[WEC] LMP Future Regulations (was Le Mans EVO rules - now hypercar rules)

[gwyllion]

Originally Posted by hcl123

[ But your energy from the answer to my previous post i don't ... that is the potential energy of the "momentum" at 320Kmh ... it decelerates, will be that if *instantaneously* stops]

I don't see what I did wrong

The same calculation is a slightly different way, but this the same result:
deceleration force F = a * m = 29.43 m/s² * 900 kg = 26.5 kN
dissipated energy E = F * d = 26.5 kN * 134 m = 3.55 MJ

[gwyllion]

Originally Posted by hcl123

Joule = Kg.m²/s² ... J = 900(133.08)²/(3.02)² = 1,747,698.98 joules that is generated ~1.75MJ ( 8 events = ~14MJ ) ... hope it answers your question... brakes almost fall off, of red hot lol

In practice, there are only 4 braking zones in Le Mans where the car decelerates from 320 km/h to (below) 100 km/h: 2 chicanes, Mulsanne corner and Indianapolis corner.



3.55 MJ is the absolute theoretic maximum of kinetic energy that can recovered per braking zone.

[TF110]

Originally Posted by gwyllion

In practice, there are only 4 braking zones in Le Mans where the car decelerates from 320 km/h to (below) 100 km/h: 2 chicanes, Mulsanne corner and Indianapolis corner.



3.55 MJ is the absolute theoretic maximum of kinetic energy that can recovered per braking zone.

Itd be interesting to know what the efficiency of energy capture is from the 3 teams. Remember Toyota saying they could do 'double' the 500kj in the capturing of braking energy. I think saying the 16mj per lap could be a goal in the future is not out of reason.

[hcl123]

Originally Posted by gwyllion

I don't see what I did wrong

The same calculation is a slightly different way, but this the same result:
deceleration force F = a * m = 29.43 m/s² * 900 kg = 26.5 kN
dissipated energy E = F * d = 26.5 kN * 134 m = 3.55 MJ

Actually are both approximations... the correct would be to calculate using "derivates"

Besides its "deceleration" the force is negative... that is the displacement, the movement, is *negative* related to force(opposite directions) -> in each delta time of the duration of the event, the force may maintain the same, yet the "work" ( which is equivalent to energy) is smaller and smaller, since for each of those delta times the displacement, i.e., the distance accomplished in each delta time, is smaller and smaller ... until stop.

E = F * d ; Work = F*d ... what you did is calculate work and by the "principle of equivalence" directly calculate energy

http://en.wikipedia.org/wiki/Newton_metre

what you did was calculate a "positive" potential energy by a"conservative force" ( (= 3G)... which is also not exactly truth, since its "friction", and the smaller the rotation of the brake discs the smaller is the friction... but we do it for the sake of simplification.

http://en.wikipedia.org/wiki/Potential_energy

[hcl123]

Originally Posted by gwyllion

3.55 MJ is the absolute theoretic maximum of kinetic energy that can recovered per braking zone.

Theoretically may be ~truth... but never by only friction brakes. Electric regeneration + friction means a waste, since the "friction" part just doesn't recuperate anything but heat lol... even 1.75 MJ is yet too much, yet attending a very good strategy and only applying friction the minimal necessary, above 1 MJ / event is quite possible for those strong brake zones.

8 MJ related to LeMans must have been calculated has close to max *practically* attainable for recuperative braking( i say could be more 12 MJ is not far fetched)... that is why those tables with max 8 MJ ( 2,4,6,8 )...(FIA/ACO has plenty of engineers not only ex-drivers lol... even so they had to allow cars to *potentially* go faster in straights, the why smaller weight and better front aero [ the faster you go, then the more energetic is the braking event -> here a good exercise to calculate at 350Kmh... big diesels used to be close to 360Kmh, before the engine cut down to 3.7L]... its a Recuperative Braking Formula the criteria of those tables for Hybrids.

Yet there is more than one way to kill a cat... this is one way http://tentenths.com/forum/showpost....postcount=3290 that can give up to 5 KWh or more for those cars if really developed( for trucks can be up to 10KWh, but the speed is much lower) ( 0.275 KWh per lap -> ~ 1 MJ lap)... and as i posted earlier, the why the wall texts (A not incorrect, B) plenty of comprehensible... there is plenty of other methods, in which Audi MGU-H and Porsche "Exhaust Alternator" are included.

[hcl123]

Originally Posted by gwyllion

In practice, there are only 4 braking zones in Le Mans where the car decelerates from 320 km/h to (below) 100 km/h: 2 chicanes, Mulsanne corner and Indianapolis corner.



3.55 MJ is the absolute theoretic maximum of kinetic energy that can recovered per braking zone.

Lets say better brakes, specially with hybrid electric motors... reluctance+induction...

3.5Gs

a= - 34.3 m/s²

v0 = (350Kmh) its 11% better than the max speed in that table.

v0 = 350,000/3600 = 97.2 m.s

v1= (105 Khm faster cornering speed) 105,000/3600 = 29.17 m.s

Time v1= -at+v0-> 29.17= - 34.3t +97.2 -> t = (97.2-29.17)/34.3 = 1.98 seconds

Distance D = -at²/2 + v0t + C (constant)

Since we know v1 = 29.17m.s at time 0, the end of event -> 29.17 = -a (0²)/2 + v0x0 + C -> C= v1

-> Distance D = - (34.3 x(1.98)²)/ 2 + 97.2x1.98 +29.17 = 154.39 meters

The better the braking potential, the higher the force from higher initial velocity, the shorter the time but the higher can be the distance (can be counter intuitive lol)... and only from this we see much more energy, shorter the time may be but much more energetic ( more distance and more force, more work, more energy).

And this why Toyota is so good, and Hybrid helps A LOT, that is, shorter times even from relative less initial speed can mean much less distance... Audi may brake as strong ( not really) but it always takes more distance since it goes faster in straight ( the "effect" we see a lagging in straight car, fast approaching the front one approaching a corner).

Joule = Kg.m²/s² ... lets consider with pilot ~70Kg and some fuel = 80Kg

MAX event
J = (870+80)x (154.39)²/(1.98)² = 5,776,0,58.18 joules that is generated ~5.776 MJ... that is *potential* max, but lest consider 60% in waste that goes as heat ( already very very good).. so max event is 2.310 MJ equivalent from a event from 350Kmh

Very rouge(linear) to cut a long story short...

There are 18 points of braking in Le Mans with average speed before braking (make the average from that chart) of 197,78 Kmh ... but since the top speed is 11% better, and since there is front wing and "ground effect" lets consider lower speed the same gain... so average speed will be 219.5 Kmh with 2% for disparities 215.11Kmh

If max event is 2.310 MJ from a top speed of 350 Kmh... at 215.11 Kmh is 1.419 MJ event, and since there is almost a linear "attenuation" relation between energy and speed (all other factor the same) 350/219.5 = 1.594

Total recoverable energy from all points, since now its free = (1.419*18)/1.594 = ** 16.02 MJ ** ( may be wrong but a crude approximation )

So "12MJ /lap" is quite possible attending all zones... and 16 MJ/lap may yet be possible also -> the have to allow the cars to go faster-> 2014 is going to be faster already, i suspect

[TF110]

Didnt they define a "braking" as greater than 1g? Not sure if that rule still applies but the recovery energy it was defined as a braking of 1g or more. How many areas could you recover braking energy? You can see the major braking areas being the chicanes, mulsanne and indianapolis. But there are plenty of other 'minor' braking areas to recover energy in braking. And with two areas on the car recovering from braking thats definitely adding to the energy recovered. If they would allow 3 or more ers's we could see huge amounts of electrical power!

[hcl123]

Yes

http://www.youtube.com/watch?v=eD7qNujbr8E

There is G force metering in that footage... at the top speed zone, that in that footage is ~320Kmh at the 1th chicane, the horizontal G force approaches 3G in that strong braking ( the higher the top speed the higher the G if the braking action is stronger to)

There is also Lateral G forces that in 1 corner can pass the 2G... perhaps in suspension or the rear transmission differential... there could be a method to recover this (one more lol)

[@ TF110.. isn't the recuperation, either braking or other, free ? ... not sure, but if it is you have no worries]

[hcl123]

Originally Posted by Bandicoot17

The real question that needs answering is how much 'faster' are you if you run 8mj at Le Man's. That's worded badly but I hope you get the gist.
I believe Le Man's is still worth more to the manufacturers and therefore they are probably going to prioritise it over the remaining WEC races.

That is a very pertinent question because it means a lot of energy that can translate to real faster.

8MJ = 8,000 KW in one sec ( since 1J.s = 1W).. and lest consider each lap at 3:25 min or 195 sec gives 8000/195= 41.0256 KW.s per lap ... per hour (3600 sec) and since is inversely proportional gives (41.0256*195)/3600 = 2.222 KWh

Each lap considering *all* 18 zones of braking gives 2.222/18 = 0.12345KWh or 123.45 Wh per event... and if consider only 7 zones of braking is average 0.31746KWh or 317.46Wh...

I hope its clear... this is a LOT !

Perhaps very pertinent ...lets consider the Tesla Model S, since its the biggest battery and the longer range BEV around... its a 85KWh pack

At 2.2KWh lap, an LMP1 would take 85/2.2 = 38.25 laps to recharge a Model S battery... if we consider the all 24 h race and 348 laps it will recharge a Model S battery > 9x

2.2KWh per lap...means average (2.2*3600)/195 = 40.615 hp more in each second per lap .http://www.tvss.net/train/tools/08.htm... at 7 release events of 5 sec each, its 35 sec of total events and so a total power of events 2.2*3600/35 = 226 hp average per second ( but some events can be quite more powerful than others, or start way over 300Hp and finish quite below the 226 hp.. average in each of those 7 events )

Its enough energy to give top horsepower in the more intense release points of over 300 hp and torque figures of over 400 Nm ... and those points is usually where it matters the most... your engine is only ~500 hp and torque figures of less than 400Nm ? ... it might not matter anymore!..

[gwyllion]

You really need to learn how to use a calculator and to use correct units.

Originally Posted by hcl123

8MJ = 8,000 KW in one sec ( since 1J.s = 1W).. and lest consider each lap at 3:25 min or 195 sec gives 8000/195= 41.0256 KW.s per lap

3:25 min = 205 sec

Originally Posted by hcl123

2.2KWh per lap...means average (2.2*3600)/195 = 40.615 hp more in each second per lap .

Joule/second = Watt

8000 kJ / 205 s = 39 kW = 53 hp

[gwyllion]

In your analysis you are completely ignoring that internal combustion engine will produce less power for the biggest ERS option:

• petrol energy
  • 0 MJ ERS: 150.8 MJ/lap
  • 8 MJ ERS: 134.9 MJ/lap
  • difference: 15.9 MJ/lap (10%) -> in average power: 15.9 MJ/lap / 205 s/lap * 0.414 = 32 kW
• max petrol flow
  • 0 MJ ERS: 95.6 kg/h
  • 8 MJ ERS: 87.3 kg/h
  • difference: 8.3 kg/h (9%) -> in peak power: 8.3 kg/h / 0.220 kg/kWh = 38 kW

The whole point of the 2014 LMP1 rules is that every option gets the same amount of energy (= combustion energy + electric energy).

The only real reasons for going to the 8 MJ ERS options are:

1. potentially longer stints: same fuel tank capacity but lower fuel consumption
2. ability to temporarily exceed the maximum power restriction: the peak power of the combustion engine is restricted by the max fuel flow, but no restriction exists on the power output of the electric motors

[PascaLM]

Originally Posted by hcl123

Distance D = -at²/2 + v0t + C (constant)

Your calculation is correct in theory but the pilot can't do this. The braking must be decreasing ; strong at the beginning exploiting the downforce, then lighter. If not, the tires release smoke and the car goes spinning, for sure. So the total breaking length is more than 158 m.

[hcl123]

Originally Posted by gwyllion

You really need to learn how to use a calculator and to use correct units.
3:25 min = 205 sec
Joule/second = Watt

8000 kJ / 205 s = 39 kW = 53 hp

Sorry about that ... i did 3.25x60 = 195

Doesn't matter 8000KJ = 8000 KW.s.... 8000/205 = 39.02439 KW.s proportionally in a hour (inversely proportional ) is (39.02439*205)/3600 = 2.222KWh.. its always 8MJ no matter what.

And yes then fuel flows are adjusted to take in account the difference. Yet an electric motor ( depends, each team can have its own) can be up to 80% efficient overall, while ICE are at most 20%. Yes, i think Hybrid can equalize things concerning petrol vs diesel.

[hcl123]

Originally Posted by PascaLM

Your calculation is correct in theory but the pilot can't do this. The braking must be decreasing ; strong at the beginning exploiting the downforce, then lighter. If not, the tires release smoke and the car goes spinning, for sure. So the total breaking length is more than 158 m.

Its not the brakes "per se" ... its the rotation of the disk brakes -> as decelerates the less the rotation so the less is the friction and so the lees is the braking power. But you don't want a post full of a "wall of derivative" calculations ( yet full of assumptions, because of not having real numbers)...besides i have much better things to do.

also doesn't matter, since for 8 MJ you only have to be 0.317KWh per event recuperating... might tell nothing to nobody... my best defense is Toyota relying only on "recuperative braking" for the 8 MJ.

[ give me a break please ? ... thank you ! ]

[hcl123]

And ppl didn't understood, its not innocent this http://tentenths.com/forum/showpost....postcount=3309 and the reference to Tesla Model S, that seems to create so dislikes...

If a 24h race lasts 348 laps, and as http://tentenths.com/forum/showpost....postcount=5671 it has 13.629 Kms per lap, its 4,742.89 KM or (1/1.609) 2,949.72 miles

If 85KWh is good for 300 miles as Tesla announces... the capacity of actual LMP1s to regenerate 9.098x 85KWh batteries, would be enough for 2,729.41 miles or about ~92% of the 24h race only in electric power.

But of course Tesla test was done at 50Mph( 80.45Kmh ), and at that spped no way in hell you could regenerate 8 MJ, no matter if the car weights more than 2 tons,,, not enough momentum in any of the braking zones( matter of fact practically you don't have to brake lol).... so its a between a rock and a hard place....

Nevertheless it serves to show that making a single lap only in electric power is not much of an achievement... like Nissan ZEOD advertising stunt... and that they use this capability for not being totally honest with the public, that in a 100 Miles test circuit MPGe is always almost half of the real consumption of a car if you consider much more than 100 Miles voyage... as example the BWM i8 not 2.1 L /100Km but more like 7 L /100KM
http://www.greencarcongress.com/2014...140311-i8.html ... its a very good achievement no matter only 3 cylinders, but its a powerful sport like car and there are no free lunch or free cakes specially with obsolete tech like petrol engines

[MyNameIsNigel]

Originally Posted by TF110

Didnt they define a "braking" as greater than 1g? Not sure if that rule still applies but the recovery energy it was defined as a braking of 1g or more. How many areas could you recover braking energy? You can see the major braking areas being the chicanes, mulsanne and indianapolis. But there are plenty of other 'minor' braking areas to recover energy in braking. And with two areas on the car recovering from braking thats definitely adding to the energy recovered. If they would allow 3 or more ers's we could see huge amounts of electrical power!

The 1g rule has indeed disappeared in the 2014 rules, meaning that there is not particular restriction as regards the recovery of energy upon braking.

[Richard C]

Both F1 and WEC is mandated to use the exact same homologated FIA fuel flow sensor. In the season opener there was much drama post race as Red Bull had refused to use the data provided by the sensor to limit fuel flow. They used a internal calculated fuel flow model (injector pulse lengths, expected mass flow via injectors, etc.). The problem is that Red Bull (and potentially other teams) say that the accuracy of the sensors if not good enough and result in some teams getting an advantage. During practice and in qualifying various teams were asked by the FIA to adjust their maximum flow rates down because the sensors were saying they were exceeding the maximum flow rates. The other teams put in an offset (and ran a flow rate below what they felt was the real maximum), but Red Bull did not use an offset and the one car that finished was DSQ.

Thoughts as to impact to WEC? Any news from Toyota, Porsche or Audi regarding the FIA fuel flow sensors during testing? If I remember correctly there was to be multiple identical flow sensors in the WEC cars? Were they setup in series to average out the flow, or to do some type of dynamic software based "vote" based upon which sensor seemed to be the most accurate? Or are they wired in parallel so that if one fails, the next can be used (There is no moving parts in these sensors, so I can't see a failure requiring them to be setup in parallel with valves. That seems crazy complex). Overall, I can't remember the details as to how these are implemented in WEC.

Richard

[Spyderman]

I'm glad you brought this up Richard. I suspect that we will have issues in the WEC too.

[TF110]

Red Bull pushed it, and were found over the limit. No one else had an issue. I think these guys will be fine.

[JoestForEver]

The gill sensor was reported repeatedly with error much larger than contracted, so that's rather worrying. Cannot locate the exact source though, poor memory.

[Richard C]

Originally Posted by JoestForEver

The gill sensor was reported repeatedly with error much larger than contracted, so that's rather worrying. Cannot locate the exact source though, poor memory.

Other than Red Bull's general claims and anecdotal stories from other unnamed teams that the sensors are not accurate enough (which don't talk actual numbers) ...

As best as I can tell, there has been no public release of information saying that the sensors used by Red Bull were out of spec let alone by how much, or the offset value that the FIA requested Red Bull to use.

However! I would love to see this if anyone can provide a link!

Richard

[Richard C]

Does anyone remember how these are to be used in WEC? I think the sensors are mounted in the F1 fuel tanks, but in WEC, I think they are mounted in a recess near the exterior of the body (maybe even in the monocoque?) And am I wrong in remembering that multiple flow sensors were to be installed at the same time? I am not in a position today to dig into the rules. I think I have even see a diagram (maybe in the rules) that shows how the sensors are to be mounted.

Richard

[Spyderman]

Originally Posted by TF110

Red Bull pushed it, and were found over the limit. No one else had an issue. I think these guys will be fine.

Actually, and according to what was reported on Midweek Motorsport, other teams also had ïssues. The difference was that they turned down their engines when they were warned by the FiA. Red Bull did not. In all these cases, the team's measurements differed to those shown on the meters.

[MyNameIsNigel]

Originally Posted by Richard Casto

Does anyone remember how these are to be used in WEC? I think the sensors are mounted in the F1 fuel tanks, but in WEC, I think they are mounted in a recess near the exterior of the body (maybe even in the monocoque?) And am I wrong in remembering that multiple flow sensors were to be installed at the same time? I am not in a position today to dig into the rules. I think I have even see a diagram (maybe in the rules) that shows how the sensors are to be mounted.

Richard

Article 6.2 Fuel Flow Metering
6.2.1 Homologated "Fuel Flow Meters" (Technical List n°45) described in Appendix D must be integrated into the fuel system according to the specification included in Appendix D.
They must be fitted in the survival cell in a receptacle with minimum dimensions 150mm (width) x 200mm (length) x130mm (depth).
They must be fitted on opposite side compared to fuel tank filler.
6.2.2 This equipment must be able to be exchanged quickly in case of failure. A change during a session (race included) could be required.

Appendix D
(...)
For reliability we will use a redundant fuel flow meter. We therefore will have 2 fuel flow meters for fuel systems without a return line after the high pressure fuel pump and 3 fuel flow meters for fuel systems with a return line after the high pressure fuel pump. The redundant fuel flow meter will be placed in series with the first fuel flow meter on the feed line only.
(...)

It worth noting that the LMP1 rules mandate the use of a redundant fuel flow metering system with 2 or 3 fuel flow meters (depending on the type of fuel system) connected in series in the fuel supply line. Furthermore, the rules further mandate quick exchange of the fuel flow meters which are supposed to be easily accessible.

[Richard C]

Thank you!