC and GG do you agree with this statement? If not why?

Yes. Beyond the RA168 experience it is also clear from other papers that ignition and stable combustion of lean mixtures is enhanced by increased charge temperatures, increased fuel temperatures and reduced droplet size.

[trinidefender]

Mazada's new SkyActiv series of engines run at about 14:1 compression ratio. To reduce knock and do this they supposedly run 4-2-1 exhausts for better exhaust scavenging. High direct injection pressures with multi hole injectors. Intake air flow is kept at high speed to maximise mixing and what I find to be a novel idea, that I have wondered previously if there was any application in gasoline engines, pistons with a cavity. From pictures the cavity looks quite small, nothing like on Diesel engines but it is still there.

According to this article a BFSC of 0.28 lbs/hp/hr. Sounds pretty good to me. I wonder if anything like the piston cavity approach is used in F1.

*edit* 0.28 lbs/hp/hr = 127 g/hp/hr

[gruntguru]

Trini can you supply a link? That BSFC equates to 48% thermal efficiency which is very unlikely. I think it should be 0.38 or a TE of 35%.

Shaped piston bowls are not uncommon with DI. With their lower compression it is likely F1 engines would be using a bowl to produce a more compact combustion chamber.

[trinidefender]

Trini can you supply a link? That BSFC equates to 48% thermal efficiency which is very unlikely. I think it should be 0.38 or a TE of 35%.

Shaped piston bowls are not uncommon with DI. With their lower compression it is likely F1 engines would be using a bowl to produce a more compact combustion chamber.

It was presented here, the website doesn't look very reliable though so I'm not not sure. I was more focusing on what Mazda used to achieve their high compression ratios without knocking.

http://www.motoiq.com/MagazineArticles/ ... ology.aspx

[rscsr]

Toyota runs a CRof 17:1 in their works LMP engine. And this without direct injection. It was written in a Race Engine Technology, but I'm not sure which.

[J.A.W.]

Did the Toyota running 17:1 comp ratio.. ..incorporate a variable CR ratio head?

Likely such innovations ( & a variable CR ratio system for G.P. motorcycle racing - was trialled) are currently on
the overtly restrictive 'banned' list of technical advances..

[rscsr]

Did the Toyota running 17:1 comp ratio.. ..incorporate a variable CR ratio head?

Likely such innovations ( & a variable CR ratio system for G.P. motorcycle racing - was trialled) are currently on
the overtly restrictive 'banned' list of technical advances..

It wasn't explicitly stated that they are running a variable CR head. It pretty much sounded that they achieved through optimization of standard port injection, like they use it in the Prius. He also stated that they are developing DI but are not seeing any real advantages.
I can't show you the whole article since I lent that certain issue.

[Tommy Cookers]

Gilles Simon wrote of F1 that valve size will be compromised to minimise combustion chamber size and so give a very high CR
and that high combustion temperatures and mep will force the use of part-steel pistons as in diesels - ie cavity shape ?

that's why I wrote about dissociation (2 years ago) - I do know what it is
but any reassociation beyond the cylinder is useful/useable in a lean run turbine-compounded engine
and dissociation in-cylinder reduced 'knock' (spontaneous combustion after the sparked combustion initiation) eg in WW2 era ?
(the reason we had anti run-on valves in cars in the 60s, 70s etc)
Otto won't predict dissociation or other physical chemistry and chemical thermodynamic factors driving chamber design and CR

the 'holy grail' of design surely would be to manage combustion by managing injection rather than by managing CR
if this is possible then the current 500 bar limit injection hardware takes us nearer to it ?

in preparing fuel vapour for combustion by heating then PI may be good (as Toyota says)
fuel heating on eg the 88 Honda F1 was to defeat the viscosity/high BP (droplet size/combustibility effect) of the 84% Toluene fuel
the large difference between RON and MON for this fuel implies an unusually high detonation resistance in race use
this fuel subverted the intent of the fuel limit by volume and the intent of the Octane limit (but complied with the actual rules)
btw - this fuel has significantly lower heating value than gasolines so the BTE is even higher than has seemed to some

@trini
they ran 2% rich and/or richer not 2% lean and/or leaner (though maybe I misunderstand what you said)

[Brian Coat]

Just thinking out loud here ... Not saying any of this is 'right' ...

When I said shaft work split was an interesting choice I was referring to turbine sizing,not in-race control system tactics of
MGU-H&K and ES, although that is very interesting, too.

More turbine work extraction means a bigger turbine and it needs to be at least big enough to self sustain the Hybrid system lap after lap, I guess.

It seems to me the goal is a self sustaining hybrid system with maximum ICE efficiency?

The choice on how much work is extracted at the crank vs turbine will be affected by the static CR, but it will also be influenced by turbine design, EVO and other factors.

On the intake side, for a given knock limit, higher boost implies lower static CR and gives higher air mass flow.

The advantages/not of the higher air flow have been debated on here ad infinitum.

You could run very high CR and size the compressor just large enough to flow just enough air to completely burn the limited fuel flow rate.

Or you could run higher boost, lower CR and more air mass flow, which implies lean running.

[gruntguru]

The choice on how much work is extracted at the crank vs turbine will be affected by the static CR, but it will also be influenced by turbine design, EVO and other factors.

By far the biggest influence would be PR. Increased PR alone means higher power in the turbomachines but additionally creates increased air mass flow which further increases power in the turbomachines.

[gruntguru]

. . . . that's why I wrote about dissociation (2 years ago) - I do know what it is
but any reassociation beyond the cylinder is useful/useable in a lean run turbine-compounded engine . .

Useable but - the heat of reassociation in the header produces massively less work than the same heat added at tdc - especially with low turbine PR.

[Tommy Cookers]

some dissociation occurred in large heavily supercharged aircraft engines running at about 2500 rpm
(though it seems to me that a higher CR at a given mep or a higher mep at a given CR was allowed by this)

but is there evidence or reason to believe that dissociation would occur in our 11000rpm F1 engine ?
peak cycle temperature would be very much earlier and be of very much shorter duration (than in the aircraft engine)
there must be some threshold of time-at-temperature effect below which there is no significant dissociation ?

some such effect applies to detonation
eg 50 years ago Honda wrote in an SAE paper that their 18000 rpm 125 cc race motorcycle only needed about 75 Octane fuel
Shell wrote quite recently that eg 13.3:1 CR NA F1 only needed about 95 Octane

[Kiril Varbanov]

Both Horner and Mattiaci confirm that majority agreement to allow in-season engine upgrades will go to the next F1 commission meeting for approval.

[dren]

Both Horner and Mattiaci confirm that majority agreement to allow in-season engine upgrades will go to the next F1 commission meeting for approval.

Minor upgrades. Mercedes still holds the cards on to if they will lift the "ban" completely.