MATCHETT: Life Inside a Formula 1 Fuel Tank

Formula 1

MATCHETT: Life Inside a Formula 1 Fuel Tank

SPEED's F1 analyst Steve Matchett relates the intricacies of getting the most out of every drop of fuel in a Formula 1 car.

Steve Matchett | Posted October 16, 2007 Charlotte, N.C.

The science of F1 refueling goes a lot further than just carefully orchestrated pit stops. (LAT photo)

At strategic points of a grand prix we're used to seeing the mechanics refueling their cars via their (Intertechnique manufactured) pressurized rigs. We're familiar with the look of the rigs, the size of the delivery hose, the apparent cumbersome weight of the nozzle assembly as the crew lug the hose into position. That said, what happens to the fresh supply of fuel once actually inside the car is, perhaps, not so clear. One might suppose that the fuel is merely dumped into the car's empty tank, then pumped directly to the engine where it is burned, its power extracted before any remnants are ejected via the exhausts. And, in essence, yes, that is what happens, but Formula 1 being what it is, there is much more to the flow of the fuel from tank to engine than might be imagined.

The biggest concern for the engineers is that their car should not run out of fuel before its next scheduled pit stop. They need to ensure that every drop of fuel can be used, that the engine is supplied with a constant flow regardless of the high g-loading to which the car is subjected. It's no good having a misfire from fuel starvation, due to the fact that the engine's fuel pump pickup is mounted in the left-hand side of the tank, while all the fuel is merrily swashing around the opposite side. And vice versa, of course.

The space inside the fuel tank is fitted with a series of internal chambers, each equipped with one-way trapdoors. The fuel enters the tank from the rig and flows, via gravity into all of the chambers, each trap door swings open to allow the fuel to flow downward and toward the middle of the tank. Then the trapdoor swings shut: It's a one-way journey; once the fuel has entered a lower chamber it can never return, can never flow backwards, only downwards, always onwards; in some ways it's a little like the labyrinthine layout of a pyramid.

Mounted inside the lower chamber of this Kevlar and rubber, high-tech, flexible, bullet-proof pyramid � sitting at the very heart of the fuel system � is the Collector. Typically manufactured from carbon (for its low mass), the collector looks very similar to a high-tech mineral water bottle. It is from this small collector that the engine-driven, high-pressure "mechanical pump" takes its supply of fuel and delivers it to the engine's injectors.

During the laps immediately following a refueling stop (due to its low, central location within the car's tank) the collector is totally immersed in fuel, so keeping the collector full in these early stages presents no problem. To ensure that the collector remains full as the fuel level slowly drops, however, it is itself permanently supplied (or primed) with fuel via two, small, low-pressure electronic pumps, known as primary pumps, one mounted in each rear corner of the fuel tank.

These electronic primary pumps are working continuously, designed to oversupply the collector, filling it with more fuel than the engine's mechanical pump will ever need to deliver to the injectors in order to quench the engine's thirst. The primary pumps oversupply the collector, where any surplus fuel merely overflows the collector, pouring out of holes in the top and running back into the tank � there to be picked up once again by the scavenge pumps and delivered, over and over, back to the collector.

Inevitably, however, as the race progresses, the tank's level will drop as the fuel is consumed by the engine. A point will be reached when there is no surplus of fuel: we are now down to the remaining two liters, the quantity held within the collector. It is at this stage of the race that the two primary pumps really earn their keep: It is now the job of the primary pumps to scavenge any remaining fuel from the main tank and keep feeding the starving collector. Every gram of fuel, any last dregs are vital, every drop of fuel must be scavenged and fed to the collector.

The system is reasonably complex but the upshot of the design is that the problems of fuel-slosh are greatly reduced and every drop of fuel inside the tank is at the engine's disposal. And, if the engineers have done their calculations correctly, there should be just enough fuel to allow the car to drive back to the pits. Here the crews of mechanics will change the worn tires, replenish the fuel load and the second or third stint of the race begins� at which point the whole series of events unfolding inside the car's tank starts over.

The car's fuel consumption is carefully monitored by the engineers, not the driver. There is no in-car fuel gauge, no conventional road car float-type level sensor built within the tank. Fuel consumption is monitored by a flow meter housed within the spray-rail. This information is transmitted by the car's telemetry back to the pits and, studying this continual stream of data, the engineers (should) be in a position to calculate precisely how many laps their particular car can continue to run without spluttering to a rather undignified stop halfway around the circuit.

SPEED NOTE: SPEED WILL CARRY THE CHAMPIONSHIP DECIDING F1 SEASON FINALE THIS SUNDAY AT 11:30 AM ET DETAILS HERE

SPEED's Formula 1 technical analyst Steve Matchett presently resides in the south of France. In addition to his duties on SPEED'S F1 broadcasts alongside Bob Varsha and David Hobbs, Steve will be providing insight into the high-tech world of Formula 1 through regular video features and commentary on SPEEDtv.com.

The opinions reflected herein are solely those of the above commentator and are not necessarily those of SpeedTV.com, FOX, NewsCorp, Speed Channel, or Haymarket Worldwide.

ABOUT THE AUTHOR

Steve Matchett

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