Ferrari Power Unit Hardware & Software

[Polite]

About the topic: new design of the PU relative to the top header, upgrade for the combustion chamber!

Do you have a reliable source @Polite? Thanks in advance.

https://www.sportfair.it/2019/12/nuova- ... 20/994879/
https://it.eurosport.com/formula-1/nasc ... tory.shtml
https://www.gazzetta.it/Formula-1/20-12 ... 1298.shtml
new rear 3rd element; new cape and fw
cheers

[subcritical71]

The averaging time might be a microsecond or several seconds, and until we know that, we can only speculate and no one will get to “be right”.

I think this is the whole point and back to the basics. You cannot have an instantaneous flow rate. That would be mass divided by time, and if time = zero then you cannot solve. You have to pick something for time and we will probably never know it. Sure the sensor samples at ~2kHz but there must also be some averaging/differentiating going on.

There will also be times when a different number of injectors will be open simultaneously (and even if that number did not change the flow rate to each cylinder would be different due to different d/p's across each injector during its injection time (?)), it would be impossible to maintain the 100kg/hr flow limit when the number of simultaneously open injectors would change.

[gruntguru]

According to rule/regulations the flow through the flow meter have to be equal to the flow through the injectors (all fuel that passes through the fuel flow meter must end-up in the comnbastion chambers). If the flow through the injectors (kg/h) is more than stipulated the car time will be disqualified.
“there need be a small accumulation” The small accumulation is common to all. Re high pressure pump pressure regulating/pressure relieve-valve/s that regulates the pressure of the pump. (The pump variable displacement mechanism (flow volume) (is actuated by a sophisticated pressure regulating valve that also regulates the pressure. Says it all).
Fuel accumulation (storing) in so called ballooning/expanding fuel lines has been talked about a lot. Poeple on this here discution should please keep in mind that ‘most’ if not ‘all’ of the fuel system parts including the fuel itself would according to rules/regulations have to be approved by the FIA.

My point about "averaging" was not so much about averaging of flow measurements by the flow meter - more about smoothing the flow itself.

Putting it simply, lets say the flow rate of each injector is 80 kg/hr. This means at maximum power, the duty cycle of each injector would need to be 100/(80 x 6) = 0.208 or 20.8% ie each injector is flowing for 20.8% of the time and not flowing for 79.2% of the time. Looking at all 6 injectors there must clearly be times when more than 1 injector is open. The fuel flow to the engine will be rapidly switching between 80 and 160 kg/hr.

The flow response of the fuel pump is much slower than an injector - it cannot instantly change its output 45,000 times per minute or more. This means there will need to be an accumulator/damper built into the high pressure section of the fuel system. The capacity of the damper would not need to be very large. For example it might be capable of storing enough fuel for one cylinder charge (0.07ml) while increasing rail pressure by less than 1%. The result in this example would be a 1% fluctuation in rail pressure (with a triangular waveform) and no variation in pump flow.

Such a device provides a means to "cheat" the flow limit by varying the fuel rail pressure to suit the circumstances. Increasing the rail pressure during light load operation then reducing it gradually when extra power is required. A 20% pressure variation would (in the above example) provide about one gram of extra fuel undetected by the flow meter. The FIA closed this loophole by limiting and monitoring fuel pressure variations.

[henry]

For there not to be any variation in the 100kg/hr flow rate after the HPP I think it would be necessary for the ICEs to be even firing and the injectors to inject a square wave 120 degrees long.

I’m pretty sure they’re not even firing.

The 2021 regulations allow both a Pressure relief valve internally and externally to the HPP, and filters both before and after the Quick Disconnect coupling in the supply line between the tank collector and HPP. All of the components, including pipe work, will be either FIA specified or have a design specification. They obviously don’t want to give the manufacturers any opportunities to tinker with the fuel system.

[ncx]

Next year the max amount of fuel allowed to be kept stored outside of the tank at any time will drop from 2lt to 0.25lt. Much less with which to play already.

[saviour stivala]

The injectors are not permitted by the rules to flow more than 100 kg/h. And also not permitted under 10500 RPM to flow more than Q (KG/H) = 0.009 (RPM) 5.5.

[dans79]

The injectors are not permitted by the rules to flow more than 100 kg/h. And also not permitted under 10500 RPM to flow more than Q (KG/H) = 0.009 (RPM) 5.5.

That's for the entire engine not individual cylinders, if memory serves.

[saviour stivala]

The injectors are not permitted by the rules to flow more than 100 kg/h. And also not permitted under 10500 RPM to flow more than Q (KG/H) = 0.009 (RPM) 5.5.

That's for the entire engine not individual cylinders, if memory serves.

Of course 'its for the 'entire' engine' (6 injectors).The 100 kg/h fuel flow maximum permitted is what the engine is permitted to consume.

[godlameroso]

The injectors are not permitted by the rules to flow more than 100 kg/h. And also not permitted under 10500 RPM to flow more than Q (KG/H) = 0.009 (RPM) 5.5.

That's for the entire engine not individual cylinders, if memory serves.

Of course 'its for the 'entire' engine' (6 injectors).The 100 kg/h fuel flow maximum permitted is what the engine is permitted to consume.

So current F1 engines use ~400cc injectors?

[gruntguru]

The injectors are not permitted by the rules to flow more than 100 kg/h. And also not permitted under 10500 RPM to flow more than Q (KG/H) = 0.009 (RPM) 5.5.

There is no limit on the flow rating of individual injectors ie it would be OK for each injector to flow 200 kg/hr (1200 kg,hr for all 6). In operation, an injector that size would open for a maximum of 60 degrees per cycle at 10,500 rpm and above. (This sizing is not beyond the realms of possibility - although I think it would probably be less.)

[dans79]

There is no limit on the flow rating of individual injectors ie it would be OK for each injector to flow 200 kg/hr (1200 kg,hr for all 6).

This was the point I was trying to make.

[saviour stivala]

There is no limit on the flow rating of individual injectors ie it would be OK for each injector to flow 200 kg/hr (1200 kg,hr for all 6).

This was the point I was trying to make.

You was making a point and I was making another, the differences are a matter of interpretation. In my answer I explained/claryfied myself. “I said that “The ‘injectors’ are not ‘permitted by the rules’ to flow more than 100 kg/h. And also not permitted under 10500 RPM to flow more than Q (KG/H) = 0.009 (RPM) 5.5. ‘injector’ means one injector, while ‘injectors’ means any number that are being used. The ‘injectors’ used, although as most parts of the fuel system have to be approved by the FIA, (individually), as all the parts of the fuel system, starting from the fuel tank itself, are capable of delevering/flowing much more fuel than the rules permit. Nobody is going to design and or use any part of the fuel system that can delliver/flow less than what is permitted. The injectors flow is controlled by SECU. The software is common to all engines, but indevidual tuning.calibrations are permitted withen the rules. So finally the ‘injectors’ are not permitted by the rules to flow more than the maximum that is permitted.

[hollus]

Everybody seems to have explained their point of view clearly at this point.
Please, lets stop going in circles and lets not try to have the last word.

I’ve heard from Santa that the thread wishes to move on.

[hollus]

The discussion has been about the flow sensor for too long. That is not specific to the Ferrari PU. Neither does the They-cheat-no-they-don’t ying-yang belong here, although it was understandable to have it here for a while.
Some posts after an arbitrary cut-off point have been moved to a more fitting home here:

viewtopic.php?p=879550#p879550

This should be the place to talk about things on the Ferrari PU. Things on all PUs and wild speculation might be moved or just removed. Because some people might want to post things here about what Ferrari says is in the next iteration of the PU or similar and some people might want to read about it. There should be no need to wade through several pages of whatever to find the next on-topic post.

[MarcJ]

It appears that GPS data is not everything. It is also why aero data on F1 cars are being kept more secured than the crown jewels of England. So it is telling that even top teams don't have a confident guess on that front about the competition.

To me this is itself a conundrum and a fascinating insight. Team's are not lacking photographic evidence of their competitors cars, and photogrammetry is pretty good these days, so it seems to me reasonable that teams could get to a static model of their competitors cars visible aerodynamics without extreme effort.

Taken that as given, it seems there is something prohibitively complex between applying their in-house simulation tools to models of competitors cars, and obtaining an estimation of their aerodynamic performance.

Could it be; limitations on CFD time? the parts of the cars not able to be photographed? the presumed deflection of these parts under load that is not statically able to be photographed? or the size of the error bars on the the output of these reverse engineering efforts?

It's long been a question of mine how much money/time/effort teams spend on studying their competitors, I wonder if this episode speaks to that.

The 3D CFD code is just not that accurate to enough significant digits, you can get two packages even from different divisions of the same vendor and not have agreement past the first or second digit. 3D CFD is really only good for making engineering decisions, checking your going in the right direction.