Renault Power Unit Hardware & Software

[Vladimir]

That could be some sort of safe mode, in which engine is limited.That new engine has some new concept solutions, so is mystery for now.

[mattia.bobbo]

It has been speculated earlier that that is from opening the wastegates.

Thanks. That does make sense.

So with that in mind, is this a way of controlling sudden wheel spin out of corners? When you listen to the Honda and ferrari, and the Merc( although low volume) they are all sounding like some sort of cylinder shutoff is occurring coming down the gears and off throttle.

The renault engine, is smooth. Nothing. Nada. Nat a single babble from that engine. But then coming out of the corner, sounds like bloody vTec kicking in with the possible waste gate opening.

EDIt here is a video I took at testing.

https://www.youtube.com/watch?v=uXPuN4N ... e=youtu.be

I really don't think that any cutting of cilinders is acting like traction control.
Cutting cylinders & opening the wastegate during braking guarantees much more fuel economy than simply opening the wastegate. But the difference in sound can be made also by the way the wastegate opens. I remember in autocross, some cars made a huge BOOM when their wastegate open, other simply a bubbly sound, others a very quiet noise. sound might not directly be connected to cylinder cutting

[63l8qrrfy6]

The MGU-K shaft broke down several times. A stronger shaft is already in construction. I'm more worried about the turbo problems RBR had on last day of testing. Hopefully this is not something fundamental...

It sounds to me a lot like they have a quill shaft on the MGUK and it's breaking.

What makes you think this specifically?

I've mentioned before on a different thread that I think MGUKs are soft coupled due to their high effective inertia.
There's not that many options for soft-coupling : a compliant gear (a la DFV), hydraulic couplings (have been used in aero engines in the past), rubber couplings or quill shafts (again common on old aero engines) being the more obvious ones. These also tend to be the main points of failure under high torsional loads.

This is pretty much the reason I think it's a quill shaft. If I am right it should be fairly easy to fix (eg. increase diameter to decrease stress and increase length to maintain compliance)

[godlameroso]

It sounds to me a lot like they have a quill shaft on the MGUK and it's breaking.

What makes you think this specifically?

I've mentioned before on a different thread that I think MGUKs are soft coupled due to their high effective inertia.
There's not that many options for soft-coupling : a compliant gear (a la DFV), hydraulic couplings (have been used in aero engines in the past), rubber couplings or quill shafts (again common on old aero engines) being the more obvious ones. These also tend to be the main points of failure under high torsional loads.

This is pretty much the reason I think it's a quill shaft. If I am right it should be fairly easy to fix (eg. increase diameter to decrease stress and increase length to maintain compliance)

Interesting, what is the possibility someone is using a hydraulic coupler for the MGU-K? Too heavy and bulky?

[63l8qrrfy6]

What makes you think this specifically?

I've mentioned before on a different thread that I think MGUKs are soft coupled due to their high effective inertia.
There's not that many options for soft-coupling : a compliant gear (a la DFV), hydraulic couplings (have been used in aero engines in the past), rubber couplings or quill shafts (again common on old aero engines) being the more obvious ones. These also tend to be the main points of failure under high torsional loads.

This is pretty much the reason I think it's a quill shaft. If I am right it should be fairly easy to fix (eg. increase diameter to decrease stress and increase length to maintain compliance)

Interesting, what is the possibility someone is using a hydraulic coupler for the MGU-K? Too heavy and bulky?

actually now that you mention it it might not be legal. I think rules say it has to be a fixed ratio - a fluid coupling will have slip.
Also it has an inherent power loss. Plus what you said, yes.

[PlatinumZealot]

The renault mguh was in front of the compressor last year. Dont know where it is located now but... I imagine that the turbine has to be made on the TC shaft. That is a given.. The compressor is slid onto this shaft. That is a given. Sounds good so far? Things get a little tricky now.
Is the MGUh slid onto the same turbocharger shaft too? For aerodynamic reasons it is best to have a small diameter for the step where the compressor is placed, but with an MUGH someon distance away on that same shaft as well the step in this part of the shaft would have to be a large diameter or non exisitent if twisting is not desired. Going further down this shaft... Think about this now. The turbine can only put out a given maximum amount of torque. %100 of this torque can go towards to compressor if needed. Hence we can deduce that the compressor and MGUH has the same design torque value. In reverse, when torque flows from MGUH to compressor the compressor can only demand a maximum amount of torque just the same as if it were driven from the turbine. Hence again we can conclude the MGUH has the same design torque value as the compressor.
Ok where am I going with this? As far as i suspect, the compressor wheel is PRESSED onto its shaft by a nut - someone tell me if i am correct. And this is enough to hold all the toque the compressor will see! Therefore! the same can apply to the MGUH and it too can be pressed and held by a nut.. If this logic is sound there is no need for splines to carry the torque. Then the next question is.. Is there a need for axial movement? Or radial flexibility??? Or both? If the turbine is bolted solidly to the MGUH and accurately aligned maybe no significant radial flex is needed? Is significant axial flex needed.. Well yes. But it would not be any more than what is experienced by the compressor. The motor windings also have clearances to allow. Hmm. What I am saying is.. Is there really a need for a quill shaft? Why can't it just be a big ole single thick log of shaft?

[Singabule]

Long thick shaft would reduce weight and complexity, reduce the vibration and bending problem, and increase stiffness and reliability to all the system. I cant see there is coupler at all.

[wuzak]

The renault mguh was in front of the compressor last year. Dont know where it is located now but... I imagine that the turbine has to be made on the TC shaft. That is a given.. The compressor is slid onto this shaft. That is a given. Sounds good so far? Things get a little tricky now.
Is the MGUh slid onto the same turbocharger shaft too? For aerodynamic reasons it is best to have a small diameter for the step where the compressor is placed, but with an MUGH someon distance away on that same shaft as well the step in this part of the shaft would have to be a large diameter or non exisitent if twisting is not desired. Going further down this shaft... Think about this now. The turbine can only put out a given maximum amount of torque. %100 of this torque can go towards to compressor if needed. Hence we can deduce that the compressor and MGUH has the same design torque value. In reverse, when torque flows from MGUH to compressor the compressor can only demand a maximum amount of torque just the same as if it were driven from the turbine. Hence again we can conclude the MGUH has the same design torque value as the compressor.
Ok where am I going with this? As far as i suspect, the compressor wheel is PRESSED onto its shaft by a nut - someone tell me if i am correct. And this is enough to hold all the toque the compressor will see! Therefore! the same can apply to the MGUH and it too can be pressed and held by a nut.. If this logic is sound there is no need for splines to carry the torque. Then the next question is.. Is there a need for axial movement? Or radial flexibility??? Or both? If the turbine is bolted solidly to the MGUH and accurately aligned maybe no significant radial flex is needed? Is significant axial flex needed.. Well yes. But it would not be any more than what is experienced by the compressor. The motor windings also have clearances to allow. Hmm. What I am saying is.. Is there really a need for a quill shaft? Why can't it just be a big ole single thick log of shaft?

I believe the discussion of running a quill shaft was related to the MGUK and was to isolate it from teh torsional vibrations of the crankshaft.

The MGUH is connected to the turbo's shaft, either by gears or directly, and doesn't need a quill shaft as the turbo doesn't have the same issue with vibrations as the crankshaft.

[63l8qrrfy6]

Long thick shaft would reduce weight and complexity, reduce the vibration and bending problem, and increase stiffness and reliability to all the system. I cant see there is coupler at all.

hmmm a long thick shaft would reduce weight compared to what ? a lorry driveshaft ?

also as wuzak said - that discussion was about the K not the H

[Singabule]

Long thick shaft would reduce weight and complexity, reduce the vibration and bending problem, and increase stiffness and reliability to all the system. I cant see there is coupler at all.

hmmm a long thick shaft would reduce weight compared to what ? a lorry driveshaft ?

also as wuzak said - that discussion was about the K not the H

yeah my bad. About K, using coupler is Hard to digest to me, as adding complexity for a little benefit, suci as smoother shifting and better K reliability

[Vladimir]

Nice news on wednesday, Renault solved preseason testing problems. Is now clear that all Renault powered teams drove detuned engines at Barcelona test.
That is very promising situation for the races ahead.

[djos]

Nice news on wednesday, Renault solved preseason testing problems. Is now clear that all Renault powered teams drove detuned engines at Barcelona test.
That is very promising situation for the races ahead.

I hope you are correct but do you have a source to back you up?

[ME4ME]

"We have addressed the ERS issue which caused us reliability concerns and do not expect to see a repeat of it in Australia," said Abiteboul.

"There is a balance between pushing the envelope of performance and maintaining the requisite reliability and the trick is to stretch the margins without overstepping them.

"We know we have a strong base with the R.S.17 which puts us in good stead for the relentless development race we expect to see. We are confident in the abilities of the team to improve and develop the car over the year."

http://en.f1i.com/news/262646-ers-issue ... eboul.html

Also some carefull commments:

"The engine, I think they've made progress, but I would say we've got the third-best engine. Hopefully the gap is closing all of the time. And then the chassis, we can compare with where Red Bull are and they're ahead of us still.

https://www.motorsport.com/f1/news/hulk ... es-884587/

"--- can always happen," he told Motorsport.com. "I feel extremely sympathetic of what Honda is going through, including in their relationship with McLaren. It reminds me of something that I myself have experienced.

"I think McLaren needs to stay steady, and Honda needs to remain focused. They have to go through this, and I am sure they have the financial resources and the talent to go through that. "I am not feeling safe at all, even if I watch Honda, frankly."

https://www.motorsport.com/f1/news/rena ... at-883235/

[Blackout]

http://www.auto-motor-und-sport.de/form ... 43794.html
http://www.auto-motor-und-sport.de/form ... 32406.html

[Thunder]

https://twitter.com/andrewbensonf1/stat ... 2222557184