Audi LMP1 Discussion

[Bandicoot17]

Originally Posted by Chiana

Translate this into - "We have opted for pure LM Special as that is what actually matters"

Anyway, interesting british Q performance coming from team that had the most trouble during winter, but I think the race will be a bit different matter, particularly if there's no rain. Or snow...

Didn't Toyota always struggled to recover the full amount too? Don't see how this means they've gone for a LM special 'as that's what matters'.

Sent from my SM-G920F using Tapatalk

[MyNameIsNigel]

Let's wait and see. Audi's long runs yesterday during FP2 were pretty impressive and I do have the feeling that the battle with Porsche (and possibly Toyota) will be a close one.

[J Jay]

Originally Posted by Bandicoot17

Didn't Toyota always struggled to recover the full amount too? Don't see how this means they've gone for a LM special 'as that's what matters'.

They had some issues with recovery, but with KERS on both axles now it shouldn't be an issue for them. 6MJ equivalent on one axle was always going to be tough.

[MyNameIsNigel]

Originally Posted by J Jay

They had some issues with recovery, but with KERS on both axles now it shouldn't be an issue for them. 6MJ equivalent on one axle was always going to be tough.

This being said, the TS050 uses two MGUs with a combined hybrid power of 365kW, while Audi's single MGU has a power of approx. 350kW. If Audi struggle to harvest the 6MJ-equivalent at Silverstone, you can bet that Toyota face the same issue as the have to harvest even more energy with pretty much the same harvesting power.

[TzeiTzei]

Originally Posted by MyNameIsNigel

This being said, the TS050 uses two MGUs with a combined hybrid power of 365kW, while Audi's single MGU has a power of approx. 350kW. If Audi struggle to harvest the 6MJ-equivalent at Silverstone, you can bet that Toyota face the same issue as the have to harvest even more energy with pretty much the same harvesting power.

Isn't Silverstone one of the most difficult tracks for harvesting energy? Not that many big braking zones.

[TF110]

Toyota have two axels with a kers system, Audi has one. So they get double the help even if its not double the energy recovered. Silverstone isn't the ideal place for kers. That much is clear.

[MyNameIsNigel]

Originally Posted by TF110

Toyota have two axels with a kers system, Audi has one. So they get double the help even if its not double the energy recovered. Silverstone isn't the ideal place for kers. That much is clear.

Sorry, but the greater number of KERS does not really help. What matters is the overall harvesting power available. Audi have 350kW available on a single KERS, Toyota 368kW (combined front and rear), so pretty much the same as Audi. But Toyota need to harvest more energy as they are in the 8MJ class. If Silverstone happens to be a challenge in term of energy harvesting due to the limited number of significant braking areas, then both Audi and Toyota will be faced with the same issue.

[TF110]

Originally Posted by MyNameIsNigel

Sorry, but the greater number of KERS does not really help. What matters is the overall harvesting power available. Audi have 350kW available on a single KERS, Toyota 368kW (combined front and rear), so pretty much the same as Audi. But Toyota need to harvest more energy as they are in the 8MJ class. If Silverstone happens to be a challenge in term of energy harvesting, then both Audi and Toyota will be faced with the same issue.

That doesn't make sense to me. They have two systems regenerating energy from braking instead of one. How does that not help? If what you're saying is true, why did Audi even look into a second ers? I realize that they have near the same power available in terms of the system to release, but recovering (part of) that is going to be easier with two kers instead of one. Honda voiced their opinion on that in F1- saying the rules should allow for double kers (front and rear) instead of single kers (front) and ers-h to recover the allowed energy.

[chernaudi]

Sport Auto suggests that Audi are running an advanced FRIC type interconnected suspension system that doesn't just function front-rear (as last year), but also side to side (like Porsche last year and this year).

Also, this might shed some light on where some suspension parts are located. I think that the front torsion bars have to be pulled out of the hole/slot ahead of the pushrod. Audi also made some changes to the front suspension pick up points after the WEC Prologue.

[MyNameIsNigel]

Originally Posted by TF110

That doesn't make sense to me. They have two systems regenerating energy from braking instead of one. How does that not help? If what you're saying is true, why did Audi even look into a second ers? I realize that they have near the same power available in terms of the system to release, but recovering (part of) that is going to be easier with two kers instead of one. Honda voiced their opinion on that in F1- saying the rules should allow for double kers (front and rear) instead of single kers (front) and ers-h to recover the allowed energy.

Nope. Basic physics. Energy = Power * Time. It doesn't matter how many systems are used to harvest energy during the same braking event. Evidently, if you double the harvesting power by using two systems rather than one, that's different story, but using a single KERS or two KERS with basically the same overall harvesting power amounts to the same thing.

The only advantage of using two KERS instead of one (assuming the same overall power) may be weight distribution and packaging, but then again it all depends which engine is being used at the back. With their heavy diesel engine, Audi have rightly opted for the sole reasonable solution available to them, namely putting one "big" and powerful MGU at the front (without apparently compromising packaging at the front). Toyota have greater freedom in that respect thanks to their comparatively lighter engine, and have rightly chosen to distribute the weight by using two KERS.

[TF110]

I think were talking about two different things. So I'm just going to leave it there.

[MyNameIsNigel]

Originally Posted by TF110

I think were talking about two different things. So I'm just going to leave it there.

?

[Articus]

Originally Posted by MyNameIsNigel

Nope. Basic physics. Energy = Power * Time. It doesn't matter how many systems are used to harvest energy during the same braking event. Evidently, if you double the harvesting power by using two systems rather than one, that's different story, but using a single KERS or two KERS with basically the same overall harvesting power amounts to the same thing.

The only advantage of using two KERS instead of one (assuming the same overall power) may be weight distribution and packaging, but then again it all depends which engine is being used at the back. With their heavy diesel engine, Audi have rightly opted for the sole reasonable solution available to them, namely putting one "big" and powerful MGU at the front (without apparently compromising packaging at the front). Toyota have greater freedom in that respect thanks to their comparatively lighter engine, and have rightly chosen to distribute the weight by using two KERS.

For all braking events where the brake torque request (i.e amount the driver wants to brake) is not generating 350kw at the front axle, there is nothing Audi can do about it. They will harvest at a rate less than 350kw.

Now lets look at the Toyota. Lets pretend they have 250Kw peak KERS on the front and 118kW peak KERs on the rear (sum = 368). Say we have a braking event (change from V1 to V2) where the driver brake pedal input dictates that the Audi front axle can only harvest at a rate of 200kW. LMPs are similar weight/cornering speed/brake bias so I will assume that the Toyota would require the same braking event for the same corner on the track. This should mean that the toyota is harvesting 200Kw on the front axle (identical to the Audi) AND xxKW at the rear (xx = some function of brake brake bias). So they have recovered MORE energy for the same braking event as the Audi. Audi just throwing away energy at the rear axle as heat anytime they are harvesting under 350kW on the front axle.

I don't know what 350Kw at the front axle is equivalent to in deceleration (i.e whether that's at MAX braking, or that they can achieve it quite easily every time) but regardless, there IS a functional difference that will play itself out given the right sequence of braking events over a lap.

Toyota is 8MJ so it's even more important that they recover from both axles. Maybe Audi just can't do it because of the diesel engine weight already effecting weight bias negatively.

[MyNameIsNigel]

That makes sense. Thanks

[Articus]

If brake-by-wire is very advanced on the Audi, perhaps they are able to turn off the rear mechanical brakes completely in the light braking events. This will atleast allow them maximum KE recovery for the front axle when it is under 350kW.
Drivers may not like this however.

[Artur]

I gotta say that my understanding is the same as TF110 regarding this debate.

Afterall, what is a KERS, or, the Kinectic Energy Recovery System? Isn't it recovering the energy from the braking power during the time of the whole braking period?

If you only have one KERS, then you're only recovering the power from one axle. As you said, MyNameIsNigel, Energy = Power * Time and, during the braking time, it's better to recover the braking power from both the axles, isn't it?

[JoestForEver]

Suppose two cars are approaching a corner at the same speed. The amount of kinetic energy ( e=1/2 *mass* square of velocity) is a given. Therefore, as long as you have ERS of the same power, it should take you the same time to harvest it.(kinetic → electric) As the recovery process is the braking process, the same time taken to harness energy is exactly the same time you are using to brake. So I sort of believe that as long as they are running with similar KERS power. Front axle and both axle should just achieve similar result.

Could be wrong though. Totally relying on my physics knowledge back in high school.

Sent from my SM-G9250 using Tapatalk

[Ramius]

Joest, what you said would be true if the Toyota had recovery on both axles and the Audi was a one axle car. Because the energies of both cars are the same at a given speed and both front and rear brakes are used to slow down a car... in order for your example to be true, the Toyota would need to apply a certain braking force to BOTH axles while the Audi applies twice that braking force to only ONE of the axles. (Example: x = some stopping force; Toyota: x to front, x to rear; Audi: 2x to front, 0 to rear)

So, in that situation, yeah, it'd be the same amount of energy recovered between the Toyota and the Audi. However, in real life, both front and rear axles are/need to be braked, so the Audi would be scrubbing off *some* energy with its mechanical brakes in the rear. This is where the Toyota would be recovering more energy, because the Audi cannot only be slowing itself down with the front axle.

So, the Audi can recover up to 360kw F while the Toyota can recover (for example) 200kw F and 168kw R. In an ideal example, if both cars apply the same amount of force to slow from one velocity to another, the brake bias might call for force x to front and force (x*.5) to the rear. (stronger braking in the front, as usual) The Toyota would recover 1.5x while the Audi's situation in the front would be the same, but the (x*.5) for the rear is irrecoverable.

Exaggerated/simplified example: If x = 4, the Toyota would've recovered 4 + (4*.5) = 6 units while the Audi would have recovered only 4 units of energy.

This confused me a bit as well in the beginning as well, but the key lies in the fact that both axles are *needed* to brake. I hope I was able to explain it!

Originally Posted by JoestForEver

Suppose two cars are approaching a corner at the same speed. The amount of kinetic energy ( e=1/2 *mass* square of velocity) is a given. Therefore, as long as you have ERS of the same power, it should take you the same time to harvest it.(kinetic → electric) As the recovery process is the braking process, the same time taken to harness energy is exactly the same time you are using to brake. So I sort of believe that as long as they are running with similar KERS power. Front axle and both axle should just achieve similar result.

Could be wrong though. Totally relying on my physics knowledge back in high school.

Sent from my SM-G9250 using Tapatalk

[Artur]

Well, I see that pretty much everbody is expecting Porsche to have the upper hand on the dry. Idk, I still trust more on R18's superior aero but Lotterer and DiGrassi comments does kind of indicate to a Porsche win, tomorrow.

It will be interesting to look at the results of tomorrow.

[GasperG]

I look at it this way, if max braking power is in order of 1000 kW, then it doesn't make a lot of diference if you are using 350 kW regen on one axle or distributed over two axles.

[Adam43]

The ERS isn't good enough to give you the full stopping power on its own. Disc brakes are still better at actually slowing the car down.

Originally Posted by Artur

It will be interesting to look at the results of tomorrow.

That's the spirit

[Akrapovic]

Originally Posted by Artur

It will be interesting to look at the results of tomorrow.

It'll be even more interesting watching it. Which you will be, even if you say you won't. See you in a few hours for the race.

[TzeiTzei]

This is for F1, but might give some figures for braking power.

[MyNameIsNigel]

Originally Posted by TzeiTzei

This is for F1, but might give some figures for braking power.

Very interesting piece of information. Thanks for sharing. I would love to see Brembo share this type of data for LMP1 also.

[Articus]

^That's a great chart. If that chart was consistent with WEC braking power, then it shows that front vs dual axle KERS is not so siginificant for most corners at silverstone (what Gasper G suggested) except for the one braking event at 278kw.

You would deduce that due to braking bias. Audi will harvest at some fraction of 278Kw on the front axle while Toyota could potentially collect at 278Kw due to having both front and rear axle.