The 919 Hybrid is a dazzling complex piece of machinery. The technology it uses will influence road car design for years to come, but today that technology is all aimed at being a dominant force on a racetrack. This weekend's 6 Hours of Nürburgring will be the 919's only race in its home country this season. What goes in to getting this 900 horsepower machine successfully around the 5.148km circuit?
As we discussed in our piece on the Porsche 919's influence on road cars, the car's hybrid system collects energy in two ways. The regenerative braking system collects energy while the car is under braking, while the extra turbine in the exhaust generates further power during acceleration. Both systems feed into the 800 volt power supply system and the electric motor on the front axle.
At the Nürburgring's Grand Prix circuit, the 919 will have to decelerate and accelerate 17-times per lap. This challenging circuit replaced the full "Green Hell" in 1984, and should prove a proper challenge for the hybrid system. Both energy collection systems are wholly dependent on driving conditions. The exhaust driven system thrives on long straights. The regenerative braking system works best when the car has to slow down from a high speed into a low-speed corner. The braking system generates 60% of the car's electrical energy, while the exhaust system contributes the remainder.
In essence, the corners where the car has to slow down the most are to the regenerative braking's system's benefit. Coming off the main straight into turn one is this track's best area for the regenerative braking system. Similarly, Dunlop-Kehre (turn 8) and Veedol (turn 14) will be the 919's areas of greatest power regeneration. The track's several long straights will allow the exhaust driven system to operate at its most efficient.
Some clips of the cars lapping the GP circuit during practice sessions this week can be viewed above. The Porsches have shown tremendous pace during practice. Marc Lieb's 1m41.703s lap and Timo Bernhard's fast lap of 1m41.967s were the fastest of the practice sessions.
Every WEC event is an exciting affair. The 6 Hours of Nürburgring is the first event since the 24 Hours of Le Mans, and we are excited to see how the Porsches fair against Toyota; a team who more than ever have something to prove. As each of the hybrids lap the circuit, bear in mind that each is actively trying to scavenge energy. This additional challenge makes the race between the hybrid cars increasingly dynamic.