The new electric Cayenne will officially debut by the end of the year

In developing the Cayenne Electric, Porsche is relying more than ever on digital testing. However, the human factor is still indispensable: during the final test drives, the engineers push the SUV to its limits. And this happens in extreme weather conditions, from freezing cold to very high temperatures piese auto online.

The new electric Cayenne will officially debut by the end of the year

Developments in a virtual environment are being analyzed for their readiness for real-life use. Porsche is showing how digital transformation and engineering expertise work together in the creation of the new Cayenne Electric. The new all-electric SUV will be presented towards the end of the year and will then be offered alongside the current model range with internal combustion engines and hybrid drives. “This was the first project in which we went directly from digital testing of the entire vehicle to pre-series production,” explains Dr. Michael Steiner, Vice President and Member of the Executive Board for Research and Development. The “constructive” testing phase, which uses individually built prototypes, was no longer necessary, as the approximately 120 test vehicles, which take a lot of time to build, were largely replaced by digital equivalents. The engineers sent virtual prototypes on digital test drives right from the design phase.

Simulation and artificial intelligence have radically changed – and shortened – vehicle testing. They are based on three main directions: precisely digitized routes ranging from driving on the Nürburgring to everyday traffic, the decades of experience of the engineers from Weissach from field tests, and the significantly increased computing power of modern real-time simulation systems. This allowed the engineers not only to visualize the Cayenne virtually, but also to test it directly in a virtual environment. In a development phase in which components are initially available in digital form and can therefore be easily modified, the experts used virtual reality (VR) to carry out initial tests of the future generation of SUV models. The results of the digital tests were later verified with bench tests of real, physical components.

A completely new combined test rig has been developed for this purpose. It allows the drive, battery, energy management and charging systems to be tested together under realistic conditions. The four powerful synchronous electric motors on the test rig can be programmed to operate in such a way that they precisely simulate different road conditions, resistance during acceleration and the forces that occur during recuperation and braking. “The machines are so complex that we can even imitate different asphalt surfaces or tire slip,” notes engineer Markus Junige. Environmental conditions can also be fully simulated.

“Our test programs are unique in terms of requirements,” adds Junige. An impressive example is the Nordschleife lap of the Nürburgring, which is a vivid demonstration of the limits of what is possible. The input data for this is provided by the virtual prototype and all simulated parameters are fed into the combined test bench in real time. “Under all conditions, the car must always provide full power as soon as the driver requests it,” notes Junige. Such rapid generation of maximum power is particularly stressful for the thermal management systems of a car with such high dynamic qualities: in order to bring the battery to an optimal temperature under all conditions, the heating and cooling systems must be more powerful than in any electric Porsche to date. At any time during the Nürburgring lap, the values measured on the combined test bench are compared with those previously calculated for the digital twin. This confirms that the simulation is now so accurate that there are almost no deviations that need to be corrected after receiving the results of the physical tests.

No matter how precise the simulation is, the final tuning is still done by humans. “In reality, only humans can complete the final touches,” notes Sascha Niesen, head of the full vehicle testing team at the Porsche Development Center in Weissach. The importance of the test drivers’ experience in perfectly balancing driving dynamics and steering strategies is particularly evident on the racetrack. Whether in the city, on the highway or off-road, the Cayenne Electric is tested in all realistic operating scenarios. Particular focus is placed on charging management. “No matter how the Cayenne is driven before stopping, it must always be prepared for rapid charging,” explains Junige. Even traffic jams are taken into account by the vehicle in order to make optimal use of the energy.

Testing in extreme weather conditions presents a particular challenge. In hot regions such as the Gulf States or Death Valley in the USA, the climate control and thermal management of the battery and drive system, among other things, had to undergo demanding functional tests at temperatures of up to 50 degrees Celsius. In Scandinavia, where temperatures reach minus 35 degrees Celsius, the test program for the pre-production vehicles included cold starting, climate control, traction, steering and braking behavior, and the functional functionality of the control systems related to driving dynamics. In both climate extremes, the Cayenne Electric had to be able to charge quickly and without problems – hardly any other manufacturer demands more of its vehicles than Porsche.

Endurance tests simulate the life of a car in conditions so severe that customers would only experience them as a last resort. In everyday conditions, vehicles cover over 150,000 kilometers in shifts over the course of several months – in city traffic, on country roads and on highways.

From crash test laboratories and endurance tracks to tests under extreme conditions – the combination of digital preparation and real-world testing proves its effectiveness in all areas. It makes the development process more precise and efficient. Compared to a conventional development strategy, the development time for the Cayenne Electric was reduced by 20%. At the same time, the state-of-the-art virtual tests are also more resource-efficient thanks to the reduced material consumption.

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Developments in a virtual environment are being analyzed for their readiness for real-life use

Simulation and artificial intelligence have radically changed – and shortened – vehicle testing