Ferrari Power Unit Hardware & Software

[godlameroso]

This being a direct injection fuel system requires a secondary mechanical pump to raise line pressure. The electric pickup pump is rated between 30-40psi, to get to 500psi requires the fuel be re-pressurized.

in F1 (the limit is) 500 bar not 500 psi ?

Right, sorry about that. ~7k psi. At that pressure, a leak from the fuel rail could cut your finger off.

[stevesingo]

afaik imo and fwiw ....

what calibration of fuel injectors ?
this is not traditional cosy injection as in NA V8s (where injection is a steady flow into port air at 1 bar)

here we have DI ....
multiple timed high-rate injections against gas pressure going from 4 bar to maybe 150 bar by tdc ( and more after tdc)
there is no mandated calibration for this
and nothing that is a standard applicable to all engines at all times
each engine type will have its own in-use relationship between injector signals and fuelling outcomes
ok the injectors control the mass flow but they don't measure the mass flow

nothing can consistently be used to contravene indicated-legal fuel rates from mandated officially-calibrated fuel rate meters
yes it would be interesting to know what fuelling violations were determined in the 2 or 3 cases of contravention


and btw ....
(A) the fuel rate rules require engines to run eg all steady rpm from 10500 to 12100 on no more than 100kg/hr
but the designer might prefer to have constant ideal AFR accelerating through this rpm range
this requires iirc about 1.5 gm of fuel held back for 1 sec so that the average fuel rate accelerating is 100 kg/hr
isn't this possible without breaking fuel line rules ?
and isn't this FIA-accepted/manufacturer-intended ? - (just don't call it fuel accumulation !)

(B) in the 10500 rpm thread it was shown that they now run 10300 to 11900 rpm
the displayed sampled rpm value over-reads the true on-upshift rpm so aren't they really running 10150 to 11750 rpm ?
much reducing the fuel hold-back needed for constant AFR acceleration and helping in 'steady' running at constant AFR

isn't (B) the result of the historic scrutiny and pressure over (A) ?

Deep end?

The ECU will make a calculation of how much fuel is required based on all parameters. This will dictate the inj PW. In order for the ECU to determine inj PW it will need to know how much fuel is delivered in relation to inj opening time. This will be determined from a characterisation test from which data will be inputted in to the ECU as a constant.

This is not mandated. This is a necessity for the ECU to calculate Inj PW. Full range of Inj PW at the full range of combustion chamber pressures and full range of fuel pressure (if there is any deviation in operation) will be conducted.

saviour stivala's statement that fooling the fuel flow device could be discovered by looking at the flow at the injectors from the ECU data. I suggest that this could also be skewed by using injector characterisation data which was not a true reflection of the injector's characteristics.

[NL_Fer]

I bet the engineers are clever enough to develop a fuel rail, which can increase it’s volume by deformation at 500 bar and that somehow the rail pressure stays around a fixed value while volume is decreasing at full throttle.

[Just_a_fan]

I bet the engineers are clever enough to develop a fuel rail, which can increase it’s volume by deformation at 500 bar and that somehow the rail pressure stays around a fixed value while volume is decreasing at full throttle.

A tube with a plunger at the end would do that. Tube the spring behind the plunger to give the desired result.

[ncx]

The formula one ‘return-less’ fuel flow system (fuel transfer from fuel tank to engine combustion chambers) as in use at the present 2019 season.
Electrically driven low pressure lift pumps >> pressurized collector pot >> fuel flow sensor/meter >> high pressure mechanical engine driven pump >> fuel rail >> injectors.

Have you been able to find a source for this assertion? Why do you think the FIA have decided to enforce a different system for 2021?

This is how all high pressure fuel systems work. This being a direct injection fuel system requires a secondary mechanical pump to raise line pressure. The electric pickup pump is rated between 30-40psi, to get to 500psi requires the fuel be re-pressurized. This requires an accumulator as backflow would damage the electric pump.

The measurement point is in the "low pressure side" simply because it is closer to the fuel flow point of origin. It's not practical to place it upstream because of the accumulator required to raise line pressure.

Yes, the FFM is downstream the lift pumps and upstream the HP pump. However, as @henry mentioned a few posts ago, the diagram of the fuel system in the 2021 TRs, besides lift pumps and HP pump, also shows the presence of a primer pump, in the collector, upstream the FFM, that is, between the lift pumps and the FFM. What some of us here are trying to find out is whether that primer pump is already being used, or at least allowed, or rather it's an addition for 2021. Just to be sure, by "pickup pump" are you referring to a "lift pump" or to the "primer pump", to use the terminology of the TRs?

[63l8qrrfy6]

I bet the engineers are clever enough to develop a fuel rail, which can increase it’s volume by deformation at 500 bar and that somehow the rail pressure stays around a fixed value while volume is decreasing at full throttle.

The system compliance is restricted by the rules - doing what you suggest would be a gross breach.

[godlameroso]

Have you been able to find a source for this assertion? Why do you think the FIA have decided to enforce a different system for 2021?

This is how all high pressure fuel systems work. This being a direct injection fuel system requires a secondary mechanical pump to raise line pressure. The electric pickup pump is rated between 30-40psi, to get to 500psi requires the fuel be re-pressurized. This requires an accumulator as backflow would damage the electric pump.

The measurement point is in the "low pressure side" simply because it is closer to the fuel flow point of origin. It's not practical to place it upstream because of the accumulator required to raise line pressure.

Yes, the FFM is downstream the lift pumps and upstream the HP pump. However, as @henry mentioned a few posts ago, the diagram of the fuel system in the 2021 TRs, besides lift pumps and HP pump, also shows the presence of a primer pump, in the collector, upstream the FFM, that is, between the lift pumps and the FFM. What some of us here are trying to find out is whether that primer pump is already being used, or at least allowed, or rather it's an addition for 2021. Just to be sure, by "pickup pump" are you referring to a "lift pump" or to the "primer pump", to use the terminology of the TRs?

Pickup pump, the pump sitting inside the fuel cell, or lift pump. Not sure what primer pump is referring to, if it's before the FFM, then likely another low pressure auxillary pump.

[saviour stivala]

The scope of providing the high pressure fuel pump inlet with a low pressure fuel supply from an accumulator (collector pot) which is pressurized at low pressure is to eliminate aeration from the fuel supplied to the high pressure pump.
The high pressure fuel pump is entirely mechanical. This pump delivers fuel flow fundamentally proportional to engine RPM. The fuel consumed by the engine is also approximately proportional to RPM at full throttle, but at closed throttle, the engine uses no fuel. To match the fuel supplied to the fuel required, the pump has a variable displacement mechanism actuated by a sophisticated pressure regulating device. The injectors are – in technical parlance – precision electro - mechanical valves controlled by SECU (standard electronic control unit). The SECU hardware and control software is common to all F1 engines, but the calibrations are free within range permitted by the FIA. Fuel is delivered when the injector is energized, delivering at high pressure into the combustion chamber at precisely the right instant in the engine cycle to achieve optimum cylinder filling and preparation, ultimately promoting efficient combustion and therefore engine performance.
While being able to accurately determine how much fuel is being injected into cylinders play an important role in engine tuning. It also means the fuel flow/amount being injected is known in real time. But regulations is best enforced by the FIA homologated fuel flow sensor/meter, which measures flow 4000 times per second, and can accurately measure up to 8-litres of fuel a minute/480l/h.
If a driver is disqualified for fuel flow rate infringement, and the infringement doesn’t involve the team tempering with the fuel flow sensor/meter. It only means that the engine fuel management software is the infringer.

[Tommy Cookers]

quote with waffle removed

(A) ......the calibrations are free ....
(B) ......the fuel flow/amount being injected is known in real time.......

can someone explain how (B) is true ?
(that the fuel rate being injected is known to the FIA)
given (A) is true ie the FIA doesn't calibrate the ICEs injection

ok it's only the non-PU-manufacturer teams who have been fuelling infringers

[saviour stivala]

Have you been able to find a source for this assertion? Why do you think the FIA have decided to enforce a different system for 2021?

This is how all high pressure fuel systems work. This being a direct injection fuel system requires a secondary mechanical pump to raise line pressure. The electric pickup pump is rated between 30-40psi, to get to 500psi requires the fuel be re-pressurized. This requires an accumulator as backflow would damage the electric pump.

The measurement point is in the "low pressure side" simply because it is closer to the fuel flow point of origin. It's not practical to place it upstream because of the accumulator required to raise line pressure.

Yes, the FFM is downstream the lift pumps and upstream the HP pump. However, as @henry mentioned a few posts ago, the diagram of the fuel system in the 2021 TRs, besides lift pumps and HP pump, also shows the presence of a primer pump, in the collector, upstream the FFM, that is, between the lift pumps and the FFM. What some of us here are trying to find out is whether that primer pump is already being used, or at least allowed, or rather it's an addition for 2021. Just to be sure, by "pickup pump" are you referring to a "lift pump" or to the "primer pump", to use the terminology of the TRs?

To understand what I was/am referring to go back to page 283 post 10Nov 2019 12:21 and read what I posted.

[saviour stivala]

The fuel flow being injected is logged in data logger. if the teams know it how can the FIA don't? at least if they want to?. proof that the fuel injected is logged in data logger is what RBR fought the 2014 fuel infringement disqualification with against the FIA fuel flow meter data.

[saviour stivala]

quote with waffle removed

(A) ......the calibrations are free ....
(B) ......the fuel flow/amount being injected is known in real time.......

can someone explain how (B) is true ?
(that the fuel rate being injected is known to the FIA)
given (A) is true ie the FIA doesn't calibrate the ICEs injection

ok it's only the non-PU-manufacturer teams who have been fuelling infringers

Another answer because of your added comment after your post edit. The way I prefer to 'word-it'. After all is said and done when a fuel infringement is registered it is actually the engine manufacturer fuel management software that is the real infringer.

[henry]

The formula one ‘return-less’ fuel flow system (fuel transfer from fuel tank to engine combustion chambers) as in use at the present 2019 season.
Electrically driven low pressure lift pumps >> pressurized collector pot >> fuel flow sensor/meter >> high pressure mechanical engine driven pump >> fuel rail >> injectors.

Have you been able to find a source for this assertion? Why do you think the FIA have decided to enforce a different system for 2021?

My ‘assertion’ (your chose of word) re-the fuel flow system in use up to the present time as posted is yes ‘confident’ and a ’fact of believe’. But was not meant to be ‘forceful’. It was simply in response to an ‘assertion’ that a pump in the system before the fuel flow sensor/meter can be made to produce pulses to effect flow meter reading. I will take an ex-Williams F1 engineer technical insights writings of F1 technology in use any time as against an ‘assertion’ that “because the FIA happened to print their 2021 mandated fuel system” which is different to what is used today, the present system must be the same.

I think I have found the article from which you are taking your information. It’s in Racecar Engineering https://www.racecar-engineering.com/art ... l-systems/. It has no date but was written between 2010 and 2014 about the V8s.

Is that the case?

If so I’m still not convinced the fuel system described in the article is what is in use now. This matters because the system described would attenuate pressure pulses on the input to the Flow Meter whereas the system in the 2021 regs would not.

[Big Tea]

But the flow is measured at the point it leaves the tank is it not, and with no regard to the engine being on full throttle or over run. The actual amount taken from the supply 'pipe' (for want of a better word) will vary as will the pressure in the supply rail. when the nozzles are operated, the pressure drops fractionally until the pump can reestablish it.
Am I correct in thinking this will vary the flow by +_ a very small amount unless there is some sort of buffer and will the buffer not have to compensate for the expended fuel with replaced fuel. From the supply, but it would still give a variation at the flow meter, so no instantaneous reading?

[gruntguru]

I bet the engineers are clever enough to develop a fuel rail, which can increase it’s volume by deformation at 500 bar and that somehow the rail pressure stays around a fixed value while volume is decreasing at full throttle.

Yes they are that clever - and more. They played those sorts of tricks, got caught and the rules around accumulation have tightened.