The fuel flow meters are designed to limit the total amount of fuel used during a race, it does so by limiting the amount used per lap rather than over the entire race. Since the first race at Le Mans in 1923, endurance racing has been used as a laboratory for future technologies, and today is no different with the latest LMP1 regulations challenging engineers to rethink the parameters of an LMP1 car.  They had to extract the maximum power possible and the openness of the technical regulations and the increasing power of energy recovery systems have enabled endurance racing to meet and exceed the challenge.

Not only has fuel consumption been reduced without affecting the performance of the cars, but the different technical approaches taken by the manufacturers has also resulted in some fantastic battles on track.  At Silverstone and at Spa-Francorchamps the speed of the Porsche 919 in a straight line left the rest of the field standing, while the performance of the Audi R18 in the corners held the advantage.  The result was a thrilling on track battle that had everyone on the edge of their seats, and living proof that restricting fuel consumption doesn’t necessarily result in a lack of race action.

Prior to 2013 there were some concerns over the performance equivalencies between petrol and diesel engines.  With the introduction of the fuel flow meters and a strictly controlled energy allocation, these concerns have largely been dissolved.

FIA Technical Director Bernard Niclot and ACO Sport Director Vincent Beaumesnil spoke at the start of the 2015 season about the changes introduced in 2014 and the impact they have had.

“The Endurance Commission and the WEC organisers do not want to give a technological advantage to one fuel rather than another because they live together on the road,” said Bernard Niclot. “We therefore had to develop a technology equivalence that was not a balance of performance. This is the foundation of our regulations. After the 2014 Le Mans 24 Hours, we looked at each of these engines’ specific fuel consumption to see if it was what the manufacturers had told us. We made tiny adjustments, up to three decimal places, in the conversion factors between petrol and diesel. After the 2015 Le Mans, we will carry out the same work so that one technology doesn’t override another.”

This way of working is supported by the ACO Sporting Director Vincent Beaumesnil.  “When we defined the technical regulations we established a method and a transparency process, where we asked all the manufacturers to state their specific fuel consumption and where everyone had access to everyone else’s fuel consumption data, all of which was monitored by us. That removes all scope for cheating, as there is only two per cent leeway and heavy penalties – up to exclusion – for exceeding that margin. So it’s in each manufacturer’s interest to give us accurate data.”

These days this process has changed slightly as, with accurate data on board from last year, the manufacturers now only have to supply their fuel consumption information to the governing body, rather than to each other.

“But there’s a whole section that is not covered by the equivalency regulations, concerning the performance of hybrid systems,” says Beaumesnil. “We did seek to limit performance according to the different levels of hybridization [ERS classes] and also slow the cars down generally: they were going too fast. To be honest, we were hoping for a lap time of around 3m35s at Le Mans and a top speed of no more than 310km/h on the Mulsanne Straight. In the end the pole was set in 3m21s, the top speed exceeded 340km/h and the performances of the three manufacturers were very close from the start despite using completely different technologies. This is proof that we were right in our thinking and it’s a great satisfaction.”

While both Niclot and Beaumesnil had moments of doubt before the 2014 season, they take just as much pride in the reliability of the hybrid systems as the manufacturers themselves. “We’ve managed to circumvent any issues of the flow-meters thanks to the backing of all the manufacturers, who have always wholeheartedly supported us. That’s important to point out. From the very beginning they welcomed the technological choices and quality controls which ensure sporting fairness. In 2015 the flow-meters will evolve, becoming stronger and taking advantage of new software that allows full automation of the system.”

The Cars

GLOSSARY

MGU-K: motor generator unit – kinetic

MGU-H: motor generator unit – heat

ERS: Energy Recovery System (referring to the unit as a whole)

MJ: Mega Joules, so 1 million joules.

Joule: unit of measurement of energy, knowing that 1000 joules = 1 kW

(so 1.34 hp over a second), 8 MJ = 10.738 horsepower over a second.