Mercedes Power Unit

All that has to do with the power train, gearbox, clutch, fuels and lubricants, etc. Generally the mechanical side of Formula One.
PlatinumZealot
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Re: Mercedes Power Unit

Post by PlatinumZealot » Tue Dec 05, 2017 12:20 am

We are not talking about the gas turbine as the prime mover any more so I don't want to confuse other posters..

But since you asked, if the turbine is the prime mover for small, quick response vehicle like and F1 car the fuel efficiency wont be pretty. F1 cars present extremely variable loads, and turbines don't like that. The blades will go through rapid heat cycling. Heavy load cycling also. The compression ratio is not speed independent as a piston engine. So you need to spin that up before you can even light it. KERS will take over here putting power to the wheels and spinning up the turbine, but by the time the turbine is up to speed (small turbines may take a few seconds) the driver is off the throttle again (I imagine Monaco), the turbine is signaled to slow down even before it did anything and that's fuel wasted.
You have to keep the turbine constantly near it's best operating range too. The combustor cans work best with a certain range of air flow - go out of that range and proper fuel mixing won't happen, and they will get hot.

There are a number of gas turbine motorcycles you can view on youtube. This one will gulp 32 litres of fuel in 30 minutes, at idle!
http://turbinebike.blogspot.com/2012/05 ... -this.html
Any MGUK assist will surely help, but still doesn't mask that a turbine engine is really designed for a steady load.
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roon
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Re: Mercedes Power Unit

Post by roon » Tue Dec 05, 2017 12:47 am

PlatinumZealot wrote:
Tue Dec 05, 2017 12:20 am
We are not talking about the gas turbine as the prime mover any more so I don't want to confuse other posters..

But since you asked, if the turbine is the prime mover for small, quick response vehicle like and F1 car the fuel efficiency wont be pretty. F1 cars present extremely variable loads, and turbines don't like that. The blades will go through rapid heat cycling. Heavy load cycling also. The compression ratio is not speed independent as a piston engine. So you need to spin that up before you can even light it. KERS will take over here putting power to the wheels and spinning up the turbine, but by the time the turbine is up to speed (small turbines may take a few seconds) the driver is off the throttle again (I imagine Monaco), the turbine is signaled to slow down even before it did anything and that's fuel wasted.
You have to keep the turbine constantly near it's best operating range too. The combustor cans work best with a certain range of air flow - go out of that range and proper fuel mixing won't happen, and they will get hot.

There are a number of gas turbine motorcycles you can view on youtube. This one will gulp 32 litres of fuel in 30 minutes, at idle!
http://turbinebike.blogspot.com/2012/05 ... -this.html
Any MGUK assist will surely help, but still doesn't mask that a turbine engine is really designed for a steady load.
Why do you think these limits could not be overcome through design changes?

Singabule
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Re: Mercedes Power Unit

Post by Singabule » Tue Dec 05, 2017 3:17 am

No, it is turbine characteristic, since WWII it is not changed at all.

FW17
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Re: Mercedes Power Unit

Post by FW17 » Tue Dec 05, 2017 4:07 am

PlatinumZealot wrote:
Mon Dec 04, 2017 7:17 pm

Ok. I see. It can work indeed. But it would be too close to formula E and the existing car engine manufacturers would be alienated. General electric, IHI, rolls royce, IHI and mitsubishi would be the new engine manaufacturers. Good bye Ferrari and the rest!

Hmm. Come to think of it, I had a similar idea back before 2014 engines came out. Forgot the thread.
Not necessarily; car manufacturers would still be only outsourcing the production if drive train.

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Re: Mercedes Power Unit

Post by FW17 » Tue Dec 05, 2017 4:15 am

While a turbine uses a axial compressor which is multistage, how will it stack up against a single stage centrifugal compressor?

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Re: Mercedes Power Unit

Post by FW17 » Tue Dec 05, 2017 4:23 am

dren wrote:
Mon Dec 04, 2017 7:37 pm
A combustion turbine's efficiency is under 50%. Why the shift? For a less complex set-up? You could do the same with a diesel yet still use the diesel for direct drive if you wanted.
While it is an assumption that cars would be battery operated, the same is less likely for commercial vehicles. At the same time diesel needs to be off the roads, a gasoline or kerosene operated range extender (a turbocharger + Jet combustion chamber+ MGU H + MGU K) combined with a battery pack would take its place.

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Re: Mercedes Power Unit

Post by Postmoe » Tue Dec 05, 2017 9:50 am

dren wrote:
Mon Dec 04, 2017 7:37 pm
A combustion turbine's efficiency is under 50%. Why the shift? For a less complex set-up? You could do the same with a diesel yet still use the diesel for direct drive if you wanted.
I think it is clear: because pit stop would be fun with engineers being sucked by the turbines.

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Re: Mercedes Power Unit

Post by rscsr » Tue Dec 05, 2017 10:57 am

PlatinumZealot wrote:
Tue Dec 05, 2017 12:20 am
...
Any MGUK assist will surely help, but still doesn't mask that a turbine engine is really designed for a steady load.
I don't think so. The LMP1 cars have been using more than 1000bhp electric motors for several seconds every acceleration phase. So it would be pretty feasable to mask the poor throttle response in my opinion.

Just_a_fan
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Re: Mercedes Power Unit

Post by Just_a_fan » Tue Dec 05, 2017 10:58 am

This jet engine stuff is all very interesting, but what has it got to do with the actual Mercedes power unit?

Shame the mods aren't as hot on OT stuff here as they are elsewhere...
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PlatinumZealot
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Re: Mercedes Power Unit

Post by PlatinumZealot » Tue Dec 05, 2017 6:09 pm

rscsr wrote:
Tue Dec 05, 2017 10:57 am
PlatinumZealot wrote:
Tue Dec 05, 2017 12:20 am
...
Any MGUK assist will surely help, but still doesn't mask that a turbine engine is really designed for a steady load.
I don't think so. The LMP1 cars have been using more than 1000bhp electric motors for several seconds every acceleration phase. So it would be pretty feasable to mask the poor throttle response in my opinion.
I was on a tangent argument about the turbine as the prime mover, which I said is not a good idea for modern F1.
The original argument though, was for the MGUK as the prime mover, with the turbine only existing to recharge the batteries, which I said is going to be too close to Formula E for most petrol heads.
"Raindrops .. drop top!"

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Re: Mercedes Power Unit

Post by etusch » Tue Dec 05, 2017 8:34 pm

I think jet engine is bad idea. But if there's a way to use a bit fuel for more powerful spin at mgu-h for better generation or something like that may be good idea.
For example instead of using battery power to keep turbo at a speed level at brakes, using some fuel... I don't know maybe this is more efficient maybe not.

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Re: Mercedes Power Unit

Post by Sierra117 » Wed Dec 06, 2017 5:58 pm

I hope they push for more efficient combustion tech relying only sparingly on electric power. The engine must not die! 👺 Merc especially is very proud of their engines so I bet they'll be the ones to break new ground.

Ezekiel Khalifa
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On Board F1 Force Índia New Sound Engine

Post by Ezekiel Khalifa » Thu Dec 07, 2017 2:58 pm

On Board F1 Force Índia New Sound Engine:

https://www.youtube.com/watch?v=wKSm102g4qY&t=3s

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Re: Mercedes Power Unit

Post by MrPotatoHead » Thu Dec 07, 2017 2:59 pm

The transient response of a turbine engine is terrible.
It would be a very very very bad engine for a racecar.
Let's get back to reality shall we?

roon
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Re: Mercedes Power Unit

Post by roon » Thu Dec 07, 2017 11:22 pm

MrPotatoHead wrote:
Thu Dec 07, 2017 2:59 pm
The transient response of a turbine engine is terrible.
"Then the transient response time will need to be improved, won't it?" says the executive paying the salaries.