The Dakar Rally is one of the world's most challenging and prestigious motorsport events, testing the endurance, skill, and ingenuity of drivers, co-drivers, and teams across harsh desert terrain. The rally, which will take place in January 2024 in Saudi Arabia, will see the return of Audi's RS Q e-tron, a rally prototype that combines an electric drivetrain with a high-voltage battery and an energy converter system based on a TFSI engine and a generator. The RS Q e-tron, which made its debut in 2022, has already proven its potential by achieving six stage victories and 22 other single-day podium results in the previous two editions of the Dakar Rally. However, Audi is not resting on its laurels and has improved the RS Q e-tron in many areas to make it even more competitive, reliable, and safe for the 2024 Dakar Rally.
Safety: reducing peak loads and improving crash protection
One of Audi's main priorities was to enhance the safety of the RS Q e-tron, especially after the accidents of Stéphane Peterhansel and Carlos Sainz at the 2023 Dakar Rally. Dr. Leonardo Pascali, the project's new Technical Director, explains: "Our goal was to reduce the peak vertical acceleration during landings after big jumps." To achieve this, the engineers worked on the springs, dampers, and the bump stop in the chassis, which help distribute some of the load over time and enable optimal control of the platform, which is vital for the car's overall performance. Another factor contributing to reducing peak loads is the foam in the seats, which has been optimized for material stiffness and geometries, considering the influence of cockpit temperatures. The foam helps to distribute loads on the driver and co-driver over a longer time, thus enhancing their comfort and safety.
Another aspect of safety that Audi improved is the protection of the occupants after a hard frontal landing of the vehicle, like the one that caused Carlos Sainz's second accident at the 2023 Dakar Rally, which ended up with the car rolling over. To better absorb the energy generated during such events, the carbon-fiber reinforced polymer (CFRP) crash box at the front end of the chassis structure is now longer without compromising the angle of attack, which is crucial in cross-country rallying. The crash box is designed to deform and dissipate the impact energy while protecting the integrity of the cockpit and the high-voltage battery. Additionally, the RS Q e-tron features a roll cage made of steel tubes, which provides a robust and rigid structure around the occupants. The roll cage also serves as a mounting point for the suspension, the drivetrain and the bodywork.
Reliability: enhancing cooling and durability
Another key topic for Audi was to improve the reliability of the RS Q e-tron, which is essential for completing the grueling stages of the Dakar Rally, which can last up to 500 miles and 12 hours per day. One of the main challenges for the reliability of the Audi RS Q e-tron is the cooling of the electric drivetrain, which consists of three electric motors, one on each axle and one in the energy converter, and a high-voltage battery with a capacity of about 50 kWh. The electric drivetrain generates a lot of heat, which needs to be dissipated efficiently to avoid overheating and performance loss. To achieve this, Audi has developed a sophisticated cooling system that uses a combination of air and liquid cooling. The air cooling is provided by two large radiators at the front of the car, fed by air intakes on the hood and the roof. The liquid cooling is provided by a network of pipes and pumps, which circulate a coolant fluid through the electric motors, the battery, and the energy converter. The cooling system is controlled by a dedicated electronic unit, which monitors the components' temperature and adjusts the coolant's flow and pressure accordingly.
Another challenge for the reliability of the RS Q e-tron is the durability of the components, which are exposed to extreme stress and wear due to the rough terrain, the high speeds, and the long distances of the Dakar Rally. To ensure the durability of the components, Audi has conducted extensive testing and simulation, both on the track and in the laboratory, to optimize the design, the materials, and the manufacturing processes of the RS Q e-tron. For instance, the suspension, which consists of double wishbones, coil springs, and dampers, has been tested for fatigue and strength under different load cases and scenarios. The drivetrain, which features a single-speed gearbox on each axle and a mechanical differential lock, has been tested for efficiency and robustness under different torque and speed conditions. The bodywork, made of lightweight and resilient materials such as CFRP, aluminum, and steel, has been tested for aerodynamics and impact resistance.