Almost a year after the initial concept idea, Audi Sport has started testing the RS Q e-tron racer that it will take to the Dakar Rally in January 2022. Audi wants to be the first car manufacturer to use an electrified drivetrain in combination with an efficient energy converter to compete for overall victory against conventionally powered competitors in the world’s toughest rally.
“The quattro was a gamechanger for the World Rally Championship,” said Julius Seebach, Managing Director of Audi Sport GmbH and responsible for motorsport at Audi. “Audi was the first brand to win the Le Mans 24 Hours with an electrified drivetrain. Now, we want to usher in a new era at the Dakar Rally, while testing and further developing our e-tron technology under extreme conditions. Our RS Q e-tron was created on a blank sheet of paper in record time.”
The Dakar Rally presents engineers with special challenges, with the desert marathon lasting two weeks and daily stages up to 800 km (497 mi).
“That’s a very long distance,” said Andreas Roos, who is responsible for the Dakar project at Audi Sport. “What we are trying to do has never been done before. This is the ultimate challenge for an electric drivetrain.”
Audi has chosen an innovative charging concept because there are no charging opportunities in the desert. On board the racer is a TFSI internal combustion engine (ICE) from the DTM (German touring car) racing series used as part of an energy-conversion system that charges the high-voltage battery for electric propulsion. The ICE operates in a particularly efficient range of 4500 to 6000 rpm, so specific consumption is well below 200 g/kW·h.
The racer’s electric drivetrain features front and rear axles with motor-generator units (MGUs) from the 2021 Audi e-tron FE07 Formula E racecar, developed by Audi Sport with only minor modifications. A third identical MGU is part of the energy converter and serves to recharge the high-voltage battery while driving. In addition, energy is recuperated during braking.
The RS Q e-tron’s battery weighs about 370 kg (815 lb) and has a capacity of around 50 kW·h.
“The battery is also a proprietary development that we have realized together with a partner,” said Stefan Dreyer, Head of Development at Audi Sport for motorsport projects.
Audi has achieved a drivetrain system efficiency of over 97% in Formula E, so there’s not much more room for improvement there, according to Dreyer.
“The situation is quite different with the battery and energy management,” he added. “This is where the greatest development potential lies in electromobility in general. What we learn from the extremely challenging Dakar project will flow into future production models.”
The electric drivetrain offers many advantages, according to Audi engineers. The electric motors can be controlled extremely precisely, so can ensure good drivability. In addition, braking energy can be recovered.
The maximum system power of the racecar’s e-drivetrain is 500 kW, but how much of this can be used during the Dakar Rally is still being finalized by organizers. The current thinking is that total system power will be limited to less than 300 kW. Some other vehicle specs have yet to be determined, like a minimum weight of 2000 kg (4410 lb) without drivers and a top speed limited to 170 km/h (106 mph).
However, Audi confirmed that the racer is 4500 mm (177.2 in) long, 2300 mm (90.6 in) wide, and 1950 mm (76.8 in) tall. Acceleration on a loose surface from 0 to 100 km/h (62 mph) is less than 4.5 s.
The RS Q e-tron has only one forward gear. The front and rear axles are not mechanically connected, software taking over axle torque distribution duties. The virtually configurable center differential saves vehicle weight and space that would have been required by propshafts and mechanical differential.
Bosch is a major contributor to the racecar’s electric systems having voltages of 12, 48, and 800 V. The company supplies system control units, power management, data logger, and driver/co-driver display.
The RS Q e-tron differs significantly from conventionally powered Dakar prototypes visually.
“The vehicle looks futuristic and has many design elements that are typical of Audi,” said Juan Manuel Diaz, Team Leader of Motorsport Design at Audi. “Our aim was to symbolize ‘Vorsprung durch Technik’ (Audi’s sales slogan) and the future of our brand.”
The Dakar Rally entry is being run in conjunction with Q Motorsport.
“I think this is one of the most complex cars that I have ever seen,” said Sven Quandt, Q Motorsport Team Principal. “The electric drivetrain means that a lot of different systems have to communicate with each other. Besides reliability, which is paramount in the Dakar Rally, that’s our biggest challenge in the coming months.”
The prototype RS Q e-tron had its first roll-out in Neuburg an der Donau, Germany, earlier in July. A test program and the first test entries at cross-country rallies are on the agenda from now until the end of the year.
“This project’s schedule is extremely packed and challenging,” said Roos. “Less than twelve months have passed since the project officially started. We had to begin the development while the regulations for alternatively powered vehicles had not even been finalized yet.”
All of the development took place during the COVID-19 pandemic, he added: “You mustn’t underestimate that either. What the team has achieved so far is unique. The roll-out was a very special moment for everyone.”
Audi says that the RS Q e-tron is just the latest example of its continuing effort at electrifying its motorsport program, which began in endurance racing in 2012. Following the LMP (LeMans Prototype) program with the R18 hybrid sports car, Audi was the first German car manufacturer to compete in the all-electric Formula E racing series in the 2017/2018 season, with Audi Sport ABT Schaeffler clinching the teams’ championship title.
With the Dakar Rally effort from 2022, the company says that cross-country rallying will spearhead the factory’s motorsport commitment. In addition, the brand is preparing its return to the international sports car category, in which the LeMans 24 Hours and Daytona 24 Hours are among the key races. For the series, Audi is also relying on an electrified drivetrain in the LMDh category.