Ferrari Power Unit Hardware & Software

[Mclarettino]

http://www.motorsport.com/f1/news/techn ... es-668712/

Assumption 1. Giorgio Piola's as usual stunning drawings in this article seem to indicate that Ferrari is staying with their original turbo compressor layout they have used for the past 2 seasons - ie keeping the compressor and turbo together, which Renault have used aswell.

Assumption 2. The other 2 PU manufacturers, Mercedes and Honda, are likely to stay with their split compressor turbo layout, with all the power unit and chassis benefits this layout brings: including lower chassis centre of gravity, the compressor is kept cool by because it's not right next to the hot turbo/MGU-H, tighter packaging possible with the aerodynamic benefits this brings, and several more.

Are assumptions 1 and 2 correct? If so, are you surprised Ferrari and Renault did not adopt the split compressor turbo layout after the first season of hybrids, and really surprised it seems like they both will not be adopting it for the upcoming season? After all this layout is the basis of Mercedes advantage because of all the many other benefits it brings that all add up. And Honda are trying to use this layout but make it more compact. I am really surprised personally. I really thought Ferrari would adopt the split layout for this season, the layout change would be easily be possible within the 32 tokens.

[Brian Coat]

Just thinking ...

At full load is the CAI regime limited by the ability to tune RGF for CAI conditions, or rather by very rapid pressure rise?

If the latter, high boost lean dilution should help.

I found this FEV/Aachen paper from over 10 years ago where efficient high load boosted CAI was demonstrated, albeit under lighter operating conditions.

https://books.google.co.uk/books?id=OPe ... YQ6AEIHDAA

The potential for efficiency gains would make this worth evaluating?

[gruntguru]

Four possibilities for controlling AI (Auto Ignition) on the fly come to mind.

RGF (Residual Gas Fraction). Long time constant (must change turbine speed or control wastegate). No capacity to adjust individual cylinders.
CAT (Charge Air Temp). Time constant similar to W/G (Waste Gate). No capacity to adjust individual cylinders.
MAP Manifold Absolut Pressure). Fast response by controlling intake butterflies. No capacity to adjust individual cylinders.
DI (Direct Injection) strategy. (Changing the injection timing and multi-pulse strategies to vary mixture distribution (stratification) in the chamber.) Very rapid response. Cylinders can be tuned individually.

[ringo]

Too many acronyms there to make any sense guru.

[pgfpro]

300 bar peak-cylinder-pressure is certainly pushing the boundary. I have never heard of such a high pressure in an SI engine. Even diesels don't normally go that high.

I have heard that some of the big $$$ nitrous engines make around 300bar combustion pressure, but most only live around 6 seconds or less

I think a nitrous engine lasts more than one run!

If we are talking ALL SI engines, including mad ones, I believe using CH3NO2 fuel can get you very much higher than that.

In the gasoline-fuelled arena there are other engines in/approaching this 300 Bar region.

I guess we'd expect overall pressure ratio (CR+boost) to be the big driver?

I was being kinda sarcastic lol

The nitrous engines 300bar I quoted I should of wrote mean 300 bar. The nitrous gasoline type fuel engines at 350 bar mean pressure is where the based gasoline race fuel starts having issues and you will see some spikes and instability of the combustion.

As you know the high mean cylinder pressure is the target, the abnormal combustion that generates extremely high cylinder pressure spikes is nemeses. So as you said the (CR+boost) is the driver or producer and is easy to obtain the problem is always dealing with the abnormal combustion that leads to pressure spikes.

With todays F1 engines the fuel plays a major part of combustion stability and next it would have to be the DI engine.

[gruntguru]

Too many acronyms there to make any sense guru.

Sorry folks.
Fixed.

[ringo]

the combustion temperatures and pressures are really determined by the boost pressure, the compression ratio and heat release from the fuel. I think most engine makers will get a handle on the first two. The fuel properties and whatever the hell is going on on ignition is the mysterious part. I really have no clue.
I have noticed though that the specific heat ratio of the fuel/air mixture at elevated temperatures has a huge effect. There is so much of the potential of the engine that is depending on fuel chemistry.

[cokata]

I might be completely wrong, but boosting the peak cylinder pressure improves efficiency by speeding up combustion, which will mean that more of the pressure will be used to push the piston down, and less will be thrown out when the exhaust valves open. So this would mean less energy will be reaching the turbine and therefore the MGU-H won't be able to generate as much power. This is will be especially true if the extra pressure will come from a higher level of boost, and not from higher CR.

[Tommy Cookers]

.... I have noticed though that the specific heat ratio of the fuel/air mixture at elevated temperatures has a huge effect. There is so much of the potential of the engine that is depending on fuel chemistry.

years ago I suggested that some clever fuel chemistry would deter dissociation
(as in traditional fuels eg Avgas a rich mixture does this by chemical effect)
though with a recovery turbine present, dissociation may be less than critically important

also there was some learned input on SH ratio
(iirc following GG's advocacy of benefits of very lean AFR)
maybe in the TERS thread about 2 years ago ??

[GoranF1]

https://twitter.com/hlawiczka/status/691531294359080960

[Mclarettino]

Would it be possible to confirm whether Assumptions 1 and 2 are correct or not in my post at top of page 8?

[pgfpro]

Just wondering how many of you on here have done some combustion pressure testing???

I just started and its really interesting!!! Higher combustion pressure doesn't always mean the engine will make more torque???

Thoughts???

[wuzak]

http://www.motorsport.com/f1/news/techn ... es-668712/

Assumption 1. Giorgio Piola's as usual stunning drawings in this article seem to indicate that Ferrari is staying with their original turbo compressor layout they have used for the past 2 seasons - ie keeping the compressor and turbo together, which Renault have used aswell.

Assumption 2. The other 2 PU manufacturers, Mercedes and Honda, are likely to stay with their split compressor turbo layout, with all the power unit and chassis benefits this layout brings: including lower chassis centre of gravity, the compressor is kept cool by because it's not right next to the hot turbo/MGU-H, tighter packaging possible with the aerodynamic benefits this brings, and several more.

Are assumptions 1 and 2 correct? If so, are you surprised Ferrari and Renault did not adopt the split compressor turbo layout after the first season of hybrids, and really surprised it seems like they both will not be adopting it for the upcoming season? After all this layout is the basis of Mercedes advantage because of all the many other benefits it brings that all add up. And Honda are trying to use this layout but make it more compact. I am really surprised personally. I really thought Ferrari would adopt the split layout for this season, the layout change would be easily be possible within the 32 tokens.

I don't think that the split turbo gives a gain in CoG over the normal style turbo used by Ferrari and Renault. In both cases, the height of the turbo's shaft is dependent on the size of the MGUH and how it fits in the vee.

With turbine and compressor being of similar dimensions I don't think there is an issue for clearance to the clutch/power take off area.

Ferrari's CoG issues most likely stem from the positioning of the water:air intercooler located in the vee. For 2016 it has been suggested that Ferrari will move the inetrcooler to free up space for variable intakes, which will probably alleviate the issue.

Honda is slightly different to Mercedes in that their compressor is in the vee. It is likely this is what limits the lowering of the turbo's shaft rather than the MGUH.

Just at a glance it would appear, to my eye, that Ferrari and Renault have a better ram induction system. Mercedes and Honda have more convoluted intakes to their compressors.

[godlameroso]

Just wondering how many of you on here have done some combustion pressure testing???

I just started and its really interesting!!! Higher combustion pressure doesn't always mean the engine will make more torque???

Thoughts???

Depends when combustion occurs, then there's that little problem of valve overlap, blow-by, and the inertia of the rotating assembly, but these are mere engineering niggles.

[ringo]

Just wondering how many of you on here have done some combustion pressure testing???

I just started and its really interesting!!! Higher combustion pressure doesn't always mean the engine will make more torque???

Thoughts???

Yes that is true. I've notice this as well.
But here is why i think that is so, the same discussion about the specific heat ratio is the reason. The gas expansion has a polytropic index that characterizes the expansion and how much work is done. If the pressure is too high for a certain expansion profile; an adiabatic one with an index of the SH ratio, you will find that most of the energy will leave the engine as heat energy with a high exhaust pressure.
This can be good for the turbine and the MGUH, but crank horsepower from combustion will suffer.
Normally you will yield more power from heat energy to the crank than through the MGUH. So it would be preferred to be more biased to making power from the crank than from the turbine.

I believe the engine makers manipulate the expansion of the gases to yield lower exhaust pressures despite the higher combustion pressures; resulting in more work on the pistons. This is probably done with multiple combustion events? or a combustion product that somehow does more work compared to how much heat is released. I really don't know.
But it's all in the fuel chemistry, method of combustion, and how the combustion product behaves as it transfers energy.
The process of expansion is not what we understand it to be that's for sure.

What works with my model though, is increasing temperature yields more power most definitely. You need the right balance of temperature increase, which a combustion pressure that doesn't negatively affect your gas expansion and energy transfer to the pistons.
Just my ramblings of course.