Fuel Question for 2010

[ESPImperium]

I have been in discussion, lets say with my Dad for the past, almost 3 or 4 months now about the 2010 fuel tanks. Here comes the question, or lets say questions;

1) Can fuel be lost due to extreme heat, say theres a temprature of 40oC at Bahrain, could fuel be lost like a small puddle disapearing to make a cloud, and could this make an impact of fuel economy over a race distance???

2) Humidity - Can the humid conditions of say Malaysia hamper fuel economy over a race distance???

3) Hare & Tortoise, will teams choose to come in more regularly to gain extra performance (3 stop) or as i think, keep the current 2 stop or even go one stop for guys futher back than say 8th to 10th on the grid???

4) How much "extra" will the teams put in as a guest-amate (in laps) to make sure that they can make it over a race distance???

Thanks.

[ISLAMATRON]

Fuel can and will vaporize in extreme heat(especially a dry heat like Bahrain) and I believe the fuel F1 teams use is actually more prone to vaporization than regular pump gas, but with that being said I think the fuel systems in an F1 car are very well sealed, unlike a road car which employ a charcoal canister vapor absorption system to help mitigate environmental damage by fuel evaporation.

Humidity can hamper fuel consumption by requiring larger air inlets to achieve the necessary amount of cooling thus increasing drag.

the rest of your questions require more information than I have to answer

[flynfrog]

the fuel gets pretty warm any way from sitting in front of the engine not sure ambient will make much difference

[Raptor22]

I have been in discussion, lets say with my Dad for the past, almost 3 or 4 months now about the 2010 fuel tanks. Here comes the question, or lets say questions;

1) Can fuel be lost due to extreme heat, say theres a temprature of 40oC at Bahrain, could fuel be lost like a small puddle disapearing to make a cloud, and could this make an impact of fuel economy over a race distance???

Yes fuel can be lost. However F1 fuel tanks are not an open cavity but are rather a honeycomb like substrate; think of saturating a block of foam with water. Coupled to the fact that the tanks are sealed and can be pressurised, vapor loss is minimised

2) Humidity - Can the humid conditions of say Malaysia hamper fuel economy over a race distance???

Humidity can increase fuel consumption because the partitial pressure of oxygen in the intake charge is reduced due to the presence of H2O. Engine mapping does compensate but it could result in fuel comsumption increase by as much as 2ltrs over a race distance.

3) Hare & Tortoise, will teams choose to come in more regularly to gain extra performance (3 stop) or as i think, keep the current 2 stop or even go one stop for guys futher back than say 8th to 10th on the grid???

Not sure what the rules allows for but I thought the number of stops was mandated

4) How much "extra" will the teams put in as a guest-amate (in laps) to make sure that they can make it over a race distance???

Fuel tank capacity is set at maximum 240ltrs i believe (will check) so that limit opretty much decides what you upper limit is.
Pace, tyre choice (for fuel efficiency vs grip) and aerodynamic set up and gearing will all play a role in fuel economy. Set up strategy is going to through in a lot of variables

[DaveKillens]

The decision on what tire to use, and when, will be totally dependant on how the tire performs. If the softer compound falls off after 12 laps, then that's what it will be used for. And if the harder compound can run basically unchanged (in performance) for almost the entire race, then why pit to change it to a set of tires that will perform the same after they have warmed up?

The pre-race practice session will be critical in determining the performance and life expectancy of the various tire compounds, what they learn from the tires will be a major factor in tire selection and strategy. In fact, the teams will not have any strategy until they get the tire data.

The fuel in Formula One, although advertised as just pump gas, is specific to the cars and the requirements of the engines. They are an exotic blend of chemicals, and any deviation from the formula is a deviation from the qualities of the fuel, and is undesirable. The goal is to have exactly the fuel that arrived in containers be unchanged until it exits the fuel injectors.

The colder the fuel is, the denser it is, and thus contains more energy that can be extracted. Thus, every team cools the fuel as low as possible. In fact, the FIA regulations are specific and strict on the minimum temperature.

Keep the gas cold and uncontaminated.

[Ian P.]

There seems to be some differences in ideas for answers....good for discussion.

1. My bet is that teams will cool the fuel (to the limit of what the rules allow) befrore filling the tank. I seem to recall 10 deg C below ambient is the limit.
No more dry-ice Roger Penske fuel rigs ....drat.
Evaporation shouldn't be a big issue. Don't loose sight of the fact that the fuel in the cars currently gets warm due to the heat from the car itself. Evaporation will also limit itself due to the natural cooling effect.

2. Higher humidity levels reduce air density which should reduce the amount of fuel injected into the engine. The closed loop O2 sensor and management system will handle this. Since F1 cars are running flat out, any reduction in air density will reduce fuel flow (fuel to O2 ratio held constant) net power and overall reduce fuel consumption.

3. The number of stops is going to be a very interesting point and should highlight the differences in driving styles and early race agression. It is all going to depend on the tyres (yep, got it right again..) that Bridgstone brings to the races.

4. Based on what we used to see in the CART races, there will be different levels of conservatism applied by different teams. There will always be one or two that gamble on a safety car period or comand the driver to conserve so they can streach out tyre life and avoid a stop. Sometimes it will work and the rest...it won't. Look for some cars to be circulating slowly for the last few laps.
I saw Mark Donahue win a Trans Am race, complete the cool down lap and then they had to push it to Tech Inspection because it was empty. That is how you do it.

[ISLAMATRON]

F1 fuel management is never in closed loop, always open loop.

[Ian P.]

Question on open vs closed loop fuel management.
Have seen many pictures of what appear to be O2 sensors on the exhaust pipes. Had always thought that a closed loop system would permit management for either power, additional cooling or economy depending on the A-F ratio and any pre-programmed offset from the "optimal", ie. different mapping selections.
Insight / explanation would be appreciated.
Thanks

[Belatti]

The decision on what tire to use, and when, will be totally dependant on how the tire performs. If the softer compound falls off after 12 laps, then that's what it will be used for. And if the harder compound can run basically unchanged (in performance) for almost the entire race, then why pit to change it to a set of tires that will perform the same after they have warmed up?

The softer compounds may fall off after 12 laps with full tanks but endure 25 laps at the end of the race. 200+ Kg of fuel is a lot of weight!

Also 3 stops may work fine in terms of "overall tyre peace" but the loss of time due to a couple of laps with cold tyres at the beggining of each stint my be a problem (remember tyre warmers prohibition) so...
all new variables for the race engineers to sort the best strategy

[ISLAMATRON]

Question on open vs closed loop fuel management.
Have seen many pictures of what appear to be O2 sensors on the exhaust pipes. Had always thought that a closed loop system would permit management for either power, additional cooling or economy depending on the A-F ratio and any pre-programmed offset from the "optimal", ie. different mapping selections.
Insight / explanation would be appreciated.
Thanks

Yes they do have 02 sensors(or they call them Lamda sensors... same thing)... remember Kimi's exhaust dangling by the sensor wire in the French GP a couple years ago before the exhaust flew into the air.

But the Lamda sensors are there to tell them how the engine is running, not as a sensor for input into a closed loop system. Although it could under some very steady conditions but F1 does not have said conditions... engine revs are pretty much allways rising or falling, full throttle or none.

Back in the day of 2 way telemetry I'm sure they could have used the lamda sensor to tell them approximatly how much power they were putting out and adjust electronically from the pits, but now they have to tell the driver to switch between fuel maps.

Yes closed loop can do all those things you mentioned, but not under the conditions that an F1 engine operates. It cannot react fast enough... that is why even road cars are forced to have both open & closed loop conditions.