Ferrari Power Unit Hardware & Software

[saviour stivala]

the compressor and turbine must be on a common shaft, the mgu-h can be coupled to that shaft, all three, compressor, turbine and mgu-h rotates at the same speed, max 125k.

The MGUH may turn at the same speed as the turbo, but it doesn't have to.

We've been here before. Fixed speed ratio means that the MGUH turns at a multiple of the speed of the turbo.
That could be 1, 0.5 or 50, so long as it is not variable and cannot be changed (with a mini gearbox).

If it can be clutched, can it not be geared for highest speed then reduce speed controlled by slip?

Turbochager (compressor impellor and exhaust turbine) as well as MGU-H rotates at the same speed, maximum 125000 RPM, so what is the use of gearing? The MGU-H can be coupled to the turbo shaft.

[roon]

Clutch useful for ES<-H->K transfer mode decoupled from turbine requirements. ICE sustained turbine operation leaves the MGUH to multi-Hz generator-motor cycling; the unlimited electro-kinetic coupling between ES and K.

Ratios other than 1:1 may have motor control benefits. Just a guess. What are the limits for compressor and turbine speeds, realistically? H can't spin faster than 125k, but the sky's the limit for the turboshaft assembly. Could flow more air for a given impeller diameter. Increased pressure/MAF was suggested by the former WDC in his social media blurb.

[Big Tea]

I don't know how on earth that would work, all you're doing is wasting energy in the clutch slipping.
Slipping the clutch a little was common if your gearing was too long out of a corner to get the engine into the meat of the powerband, especially on highly tuned 2-strokes, but I can't see any way it could do what you're claiming.

It would be geared for the speed it ran normally, slip could be either or both extremities of the range.

[Mr.G]

Clutch useful for ES<-H->K transfer mode decoupled from turbine requirements. ICE sustained turbine operation leaves the MGUH to multi-Hz generator-motor cycling; the unlimited electro-kinetic coupling between ES and K.

Ratios other than 1:1 may have motor control benefits. Just a guess. What are the limits for compressor and turbine speeds, realistically? H can't spin faster than 125k, but the sky's the limit for the turboshaft assembly. Could flow more air for a given impeller diameter. Increased pressure/MAF was suggested by the former WDC in his social media blurb.

Are you sure that MGU-H is limited to 125k rpm? I was thinking it's in the other way (turbo limited, MGU-H not), but I may be wrong.

If it is as you say, then it would be indeed beneficial to gear down the MGU-H and go above 125k rpm with turbo/compressor...

[roon]

Are you sure that MGU-H is limited to 125k rpm?

viewtopic.php?p=780349#p780349

Also:

1.26 Motor Generator Unit - Heat (MGU-H) : The Heat Motor Generator Unit is the electrical machine linked to the exhaust turbine of a pressure charging system as part of the ERS.

[Tommy Cookers]

[quote=PhillipM]I don't know how on earth that would work, all you're doing is wasting energy in the clutch slipping.
Slipping the clutch a little was common if your gearing was too long out of a corner to get the engine into the meat of the powerband, especially on highly tuned 2-strokes, but I can't see any way it could do what you're claiming.[/quote]

you're doing better than just wasting energy in the clutch slipping if ......
reduced load on the engine allows it to rev higher and if this gives more engine torque - there's more wheel torque
and the greater engine torque might allow clutch slip to be reduced or stopped
it's basically the same reason that you slip the clutch to move from rest


re H gearing for higher turbine rpm - wouldn't this smaller turbine/compressor be less efficient as leakage is relatively greater ?

[godlameroso]

I don't know how on earth that would work, all you're doing is wasting energy in the clutch slipping.
Slipping the clutch a little was common if your gearing was too long out of a corner to get the engine into the meat of the powerband, especially on highly tuned 2-strokes, but I can't see any way it could do what you're claiming.

you're doing better than just wasting energy in the clutch slipping if ......
reduced load on the engine allows it to rev higher and if this gives more engine torque - there's more wheel torque
and the greater engine torque might allow clutch slip to be reduced or stopped
it's basically the same reason that you slip the clutch to move from rest


re H gearing for higher turbine rpm - wouldn't this smaller turbine/compressor be less efficient as leakage is relatively greater ?

Honda tried that, it obviously doesn't work. Would the opposite be worth considering? IE turbo which can flow the required amount at say half the RPM of the MGU-H. Would that gear reduction from MGU-H to turbo waste less energy in spooling the turbo? Would it reduce torque at the MGU-H and reduce harvesting potential?

[PhillipM]

you're doing better than just wasting energy in the clutch slipping if ......
reduced load on the engine allows it to rev higher and if this gives more engine torque - there's more wheel torque
and the greater engine torque might allow clutch slip to be reduced or stopped
it's basically the same reason that you slip the clutch to move from rest

But that would make no sense for a bike that had 'run out of gearing' - i.e, gearing was too short.

[saviour stivala]

Clutch useful for ES<-H->K transfer mode decoupled from turbine requirements. ICE sustained turbine operation leaves the MGUH to multi-Hz generator-motor cycling; the unlimited electro-kinetic coupling between ES and K.

Ratios other than 1:1 may have motor control benefits. Just a guess. What are the limits for compressor and turbine speeds, realistically? H can't spin faster than 125k, but the sky's the limit for the turboshaft assembly. Could flow more air for a given impeller diameter. Increased pressure/MAF was suggested by the former WDC in his social media blurb.

MGU-H = 1.26.
Article 5 power unit.
5.1.6 = Pressure charging.
5.2.4 = MGU-H.
The MGU-H IS GAPPED AT 125K rpm. although it can be coupled to the turbo shaft it must be direct drive, which means turbo is also gapped at 125k rpm, which in turn means no gearing between turbo and MGU-H.

[PhillipM]

Capped at, that doesn't actually mean you will run them both at full speed, and if someone wanted to run the turbine at 125krpm and the MGU-H at 100k max, they could gear it appropriately.

As we've said, repeatedly, gearing is allowed.

I don't believe it's used, but it is allowed.

[subcritical71]

If it can be clutched, can it not be geared for highest speed then reduce speed controlled by slip?

Interesting idea, maybe a type of torque converter clutch which can be modulated or locked up depending on desired operation. The regulation for the MGU-H does not specify that it needs to be the same angular velocity as the turbine and compressor, I don't see anything in the technical regulations that wouldn't allow slipping of the clutch.

It is to be a fixed speed ratio. If the clutch is used for speed control rather than engaging and disengaging the MGUH I am sure it would be deemed illegal.

A torque converter is not a clutch, but a variable speed device.

I meant something similar to the torque converter clutch (TCC). Is is used inside the torque converter to either slip or lock up. In some cars this is what gives the 'overdrive gear'. The amount of slip can be modulated so you can control the amount. I realize the regulations (or more than likely a technical directive) would prevent the use of this type of clutch because as you say it is a variable speed device. But isn't the clutch between the engine and gearbox also a variable speed device?

[saviour stivala]

Capped at, that doesn't actually mean you will run them both at full speed, and if someone wanted to run the turbine at 125krpm and the MGU-H at 100k max, they could gear it appropriately.

As we've said, repeatedly, gearing is allowed.

I don't believe it's used, but it is allowed.

What will the use of gearing be in a "direct drive?"
"GAPPED AT" is the maximum the MGU-H can be run (125k rpm) being direct driven from the turbo shaft, ditto the turbo max rpm.

[saviour stivala]

Capped at, that doesn't actually mean you will run them both at full speed, and if someone wanted to run the turbine at 125krpm and the MGU-H at 100k max, they could gear it appropriately.

As we've said, repeatedly, gearing is allowed.

I don't believe it's used, but it is allowed.

Saying it repeatedly doesn't mean it is right/a fact/actual.

[PhillipM]

You should take that advice yourself.

The exact wording is "a fixed ratio" not "the same angular velocity" - which is the term usually used in the rules to fix components to the same rpms. See the wording for compressor + turbine, etc.

[Zynerji]

You should take that advice yourself.

The exact wording is "a fixed ratio" not "the same angular velocity" - which is the term usually used in the rules to fix components to the same rpms. See the wording for compressor + turbine, etc.

A ratio could be 1.5:1.

Fixed means it can't change

It does not seem to mean it must be 1:1.