Overdriven transmission

[Tommy Cookers]

I wouldn't rule it out yet. An MGU for this purpose need only handle the power for a second or so on a launch and much less time for shifting. I think it might be able to have one larger mgu for the 1st gear and 7 smaller ones. the extra mass is somewhat offset by the absence of a clutch.
Hydraulic motors and an accumulator may be a better way to go though.

doesn't this make an ECVT (continuous mixing of 1 MGU with ICE) look simple and cheap ?

now that power electronics has finally stepped uo to the plate we can emulate stuff done by mechanical engineers 60-80 years ago
when the Fell locomotive transmission had motor mixing and gimmick-free CVT by controlling the fill of simple hydraulic couplings
intelligent control would hugely benefit these cheap devices ie as its nuances would now enable locking of the fluid couplings
yes, a huge benefit, as in the modern car automatic

they even might look at some developments eg the magnetic particle or magnetic fluid clutch again in this light
though 99.9% of the time a clutch only needs a modulation action at partial torque (except maybe in F1)
at full torque it needs only to be solid (locked)

regarding temporary over-torque or power from the MGU
whether called drives or controllers, the power electronics that make an MGU work will not support this ie they will need uprating
there is a permanent bulk/weight/cooling cost to enabling the MGU's apparently free excursions into temporary over-performance

[gruntguru]

I wouldn't rule it out yet. An MGU for this purpose need only handle the power for a second or so on a launch and much less time for shifting. I think it might be able to have one larger mgu for the 1st gear and 7 smaller ones. the extra mass is somewhat offset by the absence of a clutch.

Exactly.
I have raced many types of vehicle and I cannot remember one where I used full power at launch.
The use of the forward electrically driven annulus from stationary is solely to establish vehicle inertia.
In fact electrical launch can completely eliminate wheel spin and allow a crawl capability to unbeach the car from gravel traps.
If the ic engine is fully modulated during ratio shifts very little energy is needed.

I am certainly not knocking your ESERU in its entirety - I can see it has many advantages.

[autogyro]

I am certainly not knocking your ESERU in its entirety - I can see it has many advantages.

No problem at all gg I respect your comments.
It will either work as I think or it will not.
I just need a development budget.
I am a bit busy with a defence project at present I might need you advice on that soon.

I think the thread subject on overdriven transmissions needs more attention though.
I feel the modulators might bump these posts back to my ESERU thread if not.

je suis charlie

[riff_raff]

I didn't realize how important efficiency was for F1. an extra gearset would be a serious loss then.....

What makes drivetrain losses such a concern is because 100% of the output power of the engine passes thru the system. Improvements in drivetrain efficiency are basically free power. F1 drivetrain engineers use every trick they have to reduce mechanical losses. They use special oil seals, ceramic ball bearings, ceramic CV components, and dry-sump gearbox lube systems to minimize windage losses.

Of course, one suggestion I would make to F1 transmission designers to improve efficiency, assuming they are not already doing this, is to use a face gear type geometry for the final drive rather than a spiral bevel type gear geometry. A face gear mesh would give up to a .25 point better efficiency than a spiral bevel mesh. Plus the face gear is much easier to set up.

[autogyro]

What makes drivetrain losses such a concern is because 100% of the output power of the engine passes thru the system. Improvements in drivetrain efficiency are basically free power. F1 drivetrain engineers use every trick they have to reduce mechanical losses. They use special oil seals, ceramic ball bearings, ceramic CV components, and dry-sump gearbox lube systems to minimize windage losses.

Of course, one suggestion I would make to F1 transmission designers to improve efficiency, assuming they are not already doing this, is to use a face gear type geometry for the final drive rather than a spiral bevel type gear geometry. A face gear mesh would give up to a .25 point better efficiency than a spiral bevel mesh. Plus the face gear is much easier to set up.

There are other reasons for choosing spiral bevel gear pairs.
One reason is the control needed during deceleration.