[Tech Issue] Fuel and Flow and Sensors, oh my!

[steve_r]

What is the difference between the fuel sensor reading and the RBR's figures? Are we talking a a percent or two, or a lot more? Obviously more fuel = more power, but I'm just wondering what sort of performance advantage RBR have supposedly gained / performance disadvantage avoided due to this.

I think Christian Horner used the phrase "significant disadvantage" when discussing why they did not adhere to the FIA's request, but I dont think I have seen anything more specific in terms of exact fule rates.

With (probably) two more races to go before the hearing, I guess RBR have little choice other than to go with the flow(meter) in the meantime?

[wolfhound]

If Ricciardo had to run slower would Magnussen have been able to get ahead? We will never know.
The new rules are designed around restricted fuel usage.
Another method to restrict fuel use would be to have all the fuel to pass through a certain size opening at a certain maximum pressure. There would also need to be a minimum fuel temperature that should equate to the prevaling air temperature.
If the fuel is warmer it will expand and therefore will expand allowing less fuel to go through but a minimum temperature will prevent anybody artifically cooling the fuel.
The problem with this type of restriction is its the volume flow rate as opposed to the mass flow rate that the new regs are trying to restrict.
The current system that uses the Gill sensor seems to be mesuring device as opposed to a restriction device, I could however be wrong.

[Richard C]

Originally Posted by davyboy

I'm no expert in accurate flow measurement under the kind of conditions a racing car experiences but surely there's a better [easier] way to crack this nut. The point of flow regulation is to modulate driving behaviour - i.e. to prevent the kind of scenario you mentioned here. Isn't that easier done through engine mapping ? Wouldn't it be more straightforward to control engine revs i.e. specify thresholds based around a sample lap [and/or qualifying lap] ? After all, everyone's running a standard FIA ECU and these parameters can be easily set and reviewed.

I don't doubt there is a better way. You don't talk about it, but others have suggested a mechanical fuel limiter (such as a calibrated orifice). Two issue with that idea. First, it really only restricts maximum flow at higher RPM and may allow a larger flow at lower RPMs. I saw a theory elsewhere that the FIA wants to keep the "run through the gears" nature of F1, so that means they don't want wide powerbands that might result from a mechanical limiter. Second, I am sure we would be arguing over the calibration of the orifices and how some teams have better ones than others.

Originally Posted by VIVA GT

Actually, arguing against myself a bit here, but one reason for fuel flow reatrictions that I've just thought of is of course qualifying.
Without a flow restriction they could "do a 1980's" and crank up the boost pressure to produce phenomenal 1 lap power (but that would have a detrimental effect on the mechanical reliability...).

I have heard that mention and I believe that is a real issue they wanted to prevent.

Originally Posted by steve_r

What is the difference between the fuel sensor reading and the RBR's figures? Are we talking a a percent or two, or a lot more? Obviously more fuel = more power, but I'm just wondering what sort of performance advantage RBR have supposedly gained / performance disadvantage avoided due to this.

I think Christian Horner used the phrase "significant disadvantage" when discussing why they did not adhere to the FIA's request, but I dont think I have seen anything more specific in terms of exact fule rates.

With (probably) two more races to go before the hearing, I guess RBR have little choice other than to go with the flow(meter) in the meantime?

I doubt we will hear any numbers until the hearing and even then I expect it will continue to be who's numbers do you believe.

I don't know if it is bad form here to mention other forums or not, but there is a really good thread over on f1technical.net about this topic. On one hand you can make good arguments about the many variables that go into an accurate model such as...

Variable cylinder pressure (this is direct injection)
Fuel pressure
Stable timebase for measuring injector timing
Consistent injection motion
Injector wear
Fuel velocity
Etc.

So many of these variables may bounce around a bit from one millisecond to the next, but also may average out over time. So it might be pretty accurate for things like overall fuel consumption (will you run out or not), but just like the FIA flow sensor, it may also not be great at determining instantaneous flow. Especially if you are looking to run right up to the maximum 100kg/h limit.

Overall, it just seems to be that looking for accurate instantaneous flow is pretty hard to do.

Richard

[chillibowl]

a few fast laps at the beginning, going slow in order to go faster later, and going slow at the end are already issues created by the tires aren't they?

encouraging these types of performance difference seems to me the FIA/FOM's desired choice to make the racing look more exciting.

[davyboy]

Originally Posted by Richard Casto

I don't doubt there is a better way. You don't talk about it, but others have suggested a mechanical fuel limiter (such as a calibrated orifice). Two issue with that idea. First, it really only restricts maximum flow at higher RPM and may allow a larger flow at lower RPMs. I saw a theory elsewhere that the FIA wants to keep the "run through the gears" nature of F1, so that means they don't want wide powerbands that might result from a mechanical limiter. Second, I am sure we would be arguing over the calibration of the orifices and how some teams have better ones than others.

The driver modulates his fuel use with his right foot. All it does is controls engine speed... which in turn controls vehicle speed. If they want to regulate vehicle speed, then they either counteract the driver's right foot, or the engine speed. Counteracting engine speed seems to be a relatively simple thing to do based on whatever parameters you desire... lap speed, acceleration, deltas, outright speed, speed in gear. Don't know why they'd need to resort to something so agricultural as fuel flow.

[Mike Harte]

The one overiding factor that most of you are overlooking is that the teams and powerunit providers, collectively, are able and willing to literally spend hundreds of millions of dollars/pounds to circumvent the rules that the FIA produce.

I am pretty sure that the people that devised the latest set of regulations did so in the knowledge that people that are paid a hell of a lot more than them would be burning the midnight oil to find ways to exploit the rule book. This the teams have always done, and I have no doubt, will continue to do.

To refer to one of the previous postings, the FIA stipulated fuel cells with a maximum capacity in an effort to control the amount of fuel that could be used during a race. What did the teams do? They started cooling the fuel so that they had extra fuel to circumvent the FIA's rules.

Might I suggest that it may be a reasonable idea to not get too excited about this matter until the relevant facts are aired at the appeal hearing. I say this because, it would seem to me, Red Bull's defence at the moment appears to be that they ignored the FIA's technical delegate's instructions because there had been problems, up and down the pit lane, with the sensors since the beginning of testing in Jerez. The therefore decided, unilaterally, that their computations were more accurate than the FIA's. However, this seems to overlook the fact that this action could well have given them an advantage over the other teams who were all following the FIA's directions.

No doubt all this will come out at the appeals hearing in due course.

[Scooter185]

Originally Posted by davyboy

The driver modulates his fuel use with his right foot. All it does is controls engine speed... which in turn controls vehicle speed. If they want to regulate vehicle speed, then they either counteract the driver's right foot, or the engine speed. Counteracting engine speed seems to be a relatively simple thing to do based on whatever parameters you desire... lap speed, acceleration, deltas, outright speed, speed in gear. Don't know why they'd need to resort to something so agricultural as fuel flow.

the politics and good PR that (supposedly) comes from "being green"

[davyboy]

Originally Posted by Scooter185

the politics and good PR that (supposedly) comes from "being green"

Very good point. That makes a lot of sense.

[Adam43]

So the designers of the engines have to consider power and efficiency. More of a technical challenge?

[Teretonga]

Originally Posted by Mike Harte

The one overiding factor that most of you are overlooking is that the teams and powerunit providers, collectively, are able and willing to literally spend hundreds of millions of dollars/pounds to circumvent the rules that the FIA produce.

I am pretty sure that the people that devised the latest set of regulations did so in the knowledge that people that are paid a hell of a lot more than them would be burning the midnight oil to find ways to exploit the rule book. This the teams have always done, and I have no doubt, will continue to do.

To refer to one of the previous postings, the FIA stipulated fuel cells with a maximum capacity in an effort to control the amount of fuel that could be used during a race. What did the teams do? They started cooling the fuel so that they had extra fuel to circumvent the FIA's rules.

Might I suggest that it may be a reasonable idea to not get too excited about this matter until the relevant facts are aired at the appeal hearing. I say this because, it would seem to me, Red Bull's defence at the moment appears to be that they ignored the FIA's technical delegate's instructions because there had been problems, up and down the pit lane, with the sensors since the beginning of testing in Jerez. The therefore decided, unilaterally, that their computations were more accurate than the FIA's. However, this seems to overlook the fact that this action could well have given them an advantage over the other teams who were all following the FIA's directions.

No doubt all this will come out at the appeals hearing in due course.

You are probably right Mike, that they may have had an advantage over other teams IF the equipment ordered by the FIA was fluctuating and other teams had (already confirmed) turned the flow down so they wouldn't contravene the regulations. However the other teams could have used the data provided from the same source themselves just to confirm that they were within the regulations and may have actually done this.


The point of regulating the amount of flow is to control the amount of fuel (and ultimately power) to a maximum at any one time.
Measuring is surely to ensure the limit is not breached.

So if Red Bull is actually within the limit over the length of the grand Prix they have complied with the competitive rule and should be reinstated. If not then then they are excluding someone who has complied with the competitive intent of the rule.

If the exclusion is based purely on the methodology, then excluding despite compliance is crock full of vile substance. The point of rule has been obeyed.
The compliance should be based on the fact of the rule limit, not the method of measurement if the equipment used by the FIA is not as accurate or as consistent in its application as an alternative measurement.

F1 should be about excellence. And that should not just be technical compliance but excellence in measurement, equipment, technical and driving competition. It also includes excellence in decision making process, integrity of process and reinforcing the purpose and point of every evaluative process. If RBR's process proves they did comply then they should win the appeal.

If they do that but still lose the appeal because it is not the FIA's system of measurement and if their system actually has more inaccuracy or flaws in it then that is not excellence. It is just the FIA penalising someone because they can. That is unacceptable, ethically, competitively, and in any other way of a sporting competition. It's simply wrong.

So we will know by China's round if they are a body worthy of ruling F1 or not.

[wolfhound]

Originally Posted by Teretonga

You are probably right Mike, that they may have had an advantage over other teams IF the equipment ordered by the FIA was fluctuating and other teams had (already confirmed) turned the flow down so they wouldn't contravene the regulations. However the other teams could have used the data provided from the same source themselves just to confirm that they were within the regulations and may have actually done this.


The point of regulating the amount of flow is to control the amount of fuel (and ultimately power) to a maximum at any one time.
Measuring is surely to ensure the limit is not breached.

So if Red Bull is actually within the limit over the length of the grand Prix they have complied with the competitive rule and should be reinstated. If not then then they are excluding someone who has complied with the competitive intent of the rule.

If the exclusion is based purely on the methodology, then excluding despite compliance is crock full of vile substance. The point of rule has been obeyed.
The compliance should be based on the fact of the rule limit, not the method of measurement if the equipment used by the FIA is not as accurate or as consistent in its application as an alternative measurement.

F1 should be about excellence. And that should not just be technical compliance but excellence in measurement, equipment, technical and driving competition. It also includes excellence in decision making process, integrity of process and reinforcing the purpose and point of every evaluative process. If RBR's process proves they did comply then they should win the appeal.

If they do that but still lose the appeal because it is not the FIA's system of measurement and if their system actually has more inaccuracy or flaws in it then that is not excellence. It is just the FIA penalising someone because they can. That is unacceptable, ethically, competitively, and in any other way of a sporting competition. It's simply wrong.

So we will know by China's round if they are a body worthy of ruling F1 or not.

Red Bull say their system is more accurate but is it?

[davyboy]

There's another, even simpler, way of dealing with the underlying problem - just have the driver drive to a delta time. It's something that's already happening now in terms of controlling speed during safety car situations.

[Scooter185]

Originally Posted by davyboy

There's another, even simpler, way of dealing with the underlying problem - just have the driver drive to a delta time. It's something that's already happening now in terms of controlling speed during safety car situations.

That's not racing then, let alone the pinnacle of motorsports. I didn't follow it this year so idk if the rule is still in place, but that is one of the big criticisms of the Dubai 24hrs. And was the biggest complaint about the Bathurst 12hr qualifying rules -and that was dropped for this year.

Driving to a delta is a common practice to save on fuel or tires, and it got absolutely ridiculous last year when it was clear the field was driving something like 2s slower than their potential. That being said a minimum lap time should never be mandated in the rules imo.

[Teretonga]

Originally Posted by wolfhound

Red Bull say their system is more accurate but is it?

The technical information I have is that the sensors have a 1% margin of error.
10 years ago engineers say they could measure the fuel flow to an accuracy of 0.05% i.e. (5/100ths of 1%). If true then RBR may have the correct information....

[davyboy]

Originally Posted by Scooter185

That's not racing then, let alone the pinnacle of motorsports. I didn't follow it this year so idk if the rule is still in place, but that is one of the big criticisms of the Dubai 24hrs. And was the biggest complaint about the Bathurst 12hr qualifying rules -and that was dropped for this year.

Driving to a delta is a common practice to save on fuel or tires, and it got absolutely ridiculous last year when it was clear the field was driving something like 2s slower than their potential. That being said a minimum lap time should never be mandated in the rules imo.

Well the fuel flow regulation is causing the car to be driven to a delta... so they're ostensibly the same thing. To an extent the car's always been driven to a delta as they're invariably conserving something - tyres, engine, gearbox etc... but I agree... I'd like to see them race full on but I don't think that'll ever be the case.

[Richard C]

Originally Posted by Teretonga

The technical information I have is that the sensors have a 1% margin of error.
10 years ago engineers say they could measure the fuel flow to an accuracy of 0.05% i.e. (5/100ths of 1%). If true then RBR may have the correct information....

I would love to see some publicly available info to back up those claims. And are those claims for overall fuel usage (that seems to be what most do talk about and is not the problem we are talking about) or instantaneous flow (which is the problem here and as best as I can tell nobody is claiming accuracy at the level you mention) and lastly with all of these claims of accuracy, how are they determining the validity of these claims? In short, how are they able to measure if their instantaneous flow calculations match the actual flow at that moment?

Richard

[ciscotex]

Originally Posted by SWCRacing

Have a look at tech reg 5.10.4
Only one homologated FIA fuel flow sensor may be fitted to the car which must be placed wholly within the fuel tank.

Thanks, I'd forgotten that one. I wonder if the alleged unreliability of the sensor and its location in the tank is part of what is contributing to the very long service times the teams were experiencing in testing and Oz?

Paul

[Adam43]

Originally Posted by Teretonga

The technical information I have is that the sensors have a 1% margin of error.
10 years ago engineers say they could measure the fuel flow to an accuracy of 0.05% i.e. (5/100ths of 1%). If true then RBR may have the correct information....

Better than +/-1%:

Originally Posted by Adam43

Yes, it's the same one:
http://www.fia.com/sites/default/fil...%20Meter_0.pdf

Better than inferred measurement:

Originally Posted by Cameron Winton

This is right up my street ( work on aircraft engine fuel controls). I would trust the flow meter over a calculated flow from the ECU mapping for injector switching and injector flow rates. The tolerance stack ups in the calculations will be horrific. Both methods will suffer from changes in fuel density and viscosity but at least the flow meter has direct temperature measurement at the point of flow measurement and, from the Gill sensor website, pretty good frequency response (1 kHz) for the transient flow measurement. Also, the main 1st order variable affecting density and viscosity is temp so the calibration will account for this. The main question that would be asked is how equal are the flow meters that say Red bull has versus those that Mercedes have. That is a reapatability and correlation problem and don't see that anywhere in the paperwork.

?

[Pingguest]

Originally Posted by davyboy

Well the fuel flow regulation is causing the car to be driven to a delta... so they're ostensibly the same thing.

A fuel-flow limit does not mean engines have a maximum power output mandated by the regulations, as suggested above.

[MoMedic9019]

Originally Posted by Pingguest

A fuel-flow limit does not mean engines have a maximum power output mandated by the regulations, as suggested above.

Well...it kind of does. If you have a limit of flow, you have a limit of horsepower. Unless you can extract more HP per CC of fuel used.

[ciscotex]

Just saw this, FYI:

http://www.racecar-engineering.com/n...el-flow-meter/

Paul

[wnut]

Originally Posted by ciscotex

Just saw this, FYI:

http://www.racecar-engineering.com/n...el-flow-meter/

Paul

That is a great get.

It would seem that the evidence is clear that these flow sensors are not accurate.

Get one that under reads, you win the world championships, get one that over reads you have the RBR option - damned if you do, damned if you don't!

[Pingguest]

Originally Posted by MoMedic9019

Well...it kind of does. If you have a limit of flow, you have a limit of horsepower. Unless you can extract more HP per CC of fuel used.

A fuel-flow limit will not forbid teams to be faster than others or break records, hence there is in no way a lap time delta.

[wnut]

Originally Posted by Pingguest

A fuel-flow limit will not forbid teams to be faster than others or break records, hence there is in no way a lap time delta.

It is however a power delta for a known technology at a given efficiency, development is frozen, and the other efficiencies are pretty well set, so the lap time variances will be extremely small on a maximum fuel flow / power!

[ciscotex]

FWIW, a couple more articles on the background and implementation of fuel flow restriction:

http://www.racecar-engineering.com/t...ow-is-limited/

http://www.racecar-engineering.com/t...w-meters-work/

I think I like the idea of restricting fuel flow rather than air to the engine, but hope the questions about reliable measurement are sorted quickly. Looks like Toyota may have a workable system for the Japanese series, but, ironically, are obliged to use the controversial Gill sensor in LMP1.

If Red Bull actually argues and wins their appeal on the basis that Charlie's opinions don't constitute actual, enforceable rules, then I can see the whole series quickly descending into anarchy and chaos. Very interesting for all of the wrong reasons.

http://www.autosport.com/news/report.php/id/113091

In any event, I suspect the manufacturers love this approach, as it allows them to genuinely work toward road relevant efficiency. While I'm not sure how much of road relevance will come from F1, the sports cars are likely to yield some real world improvements and give the makers a reason to participate in motorsports other than marketing.

Paul