F1technical.net

Here's a question I have been thinking about.

What type of engine flywheel is permitted within the regulations and what is the optimum arrangement?

I'm not struggling with the 'kinematics 101' side (any more than usual!), more with whether/not there might be any hidden opportunities?

Thoughts?

presumably there is as little flywheel as possible
and no more inertia than necessary in the MGU-K, this being geared at a speed multiplication of about 3x crankshaft speed

the PU should respond as quickly as possible during shifts so that drive torque is disrupted as briefly as possible
so upshifts need a burst of generator action, downshifts a burst of electric motor action, without these actions shifts would be protracted
the step response time constant of the MGU-K being a few tens of milliseconds, about the same as the ICE's
the PU response time on shifts will thus be much as a simple race ICE's would be

Flywheel ? no flywheel just the clutch..

Hi,

Thanks, both.

I think that is correct and covers the prevailing practice & logic.

The bit I cannot figure out is whether there is scope within the regs to design/optimise/innovate an "engine flywheel" to use as a "shadow ES".

What makes it illegal?

Does it get defined as a non-ERS ES. If so, why aren't engine and (conventional) flywheel inertias classified as a non-ERS ES?

I'm probably missing an obvious point.

Thanks.

Obvious problem with the engine flywheel is it is charging when the engine is accelerating (when you probably want to accelerate the car) and vice versa.

Or another way to look at it is that you are adding inertia to the car. Not many people voluntarily ballast a car to improve lap times if they are not underweight.

Thanks for the responses.

Yes, I agree - that's pretty clear.

A usable method requires a decoupled element within the clutch/flywheel assembly which can store braking KE for deployment on acceleration, thus achieving >[125 kW+ICE], without imposing a permanent "inertia burden".

The regulatory hurdles seem to be 1.24 (ERS definition) and App. 3 (energy flows).

The arguement for legality would be that the inertia of the engine/flywheel/clutch is already an ES of sorts and is already switchable (via the main clutch). No clutches types are specifically prohibited on the engine, especially within the flywheel/clutch assy.

Reading this back, I fancy my chances in court less and less ...

No need for the polar inertia provided by a flywheel with an F1 engine. In fact, current F1 clutch packs are incredibly small and lightweight.

http://scarbsf1.com/blog1/wp-content/up ... n_hand.jpg

I think people think I am suggesting a big flywheel, when what I am really suggesting is a clutched flywheel.

Is there a *legal* way to get a clutch within-the-clutch and/or a flywheel-within-the-flywheel to create a stealth ERS.

The argument would be that there is no rule against a clutch (or multiple clutches) or a flywheel so ...

It would be relatively easy to design one, it's the legality where my doubts are growing.

That is to say, the FIA screaming : That's an ERS under 1.24 and its energy flow must be limited as a second ERS as stated in App 3.

a flywheel of continuously variable M of I typically at a fixed multiple of engine speed (+ soft freehub effect ?)
ie a small modulating power continuously controlling a high power flow to and from a flywheel

and/or a flywheel at a continuously variable speed relationship wrt the engine - implemented by differential input epicyclic stage(s)
as in the Prius etc, a small modulating power continuously controlling a high power flow (here, to and from a flywheel)

and/or the flywheel could at a continuously variable relationship on the load side of the gearbox ie upstream of the road wheels

Brian Coat wrote:I think people think I am suggesting a big flywheel, when what I am really suggesting is a clutched flywheel.

Is there a *legal* way to get a clutch within-the-clutch and/or a flywheel-within-the-flywheel to create a stealth ERS.

The argument would be that there is no rule against a clutch (or multiple clutches) or a flywheel so ...

It would be relatively easy to design one, it's the legality where my doubts are growing.

That is to say, the FIA screaming : That's an ERS under 1.24 and its energy flow must be limited as a second ERS as stated in App 3.

I have been thinking about this.
My idea was to turn kompresor, MGU-H and turbine into flywheel. make it heavier. So when there is excess energy from K during braking(above 2MJ allowed to be stored in battery), use it to spin MGU-H.
I don't know is it allowed to have clutch on turbine shaft and how would it influence ICE operation.

Instead of using a flywheel as a ES (what I think wouldn't pay out of the weight of the flywheel vs the small amount of energy). Another way to go is completely without a "real" flywheel and use the K-unit as a virtual one.

Jolle wrote:Instead of using a flywheel as a ES (what I think wouldn't pay out of the weight of the flywheel vs the small amount of energy). Another way to go is completely without a "real" flywheel and use the K-unit as a virtual one.

What would you mean by that? What's the advantage?

sosic2121 wrote:

Jolle wrote:Instead of using a flywheel as a ES (what I think wouldn't pay out of the weight of the flywheel vs the small amount of energy). Another way to go is completely without a "real" flywheel and use the K-unit as a virtual one.

What would you mean by that? What's the advantage?

Use the K unit to help the smooth running of the engine at low revs and have it very responsive at all times. Plus it saves weight.

Even in a 4l street car you can have the responsiveness of a V12 racing engine.

Jolle wrote:

sosic2121 wrote:

Jolle wrote:Instead of using a flywheel as a ES (what I think wouldn't pay out of the weight of the flywheel vs the small amount of energy). Another way to go is completely without a "real" flywheel and use the K-unit as a virtual one.

What would you mean by that? What's the advantage?

Use the K unit to help the smooth running of the engine at low revs and have it very responsive at all times. Plus it saves weight.

Even in a 4l street car you can have the responsiveness of a V12 racing engine.

I understand. maybe no use on F1 engine, but it could help with road engines.