Mercedes Power Unit Hardware & Software

All that has to do with the power train, gearbox, clutch, fuels and lubricants, etc. Generally the mechanical side of Formula One.
roon
412
Joined: 17 Dec 2016, 19:04

Re: Mercedes Power Unit

Post

Looking at how small the radiator exits are on the W08, I began to wonder if some of the radiator rejection was being routed through the exhaust pipes. The only way to legally do this would be to incorporate a heat-exhanger between the air intake/compressor and the turbine. How to do this?

Design the compressor to have two flow paths. One pulls air in for the normal operation of the engine. Another pulls in air from the downstream side of a radiator, injesting the heated air exiting it. This is then is channeled into the exhaust prior to the turbine, or into one or both of the wastegate pipes.

If dumped into the wastegate pipes, there would be less of an issue with working against exhaust backpressure—isolation from the main exhaust stream. Although this sort of emission from the power unit may not qualify as an "exhaust gas" per 5.8.2.

If dumped into the manifold or turbine, some type of checkvalve would be needed. The wasteheat flow would entrain during the pressure drops between exhaust pulses. Unless the compressor is set up to pressurize the charge air equal to or greater than the peak exhaust manifold pressure. Compressor overcharging would allow constant charge air injection into the exhaust manifold, either for the purposes of this radiator-circuit I'm proposing or to:

•play some role in the "vortex exhaust rumor" as originally proposed here: http://www.f1technical.net/forum/viewto ... 4&p=671398

•increase the volume of gas flowing in the exhaust manifold. This would be internal, integral heat exhchange within the exhaust pipes, minimizing radiative loss by entraining heat into a gas flow which can be harnessed by the turbine. Perhaps this causes a loss of blowdown harnessing, but with a goal of delivering more heat & steady pressure to the turbine. I don't mean to propose a perpetual-motion machine here, so correct me if this is way off.

The compressor could have a type of dual-scroll feature, to achieve the divided flow paths, without contravening the multi-stage compressor disallowance. Such a feature would prevent ingesting radiator heat into the engine-intake plenum & intercooler circuit.

The goal for this would be smaller radiator inlets and outlets, as well as cooling airflow at zero vehicle speed, and possibly a greater volume of heated air delivered to the turbine.

User avatar
PlatinumZealot
550
Joined: 12 Jun 2008, 03:45

Re: Mercedes Power Unit

Post

Not sure if by-passing the engine is allowed though.

And dumping cold air into the turbo is not a good idea.
Also..
Thermodynamically this is actually a waste of energy!

You use exhaust gas to compress air at a given efficiency of near 64%.. Then you plan to dump the relativelycold air into the turbine?

So there is is no gain there. Actually huge losses.. The only way you could gain something is if you were boundary cooling a given surface.... But this is not needed for a car turbo. Temps are not that hot as power generating gas turbines.
🖐️✌️☝️👀👌✍️🐎🏆🙏

hurril
54
Joined: 07 Oct 2014, 13:02

Re: Mercedes Power Unit

Post

If the exhaust system produces less of a heat load because more of it goes out the back _and_ their contribution needed a considerable amount of air to transport, then maybe that is a reason. Or they take in more air in the top scoop; if the air is cooler there then the effect of that would be a better cooling effect.

roon
412
Joined: 17 Dec 2016, 19:04

Re: Mercedes Power Unit

Post

PlatinumZealot wrote:Not sure if by-passing the engine is allowed though.

And dumping cold air into the turbo is not a good idea.
Also..
Thermodynamically this is actually a waste of energy!

You use exhaust gas to compress air at a given efficiency of near 64%.. Then you plan to dump the relativelycold air into the turbine?

So there is is no gain there. Actually huge losses.. The only way you could gain something is if you were boundary cooling a given surface.... But this is not needed for a car turbo. Temps are not that hot as power generating gas turbines.
Yeah, an exhaust gas chiller pre-turbine does sound like a bad idea now that you mention it. 8) On one hand, the amount of gas passing through the turbine would be greater, but on the other, said gas would be colder & lower pressure depending on how the two streams are combined. Mainly I'm wondering if an aerodynamic benefit could be had via smaller radiator ducting (by adding a heat exchanger circuit parallel to the ICE) , and if playing around with bleed/bypass air in the exhaust could offer some benefit. But if it absorbs too much exhaust heat pre-turbine, then...

User avatar
ringo
225
Joined: 29 Mar 2009, 10:57

Re: Mercedes Power Unit

Post

dren wrote:
noname wrote:
ringo wrote:I think most of the MGUH if not all are clutched.
3 MGUs are not clutched. Maybe even 4, I have not seen details of the 4th.
Clutching would just add more mass. As reliant as these PUs are on the MGUH, I don't see much need for clutching. Eliminating the field in the generator would have a similar effect if it was wanted.
I did not say geared, I was referring specifically to having a simple clutch. Also what evidence exists on whether the MGUH are clutched or not?
For Sure!!

User avatar
ringo
225
Joined: 29 Mar 2009, 10:57

Re: Mercedes Power Unit

Post

glenntws wrote:Hey Guys,

after creating a account in this forum to take part in the discussion of the Honda PU and reading about a vortex exhaust System, I started looking here for some ideas and found a good idea. That's why I decided, that I could maybe help you a bit with some ideas or simulations.

Please notice that I haven't studied all that (still going to high school) so I can't be 100% sure about my statements and calculations, but I'm still pretty confident about that :D

Ok, so what did I do? I started of with two pipes. One clear pipe with a inner diameter of 40mm and one with the Special shaped internal part (inner diameter also 40mm). Both pipes are 520mm long, have a wall thickness of 2,5mm and both are enclosed in a air volume.

I then simulated both pipes with the same variables. The outer air volume had a in-temp of 100°C and a velocity of 50m/s. The inner (exhaust) volume had a in-temp of 1000° , a pressure of 5bar absolute and a velocity of 100m/s.

While I won't show you screenshots of the normal exhaust simulation (useless, it's just a simple flow in one direction), I can show you some details about the vortex-style pipe.

http://fs5.directupload.net/images/170222/78hlcdrb.png
Here you can see how the heat get's trapped in the center. The vortices indeed are able to generate some kind of heat shield.
It's fascinating that these turbulent motions also make up for a barrier between the "pins" that look into the center and the exhaust gas.

http://fs5.directupload.net/images/170222/dtbf9wio.png
Here I also enabled some vector-arrows to show, how the flow looks like in these little chambers. You can see good, how there are building up little circles of flow, generating the "heat shield". Interesting is, that the vortices have a different shape for every chamber, maybe the flow that went out of one chamber directly get's into the next one and creates some different kind of motion. I don't know if I did the Simulation too short (only did 400 interations, the divergence still was pretty high) but I'm not able to do these big simulations with my current PC in a acceptable time window :D


The most important thing however is: Did we save heat energy in this process??? And, according to Autodesk CFD, it indeed does. The heat energy transfer on the normal pipe was 28767,5 watts. The energy Transfer on the vortex-shaped pipe was at only 18632,8 watts!!! That's a plus of 54,4%! And i think we all now what could be done with a extra of 10 Kilowatts > more MGU-H recovery potential.

The only negative effect is the flow resistance. In the vortex style pipe, it's 2,24 times higher... But nevertheless, I am more than sure that this is the right way to go.

The only thing that's important is the shape of these vortex inducing elements. And I'm pretty sure the ones I used weren't nearly as optimal as possible (only did one version, the Simulation is sooooo time consuming....).

Anyway, I think we really found something that MB and the others could use :)

Just remember where the idea came from ok kid? :wink:
Ole "CFD eyes" ringo 8)
Yes your model is basically the concept behind the thought process of what i suggested earlier.
There is reduced contact with the surface of the pipe walls. The main drawback is the cost and difficulty to construct the pipe and also entrapment of moisture.
This pipe could be made by hydroforming techniques however.

What you can try to do now with the pipe is change the number of ridges, and also vary the pulses of gas and see what results you may find.
For Sure!!

User avatar
ringo
225
Joined: 29 Mar 2009, 10:57

Re: Mercedes Power Unit

Post

As for the engine power, i don't think we should get too excited about what andy cowel is saying.
He chose his words wisely when he said they can get 50% of the energy from the fuel with combustion, and he is right.
This is not purely from piston to crank. It also includes the MGUH, as exhuast gases going throuh the turbine are considered in this case to be useful combustion energy for the MGUH.
So i think 831 hp is actually reasonable, maybe 60 or so HP from that is from the MGUH.
For Sure!!

SamJW
1
Joined: 09 Feb 2015, 22:31

Re: Mercedes Power Unit

Post

ringo wrote:As for the engine power, i don't think we should get too excited about what andy cowel is saying.
He chose his words wisely when he said they can get 50% of the energy from the fuel with combustion, and he is right.
This is not purely from piston to crank. It also includes the MGUH, as exhuast gases going throuh the turbine are considered in this case to be useful combustion energy for the MGUH.
So i think 831 hp is actually reasonable, maybe 60 or so HP from that is from the MGUH.
A close friend of mine who works at Mercedes AMG Petronas said that they are already producing 1000bhp and were close to it last year but since the regulations have opened up, it has allowed them to accelerate the program to achieve this!!

PhillipM
385
Joined: 16 May 2011, 15:18
Location: Over the road from Boothy...

Re: Mercedes Power Unit

Post

It's amazing how many close friends people have that tell them exact power figures for Mercs, how many miles Honda did before breaking on the dyno, and what commercial car liveries will be before the cars launch, just so they can tell people on this site.
Merc must be struggling though, because those people have been saying they've got 1000bhp for 3 years, terrible development pace! :wink:

User avatar
ringo
225
Joined: 29 Mar 2009, 10:57

Re: Mercedes Power Unit

Post

They seem to know more than Andy Cowell too, as he has admitted that the level has not been reached as yet, but he thinks it will be in the future.
For Sure!!

User avatar
FrukostScones
162
Joined: 25 May 2010, 17:41
Location: European Union

Re: Mercedes Power Unit

Post

ringo wrote:They seem to know more than Andy Cowell too, as he has admitted that the level has not been reached as yet, but he thinks it will be in the future.
I think he is just well trained in F1 politics.

why would he admit such numbers? there are mainly negativ effects in doing so.

admitting over 1000HP would increase the risk of getting development frozen. for competition reasons , safety reasons. would mean.. getting a power cap ,RB lobby winning the engines war on the "green table", kicking the Hybrid in the bin, making F1 great again , new spec PU's, earlier than 2021; or then in 2021 new spec spec "for the show NAE's" every backyard garage could built. Doh! But the noize! ...

https://www.gptoday.com/details/view/59 ... ranz_Tost/
Finishing races is important, but racing is more important.

User avatar
ringo
225
Joined: 29 Mar 2009, 10:57

Re: Mercedes Power Unit

Post

That is just speculation. The regs have already limited flow rate and engine displacement; the engine makes can make as much power as they wish once they are within the rules, so i don't see the FIA being blindsided by how much power mercedes can really make. Every engine maker knows from the start what the maximum is from perfect combustion, and perfect MGUH recovery.
The V 10 engines were nearer to the 1000hp mark, and there was no big backlash concerning engine power.
For Sure!!

User avatar
FrukostScones
162
Joined: 25 May 2010, 17:41
Location: European Union

Re: Mercedes Power Unit

Post

ringo wrote:That is just speculation. The regs have already limited flow rate and engine displacement; the engine makes can make as much power as they wish once they are within the rules, so i don't see the FIA being blindsided by how much power mercedes can really make. Every engine maker knows from the start what the maximum is from perfect combustion, and perfect MGUH recovery.
The V 10 engines were nearer to the 1000hp mark, and there was no big backlash concerning engine power.
no backlash? like taking off 2 cylinders? and myriads of cost and "powercontaining" spec regs. .
Finishing races is important, but racing is more important.

User avatar
ringo
225
Joined: 29 Mar 2009, 10:57

Re: Mercedes Power Unit

Post

hahah, i don't even know why they did all that. Maybe more to do with cost cutting and blatant rate of engine changes.
What i should say is that the HP number is insignificant, it's more what the gap looks like out on track, and also if there are any safety concerns for the amount of power being produced; ie the car is hard to control.
If mercedes has 850hp and the rest only had 750hp, then you may see some backlash. But as it stands they're all within 50 peak horsepower.
For Sure!!

gruntguru
563
Joined: 21 Feb 2009, 07:43

Re: Mercedes Power Unit

Post

roon wrote:Looking at how small the radiator exits are on the W08, I began to wonder if some of the radiator rejection was being routed through the exhaust pipes.
Heat rejection at the radiator (for current F1) is undoubtedly much lower than any other race car. Previously you would expect about 33% of the fuel energy to end up as heat from the radiators. The Mercedes is converting perhaps 55% of the fuel energy to useful power leaving 45% to be rejected to the exhaust and the radiator. Heat flow to the exhaust is considerable despite the energy extracted by the turbine. The tailpipe gas is relatively cool, but the massflow is very high due to the lean mixture. Massflow is probably about double what you would expect previously for an 850 hp engine so there is a lot of heat coming out of that exhaust.
Last edited by gruntguru on 27 Feb 2017, 06:27, edited 1 time in total.
je suis charlie

Post Reply