Ferrari Power Unit Hardware & Software

[dans79]

There will be no 'backflow' when the engine is running. The fuel pot inside the fuel tank is pressurised with fuel by 3 or 4 fuel lift-pumps lifting fuel from different parts of the fuel tank. the pressured fuel from the fuel pot passes through the fuel flow sensor according with the engine fuel consumed.

The world it's not that simple. Backflow is backflow it doesn't matter if it travels 0.0000001mm, or 1m.

It might momentarily flow backwards a thousand times a second depending on pressure waves in the fuel lines. It will all ultimately end up in the combustion chamber but that does not negate the fact that it happens and that the fuel sensor must compensate for that.

I thought the point was to trick sensors in a way it reads lower, but what you are suggesting would trick sensors in a way it would register more fuel than it's actually used.

Getting the sensor to read a lower flow rate is only part of the problem.

If you put 100 kgs in the tank, use 99, but the sensor only reports 97, then you have a 2 kg discrepancy that won't go unnoticed for long.

Thus you have two options as I see it.

• You must also get the sensor to over report fuel flow. For example it reports 99 kg/hr but you are only using 97 kg/hr.
• Get some amount of back flow that the sensor isn't reading and taking into account.

One way or the other, the fuel usage reported by the sensor must be within some tolerance of what is measured by the FIA pre and post race.

[PlatinumZealot]

can I ask someone who knows, what would be the effect on the sensor reading if the liquid was airated?
Not to the extent of being a moose, but considerably reducing the density. Air could be separated after the sensor and before the rail or high pressure pump could it not?

Air bubbles can be a friend or enemy of ultrasonic flow sensors.
Micro-air bubbles can actually help the sensors get good signal... But guess what... The liquid density would be affected of course. So measurements have to be taken with some error applied or some loose tolerance.

Also too big or too much air bubbles will also kill the signal / give irregular readings.
But otherwise... A little air bubbles is OK for general stuff..
I would imagine for formula 1 this is detrimental to the signal and accuracy. Very likely some form of (electrode setup) for capacitance sensors is built in to detect any bubbles.

[PlatinumZealot]

... the most advanced ultrasonic meters integrate the fuel flow over the entire pipe diameter, in other words they take a velocity snap-shot of the fluid and it is easy to find out what flow regime is occurring in the fluid. Any special temperature manipulation can also be captured by the sensor. Forcing the sensor to under-report the fuel has to be done by some serious outside interference!

the fuel motion through the meter in the calibration lab is presumably constant aka steady, and 1 dimensional
the fuel motion through the meter in the car is (relatively to this) as inconstant and 3 dimensional as may be ?
so eg the velocity snapshot isn't necessarily perfectly representative of the flow rate
eg so-called flow reversion (ie varying partial flow reversion) obtains even in our road cars exhaust and induction systems

neither (maybe) is the electronic sampling always perfectly representative of the actual velocity field
the F1 car carries at close range intensely varying EM fields - these not limited by the rule book
yes I have seen cases of accidental interference in less hostile EM environments

@ Velocity snapshot... One of the open type chanel sensors i used before. I remember reading the manual.. And it took sonic samples across the cross section of the pipe to create a velocity Map. Almost like a fuel or spark map in a car. Then it uses algorithms to calculate the average velocity and this is what the user sees on the screen.
Of course detecting any strange flow regimes i guess the transmitter has to be programmed to identify that.... Another thing too.. They could simply use a flow straightener where the sensor is and be done with it.

[bill shoe]

There will be no 'backflow' when the engine is running. The fuel pot inside the fuel tank is pressurised with fuel by 3 or 4 fuel lift-pumps lifting fuel from different parts of the fuel tank. the pressured fuel from the fuel pot passes through the fuel flow sensor according with the engine fuel consumed.

The world it's not that simple. Backflow is backflow it doesn't matter if it travels 0.0000001mm, or 1m.

It might momentarily flow backwards a thousand times a second depending on pressure waves in the fuel lines. It will all ultimately end up in the combustion chamber but that does not negate the fact that it happens and that the fuel sensor must compensate for that.

More food for thought. If you have a returnless fuel system, and the engine is temporarily using zero fuel, then the fuel on the engine side of the meter is typically hotter than the fuel on the tank/supply side of the meter. This makes the engine-side fuel expand slightly and therefore flow backwards through the meter. This is an actual phenomenon in real-world usage of high-accuracy FFM.

[bill shoe]

There will be no 'backflow' when the engine is running. The fuel pot inside the fuel tank is pressurised with fuel by 3 or 4 fuel lift-pumps lifting fuel from different parts of the fuel tank. the pressured fuel from the fuel pot passes through the fuel flow sensor according with the engine fuel consumed.

The world it's not that simple. Backflow is backflow it doesn't matter if it travels 0.0000001mm, or 1m.

It might momentarily flow backwards a thousand times a second depending on pressure waves in the fuel lines. It will all ultimately end up in the combustion chamber but that does not negate the fact that it happens and that the fuel sensor must compensate for that.

More food for thought. If you have a returnless fuel system, and the engine is temporarily using zero fuel, then the fuel on the engine side of the meter is typically hotter than the fuel on the tank/supply side of the meter. This makes the engine-side fuel expand slightly and therefore flow backwards through the meter. This is a regular phenomenon in real-world usage of high-accuracy FFM.

[saviour stivala]

Its not like we are talking about a domestic water supply system, we are talking about the most advanced fuel system used in car racing.

[PederJonsson]

The fuel system looks basically like this

Low pressure pump in the tank ->
Fuel flow sensor->
High pressure pump->
Pressure regulating valve->
Injectors

There is no true return line as the low pressure fuel pump is pwm controlled to meet the flow demand however the pressure regulating valve that must exist to ensure the correct pressure and for safety will always dump fuel towards the tank and or back to the inlet of the high pressure pump.

In the current set up you don’t know what is happening with the pressure that is being dumped from the pressure regulating valve. So this is where I see the potential to “cheat”

So my take on the new rule with a second fuel flow sensor is to also measure the flow from pressure regulating valve.

In this way you can see all that happens in the fuel system.

[saviour stivala]

The fuel flow to engine as used in 2019. Between 3 and 4 low pressure electrically driven fuel pick-up pumps picks-up fuel from tank comartments and supply fuel at low pressure true a one-way valve to the fuel collector-pot. Fuel collector-pot vents air and access fuel supplied back to tank through a one-way pressur/vent regulator. Fuel from pressurised collector pot flows through fuel flow meter to feed intake of high pressure mechanically driven pump (normally driven by an intake camshaft) through a one-way valve incorporated in intake of high pressure pump. The high pressure pump delivers fuel flow to the injectors fundamentally proportional to engine RPM. The fuel cobsumed 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 RPM at full throttle, the pump has a variable displacement mechanism actuated by a sophisticated pressure regulating device. The injectors fuel flow is controlled by SECU (standard electronic control unit) The SECU hardware and control software is common to all F1 engines, but the calibrations are free withen range permitted by FIA. All fuel that passes through the fuel flow meter must end-up in combustion chambers. There is no fuel return to the fuel tank and neither fuel 'backflow' through the fuel flow meter. The presurised fuel collector pot eleminates airation from the fuel supplied to the engine.

[ncx]

Except that any back flow from the high pressure area to the tank would give negative velocity readings by the FFM, unless of course they can trick it, which would be in a way assumed to be the case because the reason to make it over-read at times is to compensate for making it under-read at other times.

My guess is that the second FFM is a means to check that there are no games played within the tank/collector. Not sure whether it's necessary or just a way to make scrutineering easier and stop requests for investigations of all sorts.

[subcritical71]

The fuel flow to engine as used in 2019. Between 3 and 4 low pressure electrically driven fuel pick-up pumps picks-up fuel from tank comartments and supply fuel at low pressure true a one-way valve to the fuel collector-pot. Fuel collector-pot vents air and access fuel supplied back to tank through a one-way pressur/vent regulator. Fuel from pressurised collector pot flows through fuel flow meter to feed intake of high pressure mechanically driven pump (normally driven by an intake camshaft) through a one-way valve incorporated in intake of high pressure pump. The high pressure pump delivers fuel flow to the injectors fundamentally proportional to engine RPM. The fuel cobsumed 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 RPM at full throttle, the pump has a variable displacement mechanism actuated by a sophisticated pressure regulating device. The injectors fuel flow is controlled by SECU (standard electronic control unit) The SECU hardware and control software is common to all F1 engines, but the calibrations are free withen range permitted by FIA. All fuel that passes through the fuel flow meter must end-up in combustion chambers. There is no fuel return to the fuel tank and neither fuel 'backflow' through the fuel flow meter. The presurised fuel collector pot eleminates airation from the fuel supplied to the engine.

I think you've lifted most of these quotes from an article in Racecar engineering (https://www.racecar-engineering.com/art ... l-systems/)where they are describing the pre-2014 Formula 1 fuel pump. With the hybrid nature of the current F1 PU I can't see some of your statements working correctly in 2019.

[PhillipM]

Yeah, most of that is wrong, even down to the engines not using fuel off throttle - they most certainly do to drive the regen.

[PederJonsson]

The fuel flow to engine as used in 2019. Between 3 and 4 low pressure electrically driven fuel pick-up pumps picks-up fuel from tank comartments and supply fuel at low pressure true a one-way valve to the fuel collector-pot. Fuel collector-pot vents air and access fuel supplied back to tank through a one-way pressur/vent regulator. Fuel from pressurised collector pot flows through fuel flow meter to feed intake of high pressure mechanically driven pump (normally driven by an intake camshaft) through a one-way valve incorporated in intake of high pressure pump. The high pressure pump delivers fuel flow to the injectors fundamentally proportional to engine RPM. The fuel cobsumed 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 RPM at full throttle, the pump has a variable displacement mechanism actuated by a sophisticated pressure regulating device. The injectors fuel flow is controlled by SECU (standard electronic control unit) The SECU hardware and control software is common to all F1 engines, but the calibrations are free withen range permitted by FIA. All fuel that passes through the fuel flow meter must end-up in combustion chambers. There is no fuel return to the fuel tank and neither fuel 'backflow' through the fuel flow meter. The presurised fuel collector pot eleminates airation from the fuel supplied to the engine.

There is no high pressure pump on earth that can change its displacement so fast as it would require for this application. Without a pressure regulating valve after the high pressure fuel pump the fuel parts after the high pressure pump would explode when you suddenly let go of the throttle at high rpm and there is zero demand for fuel.

However the high pressure fuel pump is matched to the regulations so it cannot supply more fuel than the allowed amount below a certain rpm, above this rpm the excess fuel must be bled off by a fuel pressure regulating valve.

That’s the most stable way of controlling your fuel supply to the injectors. Now you have a constant pressure and flow(regulated) and only need to work with the timing of the injectors to match your demand from the engine.

F1 engineers can surely tweak and maximize this to better fit their demands but the basics will be the same.

So when you don’t measure the fuel flow that is dumped away you need to measure the fuel amount in the tank before and after the race to see if it corresponds to what you measured with the sensor. With a second fuel flow sensor you would have control over all fuel that passed the high pressure pump in every scenario.

So the potential to “cheat” in my opinion is to harvest/collect the fuel that is bled off from the pressure regulating valve and then introduce the fuel into the high pressure fuel pump when you have the demand for more power. Now you have more fuel available for the injectors than the fuel flow sensor can measure. As the engines are very “detuned” when it comes to fuel I believe even a smaller amount of fuel could make a big difference.

A likely scenario could also be that the term pressure regulating valve is just named as a safety valve. In one or another way the maximum pressure must be regulated as the high pressure pump is mechanical and works in relation to the rpm of the engine. The maximum fuel rail pressure is also regulated. On a DI engine you want as high fuel rail pressure as possible, this gives you a better consistency of your spray pattern related to the cylinder pressure.

[hape]

The fuel flow to engine as used in 2019. Between 3 and 4 low pressure electrically driven fuel pick-up pumps picks-up fuel from tank comartments and supply fuel at low pressure true a one-way valve to the fuel collector-pot. Fuel collector-pot vents air and access fuel supplied back to tank through a one-way pressur/vent regulator. Fuel from pressurised collector pot flows through fuel flow meter to feed intake of high pressure mechanically driven pump (normally driven by an intake camshaft) through a one-way valve incorporated in intake of high pressure pump. The high pressure pump delivers fuel flow to the injectors fundamentally proportional to engine RPM. The fuel cobsumed 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 RPM at full throttle, the pump has a variable displacement mechanism actuated by a sophisticated pressure regulating device. The injectors fuel flow is controlled by SECU (standard electronic control unit) The SECU hardware and control software is common to all F1 engines, but the calibrations are free withen range permitted by FIA. All fuel that passes through the fuel flow meter must end-up in combustion chambers. There is no fuel return to the fuel tank and neither fuel 'backflow' through the fuel flow meter. The presurised fuel collector pot eleminates airation from the fuel supplied to the engine.

There is no high pressure pump on earth that can change its displacement so fast as it would require for this application. Without a pressure regulating valve after the high pressure fuel pump the fuel parts after the high pressure pump would explode when you suddenly let go of the throttle at high rpm and there is zero demand for fuel.

However the high pressure fuel pump is matched to the regulations so it cannot supply more fuel than the allowed amount below a certain rpm, above this rpm the excess fuel must be bled off by a fuel pressure regulating valve.

That’s the most stable way of controlling your fuel supply to the injectors. Now you have a constant pressure and flow(regulated) and only need to work with the timing of the injectors to match your demand from the engine.

F1 engineers can surely tweak and maximize this to better fit their demands but the basics will be the same.

So when you don’t measure the fuel flow that is dumped away you need to measure the fuel amount in the tank before and after the race to see if it corresponds to what you measured with the sensor. With a second fuel flow sensor you would have control over all fuel that passed the high pressure pump in every scenario.

So the potential to “cheat” in my opinion is to harvest/collect the fuel that is bled off from the pressure regulating valve and then introduce the fuel into the high pressure fuel pump when you have the demand for more power. Now you have more fuel available for the injectors than the fuel flow sensor can measure. As the engines are very “detuned” when it comes to fuel I believe even a smaller amount of fuel could make a big difference.

A likely scenario could also be that the term pressure regulating valve is just named as a safety valve. In one or another way the maximum pressure must be regulated as the high pressure pump is mechanical and works in relation to the rpm of the engine. The maximum fuel rail pressure is also regulated. On a DI engine you want as high fuel rail pressure as possible, this gives you a better consistency of your spray pattern related to the cylinder pressure.

I really don’t know how the fuel flow system in a 2019 F1 car works but the high pressure pump is probably a positive pump type. But that doesn’t automatically mean there needs to be a pressure overflow valve in the line after the hp pump. There are variable volume positive pumps but more easily an electronic torque limiter on the drive would give you much more possibilities and control on desired pressure than a simple pressure valve. Even an internal overflow in the hp pump would be more logical than an external valve with return to the fuel tank.

If all teams would have to use a pressure valve and return line to the fuel tank, the FFM values of the amount of fuel used in the race would always be totally useless.

Furthermore, the FIA confiscated Ferrari’s fuel lines after Brasil and I’m pretty sure they won’t allow fuel return from the pressure valve buffered and on a later moment supplied to the hp pump after the FFM.
In that design it’s very simple to exceed the maximum flow of 100kg/h without noticed by the FFM. In other words, the FFM values for the flow would be useless too.

[saviour stivala]

The fuel flow to engine as used in 2019. Between 3 and 4 low pressure electrically driven fuel pick-up pumps picks-up fuel from tank comartments and supply fuel at low pressure true a one-way valve to the fuel collector-pot. Fuel collector-pot vents air and access fuel supplied back to tank through a one-way pressur/vent regulator. Fuel from pressurised collector pot flows through fuel flow meter to feed intake of high pressure mechanically driven pump (normally driven by an intake camshaft) through a one-way valve incorporated in intake of high pressure pump. The high pressure pump delivers fuel flow to the injectors fundamentally proportional to engine RPM. The fuel cobsumed 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 RPM at full throttle, the pump has a variable displacement mechanism actuated by a sophisticated pressure regulating device. The injectors fuel flow is controlled by SECU (standard electronic control unit) The SECU hardware and control software is common to all F1 engines, but the calibrations are free withen range permitted by FIA. All fuel that passes through the fuel flow meter must end-up in combustion chambers. There is no fuel return to the fuel tank and neither fuel 'backflow' through the fuel flow meter. The presurised fuel collector pot eleminates airation from the fuel supplied to the engine.

There is no high pressure pump on earth that can change its displacement so fast as it would require for this application. Without a pressure regulating valve after the high pressure fuel pump the fuel parts after the high pressure pump would explode when you suddenly let go of the throttle at high rpm and there is zero demand for fuel.

However the high pressure fuel pump is matched to the regulations so it cannot supply more fuel than the allowed amount below a certain rpm, above this rpm the excess fuel must be bled off by a fuel pressure regulating valve.

That’s the most stable way of controlling your fuel supply to the injectors. Now you have a constant pressure and flow(regulated) and only need to work with the timing of the injectors to match your demand from the engine.

F1 engineers can surely tweak and maximize this to better fit their demands but the basics will be the same.

So when you don’t measure the fuel flow that is dumped away you need to measure the fuel amount in the tank before and after the race to see if it corresponds to what you measured with the sensor. With a second fuel flow sensor you would have control over all fuel that passed the high pressure pump in every scenario.

So the potential to “cheat” in my opinion is to harvest/collect the fuel that is bled off from the pressure regulating valve and then introduce the fuel into the high pressure fuel pump when you have the demand for more power. Now you have more fuel available for the injectors than the fuel flow sensor can measure. As the engines are very “detuned” when it comes to fuel I believe even a smaller amount of fuel could make a big difference.

A likely scenario could also be that the term pressure regulating valve is just named as a safety valve. In one or another way the maximum pressure must be regulated as the high pressure pump is mechanical and works in relation to the rpm of the engine. The maximum fuel rail pressure is also regulated. On a DI engine you want as high fuel rail pressure as possible, this gives you a better consistency of your spray pattern related to the cylinder pressure.

I really don’t know how the fuel flow system in a 2019 F1 car works but the high pressure pump is probably a positive pump type. But that doesn’t automatically mean there needs to be a pressure overflow valve in the line after the hp pump. There are variable volume positive pumps but more easily an electronic torque limiter on the drive would give you much more possibilities and control on desired pressure than a simple pressure valve. Even an internal overflow in the hp pump would be more logical than an external valve with return to the fuel tank.

If all teams would have to use a pressure valve and return line to the fuel tank, the FFM values of the amount of fuel used in the race would always be totally useless.

Furthermore, the FIA confiscated Ferrari’s fuel lines after Brasil and I’m pretty sure they won’t allow fuel return from the pressure valve buffered and on a later moment supplied to the hp pump after the FFM.
In that design it’s very simple to exceed the maximum flow of 100kg/h without noticed by the FFM. In other words, the FFM values for the flow would be useless too.

“The high pressure pump delivers fuel flow to the injectors fundamentally proportional to engine RPM. The fuel consumed by the engine is also approximately proportional to engine RPM at full throttle. But at closed throttle, the engine uses no fuel. To match the fuel supplied to RPM at full throttle, the pump has a variable displacement mechanism actuated by a sophisticated pressure regulating device”. All fuel that passes through the fuel flow meter must end-up in the combustion chambers. So there is no fuel return back to tank or fuel flow return back to collector pot through the fuel flow meter.

[aral]

It looks as if we are still going around in circles, with some people creating "facts" that don't hold water (or petrol!)
Yes, following some queries from another PU supplier, FIA had to take action. They took parts from several teams including a non Ferrari team, and when they found nothing amiss with any, to allay fears and doubts, they introduced a TD . That does not mean that there was anything wrong, but was purely a step to placate others and also to deflect any more suspicion. This was similar to what they did with RBR but there they DID find something illegal going on and so penalised the team.
Some may wish to disagree but it is all rather pointless to continue all the argy bargy. Get over it...nothing illegal found...just get back to discussing the PU and drop all the personal speculation....please......and lets have a peaceful and friendly Christmas.