F1 Brake Discs

[Edis]

I suspect that inboard brakes in a modern F1 vehicle would require solutions to be found for several potential issues. A braking event is quite violent, so a structural engineer would like the torque tube to be stiff (hence large diameter) to avoid dynamic problems caused by the torque tube "winding up". On the other hand, an aerodynamicist would like the torque tube not to interfere with airflow, so he would like a small diameter tube (hence flexible). The unsprung weight reduction would be offset, to some extent, by the need to add a strong CVJ at either end of the torque tube. Cooling would be an issue that might be solved by water-cooling, but that solution would carry with it a weight overhead. Finally, there is not too much room at either axle to package inboard brakes in a modern F1 chassis

Of course if we started to design ways to convert this brake heat directly into electrical energy, then that would be a whole new ball game would it not?

It would still require friction brakes of similar dimensions

Not only would it be impossible to dimension a KERS system which can handle the sort of power consumed by friction brakes at peak load, which is in excess of 2000 kW, but the friction brakes would also be required at low speed when an electric machine lose braking torque. Friction brakes would also be required to serve as a back up in case of electrical failure.

[horse]

Friction brakes would also be required to serve as a back up in case of electrical failure.

Perhaps they should reinstate KERS as a back up for friction brakes?

[autogyro]

I suspect that inboard brakes in a modern F1 vehicle would require solutions to be found for several potential issues. A braking event is quite violent, so a structural engineer would like the torque tube to be stiff (hence large diameter) to avoid dynamic problems caused by the torque tube "winding up". On the other hand, an aerodynamicist would like the torque tube not to interfere with airflow, so he would like a small diameter tube (hence flexible). The unsprung weight reduction would be offset, to some extent, by the need to add a strong CVJ at either end of the torque tube. Cooling would be an issue that might be solved by water-cooling, but that solution would carry with it a weight overhead. Finally, there is not too much room at either axle to package inboard brakes in a modern F1 chassis

Of course if we started to design ways to convert this brake heat directly into electrical energy, then that would be a whole new ball game would it not?

It would still require friction brakes of similar dimensions

Not only would it be impossible to dimension a KERS system which can handle the sort of power consumed by friction brakes at peak load, which is in excess of 2000 kW, but the friction brakes would also be required at low speed when an electric machine lose braking torque. Friction brakes would also be required to serve as a back up in case of electrical failure.

I am not suggesting doing away with the current disk brakes.
2000KW hmm interesting.
Job for nano photon tunneling me thinks.

[riff_raff]

F1 cars already have a very effective inboard brake system at the rear. It's called "the engine". If you've ever closely watched an F1 race, you'll have noted that the drivers do something called "downshifting" as they approach a corner. The purpose of this "downshifting" procedure is to use the engine and transmission as a type of mechanical gas compression absorber device to dissipate the kinetic energy of the chassis, and thereby slow its forward velocity. It's very effective and does not require any additional hardware on the vehicle.

Diabolically clever, eh?

[raceman]

F1 cars already have a very effective inboard brake system at the rear. It's called "the engine". If you've ever closely watched an F1 race, you'll have noted that the drivers do something called "downshifting" as they approach a corner. The purpose of this "downshifting" procedure is to use the engine and transmission as a type of mechanical gas compression absorber device to dissipate the kinetic energy of the chassis, and thereby slow its forward velocity. It's very effective and does not require any additional hardware on the vehicle.

Diabolically clever, eh?

errm, uh

Terry, I kinda agree with above statement; but doesn't the regulations say engine braking is not allowed nowadays in F1?? pls tell me if I am wrong.

still, downshifting whilst approaching any corner would reduce your speed anyway without applying brakes IMO - but engine braking is different I guess

Engine Braking

[MattyT]

but doesn't the regulations say engine braking is not allowed nowadays in F1?? pls tell me if I am wrong.

Actually it's the opposite, they banned anti-engine-braking technologies. If I remember correctly, Massa had quite a time getting used to in the Australia as he was locking the rears when shifting down (due to the engine speed being slower than road speed).

Previous to this, they defeated engine braking (not sure how) allowing them to use only brakes for slowing, and being able to downshift to any gear (say from 7th to 2nd) and be ready for the exit of the corner.

The braking time in F1 is so short that engine braking would have little to no benefit to the braking distance.

[alelanza]

but doesn't the regulations say engine braking is not allowed nowadays in F1?? pls tell me if I am wrong.

Actually it's the opposite, they banned anti-engine-braking technologies. If I remember correctly, Massa had quite a time getting used to in the Australia as he was locking the rears when shifting down (due to the engine speed being slower than road speed).

Previous to this, they defeated engine braking (not sure how) allowing them to use only brakes for slowing, and being able to downshift to any gear (say from 7th to 2nd) and be ready for the exit of the corner.

The braking time in F1 is so short that engine braking would have little to no benefit to the braking distance.

Not exactly. The engine was used, computer controlled, to prevent the rear axle from locking up by controlling the amount of engine braking going on, abs like if you will. Nowadays there's still engine braking happening, but it's no longer computer controlled, instead drivers have a dial in the steering wheel to setup how much they want before going into a given corner. It's part of the setup work they do over the weekend.

[Lurk]

There is no engine braking in formula one because a formula one engine has no inerty. No inerty, no braking.

If you're not sure, compare F1 engine sound during braking to a 911 Cup (where drivers use engine brake savagely)

[autogyro]

A F1 engine is always up at high revs during a race.
The deceleration using the wheel brakes is so rapid there is almost no time for any gearshift to result in usable engine braking.
It is more important to make sure the car is in the correct gear to drive through the corner and for corner exit.
Even so, the driver has to be careful not to upset car balance with any effect from engine braking.

[xpensive]

A F1 engine is always up at high revs during a race.
The deceleration using the wheel brakes is so rapid there is almost no time for any gearshift to result in usable engine braking.
It is more important to make sure the car is in the correct gear to drive through the corner and for corner exit.
Even so, the driver has to be careful not to upset car balance with any effect from engine braking.

Boy, aren't you the smart one?

[ESPImperium]

In a F1 car, if you were to use engine braking really harshly, you would end up with flat spots on the rear tyres as they would lock up lots due to the force of a F1 engine. Thats the best case senario, with the wheels locking up, you would also probably spin the car as well, resulting in probably crash.

Where as sports cars and most tin top racing, you would typically use engine braking more than actual brakes as you would want to carry more speed thrugh a corner on a quali lap, or brake even later on a pass in a race.

Any one who uses engine barking on their road cars, like myself, can save up to arround £150 a year in fuel as you arnt wasting the energy generated for slowing down, if you take that figure on arround 6000 miles traveled each year.

Thats my take on engine braking.

Braking, in F1 needs to be a ballanced thing otherwise the car will either understeer off into the gravel or oversteer into a crash. Hence why you need the brakes to be good on a F1 car, and thats why some tracks are "neutering" themselvs at current as the brake forces would kill the car by the end of the race, a thing that wouldnt be a problem is Williams had aggreed to the discs being enlarged by up to 20mm for the 2010 season.

[alelanza]

There is no engine braking in formula one because a formula one engine has no inerty. No inerty, no braking.

If you're not sure, compare F1 engine sound during braking to a 911 Cup (where drivers use engine brake savagely)

What's inerty?

Anyways, as it seems there's still some confusion

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

For non spanish speakers, minute 3:35 and on, 'freno de motor' = engine braking. Also consider we had some kers braking so to speak last year.

[autogyro]

A F1 engine is always up at high revs during a race.
The deceleration using the wheel brakes is so rapid there is almost no time for any gearshift to result in usable engine braking.
It is more important to make sure the car is in the correct gear to drive through the corner and for corner exit.
Even so, the driver has to be careful not to upset car balance with any effect from engine braking.

Boy, aren't you the smart one?

Glad you think so, although I do not think so my self.
I was only trying to simplify the issue for the previous poster who I think meant to say inertia.
Of course if F1 is a closed shop OBN (old boys network) I will try to be more circumspect in the future. I do not wish to upset any self congratulation pacts or anything.

[Lurk]

I was only trying to simplify the issue for the previous poster who I think meant to say inertia.

Well, I think "inerty" doesn't exist in english . "Inertia" is what I wanted to say

@autogyro : I was not talking about the effectiveness of wheel brake preventing the use of engine braking, but that a formula one engine has a very low capacity of braking due to its "nearly-zero" inertia.

In an road car engine, there's a lot of rotating mass, so a lot of potential energy. When you downshift to use your engine-brake, your wheels decelerate because their energy is transfered into engine (when is going on higher revs).
But in a Formula one car, rotating mass is very low (it is why F1-engine can "sing" ), so you can't transfer wheel energy into engine.

ps: I learned this logical tip thanks to my brother, who worked on A1GP and GP2 and now has old Formula one as working tools (I remember a modified Lotus, Benetton B198 and Williams FW21. His company also has a Jaguar but I never see it). He also worked on RenaultF1 "Feel It". So I think I can trust him

Maybe engine brake was used on RS27, but in fact it should be nearly useless. And like I said in my previous post: do you ever eared a modern F1 engine screaming during braking ?

F1 downshifting -> http://www.youtube.com/watch?v=yLtbHvmn ... re=related
Porsche "engine brake" downshifting -> http://www.youtube.com/watch?v=vAFrnO_csZg

[Edis]

I was only trying to simplify the issue for the previous poster who I think meant to say inertia.

Well, I think "inerty" doesn't exist in english . "Inertia" is what I wanted to say

@autogyro : I was not talking about the effectiveness of wheel brake preventing the use of engine braking, but that a formula one engine has a very low capacity of braking due to its "nearly-zero" inertia.

In an road car engine, there's a lot of rotating mass, so a lot of potential energy. When you downshift to use your engine-brake, your wheels decelerate because their energy is transfered into engine (when is going on higher revs).
But in a Formula one car, rotating mass is very low (it is why F1-engine can "sing" ), so you can't transfer wheel energy into engine.

ps: I learned this logical tip thanks to my brother, who worked on A1GP and GP2 and now has old Formula one as working tools (I remember a modified Lotus, Benetton B198 and Williams FW21. His company also has a Jaguar but I never see it). He also worked on RenaultF1 "Feel It". So I think I can trust him

Maybe engine brake was used on RS27, but in fact it should be nearly useless. And like I said in my previous post: do you ever eared a modern F1 engine screaming during braking ?

F1 downshifting -> http://www.youtube.com/watch?v=yLtbHvmn ... re=related
Porsche "engine brake" downshifting -> http://www.youtube.com/watch?v=vAFrnO_csZg

Of course a F1 engine will provide engine braking, in fact, the engine braking is usually adjustable by a knob on the steering wheel.

When you close the throttle the engine will no longer supply the power required to keep the engine spinning. This power will then be taken from the wheels instead, where is provides some braking. The power the engine consumes is due to friction mean effective pressure, fmep, and pumping effective pressure, pmep (the losses due to friction and pumping), and the power consumed by engine accessories such as coolant pump, oil pump, hydraulic pump and alternator.

As the engine have a low inertia, this will actually improve the engine braking effect as there is little intertia keeping the engine speed up. But obviously the 'shock braking' that occur during downshifts as the engine speed is suddenly increased is obviously smaller.