Red Bull blown exhaust - possible theory?

[Chris Jenkins]

The following is quoted from an article on Yahoo Sport/Autosport.com:

Red Bull Racing's qualifying advantage could be helped by 'elaborate' engine mapping that helps make its blown diffuser more effective over a single lap.
That is the view of McLaren principal race engineer Phil Prew, who says his team is working hard on getting a grips as to why rivals Red Bull Racing have more of an advantage in qualifying than they do in a race.
"We are aiming to improve the performance of our car right the way through the range, in qualifying and in the race," said Prew, during a Vodafone McLaren Mercedes phone-in, about where he believes Red Bull's advantage lies.
"I think tyre optimisation may be one area, and the use of elaborate engine modes may be another - with the generation of downforce being quite highly influenced with the exhaust flows.
"There are many reasons why it may exist and we are aiming to improve our performance in qualifying and the race, and hopefully close in both areas."
F1 teams last year began experimenting with engine modes that pump more exhaust gases out - to help increase the airflow through a blown diffuser. This also included having gases flowing through the exhausts when drivers were off-throttle.
Red Bull Racing could be using a more extreme version of such engine mapping to dramatically increase exhaust flow in qualifying - but this would likely put a strain on its Renault power unit which could threaten reliability in the races.
Prew believes that McLaren is only a few tenths of a second behind Red Bull Racing in terms of out-and-out pace.
"I think that we are between three tenths and half a second off the pace of Red Bull, and obviously that is the gap that we are aiming to close," he said.

Interesting theory.

One person on the forum offers an explanation as to how it works:

"When the driver lifts off, in a* normal engine the fuel supply is reduced - so you get* less of an explosion, so less power turning the engine.* Just for jollies - how about you continue to spray fuel* into the cylinders - and when the driver lifts off just* don't spark the fuel. So, the unburnt fuel will be* continuously supplied into the hot exhaust - where* it'll ignite and expand and shoot out the back.*

 

[Dave Stephenson]

"When the driver lifts off, in a* normal engine the fuel supply is reduced - so you get* less of an explosion, so less power turning the engine.* Just for jollies - how about you continue to spray fuel* into the cylinders - and when the driver lifts off just* don't spark the fuel. So, the unburnt fuel will be* continuously supplied into the hot exhaust - where* it'll ignite and expand and shoot out the back.*

Same drill as aircraft reheat/afterburner. Whether or not that's allowed I don't know but it would provide a good explanation.

 

[James Chant]

Could explain some of the fuel saving messages going on, might not be just red bull!?

 

[Chris Jenkins]

Could explain some of the fuel saving messages going on, might not be just red bull!?

Quite possibly.
You don't often hear Red Bull telling their drivers to save fuel.
I suppose that's mainly because they're at the front of the pack so can afford to turn the engine down slightly.

 

[Bruno Sousa Ferreira]

Well that is an interesting idea to add excess fuel into the engine to burn in the exhaust, the issues that I see with that, is that how do you 1st make sure you don't flood the engine or the excess fuel is burnt at the correct place (exhaust) or many other number of problems I can see happening.

The afterburner in an aircraft sprays the fuel into the nozzle (after the combustion). For me if I was designing this I would work out a way to spray fuel into the exhaust itself, achieving similar effect with less problems.
And if the teams can find a way to do this, they can also have a degree of control of how much fuel it goes in the exhaust and therefore at lower speed (less throttle) they can have more fuel in the exhaust (to increase the fluid velocity) and at high throttle use the fuel can be less as you might not need as much. (also this could be a good way to control car balance)

 

[Chris Jenkins]

Seems light the FIA have put a halt to this particular development:

"Formula One leaders Red Bull may not be so dominant in Spain this weekend after the sport's governing body clamped down on the use of engine management systems to gain an aerodynamic advantage.

Some leading teams have gained performance by keeping exhaust gases flowing constantly through the rear diffuser even when drivers are not on the throttle.
"The FIA clarified some rules on engine management systems which I think are going to affect all the teams," Mercedes GP team principal Ross Brawn said at the opening of Silverstone's new pit and paddock complex on Tuesday.
"These sort of staccato exhausts that you hear, I don't think you will be hearing any more," the Briton said when asked about the impact on this weekend's Spanish Grand Prix in Barcelona.
"The teams have all been developing their engine management systems to take the maximum advantage from the exhausts and the FIA want to push us in a different direction now so there will be changes there."
Red Bull's world champion Sebastian Vettel has won three of the four races so far and started all of them from pole position.
Asked whether the changes might affect Red Bull's qualifying performance, Brawn tactfully said he had no idea what the outcome might be.
"I think it's forced all the teams to have a fresh look at what they are doing on engine strategies," he added.
Red Bull team boss Christian Horner told autosport.com that the changes would affect the majority of the grid.
"It is going to have an effect with all teams that have been utilising it," he said. "That appears to be 90 per cent of the grid, if you look at how many teams are running blown diffusers.
"It is not something unique to this year, it is something that started last year, so Barcelona will clearly show what effect this will have."
Asked whether the clarification had been triggered by a rival team's complaint, to slow down his cars, Horner added: "It is inevitable and the unfortunate consequence of success.""

 

[James Chant]

"It is inevitable and the unfortunate consequence of success.""

Nice. This will be interesting.

 

[Rupe Wilson]

To me, you cant change the rules for 2011 when where only just a few races into the season, just because somebody has a better idea than the rest. as long as its fits the rules for 2011 let it race. Maybe the people who make the rules need to do a better job in the first place.

 

[Chris Jenkins]

There's a lot of talk (and I'm neither supporting or against this) that due to the amount of former Ferarri employees now working with the FIA, that there's a lot of co-incidence between rules that the FIA either implements or clamps down on and what the Ferrari team are either struggling to develop or are weaker in. Nicknamed "Ferrari International Assistance (FIA)"

 

[Ole Marius Myrvold]

There is another reason for this. F1 is trying to get a greener image these days. Smaller engines, KERS etc. This blowed exhaust - and Renault's exhaust is using up to 10% percent more fuel as far as I understand (it might just be the Renault that is using 10%), but it is using more fuel, that's for sure.

And that doesn't fit the new image!

 

[Brian Clancy]

This is a very interesting debate...... (well it was till the FIA stated they will be banning this technology lol)

Simply injecting 'extra' fuel into the cyclinders with no ignition wont have a massive effect on exhuast gas development as the 'burning' (if any) will be very dirty and in-efficent. More-so, 'bore-wash' (the effect of unburnt fuel washing oil away/off the cyclinder bores) would have dramatic effects on cyclinder wear, especially as F1 engines run 'seized' bore sizes (a cold engine is litterally siezed as the pistons are effectivley larger than the bores at room temp!!). I would guess and its only a guess, that the teams were raising the 'idle' speed of the engine and running as lean a mixture ratio as they dare to produce extra heat in the exhuast gas, thus ensuring 'extra gas flow' at lower RPM. But of course, it will be more complex than this, I would imagine an extended idle 'map' with pulsating fuel injection values altering the mixture would be used to attain the correct temperatures for the overall 'harmonic' length of the headers/primary pipes of the exhuast system to get enough effect to make it worth while. Also ignition mapping Retard/advance could be benifical if mapped in conjunction with fuel values/mixture/pulsing

Like I said, very interesting...... If yer a techno geek petrol head like me

 

[Yann Laprevotte]

"It is going to have an effect with all teams that have been utilising it," he said. "That appears to be 90 per cent of the grid, if you look at how many teams are running blown diffusers.

Any idea on who had it(or rather, who didn't)?

There is another reason for this. F1 is trying to get a greener image these days. Smaller engines, KERS etc. This blowed exhaust - and Renault's exhaust is using up to 10% percent more fuel as far as I understand (it might just be the Renault that is using 10%), but it is using more fuel, that's for sure.

And that doesn't fit the new image!

I really doubt it. F1 is trying to get a greener image, not trying to be genuinely greener. They're putting their efforts on visible changes, like the introduction of KERS and smaller engines. This, while both probably have negative effects. KERS barely changes anything to fuel burning wise, and is understood to be problematic when it comes to recycling. On the other hand smaller engines will reduce fuel burning indeed, but it certainly won't make up the huge amount of energy used to develop them.

Meanwhile, the suppression of the blowed exhaust doesn't look like an efficient move PR wise to me. As far as I know the topic has barely been raised in mass medias so far this year. And I do not think the average fan would figure by itself it actually make the car burn more fuel.

In my honest opinion the FIA only made the move to try to slow down the Red Bull a bit and prevent Vettel to take the title to early in the season.

 

[Chris Jenkins]

In my honest opinion the FIA only made the move to try to slow down the Red Bull a bit and prevent Vettel to take the title to early in the season.

I agree with this.
People switch off and show a lot less interest if someone's running away with the championship.
As a kid, I know I did during the Schumacher/Ferrari era.

Unfortunately we live in a day and age where viewing figures and sponsorship exposure rules all.
If people switch off because the race results are too predictable, sponsors get less exposure.
Sponsors get less exposure = sponsorship withdrawals = less money for the teams = less money for Formula One.

I can't imagine sponsors such as Vodafone, Petronas, etc will be too happy with being associated with 2nd place or worse week-in week-out.