Blown Diffuser??

Here are our CFD links and discussions about aerodynamics, suspension, driver safety and tyres. Please stick to F1 on this forum.
User avatar
JohnsonsEvilTwin
0
Joined: 29 Jan 2010, 11:51
Location: SU 419113

Re: Blown Diffuser??

Post

scarbs wrote:Yes the simpler diffusers will still be benefited by a exhaust blowing over the top of them. They can't have the Red bull slot, but most of the new teams adopting EBDs havent gone for this solution.
Thank you scarbs.
More could have been done.
David Purley

User avatar
747heavy
24
Joined: 06 Jul 2010, 21:45

Re: Blown Diffuser??

Post

Hi Johnsons,

Why I can´t answer your question going forward, as what teams will do next year,
I can say, that the blown diffussor concept is not new, and was used in the past.
So it does, not require a DDD per se to work.

Early applications of a EBD, have suffered from being extremly sensible to changes
in exhaust gas flow/throttle position.
So if a driver was forced to lift off the throttle, it created a very unstable condition.

The latest version of EBD in combination with an DDD are said to be less sensitive,
so the concept has come into the limelight again.

A quick rundown about the history of EBD can be found here:

http://scarbsf1.wordpress.com/2010/06/2 ... diffusers/
"Make the suspension adjustable and they will adjust it wrong ......
look what they can do to a carburetor in just a few moments of stupidity with a screwdriver."
- Colin Chapman

“Simplicity is the ultimate sophistication.” - Leonardo da Vinci

F1_eng
F1_eng
4
Joined: 05 Aug 2009, 11:38

Re: Blown Diffuser??

Post

speedsense, I have calibrated many many control units thank you,moved away from that sector quite a long time ago as it get fairly dull, untill requests such as the one being discussed here comes along.

I'm afraid I can't say who I work for but I can tell you it's not Red Bull, it is F1.

And engine mapping is not an engine builder's job, it's a calibration engineers job. I sort of see what you mean, with low level forms of motorsport, the engine builder has a dyno where he can knock up full power runs and get a decent map. That's not proper calibration though. If he is an engine builder, he should be building engines.

What systems are you most familiar with?

delsando
delsando
0
Joined: 03 Nov 2008, 11:18
Location: Fra

Re: Blown Diffuser??

Post

Got a quick question, can you have internal structure (unmovable) within an exhaust tube(near the outlet)? such as curves/blades (see pic below). In result creating vortex gas flow or changes in exhaust scavenging.


Image



Patented Aeroturbine is an example, apparently it increases in Horsepower Torque & Fuel Economy

http://www.aeroperformanceexhaust.com/t ... rocess.htm


Here an interesting article on exhaust scavenging if you're interested.

http://www.veryuseful.com/mustang/tech/ ... enging.pdf
"The danger sensation is exciting, the challenge is to find new dangers." Ayrton Senna

speedsense
speedsense
13
Joined: 31 May 2009, 19:11
Location: California, USA

Re: Blown Diffuser??

Post

F1_eng wrote:speedsense, I have calibrated many many control units thank you,moved away from that sector quite a long time ago as it get fairly dull, untill requests such as the one being discussed here comes along.

I'm afraid I can't say who I work for but I can tell you it's not Red Bull, it is F1.

And engine mapping is not an engine builder's job, it's a calibration engineers job. I sort of see what you mean, with low level forms of motorsport, the engine builder has a dyno where he can knock up full power runs and get a decent map. That's not proper calibration though. If he is an engine builder, he should be building engines.

What systems are you most familiar with?
"low level forms of motorsport" - never knew there was a Ghetto in racing.. :lol:

Those of us who work in the "ghettos" of racing that don't have the luxury of work amongst "fleets" of engineers, but rather one or two in a team environment, have to cover every aspect of DA, and every aspect of the controller units with one person and a tech from the company of the electronics, a tech from the engine builder.
Especially engine builders, in "ghetto racing", have to not only build engines, but map them, help the team keep it to the optimum (it's in their interest to do so when racing against another engine builder).
However in spec racing, the lowest form of "ghetto racing", if you know an ECU and the rules, some advantages can be had as the engine builds/maps start at the same place. That's 90% of the racing series in America.
Same can be said for DA units, where analysis experience makes a major difference. There are many techniques in both fields, and that, but a small group of people have an upper hand on.
The units that are common, Bosch, EFI, Pectel, Motec, Magna Marelli, yet to see a Mclaren ECU, except in one case on a Mclaren Mercedes.

So as you and I have hijacked this thread, let's move on to the question we're trying to answer, and that is the presumed Retarded timing and how is it possible to be done.
As has been pointed out by a couple of posters, a retarted timing map would need the throttle plates to be open at least slightly so...
And as the FIA prescribed "filtered" throttle delay map in the SECU, is presumed to be there for gear changes, as a throttle ratio effect, which I presume is for drive ability, I can see the delay working on throttle on but don't know if it exists on throttle off motions.
what say you F1_Eng?
If yes, then it would follow that the possibility of altering the delay by gear number, and altering a high gear with a slower delay, in 7,6,5,4th can be done, so that an off throttle can have a longer delay, thereby keeping the throttle plate open for a longer time, with the ECU installing a dwell/timing map that is "retarded in timing" as an argument or condition of something like- speed vs throttle opening vs gear and vs lap distance to install the map.. (It is not known if the delay of the throttle exists in both direction, on as well as off, the spec sheet only states a throttle rate adjustment through filtering). This is my assumption as to how they would do it.
What do you think F1_Eng?
"Driving a car as fast as possible (in a race) is all about maintaining the highest possible acceleration level in the appropriate direction." Peter Wright,Techical Director, Team Lotus

speedsense
speedsense
13
Joined: 31 May 2009, 19:11
Location: California, USA

Re: Blown Diffuser??

Post

delsando wrote:Got a quick question, can you have internal structure (unmovable) within an exhaust tube(near the outlet)? such as curves/blades (see pic below). In result creating vortex gas flow or changes in exhaust scavenging.


Image



Patented Aeroturbine is an example, apparently it increases in Horsepower Torque & Fuel Economy

http://www.aeroperformanceexhaust.com/t ... rocess.htm


Here an interesting article on exhaust scavenging if you're interested.

http://www.veryuseful.com/mustang/tech/ ... enging.pdf
Sure, but items such as this, are for engines with back pressure problems. Most exhausts in racing are specifically and carefully built to prevent any need for such an item.
"Driving a car as fast as possible (in a race) is all about maintaining the highest possible acceleration level in the appropriate direction." Peter Wright,Techical Director, Team Lotus

User avatar
ringo
230
Joined: 29 Mar 2009, 10:57

Re: Blown Diffuser??

Post

Wouldn't it be pretty simple if the driver just presses the throttle while braking?
Left foot braking as they call it. We know the pedal resolution/sensititvity is programmable.
A slight resting on the pedal by the driver during braking could be all that's need to let air into the engine. I am sure it's much simpler. The mapping only has to involve timing and fuel.

The biggest issue to me isn't so much the programming either, but looking on the races so far, you have to wonder if other teams don't use an infrared camera to watch the redbulls as they go around the track in q3.
I have seen IR cameras used in the pit lane to give those pretty views of the warm tyres and engine. I am sure a team can learn a lot about the redbull trick if they turn the camera to the redbull while it's under braking.

Funny Whitmarsh never thought about this before. Maybe they would have designed their system correctly the first time out.

[youtube]http://www.youtube.com/watch?v=2yycXhln1vM[/youtube]
[youtube]http://www.youtube.com/watch?v=KeKvULfG ... re=related[/youtube]
For Sure!!

User avatar
ringo
230
Joined: 29 Mar 2009, 10:57

Re: Blown Diffuser??

Post

If an infra red fart can be videoed, an exhuast plume pattern should be! :lol:
http://www.youtube.com/watch?v=FGoUVBxkL0s
it's fake by the way, but just to proves gases can be veiwed.
For Sure!!

User avatar
747heavy
24
Joined: 06 Jul 2010, 21:45

Re: Blown Diffuser??

Post

maybe a bit simplyfied, but here is a animation regarding Ferrari`s EBD.

some of you may like it - enjoy:

[youtube]http://www.youtube.com/watch?v=jU9691zRGfs[/youtube]
"Make the suspension adjustable and they will adjust it wrong ......
look what they can do to a carburetor in just a few moments of stupidity with a screwdriver."
- Colin Chapman

“Simplicity is the ultimate sophistication.” - Leonardo da Vinci

myurr
myurr
9
Joined: 20 Mar 2008, 21:58

Re: Mclaren Mercedes MP4/25

Post

wesley123 wrote:indeed, but automated makes it actually real active aero, as you have to do something else to create the pressure wich causes it to flow, thus with valves.
But automated in this sense means a fluidic switch. No moving parts beyond the air itself - in simple terms pressure differences are used to control the air flow. As the pressures change, depending on the speed of the car, then the air flow changes in a binary fashion from one particular path to another.
wesley123 wrote:And about the EBD is true, but you can hardly ban the exhaust cant you? Afterall their placement has in any way effect on the aero, no mather how you place it. with this placement you gain some extra, there is no danger in the whole system.
You could mandate a minimum exhaust exit height above the reference plane. If the f-duct is 'unsafe' and therefore to be banned then that should be doubly true of the EBD which so far has made the cars far more unstable at the rear than the f-duct has. Personally I'd rather either see them both allowed or see them both banned.

BreezyRacer
BreezyRacer
2
Joined: 04 Nov 2006, 00:31

Re: Mclaren Mercedes MP4/25

Post

The only car that showed any instability was Hamilton's McLaren. Every other team has done fine with it. Ferarri, Williams, Red Bull, etc .. no problems.

Boost
Boost
0
Joined: 14 Jun 2010, 19:21

Re: Mclaren Mercedes MP4/25

Post

BreezyRacer wrote:The only car that showed any instability was Hamilton's McLaren. Every other team has done fine with it. Ferarri, Williams, Red Bull, etc .. no problems.
The Ferrari and others don't actually pass any exhaust into the diffuser, it is passed over the top. Only the Red Bull and McLarens pass exhaust into the system, and RBR have had rather longer to perfect theirs than McL.

As to the banning next year of the EBD I think the Ferrari solution will still be legal as it is the slots used to pass the exhaust gas in which are banned as part of the rules which prevent the DDD from being used.

vall
vall
0
Joined: 04 Nov 2008, 21:31

Re: Mclaren Mercedes MP4/25

Post

myurr wrote:
wesley123 wrote:indeed, but automated makes it actually real active aero, as you have to do something else to create the pressure wich causes it to flow, thus with valves.
But automated in this sense means a fluidic switch. No moving parts beyond the air itself - in simple terms pressure differences are used to control the air flow. As the pressures change, depending on the speed of the car, then the air flow changes in a binary fashion from one particular path to another.
wesley123 wrote:And about the EBD is true, but you can hardly ban the exhaust cant you? Afterall their placement has in any way effect on the aero, no mather how you place it. with this placement you gain some extra, there is no danger in the whole system.
You could mandate a minimum exhaust exit height above the reference plane. If the f-duct is 'unsafe' and therefore to be banned then that should be doubly true of the EBD which so far has made the cars far more unstable at the rear than the f-duct has. Personally I'd rather either see them both allowed or see them both banned.

I think the regulations are poorly written. The bit about movable aero is there to say that there should be no active change of the aerodynamic properties (or performance) of the car (I think this is what they meant. Call it spirit of the rule if you wish). The rule makers thought that movable parts were the only why to achieve active aero and so wrote only about this. They should have just written that no system that actively change of the aero performance are allowed, be it movable parts or something else. Under so written regulations, F-duct would have been illegal, but the mass dumper not. The mass dumper may make the car more stable, but it does not change the drag of the DF. The FIA decision to ban it still amazes me!!!

User avatar
forty-two
0
Joined: 01 Mar 2010, 21:07

Re: Blown Diffuser??

Post

ringo wrote:Wouldn't it be pretty simple if the driver just presses the throttle while braking?
I pondered this one. I guess that this would have it's own problems. For example, keeping the throttle pedal pressed would result in reduced (or no) engine braking. This might make the car harder to handle, but I suppose that could be something the drivers could be trained to cope with via the simulator.

A little off topic, but many years ago at a go-kart track, I noticed the staff when driving were covering the air-intake with their hands while cornering in order to keep the mixture rich (???) when the car slowed down. True, these were whimpy engines by comparison, and did not feature an ECU of ANY kind, but might something as simple as shifting the driver's seating position higher in the car help for similar reasons?
The answer to the ultimate question, of life, the Universe and ... Everything?

User avatar
Shaddock
0
Joined: 07 Nov 2006, 14:39
Location: UK

Re: Blown Diffuser??

Post

If teams started to add gurney ‘type’ flaps to their blown diffusers made from metal rather than carbon fibre they could get some interesting results.

[youtube]http://www.youtube.com/watch?v=sRvZ4WgBLto[/youtube]