Ferrari Power Unit Hardware & Software

[Big Tea]

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?

It is normally called a fluid flywheel. It depends on the drag between 2 'plates' and the viscosity of the fluid.
I have read of experiments of having a movable plate (closer = less slip) so it may well be possible, but it seems cumbersome when a small basket would do. Although, there would not be the glaze problem you get with slipping plates.

[saviour stivala]

Pressure charging: single-stage compressor and exhaust turbine on a common shaft max RPM 125k, MGU-H: max RPM 125K.

[roon]

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.

We don't know if they used gearing. We do know the RA15H compressor was undersized and couldn't be made larger due to its installation location. Gearing a sufficiently sized compressor, and locating it in a less constricted area, is another matter.

Regarding having the MGUH spin faster than the turboshaft. A bigger lower speed turbo assembly might be better for efficiency. A faster clutched MGUH rotor could be utilized as a flywheel?

Pressure charging: single-stage compressor and exhaust turbine on a common shaft max RPM 125k, MGU-H: max RPM 125K.

You are the JJ Abrams of F1 technical regulations. Here's the original:

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.

5.2.4 The MGU-H must be solely mechanically linked to the pressure charging system. This mechanical link must be of fixed speed ratio to the exhaust turbine and may be clutched. The rotational speed of the MGU-H may not exceed 125,000rpm. The weight of the MGU-H (as defined in line 13 of Appendix 2 to these regulations) may not be less than 4kg.

Have a read: https://www.fia.com/file/54257/download ... n=5JfbyV2g

[sosic2121]

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.

5.2.4 The MGU-H must be solely mechanically linked to the pressure charging system. This mechanical link must be of fixed speed ratio to the exhaust turbine and may be clutched. The rotational speed of the MGU-H may not exceed 125,000rpm. The weight of the MGU-H (as defined in line 13 of Appendix 2 to these regulations) may not be less than 4kg.

So, it possible to spin turbo at let's say 180,000rpm while keeping MGU-H under 125,000rpm limit.

Or to keep MGU-H spinning at "some electric motor friendly" rpm, while keeping turbo spinning "fast enough".

[wuzak]

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.

The rules don't say "direct drive".

The rules say that:

• The MGUH must be mechanically linked to the pressure charging system (ie turbo)
• The mechanical link must be a fixed speed ratio, and
• The MGUH can be clutched

A mechanical link could be direct coupling, gearing, belt or some other mechanical link.

Nowhere in the rules does it specify that the MGUH must be on the same axis as the turbo's shaft. It is unlikely that is the case, as the gear drive would put side loading on the turbo shaft, which is not good for reliability.

The fixed speed ratio means that whatever relationship between the MGUH's rpm and the turbo's rpm must remain constant.

Why would you consider doing this? The turbo is very large for the size of engine - both the compressor and, especially, the turbine are oversized. That means they have considerable mass moment of inertia. Without looking too closely at the maths, I believe lower rpm means that accelerating the turbo assembly requires less power.

And, of course, the MGUH can be decoupled from the turbo - when it isn't accelerating the turbo or recovering energy, or for trickier purposes such as funneling power to or from the MGUK.

[wuzak]

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.

5.2.4 The MGU-H must be solely mechanically linked to the pressure charging system. This mechanical link must be of fixed speed ratio to the exhaust turbine and may be clutched. The rotational speed of the MGU-H may not exceed 125,000rpm. The weight of the MGU-H (as defined in line 13 of Appendix 2 to these regulations) may not be less than 4kg.

So, it possible to spin turbo at let's say 180,000rpm while keeping MGU-H under 125,000rpm limit.

Or to keep MGU-H spinning at "some electric motor friendly" rpm, while keeping turbo spinning "fast enough".

Yes.

[wuzak]

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?

The clutch between the engine and gearbox has limited time of operation.

It is used by the drivers for starts.

Otherwise it is controlled by the electric/hydraulic systems.

9.2.6 When the clutch operating device is released from its maximum travel position it must return to its resting position within 50ms.
The maximum delay allowed, computed from the respective signals as recorded by the ADR or ECU, between the clutch driver control input signal and the corresponding output demand being achieved is 50ms.

9.2.7 Any device or system which notifies the driver of the amount of clutch slip or engagement is not permitted.

9.8.4 The maximum permitted duration for down changes and up changes is 300ms and 200ms respectively. The maximum permitted delay for the latter is 80ms from the time of the driver request to the original gear being disengaged.
The duration of a gear change is defined as the time from the request being made to the point at which all gear change processes are terminated. If for any reason the gear change cannot be completed in that time the car must be left in neutral or the original gear.

So, you can have 300ms of slip, but only when changing gear. Otherwise the driver has to control it.

[subcritical71]

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?

The clutch between the engine and gearbox has limited time of operation.

It is used by the drivers for starts.

Otherwise it is controlled by the electric/hydraulic systems.

9.2.6 When the clutch operating device is released from its maximum travel position it must return to its resting position within 50ms.
The maximum delay allowed, computed from the respective signals as recorded by the ADR or ECU, between the clutch driver control input signal and the corresponding output demand being achieved is 50ms.

9.2.7 Any device or system which notifies the driver of the amount of clutch slip or engagement is not permitted.

9.8.4 The maximum permitted duration for down changes and up changes is 300ms and 200ms respectively. The maximum permitted delay for the latter is 80ms from the time of the driver request to the original gear being disengaged.
The duration of a gear change is defined as the time from the request being made to the point at which all gear change processes are terminated. If for any reason the gear change cannot be completed in that time the car must be left in neutral or the original gear.

So, you can have 300ms of slip, but only when changing gear. Otherwise the driver has to control it.

I see what your saying, so they took the time to give these limitations to the gearbox clutch, but then for the MGU-H they left it as you can have one..... seems wide open for exploitation to me, assuming it makes sense with the operating characteristics of the turbine, compressor and MGU-H. Kind of like the engines are limited to 15,000RPM, but don’t spin anywhere close to that limit, due to various reasons but basically because it doesn’t make sense to operate in that region given all of the other rules.

[subcritical71]

I don’t know if this has been posted before, but it’s a great read on the strategies that could be employed on the PU’s. It was written just prior to the 2014 season. Much of its contents are very much applicable today.

https://core.ac.uk/download/pdf/82194974.pdf

[saviour stivala]

What is the maximum speed (RPM) that the MGU-H is permitted to run at and what is the maximum speed RPM that the turbocharger is ran at?.

[restless]

IIRC in 2015 due to being limited for turbo size, Honda was trying to run the turbo close to limit (125K was assumed)
And had many problems. The common reasoning in the forum was that everyone else is using lower rpms

[saviour stivala]

Fully agree, the turbo/MGU-H maximum RPM situation is the same as that of the ICE, hardly anybody ever try and approach the maximum RPM. But that doesn’t mean that those maximum RPM’S are not mandated. The actual and factual specification is as follows:. Energy recover system ERS:
Max exhaust turbine RPM = 125K.
Max MGU-H RPM = 125k.
Max power MGU-H = unlimited.
Max energy recovery per lap MGU-H = unlimited.
Max energy deployment per lap = unlimited.
Max energy storage per lap = 4MJ.
Max MGU-K RPM = 50K.
Max power MGU-K = 120KW/161BHP.
Max MGU-K energy recovery per lap = 2MJ.
Max MGU-K energy deployment per lap = 4MJ (33.33 seconds full power).
The other day henry was saying that with the turbo exhaust waste gates open the exhaust gasses are still able to assist turbine rotation. I invite him have a look at Andy Cowell graphically explaining the way exhaust gasses bypasses the turbine (Mercedes 2016 F1 exhaust explained).

[johnny vee]

I don’t know if this has been posted before, but it’s a great read on the strategies that could be employed on the PU’s. It was written just prior to the 2014 season. Much of its contents are very much applicable today.

https://core.ac.uk/download/pdf/82194974.pdf

An awesome read. Thank you Subcritical

[wuzak]

Fully agree, the turbo/MGU-H maximum RPM situation is the same as that of the ICE, hardly anybody ever try and approach the maximum RPM. But that doesn’t mean that those maximum RPM’S are not mandated. The actual and factual specification is as follows:. Energy recover system ERS:
Max exhaust turbine RPM = 125K.
Max MGU-H RPM = 125k.
Max power MGU-H = unlimited.
Max energy recovery per lap MGU-H = unlimited.
Max energy deployment per lap = unlimited.
Max energy storage per lap = 4MJ.
Max MGU-K RPM = 50K.
Max power MGU-K = 120KW/161BHP.
Max MGU-K energy recovery per lap = 2MJ.
Max MGU-K energy deployment per lap = 4MJ (33.33 seconds full power).
The other day henry was saying that with the turbo exhaust waste gates open the exhaust gasses are still able to assist turbine rotation. I invite him have a look at Andy Cowell graphically explaining the way exhaust gasses bypasses the turbine (Mercedes 2016 F1 exhaust explained).

Correct
Incorrect

The exhaust turbine speed is not restricted.
The maximum energy storage (maximum SOC - minimum SOC) at any one time is 4MJ. It is not a per lap value.
The MGUK can deploy 4MJ of energy per lap from the ES.

[sosic2121]

Fully agree, the turbo/MGU-H maximum RPM situation is the same as that of the ICE, hardly anybody ever try and approach the maximum RPM. But that doesn’t mean that those maximum RPM’S are not mandated. The actual and factual specification is as follows:. Energy recover system ERS:
Max exhaust turbine RPM = 125K.
Max MGU-H RPM = 125k.
Max power MGU-H = unlimited.
Max energy recovery per lap MGU-H = unlimited.
Max energy deployment per lap = unlimited.
Max energy storage per lap = 4MJ.
Max MGU-K RPM = 50K.
Max power MGU-K = 120KW/161BHP.
Max MGU-K energy recovery per lap = 2MJ.
Max MGU-K energy deployment per lap = 4MJ (33.33 seconds full power).
The other day henry was saying that with the turbo exhaust waste gates open the exhaust gasses are still able to assist turbine rotation. I invite him have a look at Andy Cowell graphically explaining the way exhaust gasses bypasses the turbine (Mercedes 2016 F1 exhaust explained).

IMO bolded parts are not true!

It seems from regulations that turbo speed is unlimited.

Battery effective capacity is limited to 4MJ, but you can charge it as many times you want/can - unlimited.

2MJ is the K>ES limit, but K>H is unlimited.

Also, 4MJ is limit on ES>K deployment, but not on H>K which is unlimited.

Also, having a bypass around turbo doesn't mean a portion of gasses doesn't go trough the turbine...