The Audi RS Q e-tron, an electric desert racer

The Audi RS Q e-tron, an electric desert endurance racer for the Dakar Rally has a self-charging drivetrain, a technology likely to be applied in future production vehicles.

For some time, Audi has been transitioning its lineup from internal combustion engines to electric vehicles.  The electrification of racing cars is a more recent phenomenon.  However, adoption is taking place very quickly, with standalone racing series taking place around the world. Such momentum has captured the attention of automotive manufacturers.  Audi is one such manufacturer, first with its Le Mans racer and then with its Audi RS Q e-Tron.

Audi Sport, the racing division of Audi, has built the Audi RS Q e-Tron to compete in the grueling Dakar Rally in January 2022.  From concept to prototype in a little over a year, the RS Q e-Tron is a testbed of future technology, some of which could make its way into future Audi production vehicles.

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What is the Dakar Rally?

The Dakar Rally, formerly known as the Paris-Dakar Rally, goes back to 1978 when the race was staged from Paris, France, to Dakar, Senegal.  As a result of terrorist threats, the event moved in 2020 to Saudi Arabia.  Open to both amateur and professional entries alike, amateurs make up about eight percent of the participants.

The rally is a grueling off-road endurance event as the terrain where the race takes place is much more challenging than that used in traditional rallying.  The wide variety of vehicles that participate in the Dakar are authentic off-road vehicles in every sense of the word. Participants range from motorcycles to SUVs to specially prepared full-size trucks.

The race itself takes place over two weeks, with each day making up a single stage. Thus, the distance can range from a short distance to 500 to 600 miles per day. Likewise, each stage ranges from short distances to up to 500 to 560 miles per day.

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Audi, an electric racing trailblazer

The Dakar Rally would not be Audi’s first pioneering display into electric racing vehicles.  Audi was the first manufacturer to win the 24 Hours of Le Mans with an electric drivetrain.   However, racing in Dakar represents a whole different set of challenges over Le Mans.

In Le Mans, there is a designated place for pit stops where refueling and repairs take place.  Not so in the Dakar, as there are no charging stations in the desert.  To overcome this problem, Audi needed to come up with a novel solution.

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How do you charge an electric vehicle in the middle of the desert?

Perhaps one of the biggest challenges of racing in an off-road endurance event is charging. Audi’s solution is a highly efficient TFSI engine from the DTM combined with an energy converter that keeps the high-voltage battery charged while driving. Electricity consumption is significantly below 200 grams per kWh since the combustion engine is operated in the very efficient range of 4,500 to 6,000 rpm.

The Audi RS Q e-Tron has an electric drivetrain. A motor-generator unit (MGU) from the current Audi e-Tron FE07 Formula E car, manufactured by Audi Sport for the 2021 season, is installed on both the front and rear axles. The MGU used in the Dakar Rally required only modest changes to work.

A third MGU, with the same construction as the others, is part of the energy converter and is used to charge the high-voltage battery while driving. Additionally, the system recovers braking energy.  The battery weighs roughly 370 kilos and has a 50-kilowatt-hour capacity.

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What is the battery used to run the Audi RS e-Tron?

The battery underlying the RS e-Tron is proprietary and was built with the assistance of a strategic partner.  Using a very efficient drivetrain similar to the one used in Formula E, the e-Tron platform achieves a system efficiency of 97 percent.  According to Stefan Dreyer, Audi Sport’s Head of Development for motorsport projects. “As engineers, we see development possibilities in every component.” However, the situation with the battery and energy management is different. As a result, Audi expects many lessons learned from the 2022 Dakar to make their way into future production vehicles.

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What are the advantages of an electric drivetrain in desert endurance racing?

According to Dreyer, Audi Sport’s Head of Development for Motorsport, there are several advantages to using an electric drivetrain. One of which is that electric motors offer excellent drivability due to the driver’s control over the system.  They can also be very efficient because of regenerative braking.

The Audi RS Q e-Tron has a single forward gear, as is common with electric vehicles.  Additionally, the front and rear axles are not mechanically connected. Instead, torque distribution between axles is controlled by software, resulting in a virtual and fully customizable center differential. The result is significant space and weight-saving where prop shafts and mechanical differentials would typically reside.

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The design of the Audi RS Q e-Tron

The RS Q e-Tron is very futuristic and incorporates extensive use of sharp edges found in all of the vehicles in its current lineup.  As a result, the RS Q e-Tron looks like an Audi.

At the same time, its design is very complex, reflecting the underlying nature of the vehicle itself.

For the car to work and indeed thrive in such an unforgiving environment as the Dakar, several separate systems must maintain constant communication with one another in an environment that is unfamiliar territory for an electric vehicle.

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Closing thoughts about the Audi RS Q e-Tron

Audi has been a trailblazer in the application of electrification of racing cars, first with Le Mans and then with the Dakar Rally.  Using an onboard battery charging system, the Audi is designed for the uncertainty and unforgiving terrain of endurance desert racing.  The groundbreaking technology underlying the Audi RS Q e-Tron is likely to make its way into future Audi production vehicles.

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