After a successful 2015 and 2016, Porsche has unveiled the new 919 Hybrid LMP1 race car, which aims to defend the marque’s FIA World Endurance Championship and Le Mans 24 Hours titles.

“For the 2017 season, 60-70% of the vehicle is newly developed. The basic concept of the 919 Hybrid still offers scope to optimise the finer details and further boost efficiency. The monocoque has remained unchanged since 2016, but the optimisation potential of all other components was analysed and, in most cases, adjustments made accordingly,” said team principal Andreas Seidl.

At the heart of the 919 Hybrid is a 2.0 litre turbocharged V4 petrol engine, which on its own produces 500 hp, all sent to the rear wheels. The internal combustion engine is backed by an electric motor that supplies over 400 hp to the front axle when needed, effectively providing the car with all-wheel drive.

Porsche says the total system output is rated at 900 hp, and is the only prototype to recover energy during acceleration as well as braking. The Weissach-developed car features two different energy recovery systems – a braking energy recovery system on the front axle as well as an exhaust energy recovery system – feeding a lithium-ion battery that juices the electric motor.

Entering the details, approximately 60% of the recovered energy comes from the KERS (Kinetic Energy Recovery System) on the front brakes, while the remaining 40% is generated by the exhaust energy recovery system.

The latter sees a small variable geometry turbine fitted in the exhaust tract, which spins at a speed of more than 120,000 rpm, powering a generator. As mentioned earlier, the energy generated is stored in a battery until it is needed.

Since endurance racing is all about efficiency, an average of 80% of the braking energy recovered from the front axle is immediately converted to drive energy. Porsche also notes that if the engine was required to supply this electrical power, it would to increase its output by over 100 hp (74 kW), which would increase the fuel consumption of the 919 by more than 20%, equating to an extra litre of fuel per lap.

Therefore, a highly efficient recuperation system helps to keep the fuel consumption low, allowing for more laps to be set on track and less refuelling stops. Furthermore, it enables the 919 to perform with smaller and lighter brakes, keeping the weight low and reducing air resistance as smaller brakes require less cooling air.

Aerodynamics also play a pivotal role on the 919 Hybrid, and this year’s FIA regulations will include further limitations in terms of the dimensions of some body components that affect aerodynamics. Due to safety concerns, LMP1 prototypes generate less downforce than before. Therefore, the Porsche team developed two aerodynamics packages of the race car, one for high-speed tracks like at Le Mans, while the other is geared for greater downforce on twister tracks.

Compared to the previous year’s model, the new car sports higher, wider and longer wheel arches, plus there is a new channel from the monocoque to the wheel arch. At the rear, there are now redesigned rear air intakes for the radiators.

“As a result of the aerodynamic losses we will incur due to the new regulations, we are expecting to see a three to four-second increase in lap times at Le Mans. We will have to wait and see how well the various enhancements we have made will compensate for these losses,” explains Seidl.

Two 919 Hybrid cars will be fielded, with car number 1 being driven by Neel Jani (33, Switzerland), André Lotterer (35, Germany) and Nick Tandy (32, Great Britain), the former being the WEC World Champion and 2016 Le Mans winner. Car number 2 will be shared between 2015 World Champion Timo Bernhard (36, Germany) and the two New Zealanders Earl Bamber (26) and Brendon Hartley (27).