After over 300 trips around the 13.629 kilometer (8.47 mile) circuit, Porsche edged out Toyota for the overall win in the last three minutes of the 24 Hours of Le Mans. A breakdown left the leading #5 TS050 hybrid stranded on the track with the Porsche #2 919 hybrid speeding past for the overall win. Toyota and Porsche had battled it out for the entire race, with Audi struggling with a blown turbocharger and broken suspension. That Audi’s technicians’ and mechanics could repair significant mechanical issues and have their cars complete the race within striking distance of a podium finish speaks volumes for their skills.
As usual for several years, Toyota, Porsche and Audi ran hybrid cars in the LMP1 (Le Mans Prototype 1) category, which allows either hybrid or non-hybrid power. Hybrid cars have no limit on engine size and non-hybrids are limited to 5.5 liters (340 cubic inches. Because of the speeds they can attain, LMP1 vehicles must have enclosed cockpits.
Porsche uses a 2.0 liter V-4 turbocharged engine, being fed fuel by direct injection. Pressure from the engine’s exhaust drives a generator that feeds a lithium-ion battery pack. A motor/generator on the front axle captures energy during breaking (kinetic energy recovery) and provides short burst of additional power from the battery.
Car and Driver compares this to the turbo-diesel system on the Audi R18 e-tron Quattro’s. “This setup differs wildly from that of the Audi, which uses a turbo-diesel V-6 and a pair of front-axle electric motors mated to an electric flywheel energy accumulator that feeds energy back to those motors under acceleration.”
Toyota’s TS050 uses a small engine, a twin-turbocharged 2.4-liter V-6 connected to an 8 megajoule (MJ) hybrid system. Both Toyota and Porsche have downsized engines since last year, possibly to reduce fuel use in compliance with limits in the new regulations. According to MotorAuthority.com, “the engine of the TS050 is mounted at the rear and spins the rear wheels together with an electric motor sourced from Denso. A second electric motor, sourced from Aisin AW, powers the front wheels. These motors rely on energy, either drawn from the engine or recovered under braking, stored in a lithium-ion battery.”
Despite their added complexity, these cars have dominated the LMP1 category for years, showing they combine power with reliability, all within the weight limits imposed by the WEC (World Endurance Championship) regulations. These are heartening indicators for the new technologies to be used in future aviation speedsters.
A grace note: Garage 56 has traditionally been set aside for an entrant that embodies new and challenging technology. This year, the Garage 56 entry was more about accessibility to even the highest realms of automotive competition, being a specially-prepared Morgan-Nissan adapted to the needs of Frédéric Sausset, a quadruple amputee. He and his two teammates completed the race in 39th position.
“Sausset, whose lower legs and arms were amputated to save him from a life-threatening disease and his teammates Christophe Tinseau and Jean-Bernard Bouvet received a special award at the podium ceremony. After tumultuous applause from the crowd, the entrepreneur from Blois in the center of France gave a post-race press conference: ‘I feel great now because there was lots of pressure on us. Our ultimate goal was to finish the race. We didn’t have any targets in terms of classification. Thanks to my experienced teammates Christophe Tinseau and Jean-Bernard Bouvet, we finished. And now we want to savor our success.'”