Creating a Record-Setting Porsche Hybrid
Thirty-five years and 31 days after Stefan Bellof set a lap record at the Nürburgring Nordschleife race circuit, it was bested today by Timo Bernhard, who lapped the 12.94-mile course in 5 minutes, 19.55 seconds in the Porsche 919 Hybrid Evo, a time that was better than the late Bellof’s by 51.58 seconds.
About the car:
It is based on the Porsche 919 Hybrid that took the Le Mans 24-Hours and won the FIA World Endurance Championship (WEC) in 2015, 2016 and 2017. While Porsche had made modifications for racing the car in the 2018 WEC, the company pulled the car from competition so it didn’t race in the series.
For the run at the Nürburgring, the WEC regulations weren’t required, so adjustments were made accordingly.
The powertrain hardware remained the same: a 2.0-liter turbocharged V4 engine and two energy recovery systems. (Brake energy from the front axle combined with exhaust energy are captured and stored in liquid-cooled lithium ion battery.) The rear axle is driven by the engine and an electric motor the front. For WEC there were restrictions on both fuel use and electrical energy use. So the V4 engine produced approximately 500 hp when there were restrictions on the fuel used per lap. That’s gone and software adjustments have been made, so the engine produces 720 hp.
The recuperative energy system was also restricted, but for the 919 Evo, those restrictions were removed so the e-machine output has gone from 400 to 440 hp.
Then there were aerodynamic changes, including a larger front diffuser and a very large rear wing. Each of those is fitted with a drag reduction system (DRS), which is a hydraulically actuated system. The DRS for the front and the rear are adjusted accordingly to improve the drag characteristics of the car on the track.
There are also fixed height side skirts and the tuning vanes and floor beneath the car are optimized.
As a result, there are a 53 percent increase in downforce and a 66 percent increase in efficiency compared with the previous version of the car.
For improving performance on the track, a four-wheel brake-by-wire system was added (which contributes to improved yaw control), the power steering system was setup to accommodate higher loads, and stronger suspension wishbones were deployed in the front and rear.
Mass was a focus, as well, for the car which is based on a monocoque consisting of carbon fiber around an aluminum honeycomb core. The dry weight of the 919 Evo is 1,872 pounds, which is a decrease of 86 pounds. This was accomplished by taking out several sensors, light systems, the pneumatic jack system, electronic devices required by WEC race control, the windshield wiper, and the air condition system.
Given that Bernhard did the lap in less than five-and-a-half minutes, he probably didn’t miss the air con too much.
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