I just want to clarify that the pressures there are peak cylinder pressures or BMEP?Mudflap wrote: ↑11 Mar 2018, 01:07It was claimed on several occasions that the cylinder pressure exceeds 440 bar. I assure you that no aluminium piston can see 300 bar regularly and last for as long as these engines are meant to last. Maybe they can get 400+bar with occasional knock.godlameroso wrote: ↑10 Mar 2018, 16:30According to Mercedes there's the equivalent of 4 average elephants pressing down on each piston, don't know how many elephants they've added since 2016 though.
No one that knows will say, and all we have to go on is estimates.
As far as I can tell for the Mercedes engine(the current benchmark)
1.) 800+ hp from the ICE
2.) 52MJ/kg
3.) I remember saying combustion temperatures can be as high as 2400K so somewhere around 6% oxygen in the exhaust.
4.) Boost ~5bar absolute, Compression 16:1 +-2 points, cylinder pressure ~440bar
5.) no clue.
Hello Miami, wouldn't mind looking at the article (I guess it is) re the Mercedes elephants, would you have a link please . Serious request by the way, I could imagine someone pulling your leg.godlameroso wrote: ↑10 Mar 2018, 16:30According to Mercedes there's the equivalent of 4 average elephants pressing down on each piston, don't know how many elephants they've added since 2016 though.
No one that knows will say, and all we have to go on is estimates.
As far as I can tell for the Mercedes engine(the current benchmark)
1.) 800+ hp from the ICE
2.) 52MJ/kg
3.) I remember saying combustion temperatures can be as high as 2400K so somewhere around 6% oxygen in the exhaust.
4.) Boost ~5bar absolute, Compression 16:1 +-2 points, cylinder pressure ~440bar
5.) no clue.
The elephant thing is from AMG F1:s YouTube account from 2015 or 2016, can't quite remember.johnny comelately wrote: ↑11 Mar 2018, 15:35Hello Miami, wouldn't mind looking at the article (I guess it is) re the Mercedes elephants, would you have a link please . Serious request by the way, I could imagine someone pulling your leg.godlameroso wrote: ↑10 Mar 2018, 16:30According to Mercedes there's the equivalent of 4 average elephants pressing down on each piston, don't know how many elephants they've added since 2016 though.
No one that knows will say, and all we have to go on is estimates.
As far as I can tell for the Mercedes engine(the current benchmark)
1.) 800+ hp from the ICE
2.) 52MJ/kg
3.) I remember saying combustion temperatures can be as high as 2400K so somewhere around 6% oxygen in the exhaust.
4.) Boost ~5bar absolute, Compression 16:1 +-2 points, cylinder pressure ~440bar
5.) no clue.
We are talking about peak cylinder pressures since these are what fail pistons (besides inertial loads).johnny comelately wrote: ↑11 Mar 2018, 15:30I just want to clarify that the pressures there are peak cylinder pressures or BMEP?Mudflap wrote: ↑11 Mar 2018, 01:07It was claimed on several occasions that the cylinder pressure exceeds 440 bar. I assure you that no aluminium piston can see 300 bar regularly and last for as long as these engines are meant to last. Maybe they can get 400+bar with occasional knock.godlameroso wrote: ↑10 Mar 2018, 16:30According to Mercedes there's the equivalent of 4 average elephants pressing down on each piston, don't know how many elephants they've added since 2016 though.
No one that knows will say, and all we have to go on is estimates.
As far as I can tell for the Mercedes engine(the current benchmark)
1.) 800+ hp from the ICE
2.) 52MJ/kg
3.) I remember saying combustion temperatures can be as high as 2400K so somewhere around 6% oxygen in the exhaust.
4.) Boost ~5bar absolute, Compression 16:1 +-2 points, cylinder pressure ~440bar
5.) no clue.
I know this sounds vague but it is important when there is so little info around
Yes, I remember someone else suggesting this too and it does sound plausible. There was much talk in the media about in cylinder pressure sensors (I think Ilien said something about this too) which would tie in with that.godlameroso wrote: ↑11 Mar 2018, 02:21That's what I'm thinking, that they actually allow some detonation to happen. That engine life is determined by how many detonation events have occurred.Mudflap wrote: ↑11 Mar 2018, 01:07It was claimed on several occasions that the cylinder pressure exceeds 440 bar. I assure you that no aluminium piston can see 300 bar regularly and last for as long as these engines are meant to last. Maybe they can get 400+bar with occasional knock.godlameroso wrote: ↑10 Mar 2018, 16:30According to Mercedes there's the equivalent of 4 average elephants pressing down on each piston, don't know how many elephants they've added since 2016 though.
No one that knows will say, and all we have to go on is estimates.
As far as I can tell for the Mercedes engine(the current benchmark)
1.) 800+ hp from the ICE
2.) 52MJ/kg
3.) I remember saying combustion temperatures can be as high as 2400K so somewhere around 6% oxygen in the exhaust.
4.) Boost ~5bar absolute, Compression 16:1 +-2 points, cylinder pressure ~440bar
5.) no clue.
Thanks very much for thathurril wrote: ↑11 Mar 2018, 16:39The elephant thing is from AMG F1:s YouTube account from 2015 or 2016, can't quite remember.johnny comelately wrote: ↑11 Mar 2018, 15:35Hello Miami, wouldn't mind looking at the article (I guess it is) re the Mercedes elephants, would you have a link please . Serious request by the way, I could imagine someone pulling your leg.godlameroso wrote: ↑10 Mar 2018, 16:30According to Mercedes there's the equivalent of 4 average elephants pressing down on each piston, don't know how many elephants they've added since 2016 though.
No one that knows will say, and all we have to go on is estimates.
As far as I can tell for the Mercedes engine(the current benchmark)
1.) 800+ hp from the ICE
2.) 52MJ/kg
3.) I remember saying combustion temperatures can be as high as 2400K so somewhere around 6% oxygen in the exhaust.
4.) Boost ~5bar absolute, Compression 16:1 +-2 points, cylinder pressure ~440bar
5.) no clue.
This video:
https://www.youtube.com/watch?v=Cx4HMSNx_MY
Thank you, just had to make sure.Mudflap wrote: ↑11 Mar 2018, 16:56We are talking about peak cylinder pressures since these are what fail pistons (besides inertial loads).johnny comelately wrote: ↑11 Mar 2018, 15:30I just want to clarify that the pressures there are peak cylinder pressures or BMEP?
I know this sounds vague but it is important when there is so little info around
BMEP is not a "real" cylinder pressure, just like mean piston speed is not a real piston speed. It is a derived quantity used as a displacement normalized performance indicator and can be seen as average cylinder pressure over a cycle.
BMEP will always be just a fraction of PCP, however the two are related.
There was a dwarf elephant which must be what Honda, Renault used in earlier timeshurril wrote: ↑11 Mar 2018, 16:39The elephant thing is from AMG F1:s YouTube account from 2015 or 2016, can't quite remember.johnny comelately wrote: ↑11 Mar 2018, 15:35Hello Miami, wouldn't mind looking at the article (I guess it is) re the Mercedes elephants, would you have a link please . Serious request by the way, I could imagine someone pulling your leg.godlameroso wrote: ↑10 Mar 2018, 16:30According to Mercedes there's the equivalent of 4 average elephants pressing down on each piston, don't know how many elephants they've added since 2016 though.
No one that knows will say, and all we have to go on is estimates.
As far as I can tell for the Mercedes engine(the current benchmark)
1.) 800+ hp from the ICE
2.) 52MJ/kg
3.) I remember saying combustion temperatures can be as high as 2400K so somewhere around 6% oxygen in the exhaust.
4.) Boost ~5bar absolute, Compression 16:1 +-2 points, cylinder pressure ~440bar
5.) no clue.
This video:
https://www.youtube.com/watch?v=Cx4HMSNx_MY
There will be no knocking at these pressures would be the best assumption.Mudflap wrote: ↑11 Mar 2018, 17:11Yes, I remember someone else suggesting this too and it does sound plausible. There was much talk in the media about in cylinder pressure sensors (I think Ilien said something about this too) which would tie in with that.godlameroso wrote: ↑11 Mar 2018, 02:21That's what I'm thinking, that they actually allow some detonation to happen. That engine life is determined by how many detonation events have occurred.
Uhm well, strictly mathematically it depends on torque and displacement. So it is highly dependent on all the many things that influence torque.johnny comelately wrote: ↑11 Mar 2018, 23:54Thank you, just had to make sure.Mudflap wrote: ↑11 Mar 2018, 16:56We are talking about peak cylinder pressures since these are what fail pistons (besides inertial loads).johnny comelately wrote: ↑11 Mar 2018, 15:30
I just want to clarify that the pressures there are peak cylinder pressures or BMEP?
I know this sounds vague but it is important when there is so little info around
BMEP is not a "real" cylinder pressure, just like mean piston speed is not a real piston speed. It is a derived quantity used as a displacement normalized performance indicator and can be seen as average cylinder pressure over a cycle.
BMEP will always be just a fraction of PCP, however the two are related.
BMEP (I get your definition) highly dependent on EVO timing and in a 6 cylinder its important to hold everything in context.