139 replies to this topic

[ExFlagMan]

You are very sharp, sir!
 
I again made a quick back of the envelope calculation with the values of 10500 rpm, 6 cylinders all firing, fuel flow measured in kilos at the flow meter 100 kg/h and using a modest road car alike 4 ms injection sequence getting a flow rate north of 1700 kg/h per single injector averaged over the injection sequence. Of course the F1 engines are more aggressive so the real single injection cycle flow rate per cylinder is actually closer to 10 000 kg/h.
 
So as the regulation is written, the very fuel injectors would be illegal when the car is still comfortably using the allowed 100 kg/h over even one full 720 degree ignition cycle of the engine.

Which would imply that a roughly similar transient effect would be seen on the supply side of the HP pump, with some modification to the waveform caused by the HP pump.

I assume that this is why the FFM is situated adjacent to the fuel tank, to allow some damping effect on these transients, resulting from the inertia of the fuel mass in the LP supply lines. I presume the sampling rate of the FFM, and its modification early last year, was an attempt to reduce these transients causing false high flow readings.

To my engineering biased mind, any design team which manages to extract extra performance from exploiting these physical effects, which seem to be results of the side effects of the regulations, should be applauded, rather than penalised, as they appear to have extracted performance without additional energy input.

Edited by ExFlagMan, 22 March 2015 - 21:47.

[Jvr]

Which would imply that a roughly similar transient effect would be seen on the supply side of the HP pump, with some modification to the waveform caused by the HP pump.

I assume that this is why the FFM is situated adjacent to the fuel tank, to allow some damping effect on these transients, resulting from the inertia of the fuel mass in the LP supply lines. I presume the sampling rate of the FFM, and its modification early last year, was an attempt to reduce these transients causing false high flow readings.

To my engineering biased mind, any design team which manages to extract extra performance from exploiting these physical effects, which seem to be results of the side effects of the regulations, should be applauded, rather than penalised, as they appear to have extracted performance without additional energy input.

Very much in line what TC3000 wrote last year, I could not agree more. It is like who can make the most accurate mechanical watch given certain design limitations.

Edited by Jvr, 22 March 2015 - 21:57.

[LORDBYRON]

Very clever stuff. I class it very much as cheating, they are trying to use more fuel than allowed and trick the fuel flow meter, similar to red bull designing bodywork to pass deflection tests but bend on track. Hope the FIA get on top if it or get rid of the silly fuel flow regs.

 

what there trying to do is gain more pressure after the fuel leaves the flow sensor is in the fuel tank. Who to say there is not a extra pump after the sensor to gain a % more pressure in turn gaining more horse power 

Edited by LORDBYRON, 22 March 2015 - 22:11.

[ExFlagMan]

I cannot see any (hidden or otherwise) supplementary 'pump' in the LP fuel line making much difference given that the HP pump works at up to 500bar. As most of the teams appear to run to a max of about 11500rpm rather than the 15000 rpm limit, I assume the injection system has no need for marginally enhanced input pressure to generate more HP.
Most of the field currently appear unable to exploit the power available at these reduced rev levels so I am not sure what this FIA clampdown is really all about.

[whitewaterMkII]

if it's true, it's very clever, which i like

on the other hand, i suspect this the way spec boffins will make sure the championship doesn't get handed to MB by race five

[Tapz63]

if it's true, it's very clever, which i like
on the other hand, i suspect this the way spec boffins will make sure the championship doesn't get handed to MB by race five

I know you are exaggerating but honestly I believe this will have no affect on the WCC and Mercedes will wrap it up at the earliest possible race if not the next.

[whitewaterMkII]

I know you are exaggerating but honestly I believe this will have no affect on the WCC and Mercedes will wrap it up at the earliest possible race if not the next.

oh, yes no matter what, i think mb has it in the bag, but if they can impede them, they will

[Foyle]

Around 1000 acceleration zones per GP, 100kg of fuel, so about 0.1kg of fuel per acceleration zone.  The hypothetical accumulator would need to have perhaps 5mL change in volume to make a big difference, which is quite a lot.

 

Elastomeric accumulators will most definitely not be built in, as banned and easy to spot.  Lots of O-rings or specialised gaskets could provide an accumulator like action.

 

Could maybe be done with a vapour accumulating chamber in the fuel system, like a craftily designed high pressure fuel rail air purge that was able to hold a little bubble of air (ie imperfectly purged).  Filled with air bubble at high pressure held in place at a high point by buoyancy, perhaps even continuously created by some gas-generating fuel additive sensitive to some part of the pumping/metering process (could be a heating and cooling cycle in the fuel pump or a pressure activated chemical reaction).  That could give a little extra power boost.

 

I think FIA has a continuous record of fuel flow rates from ECUs in order to monitor the fuel flow limits, so an accumulator would probably show up subtly as anomalous fuel flows off-throttle or maybe even in some of the engine injector maps.  Could be assessed by looking at injector map opening pulse durations and checking their fuel flow rates at those durations on a test rig - see if they were actually delivering more than 100kg/hr during acceleration in races.

 

But this theory wouldn't explain why Mercedes use so much less fuel per lap, which is linked to their having a lot higher efficiency (and so having much higher engine power), accumulators don't affect that.  My guess is that they have figured out a better combustion mode (perhaps homogenous charge compression ignition or better stratified charge formation for faster and more efficient burn) that manufacturers have experimented with for decades but which is too expensive, damaging or unreliable to put into production, or is ruled out by emissions regulations.  Rally cars are run with quite a lot of detonation (knock) to gain higher power/combustion efficiency at the cost of shorter engine life and maybe with sophisticated development, tricksy ignition/combustion diagnostic systems, and special tougher piston edge and ring design it is possible to run consistently closer to the edge on this.  Spending several years on optimisation of the combustion chamber design would make a big difference.

 

Alternatively if (as I have seen mentioned, but seems unlikely) Renault is running a 250 bar injector system vs 500bar for Mercedes and Ferrari that would explain a lot of their efficiency deficit with less optimal mixture formation, inlet air evaporative charge cooling, and fuel stratification.  This is pretty amateur stuff for an engine developer (until a few years back my profession), and if true Renault could only be seen as letting easy gains go to waste.

Edited by Foyle, 23 March 2015 - 03:44.

[Pimpwerx]

ExFlagMan, Jvr and Foyle have made this thread very interesting reading. Thanks, guys. PEACE.

[ExFlagMan]

Thanks for the professional view. Makes pretty good sense to me.

But this theory wouldn't explain why Mercedes use so much less fuel per lap, which is linked to their having a lot higher efficiency (and so having much higher engine power), accumulators don't affect that.

Maybe it is not MB who have been using a 'cheat' - which is why they can get better fuel mileage and the others cannot if they where to be exceeding the flow limit.

[bonjon1979a]

Around 1000 acceleration zones per GP, 100kg of fuel, so about 0.1kg of fuel per acceleration zone. The hypothetical accumulator would need to have perhaps 5mL change in volume to make a big difference, which is quite a lot.

Elastomeric accumulators will most definitely not be built in, as banned and easy to spot. Lots of O-rings or specialised gaskets could provide an accumulator like action.

Could maybe be done with a vapour accumulating chamber in the fuel system, like a craftily designed high pressure fuel rail air purge that was able to hold a little bubble of air (ie imperfectly purged). Filled with air bubble at high pressure held in place at a high point by buoyancy, perhaps even continuously created by some gas-generating fuel additive sensitive to some part of the pumping/metering process (could be a heating and cooling cycle in the fuel pump or a pressure activated chemical reaction). That could give a little extra power boost.

I think FIA has a continuous record of fuel flow rates from ECUs in order to monitor the fuel flow limits, so an accumulator would probably show up subtly as anomalous fuel flows off-throttle or maybe even in some of the engine injector maps. Could be assessed by looking at injector map opening pulse durations and checking their fuel flow rates at those durations on a test rig - see if they were actually delivering more than 100kg/hr during acceleration in races.

But this theory wouldn't explain why Mercedes use so much less fuel per lap, which is linked to their having a lot higher efficiency (and so having much higher engine power), accumulators don't affect that. My guess is that they have figured out a better combustion mode (perhaps homogenous charge compression ignition or better stratified charge formation for faster and more efficient burn) that manufacturers have experimented with for decades but which is too expensive, damaging or unreliable to put into production, or is ruled out by emissions regulations. Rally cars are run with quite a lot of detonation (knock) to gain higher power/combustion efficiency at the cost of shorter engine life and maybe with sophisticated development, tricksy ignition/combustion diagnostic systems, and special tougher piston edge and ring design it is possible to run consistently closer to the edge on this. Spending several years on optimisation of the combustion chamber design would make a big difference.

Alternatively if (as I have seen mentioned, but seems unlikely) Renault is running a 250 bar injector system vs 500bar for Mercedes and Ferrari that would explain a lot of their efficiency deficit with less optimal mixture formation, inlet air evaporative charge cooling, and fuel stratification. This is pretty amateur stuff for an engine developer (until a few years back my profession), and if true Renault could only be seen as letting easy gains go to waste.

Also, since fuel flow is measure in kg/per hour, potentially the faster you are the less time you spend on full throttle? Ie if you complete the race distance a minute ahead of everyone else in theory you use less fuel. There are obvious complications to this, ie you might be braking later and getting on the throttle sooner. But in general, if you're able to keep more speed through the corners, you are quicker coming on to the straights, you're on throttle for slightly less time as because you're quicker coming on to the straights you're on the straights ie full throttle for less time. It's a constantly rewarding circle, in this formula where fuel flow is regulated a quick car is inherently going to be the most fuel efficient.

[sreekabth]

 

Posted in jest.

the thing is that i am a hardcore ALO fan

[thiscocks]

There wont be any changes in performance between manufacturers. Its just a way for the FIA to more accurately regulate the rule.

[chipmcdonald]

Thinking back, there was a topic about Lewis Hamiltons footwork, that he is staying on throttle through the braking zone.
I know the FOM graphics don't always line up, but it does make sense if you had a "reservoir" or some sort, to fill it into a corner

 

 it would also explain why Ricciardo was having trouble with his car "accelerating under braking"....

[chipmcdonald]

The pump might operate at 500 bar, but how it provides that could be rigged.  It could have a little scavenger-well that uses a scrolling-gear mechanism that is designed to "dip" into it after a pre-determined length of time.

 

Like, 3/4 of the way down a straight.

 

You design it over-(competitor) spec, so it's running higher than it's supposed to until that point - where it should bog from a lack of fuel flow, instead it keeps going.  Fills back up on entry.

 

They can't be using the full flow of 500 bar vs. 250, otherwise their advantage would be nearly double.  So Renault has designed to 250 as the reasonable engineered solution, Mercedes/Ferrari are going over "somehow".   Fuel pump.

 

 

BUT THIS IS ALL RIDICULOUS.... there shouldn't be such a ridiculous rule in place, anyhow.... Hamstrung race horses.

[ollebompa]

If it exist it's obviously something more then just a reservoir, because that idea I even had within 5 minutes of reading the regulations for the first time. And after 5 more minutes it was clear that the idea could not be looked at as a grey area and would be balant cheating. 

[RockBrocaine]

By chance anyone know what the average fuel flow rates for the 2.4 V8's were?

[chipmcdonald]

If it exist it's obviously something more then just a reservoir, because that idea I even had within 5 minutes of reading the regulations for the first time. And after 5 more minutes it was clear that the idea could not be looked at as a grey area and would be balant cheating. 

 

 

 That's why you build your fuel pump with two impeller stages, low>high pressure, and let the low pressure side spin around with a little extra.  

[Melbourne Park]

I've never understood why the FIA just don't limit the fuel per race. Why bother with such complications in measuring fuel flows? Just limit the damn level of fuel used per race ... and that way, remove at least one ridiculous complication.

 

Is there any logic for this rule besides making F1 teams do the R&D for a device with which the FIA want to control other motor sports with?

 

And also - give back Ricciardo's 2nd place in Melbourne's 2014 race ...

Edited by Melbourne Park, 23 March 2015 - 23:23.

[icecream]

I believe the idea is to encourage more aggressive driving throughout the race.  Without the instantaneous limit (as before 2014), we saw extremely (fuel) conservative driving through large portions of the race.  How effective it really is is another question. 

[HoldenRT]

Be shock horror if McH gets even slower come China 

 

Yeah it'd be funny if Renault and Honda were the only two engines affected.

 

But it's all speculation until China.
 

[KnucklesAgain]

I've never understood why the FIA just don't limit the fuel per race. Why bother with such complications in measuring fuel flows? Just limit the damn level of fuel used per race ... and that way, remove at least one ridiculous complication.

 

Is there any logic for this rule besides making F1 teams do the R&D for a device with which the FIA want to control other motor sports with?

 

And also - give back Ricciardo's 2nd place in Melbourne's 2014 race ...

 

To avoid teams burning more than their average per-lap fuel allocation early-on while trying to gain track position, followed by an economy drive in the last third of the race. Think back to the 80ies turbos. It may not be effective and it may be possible to argue that nothing is wrong with some cars limping to the flag and other cars, who saved some fuel, hunting them down, but anyway I think that's the reason.

Edited by KnucklesAgain, 24 March 2015 - 07:52.

[Antaris]

Forgive me for my potential, probably obvious misunderstanding:

 

If Merc/Ferrari are using a reservoir after the fuel-flow measurement, will it not show more fuel usage because fuel is being pumped through, but then stored, so therefore less in the tank? If that is the case, then why do the Merc engines all seem really good on fuel usage, typically look at Hamilton @ Oz, he had less fuel consumption (albeit part of that would be due to being out in front, and not in the wake of others) then anyone else. Surely if they are pooling fuel after the measurement, then his fuel usage would appera to be worse?

 

Or have I complete misunderstood that?

[JeePee]

Mercedes is a lot faster in qualifying compared to their race pace. That could hint that they are not able to use this trick in the race because of the 100kg limit, but they can in qualy.

[GrumpyYoungMan]

Mercedes is a lot faster in qualifying compared to their race pace. That could hint that they are not able to use this trick in the race because of the 100kg limit, but they can in qualy.

OR it just could be that they pace themselves? - The fuel flow rate is still used in qualification?!?... so I don't buy that!...

[JeePee]

OR it just could be that they pace themselves? - The fuel flow rate is still used in qualification?!?... so I don't buy that!...

I was just answering Antaris.

But to comment on you: The flow rate is used in qualifying, but on raceday they have two limits: 100kg/h and 100kg/race. Considering a race takes longer than 1 hour, you can't let the "reservoir" fill up at 100kg/h (during braking) for the full race. In qualifying, you can.

[Jvr]

Forgive me for my potential, probably obvious misunderstanding:

 

If Merc/Ferrari are using a reservoir after the fuel-flow measurement, will it not show more fuel usage because fuel is being pumped through, but then stored, so therefore less in the tank? If that is the case, then why do the Merc engines all seem really good on fuel usage, typically look at Hamilton @ Oz, he had less fuel consumption (albeit part of that would be due to being out in front, and not in the wake of others) then anyone else. Surely if they are pooling fuel after the measurement, then his fuel usage would appera to be worse?

 

Or have I complete misunderstood that?

I think you are mixing two separate things. One is the fuel consumption over one lap leading into race distance consumption. Here a PU with better efficiency can show better figures since the consumption is averaged over one lap, not all of that on full throttle. The reservoir theory is just for the peak power i.e. over a short burst of time using the extra fuel in the high pressure system to momentarily exceed the allowed 100kg/h flow rate by something like 2 to 5 %. The reservoir would be "filled" during the low on the throttle periods leading to the same average consumption over one lap.

Edited by Jvr, 24 March 2015 - 13:36.

[Jvr]

The latest entry here is an interesting article by Enrico Benzing analyzing Australian GP (in Italian). http://www.formula1b...g.eu/index.html

 

At the end of the entry he is discussing about the specific weights of the fuels that seem to be climbing from 2014 to 2015 with Merc on the top of the list with the heaviest fuel. He then continues criticizing the flow meters measuring the consumption at liters. Now I have always assumed that FIA is correlating the flow meter readings in liters team by team with the measured density of the fuel taken from the sample before the event to derive the consumption in kilos but I am not any more sure.

 

What seems that teams prefer, however, is moving into the direction of heavier fuels that I find interesting. This maybe for they provide better and more efficient burning and more options in injection timings during different parts of the races. On another hand, it may be related the fuel behavior in the fuel rail before the injection and to the "optimizing" the fuel consumption reading at the flow meter.

Edited by Jvr, 24 March 2015 - 14:52.

[V8 Fireworks]

The latest entry here is an interesting article by Enrico Benzing analyzing Australian GP (in Italian). http://www.formula1b...g.eu/index.html

 

At the end of the entry he is discussing about the specific weights of the fuels that seem to be climbing from 2014 to 2015 with Merc on the top of the list with the heaviest fuel. He then continues criticizing the flow meters measuring the consumption at liters. 

 

Another fail by FIA 

 

Why is the fuel metered in litres, but then teams allowed to run denser fuels!?  Madness.

[Jvr]

Another fail by FIA 

 

Why is the fuel metered in litres, but then teams allowed to run denser fuels!?  Madness.

As I said, I have always assumed the consumption is converted into kilos by using the density measured by the sample before the event and confirmed by the one liter sample after the event team by team but I must admit I do not now know how FIA actually is doing the conversion.

[Kimble]

I guess they might be looking for some inefficient use of fuel pipe between the fuel-flow measurement and injectors?

[ExFlagMan]

Another fail by FIA 
 
Why is the fuel metered in litres, but then teams allowed to run denser fuels!?  Madness.

Possibly because it might be easier to meter by volume than mass in a the heavy vibration environment of a F1 car/engine.

[GreenMachine]

They have fuel samples to measure density, they have temperatures from the ecu, therefore litres vs kilos not an issue?

[GreenMachine]

On a more general note ...

If you want to make a rule, make it properly. Measure the compliance where you want it complied.

Expect that every engineer worth his salary, not to mention bonuses, will examine every line in the rulebook, looking for loopholes, and that some will find them.

When they do, fix the rule - properly.

End of story.

I remember a Brockbank cartoon, along the lines that the scrutineer is never happier than uncovering a crafty piece of chicanery ... sums up this sport, er, business. The people here getting their knickers in a knot over 'cheating', I suggest they take a cold shower.

[Peter Perfect]

So... do we think this had any effect this weekend?

[SealTheDiffuser]

So... do we think this had any effect this weekend?

 

isn't it implemented and controlled at China GP

[P123]

So... do we think this had any effect this weekend?

Not really. It was more down to strategy, track temp and tyre management.

[Peter Perfect]

 

isn't it implemented and controlled at China GP

 

 

Ah! I thought it was this one, althought some teams may implement it early:

 

"The FIA has asked for these systems to be implemented by the Chinese Grand Prix in April at the latest.

But it has also requested that teams do so earlier if possible, with each team set to be contacted by the FIA to evaluate how the fuel pressure will be measured and how these systems will fit in with the standard ECU."

 

Not really. It was more down to strategy, track temp and tyre management.

 

Which teams are you talking about?

[SealTheDiffuser]

AMUS:

 

Banned gasoline trickery

The FIA measures since the GP China , the flow rate of and behind the flow rate sensor. How can one prevent that is fiddling on the way from the sensor to the injectors. Ferrari had tried a system in winter testing , enlarged in the fuel lines to a rechargeable battery in diameter and were scaled down in order to save fuel is not used in a bubble. As would theoretically behind the sensor , the flow rate can be increased in the short term . On the total amount that had no effect . As a number of teams in the FIA asked, if this was allowed, there was a cancellation. Ferrari debuilt the device again.

[MrAerodynamicist]

I've never understood why the FIA just don't limit the fuel per race. Why bother with such complications in measuring fuel flows? Just limit the damn level of fuel used per race ... and that way, remove at least one ridiculous complication.

 

http://www.jamesalle...ensors-in-2014/

http://www.racecar-e...low-is-limited/

 

It also has a safety benefit. By forcing the teams to average fuel economy over the race, you reduce the amount of extreme fuel saving/coasting and the dangers of cars at vastly different speeds.