Blown Diffuser??

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jason.parker.86
jason.parker.86
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Re: Mclaren Mercedes MP4/25

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The above reminds me of all the people saying that if McLaren was using the snorkel to stall the rear wing they would eat their own hat....

Sometimes finding that extra speed means making the impossible (or very difficult) possiuble.

Richard
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Re: Mclaren Mercedes MP4/25

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Just_a_fan wrote:Distortion of the floor is the given reason for McLaren having problems (or at least why they decided to pull if off the car).
I didn't see that, got any more info on it?

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ringo
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Re: Mclaren Mercedes MP4/25

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How much more would burning fuel in an off throttle condition stress the engine?

I don't think it affects the engine to the point Renault would have to design new parts for it.
The fuel in the pipe wont combust as if it it were in the engine. It's a deflagration, not combustion. The gas is allowed free expansion since it's not resisted by the piston in a closed cylinder. The biggest issue is the temperatures in the exhuast side of the cylinder head.

It's likely this ignition temperature may be lower because there is less oxygen, at a much lower pressure, at off throttle.

The exhaust pipes and fouling of the spark plug is the bigger risk. If the exhaust pipes are thickened, or improved material, and exhibit uniform temperature variations and cooling rate along the length then it should not crack.
For Sure!!

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ringo
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Re: Mclaren Mercedes MP4/25

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Here is the difference with deflagrations and detonations. Detenations have shockwaves.
[youtube]http://www.youtube.com/watch?v=D-dLjHJuFWQ[/youtube]

I've never been to a GP, but i don't think redbull is detonating or "exploding" fuel in the pipes. :)
For Sure!!

CMSMJ1
CMSMJ1
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Re: Mclaren Mercedes MP4/25

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I can appreciate allthe ideas here..but it is the fact that this fuel burning activity i supposed to to be at a high revs situation. The gases in the exhaust are travelling at humungous speeds already, backwards and forwards, so I just do not quite grasp how burning more fuel (that they need to save in race day) is going to appreciably affect the gas velocity enough - especially at high revs.

What is the speed of the exhaust gas?

How many pulses per second of gas at this speed?

How do you time the fuel dumping at this speed so that it does not end up being drawn backwards as part of the scavenging process??

I'd be impressed if this was a viable solution..but I cannot get a grasp of it.
IMPERATOR REX ANGLORUM

myurr
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Re: Mclaren Mercedes MP4/25

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CMSMJ1 wrote:I can appreciate allthe ideas here..but it is the fact that this fuel burning activity i supposed to to be at a high revs situation. The gases in the exhaust are travelling at humungous speeds already, backwards and forwards, so I just do not quite grasp how burning more fuel (that they need to save in race day) is going to appreciably affect the gas velocity enough - especially at high revs.

What is the speed of the exhaust gas?

How many pulses per second of gas at this speed?

How do you time the fuel dumping at this speed so that it does not end up being drawn backwards as part of the scavenging process??

I'd be impressed if this was a viable solution..but I cannot get a grasp of it.
I don't know the answer to all your questions but burning fuel will produce a volume of gas many times larger than the fuel / air mix itself, the value 15 times larger rings a bell but I haven't double checked that nor have any clue how accurate it is.

The ability to time everything is already part of the engine as it is required for the existing timing of normal running - and is also controllable via the existing engine maps.

CMSMJ1
CMSMJ1
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Re: Mclaren Mercedes MP4/25

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myurr wrote:
CMSMJ1 wrote:I can appreciate allthe ideas here..but it is the fact that this fuel burning activity i supposed to to be at a high revs situation. The gases in the exhaust are travelling at humungous speeds already, backwards and forwards, so I just do not quite grasp how burning more fuel (that they need to save in race day) is going to appreciably affect the gas velocity enough - especially at high revs.

What is the speed of the exhaust gas?

How many pulses per second of gas at this speed?

How do you time the fuel dumping at this speed so that it does not end up being drawn backwards as part of the scavenging process??

I'd be impressed if this was a viable solution..but I cannot get a grasp of it.
I don't know the answer to all your questions but burning fuel will produce a volume of gas many times larger than the fuel / air mix itself, the value 15 times larger rings a bell but I haven't double checked that nor have any clue how accurate it is.

The ability to time everything is already part of the engine as it is required for the existing timing of normal running - and is also controllable via the existing engine maps.

The fuel/air is already being burned -they do not stop firing the system when off the throttle so there is already a lot of gas in the system. I suppose the crux of my point is how much difference can dumping fuel to create addiotnal gas pressure it make in a system already expelling enormous amounts of gas at high velocity?

The pressure waves do not flow one way either, so disrupting this with uncontrolled "popping" of fuel i going to cause issues with cylinder scavenging..

Am playing devils advocate here...so apart from wanting it to work, how can anyone start to shed any realistic light on it?
IMPERATOR REX ANGLORUM

speedsense
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Re: Blown Diffuser??

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WhiteBlue wrote:Microsoft has only payed. They had neither competence not input in this. They just got the right to badge it pretty much like the Ilmore engine was badged Mercedes in 1994.
Not according to this

http://asia.cnet.com/blogs/rehashplus/p ... 36&t=share

(third paragraph down)
"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
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Re: Blown Diffuser??

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gcdugas wrote:
richard_leeds wrote:AFAIK ....

Each team can put their own maps into the SECU. That is then controlled by the driver changing a switch on the steering wheel.

So the suggestion is that RB have a SECU map designed for Q3. Possibly other teams do as well, they all use a high fuel burn that would be unsustainable in normal race conditions.

The detail is that the RB map might include significantly retarded ignition to help with exhaust gas flow.

I think you are wrong. The whole point of the SECU was to contain costs of teams that were constantly experimenting with different maps etc. I think I remember reading that they had about 11 different maps. What is the point of a SECU if they can create the maps?
Sorry but this is incorrect, more like contain the costs of teams building their own electronics, and the controlling aspects of the ECU that were affecting many parts of the car. They were experimenting way way beyond just maps. The tech dept. for the FIA had a literal nightmare trying to regulate the electronics. (for instance preventing traction control after making it illegal) Some teams budgets in electronics are were in the 10's of millions.
Standardizing the ECU, not only reduces this cost and makes tech inspection standardized and in control, it also puts everyone on the same playing field without having to spend millions to do so...
Maps are the reason for an ECU and the fact you can create maps for each type of engine and that engine's demands. Also, gearing is very related to mapping.
Unless the engines are exactly the same, the maps have to be different and "user" created. IMHO
"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

Richard
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Re: Blown Diffuser??

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The SECU specification can be downloaded from the FIA website :arrow: http://argent.fia.com/web/appeloffre.ns ... penelement

From page 15 & 39 ...
FIA ECU Specification wrote:For 2008 the FIA is introducing a standard Electronic Control Unit (ECU) for Formula 1 with the aims of reducing the cost of racing, removing driver aids such as traction control and allowing the FIA to check engine use and testing mileage. The standard ECU will control the Engine, Gear Box, Clutch and Differential on the car – no other electronic controls will be allowed.
Then look at page 43 ...

2.4 Ignition Control

...

2.4.6 Team Configuration
Base spark maps, dwell time voltage/time map, minimum/maximum spark advance value clipping.

2.4.7 FIA Configuration and Limitations
Two base spark maps, selectable by driver when car stationary for 3 seconds.
Minimum/maximum spark advance value clipping.
Track session type.
Maximum dwell time update rate.
Crank sensor "fallback" switching latching in race mode until car stationary 3 seconds.
So it looks like the FIA limits the teams to defining 2 different spark maps, each team can specify their own mapping. They can only be changed when stationary. So the scope is there for a team to use one for Q3 and the other for general use.

speedsense
speedsense
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Re: Blown Diffuser??

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richard_leeds wrote:The SECU specification can be downloaded from the FIA website :arrow: http://argent.fia.com/web/appeloffre.ns ... penelement

From page 15 & 39 ...
FIA ECU Specification wrote:For 2008 the FIA is introducing a standard Electronic Control Unit (ECU) for Formula 1 with the aims of reducing the cost of racing, removing driver aids such as traction control and allowing the FIA to check engine use and testing mileage. The standard ECU will control the Engine, Gear Box, Clutch and Differential on the car – no other electronic controls will be allowed.
Then look at page 43 ...

2.4 Ignition Control

...

2.4.6 Team Configuration
Base spark maps, dwell time voltage/time map, minimum/maximum spark advance value clipping.

2.4.7 FIA Configuration and Limitations
Two base spark maps, selectable by driver when car stationary for 3 seconds.
Minimum/maximum spark advance value clipping.
Track session type.
Maximum dwell time update rate.
Crank sensor "fallback" switching latching in race mode until car stationary 3 seconds.
So it looks like the FIA limits the teams to defining 2 different spark maps, each team can specify their own mapping. They can only be changed when stationary. So the scope is there for a team to use one for Q3 and the other for general use.
Interesting it only states "Maximum dwell time update rate" and "Maximum/Mini spark advance value clipping" , niether of which include stationary statements. That can't put that in, because the FI needs the ECU to change these according to engine demand.
Wonder what the "rate" is? The dwell rate, would be for traction control purposes, so that the rate isn't retarding due to wheel spin, probably too slow of a rate.
According to Scrabs article, Red Bull is using it for one flying lap. So the rate could be at the beginning of the lap or before perticular corner corners (high speed).
Last edited by speedsense on 13 Jul 2010, 14:16, edited 1 time in total.
"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

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WhiteBlue
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Re: Blown Diffuser??

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The document is four years super ceded by reality. I bet they have a lot more maps now. Howe would they change the gear specific maps that McLaren invented. The original SECO program has probably seen 50 updates and upgrades now and the same is probably true for the SECU firmware and hardware with some smaller numbers.
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)

tok-tokkie
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Re: Mclaren Mercedes MP4/25

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CMSMJ1 wrote:
The cylinders inhale and exhale 300cc (nominally) per revolution - this is how I see it.
They don't inhale the swept volume when the throttle is closed. In fact they are able to inhale very little at all. By injecting some fuel & igniting it late it gets expanded to about 15x its original volume so the effect at the diffuser is much reduced - no power because the cylinder pressure is not increased due to the piston being well down the stroke & the exhaust valve opens before combustion is completed.

Richard
Richard
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Re: Blown Diffuser??

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WhiteBlue wrote:The document is four years super ceded by reality. I bet they have a lot more maps now.
I'd expect the principles would remain the same, ie FIA limitations on the number of maps for each fuction, and similar controllable parameters.

Anyway, the point is that the basic design of the SECU allows for some variability in the spark maps. Unless someone knows otherwise, we'll be safe to assume that is still the case.

speedsense
speedsense
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Re: Blown Diffuser??

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WhiteBlue wrote:The document is four years super ceded by reality. I bet they have a lot more maps now. Howe would they change the gear specific maps that McLaren invented. The original SECO program has probably seen 50 updates and upgrades now and the same is probably true for the SECU firmware and hardware with some smaller numbers.
BTW, MES (Mclaren) was contracted to supply the ECU hardware/components and Mclaren's user software was "altered" and "rewritten" through Microsoft oversight and programming, so that an "outside party" (other than Mclaren) could allow FIA control over the programming code, so that any alteration of code could be regulated. There are quite a few articles on this, namely Race Car engineering...
http://www.racecar-engineering.com/alla ... of-f1.html
So if there has been upgraded amounts of usage to the unit, it has been because the FIA allowed it to happen.
"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