Blown Diffuser??

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WhiteBlue
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Joined: 14 Apr 2008, 20:58
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Re: Blown Diffuser??

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richard_leeds wrote:WhiteBlue - good points. A small detail is that the SECU spec restricts changes to throttle map to times when the car is stationary for 3 seconds. So the change would be implemented for Q3.
I'm not sure that this restriction is still in place or that it is correctly interpreted. Remember the McLaren double shifting levers on the steering wheel that shifted the engine maps in parallel with the gears? Those maps need to be changed with a non stationary car. So one has to assume that F1 has long over come the limitation that maps can only be shifted when stationary.
Formula One's fundamental ethos is about success coming to those with the most ingenious engineering and best .............................. organization, not to those with the biggest budget. (Dave Richards)

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Lurk
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Joined: 13 Feb 2010, 20:58

Re: Blown Diffuser??

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Onboard lap at Monaco

Webber Pole
[youtube]http://www.youtube.com/watch?v=7Kcydu-xSY8[/youtube]

Kubica P2
[youtube]http://www.youtube.com/watch?v=X49GFlHkMTg[/youtube]

There is clearly a sound on braking which is not a Renault engine particularity.
This sound can be heard on each RB6 pole onboard video (Barcelona, Istanbul, Melbourne, etc) and no other car sounds like that.
I didn't find a race onboard lap so I don't know if it is the normal RB6 sound or not...


edit : well, I post the barcelona pole instead monaco..
Here is Monaco
[youtube]http://www.youtube.com/watch?v=oyBnNpWr07Q[/youtube]

DaveW
DaveW
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Joined: 14 Apr 2009, 12:27

Re: Blown Diffuser??

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Highly impressive videos. Webber does seem to get power down early, sometimes before the apex, apparently.

autogyro
autogyro
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Joined: 04 Oct 2009, 15:03

Re: Blown Diffuser??

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Remember the strange noise on the Ferrari video during their promo run?
Perhaps they were playing with a retard ignition map for the EBD?

timbo
timbo
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Re: Blown Diffuser??

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autogyro wrote:Remember the strange noise on the Ferrari video during their promo run?
Perhaps they were playing with a retard ignition map for the EBD?
On 7th gear on full throttle? During upshifts?
Do you imply they are retarded themselves?

autogyro
autogyro
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Re: Blown Diffuser??

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You would have to ask Alonso that timbo.
Anyway somebody said the noise was not there on the higher gear changes.
I suppose people hear what they want to hear.
Glad you confirmed it.

timbo
timbo
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Re: Blown Diffuser??

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autogyro wrote:You would have to ask Alonso that timbo.
Anyway somebody said the noise was not there on the higher gear changes.
I suppose people hear what they want to hear.
Glad you confirmed it.
You was telling for a long time that the "noise" you hear is because of TC.
Tell me, how suspected retarded ignition during off-throttle can be mistaken for a TC (which works on-throttle by default)?

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WhiteBlue
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Re: Blown Diffuser??

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The obvious development aim is to run the engine with full air intake and adjustable power. I believe that is possible by a clever multi dimensional mapping of throttle plate, ignition angle, gear selected and injection volume. Dependent of the gear selection you probably do not even have to have special maps in first, second, sixth and seventh gear. So you only have to give three gears the special treatment.
Formula One's fundamental ethos is about success coming to those with the most ingenious engineering and best .............................. organization, not to those with the biggest budget. (Dave Richards)

BreezyRacer
BreezyRacer
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Re: Blown Diffuser??

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You guys can talk about mapping all you want AND it is very relevant. However, you cannot overlook that the RB is still, lap over lap, faster than any other car out there. Why does this matter? Because it shows that the design works ALL THE TIME, not just in qually.

Please don't overlook this in your explanations of the blown diffuser. When done right it really does work without the need for engine mapping, etc.

timbo
timbo
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Re: Blown Diffuser??

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WhiteBlue wrote:I believe that is possible by a clever multi dimensional mapping of throttle plate, ignition angle, gear selected and injection volume.
I heard there was a limit on how many maps you can have and how often to change them.
Interestingly, technical regulation now state very little regarding engine mapping, other than throttle must be only controlled by a pedal.
However they state that ECU software has to be approved by FIA.
I wonder whether retarded ignition systems are against the principle that only driver controls the throttles.

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WhiteBlue
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Re: Blown Diffuser??

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CMSMJ1 wrote:It has to be linear to be driven correctly.

No..how does this work?

Advancing or retarding ignition is not a magic bullet. Ignition advance is a tool to allow for the ignition of the fuel before the compression does it for you. It does not affect in a useable way the ability to produce the power in the engine by an appreciable amount. it is a tool to prevent detonation which is bad for power, the valves and the health of your motor.
I have no doubt that they do some damage to the engine by this trick but we are talking single digit laps per engine here. You do not need the trick in most gears. So they probably only do it in third, fourth and fifth gear. As I have also said it could also be possible that they reduce the amount of fuel which also would result in less power IMO. Unfortunately I'm no expert for the firing technology of racing engines. I would have to leave that to the experts to determine. But I'm pretty sure that teams can fiddle the SECU with multi dimensional engine maps to their hearts content. Have you heard an engine sing the national anthem? One should also read scarb's blog on this.

http://scarbsf1.wordpress.com/2010/07/1 ... s-q3-pace/

Here is his picture of Map-Q retarding.

Image


http://www.atlasf1.com/99/oct06/burckmyer.html An eleven year old report on how F1 engines use ionization curve feed back to optimize ignition. At that time they were already tuning the fuel injectors for optimum ignition. McLaren electronics offer an ICU-108 module for ion current measurement for their F1 SECU.
They decided to employ a strobe circuit with the small components producing high current along with capacitive discharge to produce high voltage to produce the plasma spark.

They succeeded in producing a massive spark for the same overall energy as a conventional spark, and the system proved much more effective at igniting the air/fuel mixture. Further, the package was not significantly larger than a conventional ignition.

The system still lacked advanced control, however. VanDyne and Porreca worked over a misfire detection circuit used by Saab. It employed a simple design that used ionic conductivity to detect misfires. Porreca and VanDyne rationalized the system by which this was accomplished, and quickly devised their own circuitry.

Their system did not simply measure whether or not there was a misfire, however. The circuit they designed enabled the spark plug to detect full ionization curves for each cycle, data which could be correlated to cylinder pressure and used for engine tuning diagnostics. Using their ionization feedback, Adrenaline has developed a system that, when integrated to the cusomer's ECU, can monitor and control individual cylinder firings, adjusting the plasma spark timing, injector pulsewidth, and air/fuel ratio-on an individual cylinder, individual cycle basis.

Because of their design successes, and because their system has had tremendous appeal in test sessions, Adrenaline's SmartFire Plasma-12 ignition is currently under consideration at several F1 teams.
Formula One's fundamental ethos is about success coming to those with the most ingenious engineering and best .............................. organization, not to those with the biggest budget. (Dave Richards)

delsando
delsando
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Joined: 03 Nov 2008, 11:18
Location: Fra

Re: Blown Diffuser??

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Image

Did a quick sketch, i think this is how the concept of the RB diffuser works
Flow Lines are a bit messy, but im sure you get the idea

RED= Exhaust
ORANGE= Outside/ Upper floor flow
BLUE= Main diffuser flow
GREEN= Upper Deck diffuser flow

This is a bit better.......

Image
"The danger sensation is exciting, the challenge is to find new dangers." Ayrton Senna

Darknight
Darknight
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Location: Bahrain

Re: Blown Diffuser??

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Since attending the Bahrain GP i have been wondering about the first turn incident when there was a HUGE puff of smoke out of Mark Webbers Redbull (the only picture i could find is a link to another forum so if you want to see it pm me unless i am allowed to post the link here).

Well to get to the point, Mark Webber finished 8th in that race and the pace of his Redbull was midpack at best. Could it be that the puff of smoke was the retarded ignition map that is currently being discussed? So picture this, the lights go out and the cars race down the straight, turn one comes up and Mark is off the throttle, the ignition retards and the burn is transferred into the exhaust, the exhuast in the meantime has residual oil in it (i am assuming here) and due to the burn in the exhaust because of retarted timing the oil ignites and shoots a HUGE ball of white smoke (it was so big that the whole field of cars past through it). After that Marks pace was midpack which could mean he had to switch the retard map off.

If any of the above makes sense and is in fact what is happening then this could be proof that Redbull are using the system not only in Q3 but in the race as well.

tok-tokkie
tok-tokkie
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Joined: 08 Jun 2009, 16:21
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Re: Blown Diffuser??

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I don't think Scarbs has it quite right.
1. He shows the throttle fully closed in the retarded ignition picture.
2. Fuel will only burn when in the stochiometric range - which is quite limited.
3. I expect the throttle is somewhat open so the engine can induct quite a bit of air.
4. The fuel/air mixture is ignited late so there is no real power (pressure) developed. If power was developed then the driver's foot off throttle command would be completely negated.
5. The air then expands 15x due to the temp of ignition. The valve opens during (or before according to Scarbs) the ignition process. Blowing on the diffuser is maintained but the exhaust valve has a much increased heat load.
6. By letting more air in with the throttle artificially held partly open while the ignition is retarded there is no increase in power but the exhaust volume is more similar to the full power air flow.

delsando
delsando
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Joined: 03 Nov 2008, 11:18
Location: Fra

Re: Blown Diffuser??

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Darknight wrote: Could it be that the puff of smoke was the retarded ignition map that is currently being discussed? So picture this, the lights go out and the cars race down the straight, turn one comes up and Mark is off the throttle, the ignition retards and the burn is transferred into the exhaust, the exhuast in the meantime has residual oil in it (i am assuming here) and due to the burn in the exhaust because of retarted timing the oil ignites and shoots a HUGE ball of white smoke (it was so big that the whole field of cars past through it). After that Marks pace was midpack which could mean he had to switch the retard map off.

Image

I noticed it aswell, as soon as he finds the braking point(brake and lifts throttle) going into turn 1. Noticed small puff of smoke as soon as he lifts and then through to trun 2-3-4 excess oil burns off when throttle is applied back (thats when you see the huge puff of smoke)
"The danger sensation is exciting, the challenge is to find new dangers." Ayrton Senna