Can fuel be dumped or quickly burned during a race

[Tim.Wright]

Easy fix; In the pace car periods, switch to a map that uses them same amount of fuel as when you are running at full speed.

Tim

[010010011010]

is it legal to have a fuel line going directly to the exhaust?

i.e. burn it off without it sooting up the engine too much, basically an afterburner

[joseff]

You'll risk burning off a chunk of bodywork that way.

[mx_tifoso]

If overrun causes a pretty big flame imagine what a fuel line going directly to the exhaust would do!

[rjs]

Burning off is one thing.
I was refering to the suggested fuel dumping.

Fair enough, although I don't see how literally "dumping" fuel out of the tank could ever be considered practical from a pure safety angle, while running rich (or superrich) is perfectly feasible and has been done before.

I don't know how rich you could go before you caused problems, which is what I assumed this thread was actually about.

[The FOZ]

Afterburners?

[manchild]

Spraying into exhaust - illegal

Afterburners - illegal

Forget it, it's not worth speculating, since regs. are very strict.

[The FOZ]

Spraying into exhaust - illegal

Afterburners - illegal

Forget it, it's not worth speculating, since regs. are very strict.

Regs - no fun

[Ian P.]

I don't see why everyone is assuming that admitting to burning off fuel would cause a PR backlash. Last year it was common in qualifying to go through a "fuel burning" phase to get rid of the weight and it was regularly referred to as such in interviews.

Last year it may have been referred to as "Fuel Burn-off" but the cars were basically running lean to run as many laps as possible on a minimum amount of fuel. The FIA then let them add fuel after qualifying based on a a certain no. of kilos per lap. It wasn't so much a "burn-off" as a rules end-run to optimize qualifying and race fuel loads. If they had wanted to burn fuel, they would have run this part faster, not slower.

I am surprised that the concept of "dumping" fuel under the current set of rules hasn't been discussed earlier. I bet the stategy boffins were planning this 6 months ago. Logic would indeed be to map the engine to burn as much fuel at SC speeds as on a normal racing lap. Rain will also promote the same idea but if it is rain for at least the last half of a race, there is an advantage to "dumping" fuel early and running lighter to the end.
Anyone who is familiar with cars of the 70s will know that engines can run quite well at very rich AF ratios and you won't see anything special out the tail pipe. You could probably double the fuel consumption rate from a best performance map without problems.
Not a PR winning idea but then is it really about winning??....You Bet It Is.

[Edis]

Is running "lean" simply turning down the revs on the motor?

Or is it a case of different air fuel mixtures?
Im leaning towards the latter but have been told in no uncertain terms that F1 engines run "lean" by lowering engine revs.

Running lean means running lean.

In reality though, the teams usually have different settings that change not only one engine setting but several. There is for instance a maximum power setting, where the air/fuel ratio is slightly rich, the engine has maximum revs and the ignition is set for MBT. Then there is a setting indended to be a little easier on the engine, this setting has a slightly lower rev limit, it has a few degrees retarded ignition and a richer fuel mixture. This reduce the stress on the engine.
Then there is a fuel saving map with a slightly leaner mixture, slightly lower revs and ignition for MBT. There are probably also a few intermediate settings to, and a specific race start map and I would guess also a setting intended for safety car periods.

Here are some numbers from Cosworth, back in 2006 (CA Series 6)

Maximum power setting: 755 bhp, 19,225 rpm peak power speed
Engine save (used in free practice): approx. 735 bhp, 10 degrees ignition retard, richer fuel mixture
Engine save (during race): approx. 750 bhp, 4 deg. ignition retard, 500 rpm reduction in maximum speed

A push to pass button set engine in maximum power setting.

In general though, I don't think the teams have such a great amount of excess fuel in the cars, and a longer safety car period could probably be compensated by running the engine with the higher output setting a little bit longer.

If overrun causes a pretty big flame imagine what a fuel line going directly to the exhaust would do!

Running rich do not cause flames from the exhaust, nor do it cause a high exhaust temperature. Actually it does the opposite, it reduce the exhaust temperature.

Remember that there isn't any oxygen availible in the exhaust to burn excess fuel, so running rich will only result in higher amounts of vaporised hydrocarbons in the exhaust.

When you see flames from an engine exhaust, that is either due to an ignition cut, or misfires. That way you get both oxygen and fuel into the exhaust, which self ignite due to the temperature.

[JohnsonsEvilTwin]

Thank you edis

However, this means, from what you posted in reference to the CA2006 Cossie, that lowering revs gives a lean effect?
Retarding the ignition I would imagine to have a big effect.

Possibly my question wasnt clear enough.

Can you run lean at 18k? Or, do you have to reduce the rpm to get the desired lean running?

Take the CA2006 for example.

Did the lean running reduce the amount of revs available.

My thoughts are they would change the air fuel mixture to achieve this. Whereas what you are saying is its a simnple case of lowering the revs?

[autogyro]

It is far from simple and I think Edis explained it very well as he usualy does.
The different maps for fuel and ignition take a number of things into account that are interdependent.
You could weaken the mixture at 18.000rpm but it would not be advisable without changing other things including the rpm.
It depends on what you want to achieve.

[Edis]

Thank you edis

However, this means, from what you posted in reference to the CA2006 Cossie, that lowering revs gives a lean effect?
Retarding the ignition I would imagine to have a big effect.

Possibly my question wasnt clear enough.

Can you run lean at 18k? Or, do you have to reduce the rpm to get the desired lean running?

Take the CA2006 for example.

Did the lean running reduce the amount of revs available.

My thoughts are they would change the air fuel mixture to achieve this. Whereas what you are saying is its a simnple case of lowering the revs?

Running lean is only related to air/fuel ratio, it doesn't affect the engine speed. But since the goal isn't to run lean, but to for instance reduce the fuel consumption, running leaner is usually combined with a lower engine speed.