God help us if things like this ever wind up in our road cars.
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God help us if things like this ever wind up in our road cars.
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I don't think so. The Merc's split turbo design places the compressor at the front end of the engine, but here, we see the air inlet is at the back end of the engine which I'm guessing is where the compressor is. The turbo is not installed in this picture, it should be behind the air inlet as seen in pictures from earlier race.Originally Posted by gjoko-mkd
The advantage of split design is to allow the MGU be embedded into the V shape of the engine and not sit above. There were rumors posted earlier that Merc developed their own MGU in-house, which is probably what allow them to be able to embed their MGU better than us. If we can't pack our MGU into the V shape anyway, then I guess it doesn't give as much advantage even if we did utilize split turbo design.
Last edited by Hornet; 1st May 2014 at 05:23.
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Apparently, it is situated lower because of this which helps lower cars CG and moves weight forward for better F/R balance. The gains for the PU are shorter piping distance between compressor side of turbo & intercooler which lessens turbo lag & the separation from the exhaust side eliminates any heat transfer compared to a single housing. This means the intake air stays cooler (relatively), so you can reduce the intercooler size, too.
That lessening of both the turbo lag & cooling requirement are probably what are giving them the HP advantage. What I've read is they can put more of the power recovered by MGU-H back thru the MGU-K to actually power the wheels rather than using it to spin up the turbo, so you get more power with less fuel consumption.
Don't know that I've got it completely worked out in my mind or if the guys writing the articles even know exactly what THEY are talking about, but my eyes can sure see the difference between the cars.
Forza Ferrari !
"You need great passion, because everything you do with great pleasure, you do well." - Juan Manuel Fangio
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I think this is split situation with the turbo and compressor at Ferrari and Mercedes
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Lets do simple math here.
Following is of course a blatant exaggeration, but lets see what numbers say in worst case scenario.
Say that the turbo core is 10 cm in diameter. Lets also assume that the core is being made from homogeneous metal with highest thermal conductivity.
Of course, this is unrealistic, as the real core would have ball/journal bearings, have shaft and would be lubricated by oil/water. In other words, it will not be a slab of metal.
Al has conductivity(k) of 144, Fe 46; Inconel 9; Mg 92; Mo 81; Cu 220; Ag 235; N 0.0234;
Now the Fourier's law says that heat transferred is k*A*dT/s. Where k - conductivity, A is heat transfer area, dT - temp difference, and s is material thickness.
Say, they used pure silver, as their choice of material for core, which conducts more heat than almost any other metal. Okay, that would make = 235*(3.14*0.1*0.1)*1100/0.1 == ~82kW of heat transfer. I assumed the turbine gets to 1500 C and that compressor would get to 400 C.
We know that they use 100kg fuel per hour. Say they run engines lean. 18 A/F is pretty lean. This means the turbine will move 18*100kg of air per hour, 1800kg/h = 500g/s. Say also, that the compressor is the size of a bucket that holds 10L of water. This is a lot bigger figure than the actual compressor volume since you only have 1.6L engine powering that turbine, even though it spins up to 15kRPM. This is a size of a bucket (H=25cm,r=10cm,R=12.5cm). The surface area of such compressor would be ~2580cm^2.
Adiabatic compression of air generates heat. Say the compressor pressurizes intake air to 5bar.
Assume that air consists of pure nitrogen (75% of air at sea level is nitrogen).
We know that pV^u=constant; where u=adiabatic index. Nitrogen is diatomic gas and has u = 7/5.
The compressor will rise pressure to 5bar, that is 5 times. Solving p(Vol^7/5)=5p(comp.Vol^7/5) for comp.Vol we get the volume of compressed air to be ~3L.
From ideal gas equation pV/T=constant; we see that volume and temperature are inversely proportional, so volume being shrinked 3.3 times means temperature will raise 3.3 times. Now, if ambient temp was 30 C this means compressed air temp will be 100 C.
Now if you do calculations with heat transfer equation, on laminar(totally inappropriate as the air speeds will be really fast and turbulent, not laminar at all) surface with the numbers above, you get around 10kW heat transfer; that means you could see that the charge air temp will rise from 100 C to ~150 C.
This 50% rise of pre intercooled air is nothing extra-ordinary actually. A good intercooler will be able to dissipate much of this heat easily.
Also, keep in mind that this is worst case scenario. All the numbers are exasperated to extremes. Turbo temp will never be 1500 C(much closer to 600 C), compressor temps will never be 400 C. A turbo compressor housing of a volume of a 10L bucket of dimensions (H=25cm,r=10cm,R=12.5cm) ? Yeah, sure. The turbo core made from a slab of pure silver ?! The core never gets over 300 degrees C because it is lubricated by engine oil. Oil burns at temps 240 degrees. It burns. Like for real. So the real temps are in fact much lower. Those were pretty crazy assumptions. But even keeping by them you can see that adiabatic effect is the dominant. Keep in mind that Al melts at 600 C. And iron will melt too at 1500. Also, current engines are not running 5 bar boost pressures.
So, in real life the effect of heat transfer will be much much less than 50%. And after the IC stage the extra temperature from heat transfer will be barely noticable. I believe that the this heat transfer benefit that split turbo system brings over conventional turbo set up is grossly overestimated. If there are any efficiency benefits it is not in the heat transfer, which could be completely ignored and discarded. Besides, it has its own negatives, like the extra shaft material that only adds to inertia that combats the turbine that ads to transient throttle response...
So, yeah, my point is if it was so crucial to split the turbo and compressor and have them half a meter away, you would see such setups in real, commercial applications all day. Only that you don't. And renault, citroen and other as well as ferrari would not miss it. Enough with this hysteria.
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You forget that Turbo energises exhaust gas not ambient air so the temps are much higher like 1050 C
http://www.google.co.uk/url?sa=t&rct...65636070,d.ZGU
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You forget that it is in fact exhaust gas that spins("energises") the turbo, not the other way around. In any case, I can not see your argument, if there is one, refuting anything. The very fact that you lumped "Turbo" and ambient air temps together suggests that there is something funny going on with your concept of "Turbo". lol
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besides, it is a well know fact that honda turbo engines were cooling 150+ charged air to just about 40C, back in the days no problems...so, split turbo system. Heat transfer. Whaaa Whaaa
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Interesting analysis Hunkelberg.
I noticed that when you talk about ideal gas and different volumes you use Celsius instead of Kelvin.
30 degrees Celsius equals 300 kelvin. 3.3 Times volume difference gives 1000 kelvin that equals 730 Celsius.
Can you put that into account in your calculations?
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You obviously didn't look at the link... if you did then you would of seen a picture of a turbo glowing red from the heat and a techincal description of the engineering difficulty caused by compressed exhaust gasses reaching 1050 C
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The split turbo design limits heat transfer from the 'cold' and 'hot' parts. Heat radiation is transmitted by electromagnetic waves in the infrared part of the light spectrum. This transfer of heat is a function of the distance squared. So if the 'cold part' is twice as far away from the 'hot part' in the merc design compared to the Ferrari one the heat transfer is reduced by 2 squared i.e. a 4 fold reduction. Simples.
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I think the heat issue from the split turbo has been debunked. What it has allowed for is a lower more central location of the gearbox leading to a cleaner coke bottle and better balance.
Forza Ferrari!!
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The compressor position is not only important for the thermal side of things. Bringing it closer to the driver reduces the amount of tubing required from it to the intercooler. That then reduces the total volume of the compressed air part of the engine which makes it easier to keep pressurized. Because it is easier to keep pressurized, more stored electrical energy can be given to the crankshaft. You see, teams are allowed to use stored electrical energy to spin the compressor to reduce lag (turbo compounding). If you don't need to do this, or you can do it to a lessor degree, you have more electrical energy to power the crankshaft.
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Did not want to quote the whole post from above but 'if split turbo was so good it would be used commercially'. I disagree on the basis F1 often has strange innovations to get round the very tight rules and many are not applicable to commercial use. For example the f duct or ebd. The reason is commercial vehicles do not have such restrictive regulations and turbos can be cooled in more efficient ways in commercial use.
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Someday my sloppines will get me in trouble.
Yes, Erikejw, I was wrongly lured by my intuition of proportions and was getting anxious to get the calculations done :P
So, here goes :
The heat transfer rate from the compressor to the charged air will be less, but absolute temperature will be a bit higher. But nothing dramatic and in any case the rise in temperature from adiabatic compression of air will dominate the heat transfer from compressor housing to the charged air. The difference would be marginal for a proper intercooler. Also keep in mind they are not running 5bar boost. 3bar max, maybe. So...
Really ? Seriously, since it is "simples", please tell me, how much of the radiation is discarded by a heatshield that is what, about 0.5cm thick and filled with, say some nice asbestos :) ? 99.9% ? or 99.999% ? Not much left of it. "Simples".
There. I am done fantasizing :)
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What I would like to remind is that to produce more power from combustion one needs more air and fuel in the same engine. Wack the boost add fuel done. Merc have something clever going on with their MGH-K and MGH-U units since they consume less fuel and yet are faster on straights(peak power) as well as around the track(average power) around the clock.
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And for some reason, only works team can have the advantage of its PU. I wonder, what will happen if you flash Merc's ecu firmware to FI's or Williams'.
Religion? Ferrari!
Williams has the highest top speeds race by race. So this theory is wrong.
IF YOU CAN DREAM IT, YOU CAN DO IT - ENZO FERRARI
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Yep, the Merc's car is great in many areas, not just the power unit, which is why they are dominant. Other Merc's power car have the same advantageous power unit, but they are bad in other areas.
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Ha....
top speed...you should know better that top speed is not the fastest way around the track. Also, each track has its own power profile. On some tracks top speed is important on others not so much. You know that top speed figure is of no help when you are exiting the corner and you have no torque or abundance of it. You also know that top speed is only indirectly related to engine power. If you have high top speed it does not necessarily follow that you have top power. Perhaps you have zero DF and no drag and thus can reach high speed. But what happens in twisty bits ?
In simplistic terms top speed is not crucial. For that matter top power is not that important as well. What is much more important is "area under the curve". How you augment it with elector motor, how you harvest, budget and adapt it to driver's liking.
In any case, completely disregarding the adaptations to each specific track teams do, they have to tune transients, harvesting efficiency, harvesting during breaking, boost build up, energy flow from H to K directly, avoiding going through battery which is mandated and limited, clutching H or disengaging it...budgeting fuel to race stages, etc. Whatever man, top power output is important, but besides it, there are a lot more things involved....
If you can disprove or refute things this easy then... I dunno, you have oversimplistic concept of what is going on in a PU.
I better stop here.
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Mercedes F1 W05 - intercooler advantage23 Apr 2014
Another 'secret weapon' that the all-conquering 2014 Mercedes appears to have is an intercooler inserted into the top area of the chassis, circled here in yellow. This intercooler cools the turbocharged airflow that is going into the engine. As illustrated by the blue arrows, airflow from underneath...»
Mercedes 2014 power unit - side view17 Apr 2014
If we compare the component installations on Mercedes' and Renault's power units, it is easy to see how different their concepts are. One of the fundamental requirements of a turbocharged engine is to reduce the temperature of the charge air (the blue part of the turbo) - the cooler this charge air...»
Renault 2014 power unit - side view17 Apr 2014
If we compare the component installations on Renault's and Mercedes' power units, it is easy to see how different their concepts are. One of the fundamental requirements of a turbocharged engine is to reduce the temperature of the charge air (the blue part of the turbo) - the cooler this charge air...»
^^^Above Info From Official Formula 1 Website ^^^
It also observes the MGU-H could be connected w/one-way clutches to the 2 halves of the turbo, so any energy being fed back in to eliminate turbo-lag would only have to drive the charge air side, leaving additional energy to go to MGU-K, another small but not insignificant gain!
Such a simple idea to give a big advantage.
Also note, no comparisons are made to the Ferrari power unit, at least we may be good at keeping secrets!
"You need great passion, because everything you do with great pleasure, you do well." - Juan Manuel Fangio
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But the higher top speed IS an indicator of more power coming from the entire PU, which I think is the point Kyss4k was making.
All the things you say are valid, but the fact is Williams is not just going out in every race with a low DF setup just so they can set the top speed.
"You need great passion, because everything you do with great pleasure, you do well." - Juan Manuel Fangio
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FORZA!!!!!!!!!!!!!!!
Just wait until Monza, or some other track, where top speed really counts. I bet Mercedes would go faster than Williams if it would be all about top speed..
Religion? Ferrari!
I am just trying to stop that nonsense about Mercedes giving an underperforming engines to other teams. Williams is fastest of eevryone on top speeds and they have a solid downforce (as they were one of the faster teams ,with bad luck, on every track), so their engine has to be really strong. You just want to create some sensation.
IF YOU CAN DREAM IT, YOU CAN DO IT - ENZO FERRARI
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Not sure if this has being pasted already or not
Mercedes advantage according to Piola and The Judge confirmed by Lowe I think:
http://thejudge13.com/
Paddy Lowe met up with Giorgio Piola before the Chinese Grand Prix and congratulated him on his discovery of one the secrets that has provided Mercedes with a dominant car.
“Giorgio, you have uncovered one of our secrets but I’d like you to see the car at the end of the season so you can appreciate the other innovations we have designed which deserve as much credit for the car’s performance.”
Last year, Ross Brawn had spoken before his departure that the initial design route for the Mercedes W05 was too conservative and a decision was made after the summer break to chase very specific design goals with the new car.
As has been reported in recent weeks, the turbo and a smaller compressor are located at either end of the engine with the MGU-H mounted in the middle and connected by a shaft. The compressor is situated nearest the bulkhead whilst the turbo is located close to the gearbox. This design route was chosen because in its original spec – the hot air was heating the air coming through the air intake that was feeding the engine.
The heat exchanger for the engine has also been housed within the chassis with cooling ducts designed into the chassis. The Mercedes team also chose to use a very short exhaust which loses about 15bhp from the optimum; but the team felt the benefits of more efficient cooling allied to a less aerodynamic compromise out-weighed the loss of this power.
Aldo Costa and his team have thus been able to reduce the frontal area of the car and the placement of the relevant parts have allowed the team to reduce their dependency on longer cables, wires and pipework, which in turn has brought the car closer to the 692kg weight limit.
Mercedes have also chosen to run a larger turbo than the opposition and its reduction of turbo lag means less power needs to be harvested from the ERS to keep the turbine spooled off throttle. The surplus energy is transferred to MGU-K which delivers instant energy to the power train whilst increasing economy.
The significance of this design is that although the MGU-K is limited to recovering only 2MJ from the braking system, the MGU-H is unlimited and the Mercedes can therefore recover all it’s power levels in the regulated 36 seconds per lap that would require the other teams 50 seconds to achieve. In essence Mercedes do not have to waste a lap replenishing the full amount of electrical charge as their competition currently has to.
Ferrari and Renault are aware of this ‘secret’ installation but due to the FIA’s homologation freeze of February 28th, they are powerless to do anything this year. In a year of massive change, with limited testing both before and during the season and with the biggest change in technology in a generation, it would have made more sense to allow the manufacturers a twelve month period to get their technology up to requirements.
There are arguments for and against testing but in a similar manner to last year’s disgraceful witch-hunt of Pirelli, something has to change. Why would any company want to get involved in F1 when the supposed benefit to road car development is hampered by restrictive rules that do not allow progress.
Cruising Mode
Sauber will have a PU software update for Spain.
http://www.autosport.com/news/report.php/id/113729
Is there any info if their updated software is from Ferrari or Sauber themselves.
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Banned
well, you just can't - there is not enough data to rule that out. They might give them same hardware, sure, that would be only fair. Perhaps Mercedes know how to push right buttons. In any case, it is safe to assume they know better how to run their engine, especially on their own car since the engine and the car were designed one for another. And there is no reason to believe that their customers know more than works team, regarding the PU.
So, yeah, I am just wondering, what happens if Merc give FI their ECU blob for couple of races :)
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I think abbottcostello posted several links which agree (and go into more detail) with my previous post.
But u don't read links soo....
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For instance, having watched onboard videos posted above and some others, on the long back-straight in shanghai, Merc did accelerate from 300 to 330 in 6 seconds, while FI could not reach 330 (it did 328) in same 6 seconds, even with the aid of DRS activated. What does this tell ? Actually nothing. Only that this bit ads supports to the thesis that somehow merc get more from same power unit.
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