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2 Mar 2012, 00:55 (Ref:3033830) | #2751 | |
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I'm still wondering how the balance is going to work, how much smaller will the fuel tanks be on hybrids? Are the ACO and/or the FIA going to try and balance it so that a petrol, diesel and the equivalent hybrid combination will all be good for a single stint (like 45 minutes to there abouts) at la Sarthe?
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2 Mar 2012, 06:50 (Ref:3033881) | #2752 | ||
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But a good question would be if and how this situation affects Audi's open collaboration between the cars.
You suddenly have 2 drivers who is on a need know basis, and that will none the less demand more resources out of Audi. |
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Hvil i Fred Allan. (Rest in Peace Allan) |
2 Mar 2012, 07:38 (Ref:3033895) | #2753 | ||
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I also have the impression that regular Audi drivers sign an exclusive (one or multiple year) contract and that Audi wants to give them a meaningful program. The drivers that do not do the full WEC season get alternative programs: Jarvis has GT1 with WRT, Bonanomi has Blancpain with WRT, Rockenfeller has DTM, ... This is a special year for Audi because they are running 4 cars and hence they need 12 drivers. Next year, once the reliability and performance of the hybrid system has been proven, they can return to their usual 3 Le Mans entries. |
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2 Mar 2012, 09:20 (Ref:3033923) | #2754 | ||
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have just looked at a speed trace of a fast LMP900 car from a few years ago, the lap time was 3min 30 sec and the lowest speeds are:
Dunlop esses: 100kph Mulsanne corner: 77kph Arnage: 75kph I guess the track has changed a bit since then, but its a reasonable indication still...........looking at the whole speed trend of the the full lap I'd say the time spent in these corners is absolutley minimal, so although the 120Kph activation speeds sounds like a limitation, in reality I dont think it is.......hmmm - interesting!! Also there is 34 seconds of combined braking over a 3.30 lap time in which you can use fill the charging system........the rest is full throttle so 16% braking.........so using 2 x 75Kw generators and 34 seconds harvest time, Audi could store 150,000 x 34 = 5.1MJ over 1 lap.......divide that by the 10 main corners at LeMans and hey presto 0.51MJ between corners......simples! There is no way the Williams system will be 100% efficient.......the race engine article states 70% system efficiency for the Williams flywheel system in the Porsche GT car.........my point being that I dont think Audi will be in a position to start applying 1MJ bursts between corners like Toyota say they could. |
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2 Mar 2012, 10:14 (Ref:3033948) | #2755 | ||
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Thanks a lot for those numbers.
So you are saying that the e-tron quattro system can be used to improve traction as it can be activated in high speed corners (above 120 km/h)? I have a followup question. How long (minimum, average, maximum) do these braking moments take? According to the rules the braking must last more than 1 second. Quote:
With this limitation it seems desirable to make the capacity of the energy storage medium (battery, capacitors, flywheel, etc.) bigger than 500 kJ. In this case, more energy can be stored than necessary, if the braking takes longer than 5 seconds. This reserve energy can later be released after a braking zone that is shorter than 5 seconds. If Toyota can apply 1 MJ between braking zones, they need a bigger generator because they have to recover more than 10 MJ per lap with only 34 seconds of braking. The generator has to be 300 kW! Unless of course they count less than 10 KERS activations. In general, it will be though to harvest/release this 1 MJ on a track like Le Mans with limited braking. Last edited by gwyllion; 2 Mar 2012 at 10:36. |
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2 Mar 2012, 10:37 (Ref:3033954) | #2756 | |||
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Also as you quote, Toyota is not allowed to use more than 500kj between braking zones, so they will not be able to use all gathered energy. What intersting information we could get from that video of two cars trailing each other, is how long the different braking zones are. Because Audi believes they are long enough to gather 500kj per corner, and Toyota believes that its not, and need the carry "extra juice" from a previous corner. This is ofcourse based on the thought that Audi and Toyota wants to release 500kj everytime |
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2 Mar 2012, 10:42 (Ref:3033957) | #2757 | ||
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no problem.......looking at the info all the braking durations range from 1 second to 4.5 seconds.........consider that the data I have is a screen shot so I cannot manipulate it, there are 17 braking events in 1 lap, and 7 of those are what appear to be about 1 second light braking events, but if they are just over 1 second this then allows the KERS to be activated as per the rules, but they could be just under 1 second, shame I cant manipulate the data :-(
I think the more definitive limit will be the 2g requirement, but I dont have that data, but I think its fair to say that eliminates the 7 light braking events as the reason to activate KERS.......so lets say 10 activation points over 1 lap, but 17 generation points per lap, hence this probably keeps a small excess of stored energy once the 70% system efficiency and activation limits take effect........all starts to make sense now. |
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2 Mar 2012, 11:04 (Ref:3033965) | #2758 | |||
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Now I understand the comment from Wurz that the hybrid system from Peugeot was less powerful than Toyota's. The Peugeot 908 HYbrid4 only had one rear-axle 60 kW electric generator/motor. With that configuration they can only recover 2 MJ during 1 lap! |
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2 Mar 2012, 11:20 (Ref:3033972) | #2759 | |||
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Hvil i Fred Allan. (Rest in Peace Allan) |
2 Mar 2012, 11:21 (Ref:3033974) | #2760 | ||
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Now it makes sense why it hung around for several years but never got raced......it sounds like they needed to double up whatever it was, 120KW and 4MJ would have been more on the money......based on those numbers it would not be a match for the systems that Audi and Toyota have delivered.
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2 Mar 2012, 11:52 (Ref:3033986) | #2761 | ||
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Has Toyota officially released the specification of its hybrid system? The hybrid Supra had a 150 kW rear-axle motor/generator, so that is probably a good indication. |
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2 Mar 2012, 12:44 (Ref:3033998) | #2762 | ||
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agreed!.......nope, not a sniff of Toyotas KERS system details........although I think its fair to assume that their motor and storage systems are quite oversized for the current regs, as Toyota are boasting they could easily do 1MJ between brakig points.
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2 Mar 2012, 14:45 (Ref:3034031) | #2763 | ||
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To refresh my memory, I just read the RCE about the R18: http://be.zinio.com/reader.jsp?issue...&prev=sub&p=10
The base weight of the 2011 R18 was said to be 850 kg. That means that they had to cut weight by at least 30 kg for this year, in order to fit the hybrid system without going overweight. Last year's V6 TDI weighed about the same as the petrol V8 from the R8. Now according to Laurent Chauveau it weighs less than the R8 engine. In hindsight this is an interesting comment from Baretzky about the choice between V6 and V8. Quote:
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2 Mar 2012, 15:30 (Ref:3034039) | #2764 | ||
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2 Mar 2012, 15:37 (Ref:3034041) | #2765 | |||
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2 Mar 2012, 15:53 (Ref:3034044) | #2766 | ||
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Interesting!......heres another feature on ther Williams Hybrid Power website:
http://www.williamshybridpower.com/n...-by-audi-sport they state the flywheel will now spin to a maximum of 45,000rpm for Audi.......which is more than what they used to run the porsche system at (36,000rpm max).......so it would appear to be operating harder than before......when rated at 36,000rpm it could store up to 680KJ (0.68MJ) to be re-applied in a single event.......so the capacity of this thing is not massive, pro-rata that works out at 850KJ (0.85MJ) maximum storage capacity @ 45,000rpm |
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2 Mar 2012, 16:33 (Ref:3034053) | #2767 | ||
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Sorry to correct you, but rotational kinetic energy is quadratic proportional, not linear, to the rotation frequency. See http://en.wikipedia.org/wiki/Flywheel#Physics. If a flywheel stores 680 kJ at 36000 rpm (600 Hz), it has a moment of inertia of 0.0957 kg m^2. The same flywheel will store 1060 kJ at 45000 rpm (750 Hz). This calculation is based on the assumption that Audi is using exactly the same flywheel as Porsche, but just spinning it faster. However on the technical drawing the flywheel looks more compact. So the flywheel might have a bit smaller diameter and/or weigh less. BTW you got the 680 kJ from Race Engine magazine of August 2010. That number dates from the first hybrid 911. The 2011 version was more powerful: 2 x 75 kW instead of 2 x 60 kW electric motors. Anyway this guess work is nice, but we will probably never know unless Audi tells us. Last edited by gwyllion; 2 Mar 2012 at 16:51. Reason: I forgot a factor of 2π in my calculations |
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2 Mar 2012, 16:38 (Ref:3034057) | #2768 | ||
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I stand corrected!!!
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2 Mar 2012, 17:46 (Ref:3034077) | #2769 | ||
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I don't know what these threads would look like without gwyllion's supreme internet searching skills!
I've tried to find this question already, so apologies if it has already been answered, but I would appreciate an answer from anyone qualified to say. A wet Le Mans pretty much gaurantees and Audi win, right? Toyota seem to have issues getting the power down anyway, and there's few that do AWD like Audi. |
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2 Mar 2012, 18:05 (Ref:3034082) | #2770 | |
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2 Mar 2012, 19:31 (Ref:3034122) | #2772 | |||
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But yes i would believe that Audi is superior to Toyota in the wet. Simply on the basis that Toyota has zero experience in the wet with their new car. |
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Hvil i Fred Allan. (Rest in Peace Allan) |
2 Mar 2012, 19:32 (Ref:3034123) | #2773 | |||
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2 Mar 2012, 19:41 (Ref:3034127) | #2774 | ||
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Ermmmm, is that sarcasm?
I don't think I've ever been anywhere on this planet as wet as Le Mans in 2001 and 2007! Last edited by Gingers4Justice; 2 Mar 2012 at 20:02. |
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2 Mar 2012, 19:48 (Ref:3034132) | #2775 | ||
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