Qatar’s Nasser Al-Attiyah and his French co-driver, Mathieu Baumel, successfully defended the Dakar title they won for TOYOTA GAZOO Racing (TGR) in 2022 when they brought their GR DKR Hilux T1+ over the finish line of the final stage of Dakar 2023 with a winning margin of 1 hour 20 minutes 49 seconds.
Although they had lost almost 6 minutes to the final stage leaders, they had already built up a comfortable lead from stage 3 to be able to take overall victory. For Nasser, it’s a fifth win in the event, while Mathieu’s tally is now 4 victories. The pair have won 3 times for Toyota, with the latest victories coming in a back-to-back. Nasser’s two earliest wins were win Volkswagen (2011) and MINI (2015)
When the Audi RS Q e-tron started the 2022 Dakar Rally, there were many unknowns for the Audi Sport team. Audi Sport is no stranger to tough off-road racing – having been successful in the World Rally Championship in the 1980s with its Quattro – but the rallycar for the Dakar Rally was something entirely new. It ran primarily on electricity, something they had not done before in off-road competition.
Though the team did not win on that first attempt, it claimed 4 stage victories but more importantly, the experience helped the engineers improve the prototype rallycar in many areas. “We learned a lot at rallies and tests in our first year and implemented everything consistently – technically, logistically and organizationally. The close cooperation between Audi Sport, drivers, co-drivers and Team Q Motorsport is paying off and running very smoothly,” said Uwe Breuling, Head of Vehicle Operations.
When Audi’s RS Q e-tron starts in the 2022 Dakar Rally this weekend, it will be an entirely new challenge for the engineers. While Audi Sport is no stranger to tough off-road racing, this event will be with a vehicle that runs on electricity rather than petrol – something they have not done before in off-road competition, especially one in the Saudi Arabian Desert.
“With our drive configuration in the RS Q e-tron, Audi is a pioneer in the Dakar Rally,” said Lukas Folie, a high-voltage battery engineer at Audi Sport. “Defining the challenges for this type of competition was very demanding. There are simply no empirical values in motorsport for such a concept and for this type of endurance competition.”
Designing for unknown requirements
Compared to the Formula E World Championship, which Audi last contested with a battery-electric drive, the standards at the Dakar Rally are different: daily stages of many hundreds of kilometres, the enormous driving resistance in the soft desert sand, plus high outside temperatures and a minimum vehicle weight set by the regulations at 2 tons are extremely tough in motorsport.
“It is not possible with today’s battery technology to realize a purely battery-electric off-road vehicle for the Dakar Rally under these conditions,” said Folie. The engineering team led by Axel Loffler, Chief Designer of the RS Q e-tron, therefore had to define basic benchmarks for the overall concept of the vehicle with electric drive and energy converter without any previous data.
Due to the short project development time, Audi relied on proven cell technology. The capacity of the high-voltage battery is 52 kWh and is therefore sufficient for the maximum expected requirements on each leg of the rally. The weight of the high-voltage battery including the cooling medium is around 370 kgs.
The required energy capacity and performance, as well as control and safety mechanisms, made Audi resort to proven round cells as the basis of the high-voltage battery. The battery system is designed in such a way that the drivers will not feel any difference between a new and a used battery.
Demanding off-road charging
When the drivers depart in full electric drive on the morning of each stage with a fully charged battery pack, a highly complex control system begins. Only a few minutes before the start of the stage do the teams learn any details about the route at all when the roadbooks are handed out. The RS Q e-tron must therefore be prepared for all conditions in terms of distances, speeds, difficulty of the terrain and other factors.
The engineers and electronic technicians have programmed algorithms to keep the State of Charge (the charge level) within defined ranges depending on the energy demand. Energy extraction and battery recharging are always in balance over defined distances. If, for example, a difficult dune passage with high driving resistance requires maximum energy for a short time, the state of charge drops within a controlled range. The reason: the drive power of the engine-generator units on the front and rear axles is limited to a maximum of 288 kW in total under the regulations. However, the energy converter can only provide a maximum charging power of 220 kW.
In extreme cases, therefore, consumption is briefly higher than energy generation. “Something like this is possible for a limited time,” said Folie. “But over a longer distance, it always results in a zero-sum game: We then have to regulate the power consumption down so that the battery’s state of charge remains within a corridor. The absolute amount of energy available on board must be sufficient to cover the day’s leg.”
Energy recovery is an important factor
In order to realize maximum efficiency, the engineers are also relying on a principle that has already been used in the Le Mans sportscars and in Formula E – the RS Q e-tron will recover energy during braking. The MGU units on the front and rear axles can convert the rotational movement of the wheels into electrical energy. The aim is to recuperate the maximum energy.
The power flow in this reverse direction is not subject to the same power limitations as when accelerating. What sounds so simple requires a complex Intelligent Brake System. It combines the hydraulic braking function with the electric regenerative brake.
Efficient on the move
Thanks to this targeted design, the RS Q e-tron has an exceptional position in the starting field. This applies not only to the basic system topology of all assemblies, but also to the energy control system. Although it has to move a larger mass due to the regulations, the RS Q e-tron manages with less energy than the competition. The smaller tank volume for the energy converter specified in the regulations proves that the rally car with the four rings is very efficient.
The RS Q e-tron will contest its first Dakar Rally with 3 cars entered by Team Audi Sport, with support from Q Motorsport. The 2022 event, which is the third Dakar Rally in Saudi Arabia, has 12 stages with daily distances of more than 800 kms in some cases. The total length of the rally is 8,099 kms, with 4,252 kms of timed off-road stages.
The 2022 Dakar Rally will start on the second day of January and finish on January 14. It will be run entirely on Saudi Arabian soil, as in the previous two editions. The route will go south, passing through Riyadh, and conclude back in Jeddah. There will be 12 gruelling stages, with navigation, sand and dunes featuring more heavily than in previous editions. 80% of the route will be totally new to competitors. Managing the mechanics and physical exertion are two of the most important aspects of the event, and these aspects are never as decisive as they are during a marathon stage, where the ability to be autonomous is essential, even for those used to helping each other out. In the Empty Quarter, the two marathon days will be run ‘the old-fashioned way’.
At the very beginning of 2022, the Dakar Rally will be on again in Saudi Arabia. Among the participating teams will be Audi Sport which was a pioneer in the World Rally Championship with the quattro all-wheel drive in a rallycar. This time, it wants to be the first car manufacturer to use an electrified drivetrain to compete for overall victory against conventionally-powered competitors in the world’s toughest rally.
“The quattro was a game-changer for the World Rally Championship. 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,” said Julius Seebach, MD of Audi Sport which is responsible for motorsport at Audi.
Testing and preparation are underway with the new RS Q e-tron which has an all-electric drivetrain. The front and rear axles are both fitted with a motor-generator unit (MGU) from the current Audi e-tron FE07 Formula E car which has been developed by Audi Sport for the 2021 season. Only minor modifications had to be made to use the MGU in the Dakar Rally.
The characteristics of the Dakar Rally present the engineers with special challenges. The marathon event lasts 2 weeks and the daily stages are up to 800 kms in length. “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.”
Because there are no charging opportunities in the desert, Audi has chosen an innovative charging concept. On board of the car is the highly efficient TFSI engine from the DTM. It is part of an energy-converter that charges the high-voltage battery while driving. Since the combustion engine is operated in the particularly efficient range of between 4,500 and 6,000 rpm, the specific consumption is well below 200 grams per kWh.
A third MGU, of identical design, is part of the energy converter and serves to recharge the high-voltage battery while driving. In addition, energy is recuperated during braking. The battery weighs about 370 kgs and has a capacity of around 50 kWh.
The maximum system power of the e-drivetrain is 500 kW. How much of this may be used during the Dakar Rally is still being finalized by the organizers. The electric drivetrain offers many advantages. The electric motors can be controlled extremely precisely and can thus ensure good drivability. In addition, braking energy can be recovered.
The RS Q e-tron only needs one forward gear. The front and rear axles are not mechanically connected, as is also common in electric vehicles. The software developed by Audi takes over the torque distribution between the axles and thus creates a virtual and freely configurable centre differential, which has the positive side effect of being able to save the weight and space that would have been required by propshafts and a mechanical differential.
“As engineers, we basically see development potential in every component. But in terms of the drivetrain system, we have already achieved a system efficiency of over 97% in Formula E. There’s not much more room for improvement,” revealed Stefan Dreyer, Head of Development at Audi Sport for motorsport projects.
“The situation is quite different with the battery and energy management. 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. As always, we are also working closely with our colleagues from road car development on this project,” he added.
The Dakar Rally entry is being run in conjunction with Q Motorsport. “Audi has always chosen new and bold paths in racing, but I think this is one of the most complex cars that I have ever seen,” said team principal Sven Quandt. “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.”
Quandt compares Audi’s Dakar project to the first moon landing. “Back then, the engineers didn’t really know what was coming. It’s similar with us. If we finish the first Dakar event, that’s already a success!” he said.
The prototype of the RS Q e-tron had its first roll-out in the plant only at the beginning of this month. An intensive 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 12 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. And all of the development took place during the coronavirus pandemic. 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.”
