Ferrari Power Unit Hardware & Software

[Chene_Mostert]

Max 100Kg/hour @10000rpm.

No. The 100kg/hr is always the limit.

5.1.4 Fuel mass flow must not exceed 100kg/h.

No limit to running 100KG/ hour @8000rpm.

Below 10500rpm, a lower limit applies - 77.5kg/hr at 8000rpm

5.1.5 Below 10500rpm the fuel mass flow must not exceed Q (kg/h) = 0.009 N(rpm)+ 5.5.

If at any time there is more fuel flowing than these limits then the system is illegal. Having fuels that increase density between the fuel flow meter and the injectors (beyond those that must naturally occur due to temperature changes) is illegal as it means that the mass flow is above the limits set by the regulations.

At lift and coast, engine running @ 8000 rpm but 0 injector pulses?
The rail must remain pressurised? So fuel can flow into the rail at 77.5 KG/hour but injected can be much less.
The rule states all fuel must enter the cylinder, that will still happen at some point.

[Chene_Mostert]

Then you run into the issue of the fuel discrepancy in the tank after the race. Whether you accumulate flow after the meter or not, it still at some point saw that mass flow pass thru. A fuel discrepancy leads one to believe the meter was tricked or bypassed.

Yes you do, if you don't calibrate the injector timing pulses. to the correct density of the fuel in the rail. You will end up with egg on your face

[PlatinumZealot]

This can increase the density of fuel after the FF meter, thus allowing a greater mass of fuel to be stored for a given volume after the FF meter and still comply with the FF rule of 100Kg/h.
There is no cheating the FF meter, and there is no regulation covering this.

Incorrect. The fuel flow rate is limited to 100kg/hr everywhere in the system. If they store fuel after the FF meter, and then flow more than that rate through the injectors (why else do it?), they are breaking the flow rate limit rule.

If the fuel changes properties in order to change the mass flow rate through the fuel system, then it is also in contravention of the following rule as it is a procedure (and indeed a system):

5.10.5 Any device, system or procedure the purpose and/or effect of which is to increase the flow
rate or to store and recycle fuel after the measurement point is prohibited.

Basically, anything you do to move more than 100kg/hr through the fuel system is illegal.

Not exactly. The fuel flow meter is ultrasonic. It measure speed of particles using the doppler effect. Basically measures volume flow rate and they use a look up table of density with temperature to calculate the mass flow rate. If the density can be increased you can increase the mass flow rate without increasing the volume and as such the flow meter will not detect any wrong doing.

[Chene_Mostert]

This can increase the density of fuel after the FF meter, thus allowing a greater mass of fuel to be stored for a given volume after the FF meter and still comply with the FF rule of 100Kg/h.
There is no cheating the FF meter, and there is no regulation covering this.

Incorrect. The fuel flow rate is limited to 100kg/hr everywhere in the system. If they store fuel after the FF meter, and then flow more than that rate through the injectors (why else do it?), they are breaking the flow rate limit rule.

If the fuel changes properties in order to change the mass flow rate through the fuel system, then it is also in contravention of the following rule as it is a procedure (and indeed a system):

5.10.5 Any device, system or procedure the purpose and/or effect of which is to increase the flow
rate or to store and recycle fuel after the measurement point is prohibited.

Basically, anything you do to move more than 100kg/hr through the fuel system is illegal.

Not exactly. The fuel flow meter is ultrasonic. It measure speed of particles using the doppler effect. Basically measures volume flow rate and they use a look up table of density with temperature to calculate the mass flow rate. If the density can be increased you can increase the mass flow rate without increasing the volume and as such the flow meter will not detect any wrong doing.

Thanks, You explained much better than my attempt.

[PlatinumZealot]

I say density but really... If you can use another fluid the flowmeter was not calibrated for and it will throw it off. If the speed of sound is different in the fluid that is. Of course FIA does not expect anyone to use a fluid with different or changeable properties than what they homologated! Lol. That's outright cheating of course.

[timbo]

I say density but really... If you can use another fluid the flowmeter was not calibrated for and it will throw it off. If the speed of sound is different in the fluid that is. Of course FIA does not expect anyone to use a fluid with different or changeable properties than what they homologated! Lol. That's outright cheating of course.

The composition of fuel is tightly regulated and easily monitored. IMO this is a last place to seek for something wildly abnormal.

[Tommy Cookers]

....The fuel flow rate is limited to 100kg/hr everywhere in the system. If they store fuel after the FF meter, and then flow more than that rate through the injectors (why else do it?), they are breaking the flow rate limit rule....

untrue
the fuel injection rate will exceed 100 kg/hr (within the cycle)
so-called fuel storage is unavoidable

btw fuel compresses about 4% at the high pressures used

[Just_a_fan]

If the density can be increased you can increase the mass flow rate without increasing the volume and as such the flow meter will not detect any wrong doing.

And that is illegal. The fact that they struggle to detect it doesn't make it legal.

Indeed, the FIA admitted last season that there were things going on in the Ferrari's PU that they struggled to understand. Adding an additional FF meter is an indication that they thought that wrong doing was happening.

[Just_a_fan]

Max 100Kg/hour @10000rpm.

No. The 100kg/hr is always the limit.

5.1.4 Fuel mass flow must not exceed 100kg/h.

No limit to running 100KG/ hour @8000rpm.

Below 10500rpm, a lower limit applies - 77.5kg/hr at 8000rpm

5.1.5 Below 10500rpm the fuel mass flow must not exceed Q (kg/h) = 0.009 N(rpm)+ 5.5.

If at any time there is more fuel flowing than these limits then the system is illegal. Having fuels that increase density between the fuel flow meter and the injectors (beyond those that must naturally occur due to temperature changes) is illegal as it means that the mass flow is above the limits set by the regulations.

At lift and coast, engine running @ 8000 rpm but 0 injector pulses?
The rail must remain pressurised? So fuel can flow into the rail at 77.5 KG/hour but injected can be much less.
The rule states all fuel must enter the cylinder, that will still happen at some point.

The rules state that no system may be used to store fuel after the FFM. If the above is used to store fuel over and above what happens naturally then it's illegal.

[Just_a_fan]

....The fuel flow rate is limited to 100kg/hr everywhere in the system. If they store fuel after the FF meter, and then flow more than that rate through the injectors (why else do it?), they are breaking the flow rate limit rule....

untrue
the fuel injection rate will exceed 100 kg/hr (within the cycle)
so-called fuel storage is unavoidable

btw fuel compresses about 4% at the high pressures used

Of course any pipe between the FFM and the injector is, in effect, a store. As you say, storage is inherent. What is not allowed is storage in addition to the inherent nature of a "rigid" pipe.

[ncx]

This can increase the density of fuel after the FF meter, thus allowing a greater mass of fuel to be stored for a given volume after the FF meter and still comply with the FF rule of 100Kg/h.
There is no cheating the FF meter, and there is no regulation covering this.

Incorrect. The fuel flow rate is limited to 100kg/hr everywhere in the system. If they store fuel after the FF meter, and then flow more than that rate through the injectors (why else do it?), they are breaking the flow rate limit rule.

If the fuel changes properties in order to change the mass flow rate through the fuel system, then it is also in contravention of the following rule as it is a procedure (and indeed a system):

5.10.5 Any device, system or procedure the purpose and/or effect of which is to increase the flow
rate or to store and recycle fuel after the measurement point is prohibited.

Basically, anything you do to move more than 100kg/hr through the fuel system is illegal.

Not exactly. The fuel flow meter is ultrasonic. It measure speed of particles using the doppler effect. Basically measures volume flow rate and they use a look up table of density with temperature to calculate the mass flow rate. If the density can be increased you can increase the mass flow rate without increasing the volume and as such the flow meter will not detect any wrong doing.

It uses time-of-flight, not Doppler. It measures velocity of the flow, speed of sound and temperature. All this info is then combined with the thermal models of the FFM (which is made of only one metal so to make the model more accurate) and of the fuel (they build it using fuel samples from the teams). Then the mass flow is calculated.

The second FFM cannot be "just before the engine", as some suggested, because it cannot withstand the pressure after the HPP.

The measurements of fuel flow within the injection system are indirect, unreliable and quite easily altered.

Look up the posts here a few months back. FFM possible trickery was discussed to exhaustion, of the topic and of the posters

[PlatinumZealot]

I stand Corrected. I did a number of years in wastewater. Got my sonic flow meters mixed up! (doppler for dirty fluids time of flight for clean fluids). At least people know im not a googler. ha!
Anyway same principle applies!

[ncx]

If the model of the physical properties of the fuel is sufficiently accurate, the speed of sound may provide a double check on the density, though I don't know whether the overall uncertainty on the estimate would be small enough.

[timbo]

I don't think "the trick" involves the storage of fuel because from what I have seen, the extra power was available only in Q3 and the first lap of the race. Other than that Ferrari was fast on the straights but not unusually so.
I don't see a reason why strategies using fuel storage can't be used multiple times in the race.
Could it be something like chilling of the intercooler? Perhaps letting oil or fuel evaporate while the car is slow?

[hollus]

Anything involving evaporation is forbidden in the rules. "No intentional change of phase". Inside the cooling system, or course. Outside, who knows.

7.5 Cooling systems :
The cooling systems of the power unit, including that of the air destined for combustion, must not intentionally make use of the latent heat of vaporisation of any fluid with the exception of fuel for the normal purpose of combustion in the engine as described in Article 5.10.3.