29.1 b) Fuel may not be added to nor removed from a car during a race
F1 Sporting Regulations - 10 February 2010 © 2009 Fédération Internationale de l’Automobile
For the first time since 1994, in-race refueling has been banned from Formula 1. There have been many discussions about how this will affect race strategies, tire usage, driver styles, safety, traffic management, and race pace vs. fuel efficiency. It certainly does create a whole new paradigm to be dealt with by engineers, drivers, and strategists.
Last year at Abu Dhabi, Fernando Alonso started the race with 103.8kg of fuel onboard. That is approximately 142 litres, and while perhaps not the biggest fuel load seen all season, it was significant. According to Jon Wheatley, team manager for Red Bull Racing, most fuel cells in F1 in 2009 were between 90kg and 120kg of capacity. Alonso made his only stop at the Yas Marina circuit on lap 34 and, assuming the same fuel consumption rates for the remaining 21 laps; his total fuel consumption would have been 167kg, or approximately 228 litres.
According to F1 Yearbook and supported by RubberGoat on his blog Making Up The Numbers, Renault had the best fuel efficiency of any team. In theory this means that their fuel tank would be the smallest one on the grid. Other teams with poor fuel efficiency would require even larger tanks. This marks a significant change in chassis design parameters and will require redesigned fuel tanks.
The full-race fuel load requirement resulted in 2010 cars having a much longer wheelbase. The FIA F1 technical rules limit the placement of the tank. It must be in front of the engine and can only be 400mm from the longitudinal center line of the car. This gives it a maximum width of 800mm. Once you have reached the maximum width, one must make the tank longer until you have reached the required capacity. Secondly, the fuel tank can be no more than 300mm forward of the driver’s back. Since the driver sits in a reclined position, this measurement is taken from the top of his back. This leaves a little space beside the driver’s seat to place a portion of the tank.
Most, if not all, fuel tanks used in Formula 1 are constructed by ATL (Aero Tech Laboratories). ATL is a specialist company whose expertise lies in flexible composites. Their client list includes industries involved in aerospace, aviation, industrial production, automotive, as well as various branches of the military.
The tanks themselves are really quite unique and are nothing like the tanks in a road car. ATL manufacturers the tanks from a composite construction of Kevlar and rubber that is strong, but flexible. High speed impacts on a race car demand tank flexibility and strength. The integrity of the tank must be maintained even in the worst situations. The term commonly used to describe their durability is “bullet proof,” and the tanks have held up well and have proven to be safe. The tanks are “stuffed” into the cars via a small hole in the bottom of the chassis.
Inside the tanks one finds many unique features. High g-loads under braking, cornering, and acceleration cause fuel to slosh around in the tank. Car balance and stability demand that the fuel not behave that way. In the old days, we referred to a sudden change in direction as a “tank-slapper.” This slapping destabilizes the balance of the car. To prevent this, the tanks are fitted with internal chambers to baffle the effect. The chambers are independent of one another and have a trap door that acts as a “check valve” to prevent reverse flow. Gravity induced flows route the fuel from chamber to chamber toward the mechanical pump.
One of the concerns with fuel supply is engine starvation. The mechanical pump is outside the tank at the rear and is at the lowest point. These pumps require a minimum amount of fuel to be present in a collector in order to function properly. Some manufacturers require 6kg, but others can function properly with much less, perhaps as little as 3kg. When the tanks are full this isn’t a problem, but when the fuel level is low one must keep the fuel flow to the pump consistent. The main pump is fed from the collector. The collector sits very low in the last chamber of the supply network. It is fed by two small scavenger pumps. These pumps reach into the corners of the tank to collect fuel. They are not necessary with high fuel levels in the tank, but are absolutely necessary when levels drop. They are electric and pump fuel continuously. Their job is to keep the collector filled at all times and to scavenge the last bits of fuel in the tank.
You probably remember the two race suspension given to BAR in 2005 for “conducting themselves dishonorably.” The scrutineers determined that the car was underweight. At that time the minimum dry weight was 600kg. There were discussions about the definition of dry weight, but it was common knowledge that the car should have no fuel onboard during the post race inspection.
BAR argued that their mechanical fuel pump required 6kg of fuel to operate properly, and that the design of their car did not facilitate draining the collector for scrutineering. Fair enough, but the collector was hidden away behind a bulkhead with only a fuel line to indicate its presence. And, there was another problem. The collector was determined to have a capacity of 11.5kg.
This was impossible to explain and they were suspended.F1 fuel tanks are much more complicated than the fuel tanks that we deal with on most vehicles. They have a unique construction to guarantee safety. They have a unique internal structure to minimize the effects of unwanted fuel movement. And, they have a complicated mechanical set up to guarantee fuel delivery and reliability.
Like most things in Formula 1, the fuel storage and delivery system is a complicated technical marvel. It works very well with these high demand 2.4L V8 engines.