Road Relevance of 2014 F1 Engines

[pgfpro]

Some things to consider.

Most modern race turbocharger engines will run with less back pressure then intake pressure for a positive Delta P.

There's 1.8L and 2.0L stock valve, stock port engines making 1000+HP Their BSFC numbers do increase as boost increases but most of it is due to using fuel for thermal management to prevent detonation. Even though some of the engines above are running BSFC numbers at around .38 lb/hr or 231 g/kWh.

So my point is there is a lot successful turbocharged engines that are not having any exhaust valve flow issues from high charge pressures. This is also being done with a lot of HP left on the table, meaning a MGUH/ERS system could benefit from this easily. The other sad part is all this new knowledge cam from the "Grass Roots Racer" and not from the Turbocharger manufacturers or OEM level. Thanks to the local tracks the "average Joe" is doing all the testing and the OEM car manufacturers and Turbo companies are making changes on the out comes.

[xpensive]

231 g per kWh is an efficiency of xactly 33%, which means the 2014 engines would produce only 433 kW (588 Hp) at 27.8 g per second with the same efficiency, why I hope the KERS/HERS will contribute in a serious fashion?

[pgfpro]

231 g per kWh is an efficiency of xactly 33%, which means the 2014 engines would produce only 433 kW (588 Hp) at 27.8 g per second with the same efficiency, why I hope the KERS/HERS will contribute in a serious fashion?

Keep in mind that the 231g/kWh BSFC numbers I speak of are on engines that were produced over 20 years ago and were OEM passenger engines design originally at only 135HP to 200HP. IMO I think that a purposely built turbocharge race engine ie. with all the new technology, F1 will have BSFC numbers around .30 lbs/hr or 182 g/kWh BSFC to produce around 741HP.

[xpensive]

An efficiency of 42%, that would indeed be impressive?

[Tommy Cookers]

'fuel for thermal management to prevent detonation' EDITED

A rich mixture has a beneficial effect against detonation that is independent of thermal effects (of course thermal effects are also useful).
Thermal effects (heat extracted by evaporation) are relatively large with modern pump fuel, due to the high 'oxygenate' content (ie 5% alcohols now mandated for fake green credibility), to maintain high octane number. These effects are not particularly dependent on mixture richness
Avgas was designed and made for a particularly large benefit with rich mixture independent of thermal effects (about ten times better than pump fuel), and still does this today. Anything like oxygenate is kept out of Avgas (it has a stringent spec to avoid vapour lock etc).

Maybe track use is kinder re. detonation to any type of engine than the worst road use would be ? Very high revs (without overheating) are less likely to support detonation , as the mep is less ?

I suppose the aircraft engines design implies that the turbocharger is no better than the same compressor driven mechanically. The compressor has a delivery proportional to the square of its rpm (and a lot of inertia at 40000 rpm), so a mechanical drive would be no good in a car (unless at Indianapolis etc). The exhaust drive gives regulation over the big range of speed and power needed in a road car (wastegate etc).

Anyway, 1000 bhp sounds good ! Thanks for the information.

[olefud]

The Turbo-Compound (as did many engines of this generation) had an artificially low compression ratio, to allow very high max MEP and power by allowing very high pressure supercharging, so the exhaust emerged at relatively high pressure. This was why they had the turbines (unlike other versions of the same engine).

I can't see how this avoids the significant losses around the valve and before the turbine, but I'm open to being proved wrong. Does the higher overall pressure in the forced induction engine at this point make available the turbine some of the pressure drop that would otherwise be wasted ?

I know there's a lot about feeding exhaust pulses to the turbine; but after 80 years of viable turbocharging we still don't have clear statements/measurements showing what goes on IMO. Such pulses could equally be called low amplitude explosions whose energy (partly) decays before it can be used ? Explosion means supersonic/shock conditions that degrade and can't be conserved.

In racing we harvest exhaust pulses after degradation via our exhaust system design with naturally aspirated engines (to increase mass flow/MEP, ie some 'free supercharging'); one revelation of the F1 turbo era was that turbos need exactly the same exhaust system design ?

I’m stretching a bit here, but, as to the “explosive” nature of exhaust flow, it may be useful to distinguish between sonic (pressure wave) energy and actual exhaust gas flow. Generally, rapid gas flow expansion with no resistance leads to high entropy and waste energy. I believe this is the flow with the great part of the harvestable energy (mass times velocity squared) that can be extracted by a turbine.

On the other hand the sonic pulses can do limited work and are the subject of Constantineu’s theory of sonics. The sonic pulses are more analogous to the use of electrons in control systems while the physical gas flow is analogous to electrical power systems.

The “free supercharging” is a sonic wave phenomenon. The sonic wave travels through the exhaust pipe until it reaches the “end” i.e. an enlarged cross-section or outlet. It there changes its sign and direction and travels back through the pipe to the exhaust valve changes sign etc. The pulses are alternative rarefied and denser “waves”. With proper tuning, a dense wave in the intake fuel mixture flow can be positioned in the combustion chamber provided enhance volumetric efficiency. It’s surprising that the sonic pulses apparently travel through a turbine.

I’m taken with compounding since it utilizes the primary stream of waste energy and directly utilizes the energy to reduce the engine fuel requirements for a given power output. It seems to me that it would be more effective than electrically harvesting and chemically storing energy.

[aussiegman]

'fuel for thermal management to prevent detonation'

Running a mixture between 12.0 & 12.5:1 in a turbo engine has been the normal for standard petroleum fuels for the last 15 to 20 years to prevent detonation due to increased in cylinder temperatures. Newer fuels with higher octane numbers around the 98 to 100 range, such as have been available in Japan for years, are now increasing efficiency by increasing detonation resistance. The added benefit for a small turbo engines is that by running leaner they produce more energetic exhaust gases (hotter) that drives the turbine with greater ease.

Also, the increased use of ethanol fuels such as E85 which may have a lower calorific value than say 98 octane petrol (approx. 33% less) but the equivalent of 108+ octane allows much higher compression ratio's to be used vs. a petrol based engine. It also has a cooling effect on the intake charge as it evaporates in the runner behind the intake valve cooling the charge prior to entering the cylinder.

You have also totally disregarded the advances of component coatings, metallurgy and general engineering that has seen engine components able to withstand greater temperatures with lighter materials. The new Indy car turbos by Borg Warner (which I have experience with) are an example. Ceramic bearings, titanium vs. inconel turbine wheels, drastically improved aerodynamic profile thanks to CNC machining as opposed to casting. The list is endless.

I have two (2) small 2.2Lt, 4 cylinder race engines running on E85. One runs 13.5:1 and 2.0bar positive boost pressure and the other runs 10.0:1 and 3.0bar positive boost pressures. They both make well over 600hp and we have even pushed one to 800+hp before we had issues with head studs stretching at 3.25bar.

A rich mixture has a beneficial effect re. detonation that is independent of thermal effects (of course thermal effects are a symptom of a rich mixture, and are also useful).

I would disagree as my experience shows that a rich mixture works by allowing the fuel to absorb the heat from the intake charge as well as components such as valves, valve seats, piston crowns etc through evaporation when contact is made. The negatives are incomplete combustion due to inadequate oxygen in the intake charge. It is the same mechanism used for cooling NA engines during lift off throttle over-run. Vaporised, unburnt fuel is then moved down the exhaust and finally burns when it reaches the atmosphere and oxygen is again sufficient to support combustion. The flames from the tail pipe we all know and love. This is different to what you see with drag engines were the runners are actually displaying combustion events that run past the valve and down the exhaust rather than a separate, much less energetic combustion event.

Avgas was designed and made for a particularly large benefit with rich mixture (about ten times better than pump fuel), and still does this today.
Maybe track use is kinder re. detonation to any type of engine than the worst road use would be ?

Seriously?? AVGAS?? I wish you good luck getting AVGAS (as opposed to Jet A/Jet A1 /Jet B) or any high lead/highly toxic fuel passed as an alternative. Low Lead AVGAS runs a lead content of 0.56g/Lt and up I do not think so. F1 banned the Toluene based exotic fuels years ago due to health and environmental concerns and there is no way in hell they are going to allow a lead containing AVGAS or Toluene based fuel back in the race. That thinking is in direct opposition to the "greening" of F1 and about 20 years behind the current safety standards.

Anyway, 1000 bhp sounds good ! Thanks for the information.

Using off the shelf parts it is indeed possible for a 1000hp 4 cylinder engine to be built outside of an F1 team. Further to this a 1200+hp 4.0/4.2/4.4Lt V6 is possible as seen in recent highly developed R35 GTR's running stroked and bored VR38DETT.

Turbo technology has moved on a great deal from your comparisons to WWII technology. You would do better to relate your thinking to more modern examples

[Tommy Cookers]

Thanks for the information !

I have nothing against a dose of evaporative cooling with forced induction, the first 2 WDCs were won this way.

I was just pointing out that all pump fuel has an inherent gain in detonation resistance with rich mixtures independent of temperature . That is why mixture temperature has been fixed in fuel testing for the last 80 years, and why mixture strength must be manipulated to give the worst result (while the temp is held constant). That's RON & MON.

So some gain credited to a rich mixture really belongs to the fuel itself.
(Avgas was literally designed for this, it's less natural than pump fuel).

Most EC is due to the basic fueling, not the extra fueling for richness (although that could be important).
With today's fuels there is more EC than in the past.

Toluene etc (being very dense) was used to defeat the FIA attempts to limit turbocharged F1 power by limiting fuel quantity by volume (not weight), that's why they don't like it . It was beaten by introducing limits on induction pressures (and de-limiting fuel quantity ?).
Since when there's been no limit on fuel quantity (till 2014).

My issue is with the FIA.
They talk a good act (of greeness/road relevance), but the 2014 rules allow only 1 design approach to this. This favours an expensive product mix ( the 200 bhp road car that is 'all-electric' in town), F1 will be a constant advertisement for this.
At present KERS in F1 also recovers non-KE

My interest in the turbocharger is how much of its drive is recovery from what is wasted in the exhaust of the NA engine (also this is related to compounding), and how this compares with engines (10 million and rising?) that have greater expansion before exhausting.
I can believe that the turbo engine can be more efficient than the NA engine even without any recovery from exhaust at NA exhaust state.

These are interesting times for engine design !

Good luck with those turbos !

[Tommy Cookers]

ATTN MR OLEFUD

Good stuff ! I thank you

[Dragonfly]

Thanks for the information !
My issue is with the FIA.
They talk a good act (of greeness/road relevance), but the 2014 rules allow only 1 design approach to this. This favours an expensive product mix ( the 200 bhp road car that is 'all-electric' in town), F1 will be a constant advertisement for this.

Yes, millions thrown on the wind instead of allowing a less restricted design where R&D can lead to road car applicable innovations.

[pgfpro]

My interest in the turbocharger is how much of its drive is recovery from what is wasted in the exhaust of the NA engine (also this is related to compounding), and how this compares with engines (10 million and rising?) that have greater expansion before exhausting.
I can believe that the turbo engine can be more efficient than the NA engine even without any recovery from exhaust at NA exhaust state.

First off this is a great thread!

From my calculations for an engine that makes around 636HP with a turbo charger the turbo shaft power will be around 100HP. At 445HP the turbo shaft power will be around 69HP. Both examples would be around a 70% turbine efficiency and 1650F exhaust inlet temperature. I for see that F1 will be running around a 80% turbine efficiency.

[machin]

Keep in mind that the 231g/kWh BSFC numbers I speak of are on engines that were produced over 20 years ago and were OEM passenger engines design originally at only 135HP to 200HP. IMO I think that a purposely built turbocharge race engine ie. with all the new technology, F1 will have BSFC numbers around .30 lbs/hr or 182 g/kWh BSFC to produce around 741HP.

At a talk I went to a couple of weekends back Ben Bowlby spoke of the Deltawing's 1.6 Litre direct injection petrol engine (badged as a Nissan, built by RML) which makes 300bhp @ 7500rpm:-

Q: Under race conditions what does the engine do MPG wise?
On the dyno it does 230g/kWhr... there is virtually no petrol road car that makes horsepower at that small a fuel burn... on the race track it equates to around 12 miles per UK Gallon; it doesn’t sound that good but that is actually an impressive number; about double what the petrol LMP1 cars will get.

[xpensive]

...
First off this is a great thread!
...

It is indeed, but what efficiency is reasonable to xpect from the 2014 engines, xcluding the recoveries?

[machin]

And from the excellent book "McLaren Honda Turbo -A Technical Appraisal" by Ian Bamsey, published in 1990, talking specifically of the 1.5 litre twin-turbo RA-168-E:-

To obtain the best fuel consumption at 2.5Bar Honda found it necessary to run a charge air temprature of 70 degrees centigrade and a weak mixture -an air ratio off 1.02 - and a fuel temperature of 80 degrees centigrade. Under these conditions Honda was able to produce an extremely frugal race engine having a brake specific fuel consumption of 264 g/kWhr at 12,000rpm and giving a maximum power of 620bhp a 12,500rpm.

In "best power" mode the BSFc rose to 314g/kW.hr, and power rose to 685bhp.

[xpensive]

...
In "best power" mode the BSFc rose to 314g/kW.hr, and power rose to 685bhp.

If you use 47.2 MWs per 1000 g of gasoline, 314 g per kWh is a measly 24.2% efficiency, hope they can do better than that?