Infernal heat in the Dakar: this is how the electric Audi faces the cooling puzzle

An electric car born to race in the extreme heat of the Dakar 2022, among the deserts of Saudi Arabia. How is the cooling of organs such as the battery of the Audi RS Q e-tron managed?

The Audi RS Q e-tron is preparing to face the desert of Saudi Arabia in the 2022 edition of the Dakar. The rally raid also hosts low-emission prototypes this year, the first signs of what will happen in the coming years when the FIA ​​and the Dakar organizers’ plan to make the race less impacting on the environment comes to life. In 2026 all Elite car and motorcycle riders will have to race with green prototypes, in 2030 only vehicles of all categories with very low emissions will be able to participate in the competition. Audi has already decided for this edition to run with an electric car, equipped however with the “range extender” system: the RS Q e-tron is powered by three electric motors, but since in the desert it is highly unlikely to find a column, on board there is a heat engine with the exclusive task of recharging the battery. A car developed in just twelve months, during which the Audi engineers had to face and solve many technical aspects including thermal management in a context of very high temperatures during the day and bitter cold at night. Here’s how the RS Q e-tron beats the extreme heat of the Dakar 2022.

LOW TEMPERATURE BATTERY AND MGU

The heart of the RS Q e-tron is the high-voltage battery that powers the motors. On common electric cars, the accumulator is air-conditioned so that it works at the ideal temperature, an even more essential condition when a battery has to supply energy to a car racing in the desert. Audi has relied on Novec non-conductive coolant, also known as “dry water”, whose radiator is located under the front hood. Like the battery, the temperature of the electric motors must also be managed. Of the three MGUs, two are located in correspondence with the respective axles and take care of traction, while the third acts as a generator to recover energy to be sent to the battery. They are connected by means of a low temperature circuit, at whose service there is a specific radiator also positioned in the engine compartment.

ENGINE STEERING OIL AND MEDIUM TEMPERATURE AIR CONDITIONING

If the battery is the component to be kept at the lowest possible temperature in the desert, a few degrees more is granted to the air conditioning of the passenger compartment and to the cooling of the oil necessary for the operation of the steering, which is particularly stressed in off-road driving. Next to the radiator used for the cooling system of the three MGUs is the one used to keep the temperature of the steering components at bay, the same used also by the jacks for lifting the car in the event of a puncture. At the same time, the front right air intake houses the air conditioning condenser.

HIGH TEMPERATURE RANGE EXTENDER

A challenge that cannot be overcome at the moment is to recharge the battery of an electric car engaged in a rally in the desert like the Dakar. The solution adopted by Audi is a Tfsi petrol engine as a range extender, not connected to the transmission but with the exclusive task of generating energy to be stored and then conveyed to the Mgu. The four-cylinder petrol engine is derived from the one used in the Dtm championship and placed transversely behind the passenger compartment, it is served by a specific cooling circuit as well as a heat exchanger for the lubricant. An additional heat exchanger is used to cool the turbocharger, both are positioned side by side at the rear axle and take advantage of the incoming air flows from the air intakes on the car roof.

a flash project

Realizing the RS Q e-tron was not easy, the Audi engineers had to work on a completely new concept capable of facing a tough challenge like the Dakar starting from a wealth of technical and sporting experiences gained mainly on racing cars used on the ‘asphalt. The goal: to demonstrate that an electric car can compete and win a rally raid, something completely different from the sporting commitments that the ring house has faced in recent years, such as going from designing and building a car for the 24 hours of Le Mans to a prototype capable of running for 14 days under the desert sun. Also because, there is still no regulation dedicated to the Evs taking part in the Dakar. All the Audi Sport departments worked on the RS Q e-tron: from the engine engineers to the aerodynamics, from the suspension system technicians to the engineers in charge of the electric powetrain and the body. If transporting the technique adopted on road cars to a rally vehicle was complex, it was even more difficult to think in terms of maximum rationalization of the weights: every excess kg was filed down, every component was made as light as possible. . “The Audi RS Q e-tron project”, says Julius Seebach, CEO of Audi Sport GmbH and head of the brand’s international sporting activities, “was carried out in record time, about 12 months, and represents the maximum expression of the claim. advantage through technology (At the forefront of technology) “. The first ignition of the car, which took place on 30 June 2021 at the Audi Motorsport Competence Center in Neuburg an der Donau, and the start of the Dakar, scheduled for 1 January 2022 in Ha’il, Saudi Arabia, are separated by only 6 months. “A very short period of time – concludes Seebach – to develop such an ambitious project. I will never stop emphasizing that the Audi RS Q e-tron is the most refined and complex competition car that Audi Sport has ever made ”.

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Infernal heat in the Dakar: this is how the electric Audi faces the cooling puzzle

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