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Le Mans 2014 fuel allocation system


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#1 inox

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Posted 25 June 2013 - 07:16

These technical regulations for Le Mans 24 hour race have been released over a year ago, but does anyone actually know how they are going to control fuel allocation rules? What I have understood the idea is to allow amount of fuel per each lap but what kind of control unit will be used for this?

http://www.lemans.or...lation_2014.pdf

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#2 Woody3says

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Posted 25 June 2013 - 09:08

"All the figures are defined on the basis of one lap of the Le Mans circuit."

The actual values for what the ACO allow in tank size for each type of fuel was determined (per this directive) in Sept '12





All they are saying is that the ACO is changing the engine rules for more efficiency. This will not be controlled by some super control unit thingamajigger, but as it is now, by a set size in fuel tank compacity.

#3 gruntguru

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Posted 25 June 2013 - 10:15

The regs also mention a fuel flow meter to limit power output. This will limit power output, replacing the current air restrictor. It will also encourage fuel efficiency.
Electromagnetic valve actuation is banned on the pretext of cost capping. Looking into the future but near-sighted IMHO.

Edited by gruntguru, 25 June 2013 - 10:19.


#4 inox

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Posted 25 June 2013 - 10:31

"All the figures are defined on the basis of one lap of the Le Mans circuit."

The actual values for what the ACO allow in tank size for each type of fuel was determined (per this directive) in Sept '12





All they are saying is that the ACO is changing the engine rules for more efficiency. This will not be controlled by some super control unit thingamajigger, but as it is now, by a set size in fuel tank compacity.



So you mean teams are allowed to refuel only as many liters as the race has progressed? The easiest way to control this would be to allow cars to be freely filled up before the race start. Then during the race each completed lap would increase the refueling reserve (refueling reserve = completed laps x fuel allocation/lap").

#5 Woody3says

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Posted 25 June 2013 - 14:44

No you misunderstand what I meant. They will be held in check just as now. Diesel get X and Petrol gets Y for the fuel tank size. HOWEVER as gruntguru says there will be a fuel flow meter. The premise is still the exact same. All that has changed is now they regulate power by air restrictors, dump as much fuel as you want, but air limitations will keep you in check. Next year they swap air for fuel. The same will happen. It will be of no use to have a huge intake if you only have limited fuel, just as now dumping loads of fuel only go so far. Power is still in check, just going at it from a different direction.

The ACO want better efficiency. Reduction in engine size has came full circle to almost the same lap times as before. The rule makers are coming at it from a new direction, but the end result will be similar. Give engine manufacturers less and less to work with to push the technology forward. It will be interesting for sure!

#6 desmo

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Posted 25 June 2013 - 21:38

Electromagnetic valve actuation is banned on the pretext of cost capping. Looking into the future but near-sighted IMHO.


Is there any real possibility though that camless valve actuation is actually feasible for a racing engine. Last I looked it seemed unlikely. Probably more feasible for a low speed boring street engine.

#7 inox

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Posted 26 June 2013 - 06:53

No you misunderstand what I meant. They will be held in check just as now. Diesel get X and Petrol gets Y for the fuel tank size. HOWEVER as gruntguru says there will be a fuel flow meter. The premise is still the exact same. All that has changed is now they regulate power by air restrictors, dump as much fuel as you want, but air limitations will keep you in check. Next year they swap air for fuel. The same will happen. It will be of no use to have a huge intake if you only have limited fuel, just as now dumping loads of fuel only go so far. Power is still in check, just going at it from a different direction.

The ACO want better efficiency. Reduction in engine size has came full circle to almost the same lap times as before. The rule makers are coming at it from a new direction, but the end result will be similar. Give engine manufacturers less and less to work with to push the technology forward. It will be interesting for sure!


I don't quite figure out how this fuel allocation will be monitored because:
1) The car may have different level hybrid system ( 0 - 8 MJ ) and hence different level of fuel allocation per lap, while still having identically sized fuel tank
2) You can limit peak power with fuel flow meter, but limiting the flow to certain amount for each lap sounds too complicated. How do you regulate the flow during the lap? Cutting fuel injection totally towards the end of the lap if you have been over using the fuel?

Therefore it sounds much simpler to limit how much you are allowed to refuel as I explained in my previous post. In that scenario serious over usage of the fuel would just cause excessive pit stops towards the end of the race. In the worst case you would end up refueling in every lap to get 1 lap of fuel allocation filled in.

#8 Woody3says

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Posted 26 June 2013 - 09:09

The chart on pg 6 in your above link shows the allocation of both tank size and amount of fuel flow allowed (again, based off 1 lap at Le Man) They dont explain how that will pan out on other tracks, but there will be some number given for each track.

The fuel allocation wont be, monitored exactly, but sort of. I'll try and explain a different way. I think that is where we are on different pages.

Currently: you have a certain tank size and a certain air restrictor petrol vs diesel. The air restrictor is what limits power to try and both balance petrol/diesel and also to keep power levels in check. Audi and Toyota have done such a good job at working around the air restrictors that they have lap times down to the times set a few years back with much larger power plants.

Next year the flow rate will be the limiting factor. Use whatever air intake you want, but you only get so much fuel per lap. There is still a set tank size, but you can only inject X amount of fuel. The PDF breaks it down for both petrol and diesel. It also breaks down the amount of fuel allowed based on what hybrid power level used.

I'm not sure where we are getting mixed up, do you see how the chart outlines this?

Therefore it sounds much simpler to limit how much you are allowed to refuel as I explained in my previous post. In that scenario serious over usage of the fuel would just cause excessive pit stops towards the end of the race. In the worst case you would end up refueling in every lap to get 1 lap of fuel allocation filled in.

That is not the goal of the ACO. They want efficiency in powerplants. Audi was a perfect example of what the DIDN'T want this year. Audi went 2 laps SHORTER than Toyota, but still outran and won. The ACO dont want black smoke pouring diesels. This is a winning formula now, but not the intent of the rules in the first place.

The ACO want technological advancement in engine efficiency (and hybrid technology) to win.

Edited by Woody3says, 26 June 2013 - 09:18.


#9 Woody3says

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Posted 26 June 2013 - 09:23

Is there any real possibility though that camless valve actuation is actually feasible for a racing engine. Last I looked it seemed unlikely. Probably more feasible for a low speed boring street engine.

I think they will get there sooner than you might think. Good start here

Camless

#10 inox

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Posted 26 June 2013 - 12:04

The chart on pg 6 in your above link shows the allocation of both tank size and amount of fuel flow allowed (again, based off 1 lap at Le Man) They dont explain how that will pan out on other tracks, but there will be some number given for each track.

The fuel allocation wont be, monitored exactly, but sort of. I'll try and explain a different way. I think that is where we are on different pages.

Currently: you have a certain tank size and a certain air restrictor petrol vs diesel. The air restrictor is what limits power to try and both balance petrol/diesel and also to keep power levels in check. Audi and Toyota have done such a good job at working around the air restrictors that they have lap times down to the times set a few years back with much larger power plants.

Next year the flow rate will be the limiting factor. Use whatever air intake you want, but you only get so much fuel per lap. There is still a set tank size, but you can only inject X amount of fuel. The PDF breaks it down for both petrol and diesel. It also breaks down the amount of fuel allowed based on what hybrid power level used.

I'm not sure where we are getting mixed up, do you see how the chart outlines this?


Yes I see the contents of chart. I think we have both understood the idea of air restrictor vs. fuel restrictor from the outset. But I think neither of us know how ACO plans to monitor the fuel flow lap wise. Perhaps they just check how many liters of fuel a team has used after the race. Or alternatively just limit the max fuel inflow. Latter mechanism alone is a poor solution as teams could invent a way to run always on the max fuel inflow in order to gain maximum acceleration performance.

That is not the goal of the ACO. They want efficiency in powerplants. Audi was a perfect example of what the DIDN'T want this year. Audi went 2 laps SHORTER than Toyota, but still outran and won. The ACO dont want black smoke pouring diesels. This is a winning formula now, but not the intent of the rules in the first place.

The ACO want technological advancement in engine efficiency (and hybrid technology) to win.


Yes. Understand this, but actually the fuel reserve idea I presented wouldn't have encouraged to run over the fuel allocation limit. It would have caused stints to get shorter and shorter, effectively ruining the race.

#11 TC3000

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Posted 27 June 2013 - 02:05

Yes I see the contents of chart. I think we have both understood the idea of air restrictor vs. fuel restrictor from the outset. But I think neither of us know how ACO plans to monitor the fuel flow lap wise.


They will use a sensor developed by Gill-Sensors, which is also the official supplier for F1 next year.
You can see a photo of the sensor and some dimensions.
It's based on an ultrasonic measurement which measures at 2kHz and is said to provide a accuracy of max. +/- 0.25% error (with an averaged error of +/- 0.15% in most cases).
Fuelflow can me monitored and controlled in quasi real time, which will also limit the max. achievable power output for a given engine efficiency (better efficiency --> more power at the wheels)
At the moment the sensor is said to work alright with gasoline and E10, but a bit more fine tuning is still needed for diesel.
Apparently Starworks has run the sensor for testing during the test days in Le Mans but didn't race it.

There is a article about how this is going to work in the April 2013 issue of RaceCar Engineering

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#12 WhiteBlue

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Posted 27 June 2013 - 02:50

Racecar engineering explains pretty good how it will work ..read here. The ACO will use FiA homologated fuel flow meters. Over at F1technical most people agree that it will be a Gill manufactured ultrasonic analogue and integrating sensor with digital bus interface. ..here is the link to the manufacturer's page. The sensors integrate the discontinuous fuel flow from the injectors over a period of time and communicate the result to the data loggers. It follows that LMP1 cars will have to have a homologated data logging system from 2014 if they haven't got one already. I'm not so sure about this point.

If you follow the Bosch article on racecar engineering you find that the per lap figures will translate to a a volumetric per time flow rate in the regulations that will be differentiated by diesel or petrol for starters. On top you get certain reductions of the flow rate depending on the amount of energy that your hybrid system processes in one lap. As a privateer you can use zero electric energy but as a manufacturer you have to use hybrid between 2 MJ and 8 MJ per lap. It is thought that all manufacturers will go to the six and 8 MJ systems and go AWD with the electric motor/generator units (MGUs).

There is a second element to fuel allocation though. F1 uses a per race cap but that would be impractical in endurance racing. So LMP1 will continue to use capped refuelling quantities that will continue to be diesel and petrol specific. It is thought that this second element will also be used in future to do balance of performance. It opens an interesting perspective for the comming fight of Porsche with petrol vs Audi with diesel. Both companies will be bringing a brand new down sized turbo engine and a new chassis next year. And I bet they will do some serious sand bagging in the run up to Le Mans in order to avoid big BoP measures. The spoiler in the pack will be Toyota Germany (TMG) who have announced that they will continue to use their old V8s with a bit of cosmetic development. Rebellion will also use these engines or older versions. They could potentially fall so far behind Porsche in the petrol efficiency that Audi will be hit with BoP.

#13 inox

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Posted 27 June 2013 - 08:56

Thanks for your posts. It appears the sensor technology is so advanced already that you can really control the fuel amount lap wise.

Interesting that Toyota might pursue naturally aspirated route. That is a hard way for sure.

On the civil cars though, Toyota can match or even beat VW 1.4 turbo engine in economy with their 1.8 liter naturally aspirated engine with similar power. As far as I recall, Mazda's 2.0 liter skyactiv engine is even more impressive with power/consumption ratio. But in sporty driving the turbos are generally more efficient. It remains to be seen if there is a way to make naturally aspirated engine competitive enough.

#14 inox

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Posted 27 June 2013 - 11:11

Toyota is certainly in for a tough times. They did have 26% larger tank in the car than Audi, but due to 3 litre increase via BoP the figure went up to 31%. Now, in 2014 the difference is only 21%. More powerful hybrid systems will of course balance that out somewhat.

#15 WhiteBlue

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Posted 27 June 2013 - 11:38

Toyota is certainly in for a tough times. They did have 26% larger tank in the car than Audi, but due to 3 litre increase via BoP the figure went up to 31%. Now, in 2014 the difference is only 21%. More powerful hybrid systems will of course balance that out somewhat.

Toyota will be toast next year. All other brands will also have powerful hybrid systems with all wheel drive. Their lack of development on the engine will doom them unless the ACO does something dumb on BoP.

#16 murpia

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Posted 27 June 2013 - 11:50

Interesting that Toyota might pursue naturally aspirated route. That is a hard way for sure.

The last time a naturally aspirated car won Le Mans was 1999. You just don't get the ability to trade power vs. fuel consumption well enough without boost control.

Regards, Ian

#17 indigoid

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Posted 27 June 2013 - 13:58

On the civil cars though, Toyota can match or even beat VW 1.4 turbo engine in economy with their 1.8 liter naturally aspirated engine with similar power. As far as I recall, Mazda's 2.0 liter skyactiv engine is even more impressive with power/consumption ratio. But in sporty driving the turbos are generally more efficient. It remains to be seen if there is a way to make naturally aspirated engine competitive enough.


They can? I would like to see your data on the Toyotas. What models? Not Corollas, surely, and what other cars do they put the 1.8L NA engines in?

In May Tiina and I drove somewhere over 1500km in Finland in a rented Golf TSI and got ~5.something L/100km out of it in a mix of open road and city driving.

Conversely, I've driven at least one example of every generation of Corolla ever made, from model year 1966 to today (and owned most of them), and none of them has ever returned better than 7.2L/100km.

And looking beyond economy - they might have comparable peak power, but it felt like the "area under the curve" was far greater for the TSI powerplant. I never needed to wring its neck to accelerate properly.

I love my Toyotas, as you might have guessed from the above, but that VW TSI powertrain is a class above. Outstanding.

I agree with the other posters - would be very surprised to see Toyota ditch forced induction in LMP.

#18 WhiteBlue

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Posted 27 June 2013 - 16:23

Toyota will keep their existing V8 with some reworking for the efficiency formula. TMG have no budget to burn like Audi or Porsche. They are essentially a profit centre and have €30m per annum. Audi spends at least €100m and Porsche will be north of €200m. Both companies from the VW group will design brand new turbo engines, new chassis and new hybrid systems for next year. TMG will compete with something that is essentially a NA V8 now with a brake thermal efficiency below 30%. They may be able to raise that by 2% by giving it all the bells and whistles that are allowed next year. Audi and Porsche will bring downsized turbo engines with something like 38% of brake thermal efficiency. That is going to be a huge power difference in a fuel flow controlled formula. The fuel flow in LMP1 will be quite severe. It will be almost 20% less than the fuel flow of the F1 engines. I expect Audi and Porsche to have 50-100 bhp more from the higher efficient engine. They will be alone in a race of their own just by merit of their performance. Toyota and Rebellion cannot even hope to get a better reach and run longer stints because Porsche will have a similarly powerful petrol turbo engine in comparison to the Audi turbo diesel. I do not see much scope for giving petrol powered cars more refuelling capacity motivated by BoP unless the ACO balances NA engines vs turbo which they probably will not do.

#19 Woody3says

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Posted 28 June 2013 - 01:47

RLM team mentioned during the race that Toyota would be AWD next year.

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#20 WhiteBlue

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Posted 28 June 2013 - 07:25

RLM team mentioned during the race that Toyota would be AWD next year.

All manufacturers will have big hybrid systems with AWD next year. That's where a part of the performance advantage is going to come from. But it will be expensive. So privateers like Rebellion will not have it or use older, cheaper systems.

Edited by WhiteBlue, 28 June 2013 - 07:26.