Renault 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.
Tommy Cookers
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Re: Renault Power Unit Hardware & Software

Post by Tommy Cookers » Tue Jan 08, 2019 8:49 pm

Brake Horse Power wrote:
Tue Jan 08, 2019 8:07 pm
.... wastegate open ......The exhaust pulsation can maybe also be better utilisied as in a NA engine...
if the wastegate is open the mean exhaust pressure is maybe 1.05 bar
if the wastegate is closed the mean exhaust pressure is maybe 4.05 bar

even with an active turbine surely the 4.05 bar stream has bigger pulse reflections available than the 1.05 bar stream does ?
what did the 80s F1 turbo engines do ? (though they might have had no use for the benefit as they didn't recover power)

ok the 4.05 bar stream the pulse energy has less energy relative to the steady flow energy (than does 1.05 bar stream)
because less of the 4.05 stream's flow will be choked as the gas acceleration will be less due to the higher density
Last edited by Tommy Cookers on Tue Jan 08, 2019 9:36 pm, edited 1 time in total.

djos
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Re: Renault Power Unit Hardware & Software

Post by djos » Tue Jan 08, 2019 9:29 pm

Tommy Cookers wrote:
Tue Jan 08, 2019 8:49 pm
Brake Horse Power wrote:
Tue Jan 08, 2019 8:07 pm
.... wastegate open ......The exhaust pulsation can maybe also be better utilisied as in a NA engine...
if the wastegate is open the mean exhaust pressure is maybe 1.05 bar
if the wastegate is closed the mean exhaust pressure is maybe 4.05 bar

even with an active turbine surely the 4.05 bar stream has bigger pulse reflections available than the 1.05 bar stream does ?
what did the 80s F1 turbo engines do ? (though they might have had no use for the benefit as they didn't recover power)
Iirc they had blown diffusers in the 80's turbo era.
The impossible often has a kind of integrity which the merely improbable lacks.

henry
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Re: Renault Power Unit Hardware & Software

Post by henry » Wed Jan 09, 2019 10:37 am

Tommy Cookers wrote:
Tue Jan 08, 2019 8:49 pm
Brake Horse Power wrote:
Tue Jan 08, 2019 8:07 pm
.... wastegate open ......The exhaust pulsation can maybe also be better utilisied as in a NA engine...
if the wastegate is open the mean exhaust pressure is maybe 1.05 bar
if the wastegate is closed the mean exhaust pressure is maybe 4.05 bar

even with an active turbine surely the 4.05 bar stream has bigger pulse reflections available than the 1.05 bar stream does ?
what did the 80s F1 turbo engines do ? (though they might have had no use for the benefit as they didn't recover power)

ok the 4.05 bar stream the pulse energy has less energy relative to the steady flow energy (than does 1.05 bar stream)
because less of the 4.05 stream's flow will be choked as the gas acceleration will be less due to the higher density
So the wastegate opening impacts 3 areas of performance?

It reduces the pressure in the exhaust stream by providing a freer flow route than solely going across the impeller. ICE crank output goes up, turbine output goes down.

It changes the tuned pressure wave reflections in the exhaust system that aid cylinder filling (I believe this is what you are referring to). ICE performance goes down?

It changes the kinetic energy of the exhaust stream (density down) that drives the blowdown stage in the turbine. Turbine output goes down.
Fortune favours the prepared; she has no favourites and takes no sides.
Truth is confirmed by inspection and delay; falsehood by haste and uncertainty : Tacitus

godlameroso
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Re: Renault Power Unit Hardware & Software

Post by godlameroso » Wed Jan 09, 2019 2:14 pm

Tommy Cookers wrote:
Tue Jan 08, 2019 8:49 pm
Brake Horse Power wrote:
Tue Jan 08, 2019 8:07 pm
.... wastegate open ......The exhaust pulsation can maybe also be better utilisied as in a NA engine...
if the wastegate is open the mean exhaust pressure is maybe 1.05 bar
if the wastegate is closed the mean exhaust pressure is maybe 4.05 bar

even with an active turbine surely the 4.05 bar stream has bigger pulse reflections available than the 1.05 bar stream does ?
what did the 80s F1 turbo engines do ? (though they might have had no use for the benefit as they didn't recover power)

ok the 4.05 bar stream the pulse energy has less energy relative to the steady flow energy (than does 1.05 bar stream)
because less of the 4.05 stream's flow will be choked as the gas acceleration will be less due to the higher density
Are pressure waves affected by higher inertia due to increased mass flow?
The height of cultivation is really nothing special. It is merely simplicity; the ability to express the utmost with the minimum. Mr.Lee

dren
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Re: Renault Power Unit Hardware & Software

Post by dren » Wed Jan 09, 2019 4:22 pm

Wave velocity increases when exhaust gas velocity increases, if that's what you're asking, assuming density and temperature stays the same.
Honda!

Mudflap
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Re: Renault Power Unit Hardware & Software

Post by Mudflap » Wed Jan 09, 2019 5:35 pm

Pretty sure wave velocity is always local speed of sound.
How much TQ does it make though?

PlatinumZealot
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Re: Renault Power Unit Hardware & Software

Post by PlatinumZealot » Wed Jan 09, 2019 5:52 pm

The fact that all the Manufacturers spent time redesigning their waste-gates each season certainly shows they are integral for performance. The Ferrari and Mercedes has very noticeable waste gate sounds over the course of the lap.Whatever trickery they do with them besides boost control and electric supercharging beats me.
"The true champions are also great men. They are capable of making difficult decisions, of admitting their mistakes and of pushing harder than before when they get up from a fall."

- Ferrari chairman Sergio Marchionne

Tommy Cookers
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Re: Renault Power Unit Hardware & Software

Post by Tommy Cookers » Wed Jan 09, 2019 6:29 pm

henry wrote:
Wed Jan 09, 2019 10:37 am
So the wastegate opening ......
It changes the tuned pressure wave reflections in the exhaust system that aid cylinder filling (I believe this is what you are referring to). ICE performance goes down?
imo
2x 3 tuned length headers should work equally well (gains proportionate to exhaust pressure) for either exhaust pressure
ie wastegate closed the F1 engine would have free supercharge potential of eg (1.25 -1) x 4 atm
and wastegate open would have free supercharge potential of (1.25 -1) x 1 atm
(but a pipe with the turbine upstream of the tuned length point only (1.25-1) x 1 atm free supercharge wastegate closed)

EDIT (and tbf some the 25% tuned length benefit is from the inlet side)
ie wastegate closed the free supercharge reduces substantially the compressor work needed from the turbine and H motor
substantially increasing H recovery
Last edited by Tommy Cookers on Wed Jan 09, 2019 6:47 pm, edited 2 times in total.

e36jon
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Re: Renault Power Unit Hardware & Software

Post by e36jon » Wed Jan 09, 2019 6:38 pm

Mudflap wrote:
Wed Jan 09, 2019 5:35 pm
Pretty sure wave velocity is always local speed of sound.
Greetings Mudflap

I believe it works like this: If you're in an airliner going 700mph, the speed of sound inside is what it is (Driven by temp, pressure, etc.). Seen from the outside though, the speed of your sound inside the airplane is + or - 700mph.

Same thing in an intake or exhaust manifold: The bulk air is moving, and the speed of sound is what it is within that bulk air, but is seen by external elements as + or - the speed of the bulk air.

Or I am completely wrong and must go sit in the corner...

Jon "Blowing hot air"

godlameroso
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Re: Renault Power Unit Hardware & Software

Post by godlameroso » Wed Jan 09, 2019 6:39 pm

Tommy Cookers wrote:
Wed Jan 09, 2019 6:29 pm
henry wrote:
Wed Jan 09, 2019 10:37 am
So the wastegate opening ......
It changes the tuned pressure wave reflections in the exhaust system that aid cylinder filling (I believe this is what you are referring to). ICE performance goes down?
imo
2x 3 tuned length headers should work equally well (gains proportionate to exhaust pressure) for either exhaust pressure
ie wastegate closed the F1 engine would have free supercharge potential of eg (1.25 -1) x 4 atm
and wastegate open would have free supercharge potential of (1.25 -1) x 1 atm
(bit a pipe with the turbine upstream of the tuned length point only (1.25-1) x 1 atm free supercharge or worse wastegate closed)

ie wastegate closed the free supercharge reduces substantially the compressor work needed from the turbine and H motor
substantially increasing H recovery
Ties in very nicely with balancing ICE power and MGU-H power.
The height of cultivation is really nothing special. It is merely simplicity; the ability to express the utmost with the minimum. Mr.Lee

Big Tea
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Re: Renault Power Unit Hardware & Software

Post by Big Tea » Wed Jan 09, 2019 7:08 pm

e36jon wrote:
Wed Jan 09, 2019 6:38 pm
Mudflap wrote:
Wed Jan 09, 2019 5:35 pm
Pretty sure wave velocity is always local speed of sound.
Greetings Mudflap

I believe it works like this: If you're in an airliner going 700mph, the speed of sound inside is what it is (Driven by temp, pressure, etc.). Seen from the outside though, the speed of your sound inside the airplane is + or - 700mph.

Same thing in an intake or exhaust manifold: The bulk air is moving, and the speed of sound is what it is within that bulk air, but is seen by external elements as + or - the speed of the bulk air.

Or I am completely wrong and must go sit in the corner...

Jon "Blowing hot air"
Is it not Dependant on air (or medium) density?
One test is worth a thousand expert opinions

Tommy Cookers
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Re: Renault Power Unit Hardware & Software

Post by Tommy Cookers » Thu Jan 10, 2019 2:17 pm

the thing we call the speed of sound in air is driven by temperature not pressure

btw and imo
blowdown is a choked process
that is why they can use both wastegate open and wastegate closed with the same EVO timing
dropping mean exhaust pressure from 4 bar to 1 bar makes little difference to blowdown ie doesn't demand later EVO timing
(and blowdown would still be a choked process if the exhaust valves were infinitely large and opened instantaneously)
because it takes a disproportionate pressure for the gas to accelerate itself to scavenge the cylinder in less than 1 millisec
the early velocity (of this pressure pulse aka 'shock wave') is supersonic

PlatinumZealot
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Re: Renault Power Unit Hardware & Software

Post by PlatinumZealot » Thu Jan 10, 2019 7:55 pm

Define blowdown...

I have only seen this word in very old PV graphs... for turbocharged 2 strokes? But never saw a good explanation. Granted, I have not really tried researching that term too much.
"The true champions are also great men. They are capable of making difficult decisions, of admitting their mistakes and of pushing harder than before when they get up from a fall."

- Ferrari chairman Sergio Marchionne

henry
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Re: Renault Power Unit Hardware & Software

Post by henry » Thu Jan 10, 2019 8:18 pm

PlatinumZealot wrote:
Thu Jan 10, 2019 7:55 pm
Define blowdown...

I have only seen this word in very old PV graphs... for turbocharged 2 strokes? But never saw a good explanation. Granted, I have not really tried researching that term too much.
Fortunately there’s a whole thread on the topic

viewtopic.php?f=4&t=20312
Fortune favours the prepared; she has no favourites and takes no sides.
Truth is confirmed by inspection and delay; falsehood by haste and uncertainty : Tacitus

PlatinumZealot
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Re: Renault Power Unit Hardware & Software

Post by PlatinumZealot » Thu Jan 10, 2019 11:05 pm

henry wrote:
Thu Jan 10, 2019 8:18 pm
PlatinumZealot wrote:
Thu Jan 10, 2019 7:55 pm
Define blowdown...

I have only seen this word in very old PV graphs... for turbocharged 2 strokes? But never saw a good explanation. Granted, I have not really tried researching that term too much.
Fortunately there’s a whole thread on the topic

viewtopic.php?f=4&t=20312
Nope! I remember that thread! I won't re-enter!

There was no clear answer.. I have a Pressure-Volume graph with blow-down featured on it, which I might post if anyone is interested.. and some other very old references. But I would like a clear definition for everyone to be able to join the discussion. It's mostly the old-heads you hear with this blow-down term.
"The true champions are also great men. They are capable of making difficult decisions, of admitting their mistakes and of pushing harder than before when they get up from a fall."

- Ferrari chairman Sergio Marchionne