As per the other thread ( http://the-pit-lane.co.uk/index.php?showtopic=8067&st=0 ) in F1, Williams and BMW are being investigated in relation to the temperature of the fuel samples from their cars after the race. The rules state that the fuel cannot be more that 10C below ambient temperature. Also, no processes can be used to reduce the intake temperature other than fuel being sprayed into it for combustion, and I assume that the 10C ruling is to prevent super chilled fuel from helping increase the charge density?

Analysis, Dr Flood?

Fact: Cold fuel is denser, thus allowing more into the engine to enhance horsepower.
Fact: Mixing it with forced air makes fuel colder, due to wind chill etc.
Fact: All internal combustion engines require such a mixture to run.
Fact: Teams running in hot climate often use dry ice to chill bits of the car before the start. Another fact is that it doesn't always stay put!
Speculation: Some dry ice has gotten loose and gone into, or near the fuel tank? Knowing how picky the FIA are about how much of a difference is needed it could easily cause a temprature difference. if there was any left of course.

I'm well aware of all those facts! The dry ice would never last an hour and a half in Brazil, let alone stuck inside a car as far as I'm concerned. I'm more interested in whether or not there was an advantage gained, and how they'd keep the fuel cooler......

OK, fuel density changes about 1% for every 10 degrees F in temperature change. As Stig said, a more dense fuel has more potiential energy than a less dense fuel. So, if you ran a cooler fuel, it would provide better combustion per volume, would weigh more per volume, and take up less space in your fuel cell.

I think if an F1 car had fuel that was too cool, it would be a result of a higher ambient temperature from which it is compared. I doubt if the fuel has a surprisingly low temperature, but one that had failed to rise to match the temperature of 97 degress F at Brasil.

The engine temps are maintained at the same operating temp regardless of the ambient through airflow manipulation.

I would also like to know how much this fuel exceeded the standard deviation allowed.

Well in that case, note the position of the fuel tank relative to the position of the side pods and airbox... how easy would it be to have air blown over it on the way to the radiators/air intakes etc.

Here's what I'm saying. The engine maintains roughly the same temperature regardless of the ambient temp. The fuel more are less does the same thing and is in an area insulated from ambient temps.

So, in 60 degree F weather the fuel may be warmer than ambient, while at 97 degrees F it may be cooler, much cooler.

The investigation will focus on this as an anomoly rather than an effort to circumvent the rules artificially. If all things are normal technically, they will ignore the findings.

On what lap did these guys last refuel?

Hmm, an insulated tank? Prehaps the problem is with the fuel rig then?

To some degree (pun), all fuel tanks in race cars must be protected from excessive engine temps. The vapor pressure of fuel is temp dependant. It must be somewhat consistant or the combustion ratio would change constantly. In road cars this is adjusted by a temperature sensor that adjusts the air volume. Road fuels are adjusted seasonally to compensate for vapor pressure changes due to ambient temperature of the air and the fuel.

I think it is an anomoly and no action was taken by any team to "cause" this.

It appears that the temp measurements are taken during refuelling. Therefore, Stig is right in that it has to do with the storage temp of the fuel and not the onboard temp.

This also would explain why it is not post race scrutineering but, in fact, is done at the pit stops. So, no extra post race time is required to make these determinations.

Oh s**t! I am just about fed up with all of this ....

From Autosprout:

I have found an estimate for the volume expansion coefficient of petrol - 950 X 10^-6 per deg C.

The figures quoted for the difference in temperatures (a maximum of 4 deg C) means that the amount of fuel difference is miniscule (for 25 l the additional fuel is 0.095 l).

Finally, the stewards report indicates that there is an uncertainty of more than 2 deg C in each of the temperatures given in a previous post. This was their reason for not imposing a penalty.

On the basis of the above it will be very difficult for McLaren to win their appeal, I would have thought.

But where do you draw the line. You can't suddenly start applying shades of grey to clear cut rules. What if someones car was 2 KG under weight. would you let them off because the advantage they go was hardly measurable. Or if someone exceeded the pitlane speed limit by 5 MPH? Let them of because the time they gained would be negligible? The rules are there for a reason. As for the uncertainty of the temperature measurement, why do they have a rule that can't be enforced effectively? Also, if you note, 18 other cars had no irregularities with their fuel temperature.

Your point is a valid one, Andy. It does help when seeing the numbers to determine what effect this might have on performance. It means that the cars in question could cover 0.38% more distance than if they had the correct temperature fuel. It also makes them that amount heavier after refuelling <think>

The clincher for me is the uncertainty in the reported temperatures. This appears to be due to the high ambient temperatures in Sao Paulo. I am inclined to see this as a mistake that is very similar to the rule broken by Hamilton and McLaren on Friday.

My feeling is that, if the stewards knew that the temperatures would be high in Brazil (as they normally are), then why didn't they take steps to ensure that they could accurately measure temperature and why didn't they warn the teams of possible indiscrepencies or problems?

I think *all* of the refuelling equipment should be supplied to the teams from the FIA, sealed and tagged. If the teams cannot alter the settings of the fuel rig, they cannot bend the rules on fuel temperature, and thus ends this debacle. All the teams should be able to do with a fuel rig is dispense fuel from it, and no more.

I thought they were (!)

and if they are... there's another reason for no punishment.

I think it's just the couplings they can't fiddle with. I'm not sure about anything that might affect the temperature of the fuel. To be honest, I thought it was just a pressurised tank, I didn't realise it could effectively refridgerate fuel as well! I wonder if Kimi uses one of Ferrari's for vodka?

Well here's what the regs have to say about re-fueling.


2007 F1 Sporting Regulations 15 of 39 13th July 2007
29) REFUELLING
29.1 a) Refuelling is only permitted in the team’s designated garage area or the FIA garage.
b) Fuel may not be added to nor removed from any car eligible to take part in Q3 during that period.
Fuel used during Q3 may be replaced immediately after the cars are released from parc fermé on the
day of the race, this will be carried out in grid order.
Every car which was eligible to take part in Q3, with the exception of those unable to take part, must
comply with the above. Any Competitor whose car is eligible but unable to take part in Q3 must, prior
to the start of Q3, inform the FIA in writing what quantity of fuel they wish to add to the car when it is
released from parc fermé on the day of the race.
c) Other than a fuel breather and an external fuel pressurising device for starting the engine (in which
case only fuel on board the car may be used for running the engine), no connection may be made to
the fuel system of any car eligible to take part in Q3 during that period.
d) Other than a fuel breather and an external fuel pressurising device for starting the engine (in which
case only fuel on board the car may be used for running the engine), or when race fuel is being
added, no connection may be made to the fuel system of any car between the end of qualifying
practice and the start of the race.
e) If a race is suspended refuelling is forbidden unless a car is already in the pit entry or pit lane when
the signal to stop is given.
29.2 The driver may remain in his car throughout refuelling but, unless an FIA approved race refuelling system
is used, the engine must be stopped.
Race refuelling systems may only be used in the pit lane but may not be used during, or immediately after,
any free practice session.
Whilst being used during the qualifying practice session or the race all team personnel working on the car
must wear clothing which will protect all parts of their body from fire.
29.3 Each competitor must ensure that an assistant equipped with a suitable fire extinguisher of adequate
capacity is beside the car throughout all refuelling operations.

From : Here

Note if you will, regulation 29.2 - specifically the words FIA Approved. Since all F1 teams refuel with the driver in and the engine running, this would suggest at some point the FIA have inspected the machinery and would have discovered any illegal chilling mechanisms then?

Well, does the 'refuelling system' just mean the fuel coupling, or absolutely everything? Furthermore, it only says 'approved' and not 'supplied'. Maybe they have some form of temperature stabilising built in? How often are they inspected.

Bit like an MOT - the certificate says the car/bike passed the test, but doesn't say it hasn't been tampered with afterwards!

I am assuming that the fuel is allowed to be chilled to a certain extent for safety reasons, hence the allowance of 10 degrees C below ambient temperatures.

This it does not say, however it would be reasonable to assume that all the rigs are scrutineered before each race.