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

[repa]

Originally Posted by gwyllion

That does not explain why Toyota claims that the efficiency target for diesel engines is only 42.5%. Your calculations suggest that it should be above 45%, exactly what Toyota is asking for.

Yes, it's true, even with the higher heating value, you get 43,4% of efficiency, which is still far away from the 42,5%. You can get the Toyota numbers if you calculate the diesel engine efficiency with the gasoline heating value!
But i don't know what to think, because 41,5% looks really untouchable for petrol engines, but the higher heating value for gasoline doesn't seem realistic for me for an E20 fuel, so at least one factor is out of the acceptable limit. I'm on the subject to get some information about a racing gasoline, but it won't be E20... While i wrote these lines i found data of the Sunoco race fuels.
Here the Green E15 has 17500 Btu/gallon which is 40,7 MJ/kg which means 43,4% of efficiency for petrol, but this number is the lower heating value, we still don't know the higher one (which is the real one)...

While at the diesel part, everything looks acceptable even with the average numbers.
My prof said that 45% of efficiency is achievable for diesel, but the 38% is the upper limit for the petrol engines, but their efficiency is rather below it.
And why Pesca is happy about the new regs, when Toyota's chief isn't? Henri was the man who wanted equivalence in the recent years and if the new regs would not give it, he would complain nowadays too...
Seems for me, that probably we really haven't got the real numbers of the aco...

[Victor_RO]

Originally Posted by repa

And why Pesca is happy about the new regs, when Toyota's chief isn't? Henri was the man who wanted equivalence in the recent years and if the new regs would not give it, he would complain nowadays too...

I'm not sure that's what he was saying, I think he was praising his engineers in being so precise in figuring out at what kind of disadvantage his team really was to the diesel cars.

[chewymonster]

Originally Posted by repa

Yes, it's true, even with the higher heating value, you get 43,4% of efficiency, which is still far away from the 42,5%. You can get the Toyota numbers if you calculate the diesel engine efficiency with the gasoline heating value!
But i don't know what to think, because 41,5% looks really untouchable for petrol engines, but the higher heating value for gasoline doesn't seem realistic for me for an E20 fuel, so at least one factor is out of the acceptable limit. I'm on the subject to get some information about a racing gasoline, but it won't be E20... While i wrote these lines i found data of the Sunoco race fuels.
Here the Green E15 has 17500 Btu/gallon which is 40,7 MJ/kg which means 43,4% of efficiency for petrol, but this number is the lower heating value, we still don't know the higher one (which is the real one)...

While at the diesel part, everything looks acceptable even with the average numbers.
My prof said that 45% of efficiency is achievable for diesel, but the 38% is the upper limit for the petrol engines, but their efficiency is rather below it.
And why Pesca is happy about the new regs, when Toyota's chief isn't? Henri was the man who wanted equivalence in the recent years and if the new regs would not give it, he would complain nowadays too...
Seems for me, that probably we really haven't got the real numbers of the aco...

Speaking purely of brake specific fuel consumption and energy efficiency a gasoline engine with Atkinson cycle (like on road going and weak Toyota hybrids) tops out at 37%. Like you said 38% appears to be a theoretical limit for gasoline engines. And that is for a 1.8 liter engine that produces only 98 horsepower @ only 5,200 RPM and is all about maximizing efficiency above all else. That ain't gonna cut it in racing. Everything else is worse. Supposedly the new Ford Ecoboost turbo with direct injection is good for 34%. This is the same technology that Audi pioneered with the R8. I still don't know why Toyota claimed an unrealistic figure for their engine.

Everything I have seen for passenger diesels is a peak efficiency of at most 42%*. Anything higher is probably from marine diesels spinning under 500 RPM. Practically irrelevant in the discussion.

* Taking emissions equipment into consideration perhaps racing engines might do a little better than what I mentioned as they have little to no emissions requirements compared to road engines. Also the peak efficiency figures quoted here occur only at about 3/4 throttle at lowish RPM.

[deggis]

Originally Posted by gwyllion

That does not explain why Toyota claims that the efficiency target for diesel engines is only 42.5%. Your calculations suggest that it should be above 45%, exactly what Toyota is asking for.

+

Originally Posted by repa

Which is interesting that in the august issue of the Racecar Engineering, they write that these numbers are not the same numbers what the constructors saw earlier... And also there is an interesting quote from Pescarolo: "Bruno Famin told me i had to congratulate my technical team because every time we said their power we were right!"
So if Henri is happy with the new regs, than it looks for me that ACO has written them in the right way!

Maybe the Kinosh!ta inteview was made before ACO released the figures? The story is dated June 20, ACO held the press conference/presentation on June 14.

[deggis]

Btw, here is the RCE Aug issue article repa mentioned above (direct link to the article): http://www.zinio.com/pages/RacecarEn...16229686/pg-44

At least I had missed this.

[FstrthnU]

http://www.autoblog.com/2012/10/03/e...%28Autoblog%29
Eccelstone says he could drop the Turbo V6 engines for F1, perhaps that will affect the 2014/5 engine choices?

[Canada ALMS fan]

Originally Posted by FstrthnU

http://www.autoblog.com/2012/10/03/e...%28Autoblog%29
Eccelstone says he could drop the Turbo V6 engines for F1, perhaps that will affect the 2014/5 engine choices?

He is only the commercial rights holder. Unless he can get Todt to change his mind, who cares what Bernie thinks? Surely the manufacturers will lobby to have a standard than could potentially race elsewhere and be more road relevant.

[gwyllion]

Originally Posted by deggis

Btw, here is the RCE Aug issue article repa mentioned above (direct link to the article): http://www.zinio.com/pages/RacecarEn...16229686/pg-44

At least I had missed this.

I missed that article as well. Thanks a lot for the reference.

The following is crucial for the ongoing discussion:

For the press conference only, the ACO converted the amount of energy allowed for each car per lap to a fuel allowance. The reasoning was that a quantity of fuel could be easily understood, while a quantity of energy could not. However, that led to considerable confusion, and engineers in the Le Mans paddock were advising observers to ignore the published figures.

...

The final set of regulations concerning energy permitted per car will be set once the chosen fuel supplier - at the time of writing thought to be Shell - release the calorific value of its fuel, both petrol and diesel. The fuel will be standard E20, up from E10 in 2012. Until this is finalised, no complete set of figures can be released.

So it does not make sense to do any calculations on the published numbers.

[gwyllion]

Originally Posted by gwyllion

source: http://www.lemans.org/wpphpFichiers/...ation_2014.pdf

I wonder what "variable admission systems" are. Variable valve timing? Or VTG turbos?

According to the RCE article by Andrew Cotton, variable valve timing will still be banned.

Variable geometry exhausts are also banned, as is variable valve timing and variable valve lift profile systems.

So the lobbying attempts by Baretzky have been unsuccessful.

[TF110]

Kinda sad to see some of that tech not allowed. I guess it's 'cost' effective in their eyes.

[repa]

Originally Posted by gwyllion

I wonder what "variable admission systems" are. Variable valve timing? Or VTG turbos?

I think it means that constructors can varies the effective length of the inlet duct for example. These technologies are banned now, only available in the GT category if the road going version also has it, as i remember. And it's written next to the air inlets, so it means how air can get into the engine, but not into the cylinder. And the last would be the VVT.
As i see, you can vary things only at the intake side, so VTG will be banned, because there you modify the turbine's angle.

[gwyllion]

Originally Posted by repa

As i see, you can vary things only at the intake side, so VTG will be banned, because there you modify the turbine's angle.

I don't see this happening. It would be a big step backward if they had to go back to waste gate turbos.

VTG turbos have been allowed by the ACO since 2006 and Audi has been using them since 2010. Baretzky is a big fan of VTG technology because he lobbied hard (unsuccessfully) to get it allowed in the 2014 F1 engine rules.

[gwyllion]

According to the RCE article the numbers in the table of press release about the 2014 rules should be ignored completely.

However, the article does mention the correct efficiency targets that the ACO has in mind:

The target efficiency of an engine is 220 g/kWh for petrol, while diesel is 195 g/kWh, already a huge step up over the 2012 engines, although they are air restricted and therefore not working to full efficiency.

These numbers make it possible to calculate the required engine efficiency.
The only unknown factor is the energy content of the E20 fuel and diesel that will be used in Le Mans. As pointed out in the RCE, this can only be determined accurately when the fuel supplier has been selected.

220 g/kWh signifies that a petrol engine must produce 1000/220 * 3.6 = 16.36 MJ useful energy with 1 kg of petrol.
According to this recent article, which measures the property of different biofuel blends, E20 fuel has a density of 0.7541 kg/liter and a heating value of 32.43 MJ/liter. That means that E20 contains 43 MJ/kg energy. Clearly this is not state-of-the-art racing fuel, but it does give a good indication.
Using that number, the target engine efficiency is 16.36/43 = 38% for a petrol engine.

195 g/kWh signifies that a diesel engine must produce 1000/195 * 3.6 = 18.46 MJ useful energy with 1 kg of diesel.
We do not know the heating value of Shell's GTL-BTL-diesel blend that is used at Le Mans. This presentation states that a GTL-diesel blend, which is commercially available, has a net heating value of 42.8 MJ/kg.
Using that number, the target engine efficiency is 18.46/42.8 = 43% for a diesel engine.

Those target numbers seem in line with production engines. However, the target for the diesel is probably be a bit easier to achieve.

[Flo aus N]

mhm, according to the PDF of the ACO

Free air inlets: air restrictors cancelled, variable admission systems allowed

So, if i would move the VTG Charger direct to the entrance of the Air Intake or the VTG is very close to that, would this count as a variable admission system ?

It's just some reading between the lines of mine.

[gwyllion]

I must confess that the fuel quantity numbers in the press release seem to make sense after all.

We know that the target efficiency is 16.36 MJ/kg for petrol and 18.46 MJ/kg for diesel. And we can assume that the fuel density is 0.754 kg/l for petrol and 0.8338 kg/l for diesel.

This means the following amount of energy is available per lap for the different powertrain options:

• petrol, 0M hybrid: 16.36 * 0.7540 * 4.95 + 0 = 61.07 MJ
• petrol, 2M hybrid: 16.36 * 0.7540 * 4.80 + 2 = 61.22 MJ
• petrol, 4M hybrid: 16.36 * 0.7540 * 4.65 + 4 = 61.37 MJ
• petrol, 6M hybrid: 16.36 * 0.7540 * 4.50 + 6 = 61.52 MJ
• petrol, 8M hybrid: 16.36 * 0.7540 * 4.42 + 8 = 62.53 MJ
• diesel, 0M hybrid: 18.46 * 0.8338 * 3.99 + 0 = 61.42 MJ
• diesel, 2M hybrid: 18.46 * 0.8338 * 3.93 + 2 = 62.50 MJ
• diesel, 4M hybrid: 18.46 * 0.8338 * 3.81 + 4 = 62.62 MJ
• diesel, 6M hybrid: 18.46 * 0.8338 * 3.68 + 6 = 62.65 MJ
• diesel, 8M hybrid: 18.46 * 0.8338 * 3.56 + 8 = 62.80 MJ

Some observations can be made:

1. Hybrids get a bit more energy per lap. This can be explained by the fact that they have to be 20 kg heavier and hence need a bit more energy during acceleration.
2. Diesels get a bit more energy per lap. Perhaps this can be explained by the fact that diesel engines require more cooling than petrol engines and they will have a worse weight distribution and center of gravity.
3. More powerful hybrids get a bit more energy per lap. Perhaps this can be explained by the fact that they require additional cooling and hence will produce more drag.
4. I do not understand why there is such a big jump in the energy allocation for the 8 MJ hybrid petrol.

[chewymonster]

Originally Posted by gwyllion

According to the RCE article the numbers in the table of press release about the 2014 rules should be ignored completely.


Those target numbers seem in line with production engines. However, the target for the diesel is probably be a bit easier to achieve.

If those are the targets than the ACO is way off. Gasoline engines are not even close to 220. As I said earlier Atkinson cycle engine is at 225. Perhaps adding direct injection to it (as Toyota will in a couple of years) might make it a little better. A direct injected turbo is at 245. Deltawing claims 230-250 for their direct injected turbo (I am going to go with something closer to 250 being the true figure) If those are the figures that the ACO is using they are imagining things.

[joeb]

One thing that kinda bugs me about these energy regulations is that aero will become even more critical. And while I do enjoy aero efficiency, I worry about getting into a situation like F1 where the Aero has gotten so dependent on clean are that regulations have to be made that make passing possible.

[gregtummer]

Originally Posted by joeb

One thing that kinda bugs me about these energy regulations is that aero will become even more critical. And while I do enjoy aero efficiency, I worry about getting into a situation like F1 where the Aero has gotten so dependent on clean are that regulations have to be made that make passing possible.

It is different for Sportscars though, especially with the closing rates in the WEC.

Even if you got to an F1 situation where you can't pass, you will have MANY opportunities to set someone up for a pass in lap traffic.

[gwyllion]

Originally Posted by chewymonster

If those are the targets than the ACO is way off. Gasoline engines are not even close to 220. As I said earlier Atkinson cycle engine is at 225. Perhaps adding direct injection to it (as Toyota will in a couple of years) might make it a little better. A direct injected turbo is at 245. Deltawing claims 230-250 for their direct injected turbo (I am going to go with something closer to 250 being the true figure) If those are the figures that the ACO is using they are imagining things.

The efficiency of the 2014 F1 engines is actively discussed on the autosport technical forum.

Over there, someone is convinced that 220 g/kWh can be achieved with a Miller cycle and turbocompounding and 235 g/kWh is possible with lean burning and a conventional turbo. See http://forums.autosport.com/index.ph...post&p=4756027 and http://forums.autosport.com/index.ph...&#entry5779184

[TF110]

I'm sure LMP's punch a good size hole in the air, so with the draft they won't need a 'DRS' like device.

[Adam43]

Originally Posted by gregtummer

It is different for Sportscars though, especially with the closing rates in the WEC.

Even if you got to an F1 situation where you can't pass, you will have MANY opportunities to set someone up for a pass in lap traffic.

When naturally battling for position the cars need situations like this to aid overtaking at the moment an have for sometime. IMO.

[gregtummer]

How much extra drag does the Big Honkin' Fin and the Big Honkin' Holes add?

How much does that help in drafting?

Maybe MulsanneMike would know.

[chewymonster]

Originally Posted by gwyllion

The efficiency of the 2014 F1 engines is actively discussed on the autosport technical forum.

Over there, someone is convinced that 220 g/kWh can be achieved with a Miller cycle and turbocompounding and 235 g/kWh is possible with lean burning and a conventional turbo. See http://forums.autosport.com/index.ph...post&p=4756027 and http://forums.autosport.com/index.ph...&#entry5779184

I think those are best case scenario figures. The Miller cycle is the more advanced version of the Atkinson cycle I was talking about and needs a supercharger to work. Mazda had one such engine in mid 1990s but not anymore. It might be better in theory but if it really was better than everyone would be using it but no one does.

Just for reference the current F1 engines are at about 270 peak efficiency but at race RPM are in the 350+ and higher.

[lms]

Originally Posted by TF110

I'm sure LMP's punch a good size hole in the air, so with the draft they won't need a 'DRS' like device.

exactly. manufacturers can also create a low drag aero package for le mans, so there is no point introducing drs.

[JAG__]

A look at the '14 P1 regs.

Nice surprise, big rear wings are back!

http://www.mulsannescorner.com/newssept12.html