Is engine braking really necessary?

All that has to do with the power train, gearbox, clutch, fuels and lubricants, etc. Generally the mechanical side of Formula One.
autogyro
autogyro
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Joined: 04 Oct 2009, 15:03

Re: Is engine braking really necessary?

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From a modern technology point of view the whole powertrain in F1 and its methods of operation are completely 'artificial' and forced solely by regulations.
This is very obvious in overrun braking/energy harvesting.

There should be no need to use the engine for braking whatsoever now, KERS can achieve a much better result and supply both traction control (under braking and acceleration) and a full range of diff action.

All current problems are being caused by the need to cobble up this incomplete use of available technology.

It is all being done for the sake of aero, the almost standardised powertrains resulting from this and the close racing that results.

Tommy Cookers
Tommy Cookers
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Joined: 17 Feb 2012, 16:55

Re: Is engine braking really necessary?

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Good stuff !
I shall attempt to follow your suggestion.

I've tried to avoid thinking about KERS, calling it 'pretend KERS' because it only recovers about 2% of brake energy.

On some tracks (Monaco?) it must be difficult to fully charge; now I think you're saying that it's charged partly on 'waste energy' deliberately created (in part) for this ? So they didn't even hide this as I suggested !

Maybe F1 doesn't always tell us (or itself) the whole truth ?


Any way, there's always some EB, we all know this. It could be quite large (relative to grip) in eg a 1968 Can Am car or a 1937 GP car ?

Often the track forces a blend from braking to corner entry, so we are all unknowingly trail brakers via the inherent residual EB. Both types of driving will have have the same EB at this point.

This is good EB, but not what is generally regarded as EB.

autogyro
autogyro
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Joined: 04 Oct 2009, 15:03

Re: Is engine braking really necessary?

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Those of us involved with electric and hybrid road car development soon realise that the best way to save energy on an average road journey is to coast the powertrain in deceleration.
I had an A95 Wetminster that did this with a freewheel cable on a Borg Warner overdrive unit in 1969.
This saves far more energy than trying to rcover it.

KERS's only come into there own for stop start motoring mainly in Cities and Towns and in hard braking conditions such as motorsport, so there is little direct comparison between F1 and the real world.

autogyro
autogyro
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Joined: 04 Oct 2009, 15:03

Re: Is engine braking really necessary?

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gato azul wrote:
Tommy Cookers wrote: ANSWER !

I think drivers change down sequentially because the rules were changed to force this (before KERS), this was to cut down on conspicuous involvement of software.
I would like to see, that rule you refereing to.
The main reason that they change down sequentially, lays in the layout/design of the gearbox/gear selection mechanism.

Ever since people stoped using H-pattern gear selectors, you will be hard pressed to "skip" a gear on downshift.

I don't think F1 rules, have ever mandated "sequential" gearboxes, it's just much easier to "automate/assist" an sequential g/box, than it is to do the same with an H-pattern shift.
(Subarus frist pedal shift in the Gr.A Legacy/Imprezzas,a.k.a. the "ghost box", would be the only one, which comes to my mind, when people "automated" an H-Pattern selector box.
There are may others, but I'm not aware of them in racing/rallying, BMW's first SMG would be a road car example).

Even in racing series, where there is no KERS, and no paddle shift (AGS), drivers racing sequential boxes, will still shift down in sequence, as you "can't skip a gear" with this boxes.

Having worked, in one of the few series, which until some years ago, still raced H-pattern g-boxes, I can tell you, that very few drivers, and only under some specific conditions, would change, let's say from 5th to 2nd, without "going through the box".
Most of the time, they would still downshift sequential, and make use of EB, to assist with decelleration/braking.
KERS would have nothing to do with it, as it is not used there.

Top drivers will use missed shifting (down) and short shifting (up) far more than the also rans.

With a layshaft fixed ratio gearbox even with button or paddle shift systems, it is possible to design the shift mechanism to allow shifts from any gear to any other gear when ever required.
Regulations are the main reason for sequential, although I discussed sequential with Garry Anderson for the Jordan F1 cars before anyone else did, because they could not afford a fully automatic gear system at the time and sequential MCycle was faster at the time and kept Jordan up to speed for less money. (ask Garry he is now on telly).
Jordan chose 7 ratios which became the regulated maximum number of gears allowed in F1.

Motorcycles were the only standard application before that and are still using a silly lever in a bowl of custard operated by the riders foot, in a similar obsolete way to a horse control system for a guy driving a chariot in Roman times.
Motorbikes are so out of date it is untrue.
Wiggling your ankle and leg when trying to control cornering lean, how silly can you get.
I offered Honda an alternative powertrain decades ago.
I think it is the hells angels emotional overview that keeps MC's in the stoneage.
Hairy bikers and all that.

KERS does not prevent missing gears in downshift sequence, in fact with a 'properly' (not F1) designed powertrain with energy recovery system, it is possible to idle the engine on overrun and provide both generator recovery/braking totally smoothly with no torque gaps and complete braking and diff control.
With sufficient energy storage and control and with front wheel generators added, it is possible to do away with conventional brakes all together,
This is where F1 should be, it should not be stagnant pandering to aero downforce.

Tommy Cookers
Tommy Cookers
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Joined: 17 Feb 2012, 16:55

Re: Is engine braking really necessary?

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thanks for the above, useful info !


Surely full F1 braking based on recovery would only be viable with mechanical systems both for recovery and storage, combinihg gear (differential input(s) including CVT) for recovery, and flywheel(s) or flybar(s) for storage ?
F1 brakes are 5000-7000hp systems, equivalent electric recovery systems would be much too heavy and bulky for F1.

(mechanical system) ....... 4 cyl 400hp engine running at 100% continuously, and power exported to the transmission (also recovering brake energy), the transmission then driving the car as required, using both recovered and engine power

.... how hard can it be ?


Agreed, if F1 is to spawn 'son of pretend KERS', the next step is multiple motor/generators, these might recover 5% of brake energy !

gato azul
gato azul
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Joined: 02 Feb 2012, 14:39

Re: Is engine braking really necessary?

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autogyro wrote: Regulations are the main reason for sequential
Show me the regulations, that demand a sequential gearshift mechanism please, in any championship which does not use a mandated gearbox.
Surely, neither the current, nor the so far published draft version of the 2014 F1 technical Reglement, demand a sequential gear shift mechanism.
autogyro wrote: Top drivers will use missed shifting (down) and short shifting (up) far more than the also rans.
If this is the case, and they see an advantge in it, then I guess it would be fair to assume, that they would demand such a possibility in their current gearboxes, if permitted by the rules - why give away a benefit to the "also runs".

And BTW, we may have a different understanding of the term "short shifting", which is o.k. - maybe you can elaborate a bit on the advantages on skipping a gear while upshifting.
Assuming a resonable ratio choice to start with, which would be the case in almost any race series, which allows for free ratio selection.

autogyro
autogyro
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Joined: 04 Oct 2009, 15:03

Re: Is engine braking really necessary?

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If this is the case, and they see an advantge in it, then I guess it would be fair to assume, that they would demand such a possibility in their current gearboxes, if permitted by the rules - why give away a benefit to the "also runs".

And BTW, we may have a different understanding of the term "short shifting", which is o.k. - maybe you can elaborate a bit on the advantages on skipping a gear while upshifting.
Assuming a resonable ratio choice to start with, which would be the case in almost any race series, which allows for free ratio selection.
The huge levels of downforce prevent both worthwhile use of missing shifts during downshifting and any development in powertrains to make use of the benefits. I believe this is now referred to as 'short shifting' probably because few these days have full knowledge of transmission control potential. We always referred to short shifting for upshifts but it is much the same definition for both.

I miss gears during upshifting all the time (by choice :lol: ), it is a good way to save fuel (energy) when high acceleration is not required or when the car is going down hill, for the same reason and also to help balance braking and throttle control.
High downforce also prevents this skill.

The balancing act of engine braking, wheel brakes and energy recovery is almost impossible to deal with when the powertrains are in the current configuration.

autogyro
autogyro
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Joined: 04 Oct 2009, 15:03

Re: Is engine braking really necessary?

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Tommy Cookers wrote:thanks for the above, useful info !


Surely full F1 braking based on recovery would only be viable with mechanical systems both for recovery and storage, combinihg gear (differential input(s) including CVT) for recovery, and flywheel(s) or flybar(s) for storage ?
F1 brakes are 5000-7000hp systems, equivalent electric recovery systems would be much too heavy and bulky for F1.

(mechanical system) ....... 4 cyl 400hp engine running at 100% continuously, and power exported to the transmission (also recovering brake energy), the transmission then driving the car as required, using both recovered and engine power

.... how hard can it be ?


Agreed, if F1 is to spawn 'son of pretend KERS', the next step is multiple motor/generators, these might recover 5% of brake energy !
With induction brakes it depends what you do with all the energy.
Dont forget the brakes used to deal with it now are not that big or heavy.
Ancient idea though.
It should be fairly easy to achieve a 'proper' system.
It wont happen with the current regs though.

autogyro
autogyro
53
Joined: 04 Oct 2009, 15:03

Re: Is engine braking really necessary?

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Show me the regulations, that demand a sequential gearshift mechanism please, in any championship which does not use a mandated gearbox.
Surely, neither the current, nor the so far published draft version of the 2014 F1 technical Reglement, demand a sequential gear shift mechanism
I think you are correct as regard to a specific regulation.
However, all the other regulations that allow high downforce and restrict powertrain development more or less mandate a sequential shift.

http://en.ria.ru/sports/20120518/173537362.html

Perhaps I should give them a ring?