4 wheel engine braking

All that has to do with the power train, gearbox, clutch, fuels and lubricants, etc. Generally the mechanical side of Formula One.
Federico
1
Joined: 20 Jun 2009, 19:04

Re: 4 wheel engine braking

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You have to understand engine braking put more stress and additional wear to the drive chain and engine. Maybe you "ride the brakes for a fraction less" but you end up with substantial fatigue to the differential, clutch, shifter cogs, engine pistons, camshaft, etc. etc...
azarion wrote: so when you do need the full power of the brakes , they are there at the end of the race , =D>
they are there anyway, just make them 1mm ticker :P I bet the weight of this extra carbon is pretty much irrelevant...

alexbarwell
0
Joined: 20 Mar 2008, 14:19
Location: London

Re: 4 wheel engine braking

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Older forms of racing used engine braking as the drum brakes they had weren't up to much and might wel have had enough halfway through - seeing old jags starting to brake 100m before paddock bend is a bit of a hint. The brakes on F1 cars are massively more effective than engine braking; late braking keeps speed up until the last minute, but weaker braking needs to start earlier so is more like dragging the brakes - the plots of brake/throttle position of a racer looks very on/off, not much half-effort, engine braking augments and with the controlling power of the engine can even out the braking reducing the snatching that might happen. Closing throttle, reducing engine speed will act against the transmission speed as derived by the current inertia and gearing. Engine speed>transmission speed=acceleration, engine speed<transmission speed=deceleration(engine braking).
But you all know that I hope.
On the subject of smaller brakes as less weight and energy needed, they won't have the capacity for energy dissipation - hello mr brake-failure. Smaller brakes could be used where braking effort is less.
Or to save the brakes avoid using them.
I am an engineer, not a conceptualist :)

Jersey Tom
166
Joined: 29 May 2006, 20:49
Location: Huntersville, NC

Re: 4 wheel engine braking

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azarion wrote:i have noticed that every one has the idead that , engine braking is taking over the brakes ?? [-X just like a race car , its everything togeather , as a package , if you can not ride the brakes for a fraction less ( we all know how much a fraction adds up to in a race , smaller brakes means lower weight , less cooling means better aero (brake ducts),longer brake life , so when you do need the full power of the brakes , they are there at the end of the race , =D>
Braking distances are for the most part limited by the tires. More engine braking wouldn't shorten the braking distance or time.
Grip is a four letter word. All opinions are my own and not those of current or previous employers.

autogyro
53
Joined: 04 Oct 2009, 15:03

Re: 4 wheel engine braking

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4 wheel drive is out of F1 because of regulations but if all relevant regulations like tire size were open, 4WD would still not be a winning move unless perhaps in the wet. The complexity and weight of shafting etc would not give sufficient benefit over the traction ability of suitable rear tires on a 2WD set up.

It would be possible to do away with all wheel brakes if Kers was developed however. A generator inboard at the front with a torque balancing diff would harvest front wheel braking and I have a generator motor design integral with the gearbox for the rear, which would replace engine over run braking and rear disk braking with energy harvesting there.Why waste braking energy heating up bits of carbon?

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safeaschuck
1
Joined: 23 Oct 2008, 07:18

Re: 4 wheel engine braking

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Worth remembering that if doing away with traditional brakes the torque applied through every part of the drivetrain up to the engine/flywheel/braking mechanism would be much greater when braking than accelerating.
0-100mph in what? 4.5 seconds flat out, each part of the transmission and engine optimised for weight to tansmit this turning force. Brakes right by the wheels.
Then you change the requirements and brake the entire drivetrain 100-0mph in what? less than 2 seconds currently? double the turning force of acceleration and then some. Means every part from driveshafts, to layshaft to gear ratios, spiral bevel gear (argh) and maybe crankshaft needs beefing up big time. Nice idea, Not worth it???

autogyro
53
Joined: 04 Oct 2009, 15:03

Re: 4 wheel engine braking

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No lay shaft in my transmission it is all epicyclic with much higher burst loads.
Rear energy transfered electro magnetically as would be the case at the front with central generator. The transmission retardation on the rear would be fully progressive and not subject to the steps in ratios in current over run braking.
Inboard braking is not new and reduces unsprung weight.
It would all depend on development to give fast enough energy storage and capacity and the possible addition of an electronic heat dissipation system if the storage and charge rate were exceeded.

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flynfrog
Moderator
Joined: 23 Mar 2006, 22:31

Re: 4 wheel engine braking

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All of that complexity.

Or I could have a couple of squeezers and disks.

Ill take the disks any day lighter simpler less failure prone ect.

Not to mention I have yet to see a battery chemisty that will take the charge rate produced by F1 brake loads.

autogyro
53
Joined: 04 Oct 2009, 15:03

Re: 4 wheel engine braking

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Much less complex in actual fact.
No brake system and no conventional clutch in the transmission either.
I generator and a torque balancing cross shaft at the front and a smaller than current gear train at the rear. Seven stepped ratios for up shifts and much stronger.
Only addition would be wiring and electrical system.
With enough electrical power available after full Kers development, eventually there would be no need for the ice either.