Off throttle gases - without engine maps

[Cam]

knowing that engineers can't 'unlearn' things, and seeing RedBull and others continually trying to seal the diffuser, even after the engine maps were change to disallow it, got me thinking - can they achieve a similar result some other way.

The trick is to get exhaust gases to continue, to seal the diffuser, when you're not on the throttle, correct? Previously, this was done via engine maps - now banned.

Could you get a similar result by playing with the clutch? That is - clutch in & rev like mad - to produce more off throttle gases than normal?

I'm no engineer, but I drive a manual car and I can do this method in that, and I assume it produces more gases, so could some tricky be invoked to bypass the mapping rules to allow this? Would it be viable even? Just a theory.

[flynfrog]

an F1 clutch is tiny and will only last for a couple of launches. It would die a quick death trying to slip it in a corner.

[youtube]http://www.youtube.com/watch?v=89kE6mcF2JM[/youtube]

[Lycoming]

My first immediate thought is "sounds like a fantastic way to destroy the clutch, the engine, or both".

But hey, while we're on this train of though, why not have an engine that operates at a high, constant RPM, and then modulate torque demand purely using the clutch? You could design your engine for an almost infinitesimally small power band and reap the reward in peak power without any of the disadvantages in terms of driveability. As a bonus, you get a pretty much constant supply of exhaust gasses. All you need is a clutch that can survive, which means dissipating the heat caused by slip when not fully engaged (ie. the exit of almost every corner), and an engine controller that can hold a constant RPM in the face of rapidly varying torque demand.

I'll leave it to others to comment on the feasibility of those two items. Also, note that I'm just throwing this out there; I'm not exactly endorsing the idea.

[bhall]

[...]

But hey, while we're on this train of though, why not have an engine that operates at a high, constant RPM, and then modulate torque demand purely using the clutch? [...]

'Cause it's illegal.

5.6.4 Engine control must not be influenced by clutch position, movement or operation.

EDIT Trois: I just realized the first two had nothing to do with the stated purpose of the thread.

[flynfrog]

But hey, while we're on this train of though, why not have an engine that operates at a high, constant RPM, and then modulate torque demand purely using the clutch? /snip

When I was racing 2 stroke race bikes. Some of the engines were pretty peaky we used the exact method you mentioned. You would slip the clutch in the corner to keep the engine up on the pipe so you can get a good drive off of the corner. We would build the engines with extra clutch plates and steels to take the abuse. A clutch would last maybe 15 hours of use depending on the power of the motor.

[autogyro]

If you were to slip an F1 clutch without electronic torque modulation from the start, the clutch would burn out in maybe 20 seconds.
The clutch is only 'slipped' or disengaged when the car is dynamic in conjunction with an engine mapping program.
This has to be done to cover the 'gap' in the so called seamless gearshifts.

If you wanted to 'slip' an F1 clutch without modulation, it would have to be a lot larger and much heavier.
As it is the moving parts in an F1 engine are so light, there is very little inertia.
An F1 car is also very light so it is easy to move from stationary without using high torque levels.

An F1 powertrain cannot be compared to conventional vehicles.

Any diffuser/wing blowing from the exhaust has to be achieved either during deceleration or with the clutch disengaged if their is no mapping.
It cannot be done by 'slipping ' the clutch without putting huge wear on the friction plates.
Off throttle gas flow without using an engine map would not be very useful.
A decent volume of exhaust gas off throttle can only be achieved if the fueling is maintained or increased and the engine output torque is reduced through control of the ignition system. (variable valving is illegal)

[Nando]

The clutch won´t take any damage,

That is - clutch in & rev like mad

This would mean the clutch and gearbox is disengaged and essentially dry-revving the engine.
If anything it´s the engine that will take damage.
It would only be possible to do after all your downshifting is complete though unless you have some trick-software which most likely would be illegal.

[flynfrog]

The clutch won´t take any damage,

That is - clutch in & rev like mad

This would mean the clutch and gearbox is disengaged and essentially dry-revving the engine.
If anything it´s the engine that will take damage.
It would only be possible to do after all your downshifting is complete though unless you have some trick-software which most likely would be illegal.

and what do you think happens when the engine and gearbox has to magically be back at the same speed on exit of the corner?

[Nando]

and what do you think happens when the engine and gearbox has to magically be back at the same speed on exit of the corner?

Either automatic or manual rev-matching.
And it would be before the exit of the corner,

[tim]

Although illegal I would have thought I completely different gearbox philosophy such as CVT would be the solution. You need too also bare in mind the engine won't produce so much high energy exhaust flow unless their is load on the engine or an "exotic"engine map.

[Nando]

the whole idea is quite mad and unrealistic on many different levels yes.

[langwadt]

Although illegal I would have thought I completely different gearbox philosophy such as CVT would be the solution. You need too also bare in mind the engine won't produce so much high energy exhaust flow unless their is load on the engine or an "exotic"engine map.

yep with no load the engine wouldn't produce much exhaust energy unless you play with the ignition etc, so it blows
instead of producing torque, which is illegal

Though it might be hard on the engine maybe you could "abuse" the rev limiter?

5.7 Engine high rev limits :
...
Except for the above conditions, ignition, fuelling and throttle may not be used to artificially control the engine speed or alter the engine response in a rev range more than 1,000rpm below the final rev limit.

[Tommy Cookers]

the new Renault throttle mapping article appears (as do previous features) to say that when the driver has fully lifted
the engine's throttles must control the engine to produce no more than zero torque throughout the lifted phase

with fuel cut off (as in a road car) in this phase the engine would develop a negative torque of about 20% of its maximum (ie the frictional and pumping losses, aka 'engine braking')
this does not happen in F1, sufficient fuel and air induction is used to cancel most or all the losses
RenaultSport in the Oct 2012 article said this 'overrun push' consumes up to 2 kg of fuel/race

this 'zero torque' rule gives deliberate and sustained running of the engine producing about 100 bhp worth of exhaust gas
this is 'cold blowing' ie normal ignition timing must be used
(hot blowing allowed retarded timing, degrading efficiency to produce more and hotter exhaust within the zero torque rule)

so apparently there is still today significant exhaust for manipulating the aero

(and the KERS is (conveniently) not really harvesting energy that is genuine/waste KE
because 2kg overrun push fuel/race will artificially increase the KE and supply all the KERS energy ie 400 kJ/lap !!)

[timbo]

Not quite along the thread discourse, but on topic for the title=)

It seems that teams now play with engine blowing during downshifts. There were videos from Australia with a loud noise during downshifts from Ferrari, and now there's videos of recent pole lap of Nico Rosberg, and you can hear bursts of noise that coincide with his downshifts.
So I guess teams started to use throttle blips to maximize exhaust flow during braking.

[Shrieker]

Although illegal I would have thought I completely different gearbox philosophy such as CVT would be the solution. You need too also bare in mind the engine won't produce so much high energy exhaust flow unless their is load on the engine or an "exotic"engine map.

Too bad they banned CVT back in 1993 lol