RB query about Mercedes engine plenum Sept 2021

All that has to do with the power train, gearbox, clutch, fuels and lubricants, etc. Generally the mechanical side of Formula One.
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hardingfv32
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Joined: 03 Apr 2011, 19:42

RB query about Mercedes engine plenum Sept 2021

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Using the current rules but eliminating the requirement to be '10 deg C above ambient', is it possible to get the engine plenum below ambient?

How would this be done.... remember all other rules apply.

Brian

Hoffman900
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Joined: 13 Oct 2019, 03:02

Re: RB query about Mercedes engine plenum Sept 2021

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You forgot the key part, 10* below ambient* over the average of one lap, but not including the first.

*ambient is measured at a weather station the FIA places somewhere, so it's not a fixed point. A large track like Spa, with elevation changes, etc., it's not going to be the same everywhere. If the weather station is in the pits, it'll likely be higher due to a localized heat island effect. It's not an instantaneous measurement, no team would pass that.

There are many ways to do it. Super cooling at the intercooler, evaporative cooling via fuel or another compound, cooling via gas expansion, cooling the plenum (though, this isn't as effective). Some are legal, some are grey, some are illegal.

I've even seen NOS or another gas sprayed on intercoolers where it was legal and made sense.

Jolle
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Joined: 29 Jan 2014, 22:58
Location: Dordrecht

Re: RB query about Mercedes engine plenum Sept 2021

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Hoffman900 wrote:
06 Sep 2021, 22:25
You forgot the key part, 10* below ambient* over the average of one lap, but not including the first.

*ambient is measured at a weather station the FIA places somewhere, so it's not a fixed point. A large track like Spa, with elevation changes, etc., it's not going to be the same everywhere. If the weather station is in the pits, it'll likely be higher due to a localized heat island effect. It's not an instantaneous measurement, no team would pass that.

There are many ways to do it. Super cooling at the intercooler, evaporative cooling via fuel or another compound, cooling via gas expansion, cooling the plenum (though, this isn't as effective). Some are legal, some are grey, some are illegal.

I've even seen NOS or another gas sprayed on intercoolers where it was legal and made sense.
It’s above, not below ambient.

Cooling inside the plenum, which is under 2-2.5 par of pressure not the easiest I think, especially because you can’t evaporate anything in there (fuel would be an obvious choice, but that’s only injected right in the combustion chamber and not like before 2014 with showers above the trumpets). Cooling more then 10 above ambient would be logical with an intercooler or making the intercooler work harder. So… maybe it’s just as simple as a second stage intercooler or something? Or it’s just something completely else, and it’s got nothing to do with temps. Temps are less of an issue by the way then in the NA days, because the air is forced in and not sucked and there is a fuel flow limit. If they would like an extra boost by having more air temporary, you can just boost the H unit for a moment.

Hoffman900
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Joined: 13 Oct 2019, 03:02

Re: RB query about Mercedes engine plenum Sept 2021

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Thanks for the correction. I knew that. #-o

Air density (which comes from cooling) still matters for both. ESPECIALLY with the fuel rules F1 has.

Air isn’t "forced" or "sucked" in. All boost does is create an artificially higher atmospheric pressure. The moving piston creates a depression below atmospheric, but it’s never zero. Cam timing isn’t all that (relatively) different than a NA engine because at some point, port pressure and cylinder pressure are going to meet, it’s just at a higher value for a boosted engine, but doesn’t necessarily take more time to do so.

You can play with this in in a simulation by just changing atmospheric pressure. Cosworth in developing the GBA V6 engine, used a compressor with the BDx engine and the GBA to experiment with boost pressure, independent of having to develop the rest of the system:


About 13:00 in.

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BassVirolla
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Joined: 20 Jul 2018, 23:55

Re: RB query about Mercedes engine plenum Sept 2021

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Hoffman900 wrote:
06 Sep 2021, 23:07
Thanks for the correction. I knew that. #-o

Air density (which comes from cooling) still matters for both. ESPECIALLY with the fuel rules F1 has.

Air isn’t "forced" or "sucked" in. All boost does is create an artificially higher atmospheric pressure. The moving piston creates a depression below atmospheric, but it’s never zero. Cam timing isn’t all that (relatively) different than a NA engine because at some point, port pressure and cylinder pressure are going to meet, it’s just at a higher value for a boosted engine, but doesn’t necessarily take more time to do so.

You can play with this in in a simulation by just changing atmospheric pressure. Cosworth in developing the GBA V6 engine, used a compressor with the BDx engine and the GBA to experiment with boost pressure, independent of having to develop the rest of the system:


About 13:00 in.
What a great documentary!!

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lio007
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Joined: 28 Jan 2013, 23:03
Location: Austria

Re: RB query about Mercedes engine plenum Sept 2021

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BassVirolla wrote:
08 Sep 2021, 20:54
Hoffman900 wrote:
06 Sep 2021, 23:07
Thanks for the correction. I knew that. #-o

Air density (which comes from cooling) still matters for both. ESPECIALLY with the fuel rules F1 has.

Air isn’t "forced" or "sucked" in. All boost does is create an artificially higher atmospheric pressure. The moving piston creates a depression below atmospheric, but it’s never zero. Cam timing isn’t all that (relatively) different than a NA engine because at some point, port pressure and cylinder pressure are going to meet, it’s just at a higher value for a boosted engine, but doesn’t necessarily take more time to do so.

You can play with this in in a simulation by just changing atmospheric pressure. Cosworth in developing the GBA V6 engine, used a compressor with the BDx engine and the GBA to experiment with boost pressure, independent of having to develop the rest of the system:


About 13:00 in.
What a great documentary!!
Indeed!
If only the documentation was a bit longer to see how it continued.

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BassVirolla
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Joined: 20 Jul 2018, 23:55

Re: RB query about Mercedes engine plenum Sept 2021

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lio007 wrote:
09 Sep 2021, 09:28
BassVirolla wrote:
08 Sep 2021, 20:54
Hoffman900 wrote:
06 Sep 2021, 23:07
Thanks for the correction. I knew that. #-o

Air density (which comes from cooling) still matters for both. ESPECIALLY with the fuel rules F1 has.

Air isn’t "forced" or "sucked" in. All boost does is create an artificially higher atmospheric pressure. The moving piston creates a depression below atmospheric, but it’s never zero. Cam timing isn’t all that (relatively) different than a NA engine because at some point, port pressure and cylinder pressure are going to meet, it’s just at a higher value for a boosted engine, but doesn’t necessarily take more time to do so.

You can play with this in in a simulation by just changing atmospheric pressure. Cosworth in developing the GBA V6 engine, used a compressor with the BDx engine and the GBA to experiment with boost pressure, independent of having to develop the rest of the system:


About 13:00 in.
What a great documentary!!
Indeed!
If only the documentation was a bit longer to see how it continued.
https://youtu.be/frU7cVt_qKc

:wink:

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lio007
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Joined: 28 Jan 2013, 23:03
Location: Austria

Re: RB query about Mercedes engine plenum Sept 2021

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BassVirolla wrote:
09 Sep 2021, 09:36
lio007 wrote:
09 Sep 2021, 09:28
BassVirolla wrote:
08 Sep 2021, 20:54


What a great documentary!!
Indeed!
If only the documentation was a bit longer to see how it continued.
https://youtu.be/frU7cVt_qKc

:wink:
Oh dear...feeling ashamed :lol:
I would have had to find that out myself.

Big thank you btw!

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El Scorchio
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Joined: 29 Jul 2019, 12:41

Re: RB query about Mercedes engine plenum Sept 2021

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Equinox- such a blast from the past! Iconic title sequence. Will give this a watch later. Thanks for posting!

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