New Audi RS Q e-tron for the Dakar victory
The brand new body has significantly better aerodynamics. It helps lower the weight and center of gravity of the prototype. New operating strategies also improve the efficiency of the electric drive.
Second phase of the development program
“We made a good debut at the Dakar with the Audi RS Q e-tron (ninth place; ed.) and even managed to win the first stage in a motorsport discipline that was new to us,” says Rolf Michl, Managing Director of Audi Sport GmbH . “As is usual at such an early stage, the driver, co-drivers and technicians quickly agreed on the next development goals. We have summarized the result in a new evolution package – the RS Q e-tron E2.”
This marks the beginning of the second phase of the development program. In October, Team Audi Sport is preparing for the 2023 Dakar Rally with the new prototype in Morocco.
Gentle in the wind, light in the sand: the new body
“The Audi RS Q e-tron E2 does not adopt a single body part from its predecessor,” says Axel Löffler, Chief Designer of the RS Q e-tron. In order to comply with the prescribed interior dimensions, the cockpit, which was previously drawn in tightly towards the roof, is now significantly wider. The front and rear hoods have also been redesigned.
In the future, T1U prototypes will have to weigh 2,100 instead of 2,000 kilograms. Since the first generation of the RS Q e-tron was still overweight, it was still necessary to save several dozen kilograms. This is accompanied by a lowering of the vehicle’s center of gravity.
The aerodynamic concept in the body area below the hood is completely new. This section is almost reminiscent of the shape of a boat hull: its widest point is at the level of the cockpit, while the body narrows significantly towards the front and rear. Audi now dispenses with the part of the fenders that was behind the front wheels and represented the transition to the door. Internally, this structure was called “elephant’s foot”. As a result, the designers save further weight and optimize the air flow.
“The aerodynamic aspect should not be underestimated in desert rallying either,” says Löffler. The body has a larger and therefore less favorable cross-section due to the new cockpit dimensions. Nevertheless, it was possible to reduce the overall aerodynamic drag by around 15 percent, i.e. the product of the drag coefficient and the frontal area (A). This does not change the top speed. It remains limited to 170 km/h in the regulations.
The improved air flow still offers a big advantage. “It further reduces the energy requirement of the electrically powered car,” says Löffler.
Even more environmentally friendly: optimized energy management
The electric drive of the Audi RS Q e-tron E2 consists of an energy converter (combustion engine plus generator), a high-voltage battery and the two electric motors on the front and rear axles (maximum system output: 580 hp). Its energy management has been improved once again.
Background: In extreme cases at the Dakar Rally, Audi noted short-term excess power in situations in which the wheels had little contact with the ground when jumping or on uneven terrain. Those responsible at the World Automobile Association (FIA) intervene from a threshold of 2 kilojoules of excess energy and hand out sports penalties. “For comparison: Within the permissible limits, more than one hundred times the amount of energy flows to the motors per second,” says Florian Semlinger, Development Embedded Software, Application and Test Bench.
“We could have taken it easy and lowered our threshold by several kilowatts, but that would have meant performance disadvantages. Instead, we put a lot of fine-tuning into the power controls.”
The software now recalculates two individual limits – one for each machine – in the millisecond range. It thus works exactly along the permissible limit. So-called secondary consumers also benefit from optimized control. The servo pump, the cooling pump of the air conditioning system and the fans have a measurable influence on the energy balance.
In the course of the 2022 debut season, the Audi and Q Motorsport rally team gained valuable experience that will enable a better rating. Take the air conditioning system, for example: It works so extremely that the coolant threatened to freeze at constant maximum output. In the future, the system will run in intermittent operation. It saves energy, but the interior temperatures fluctuate only slightly, even over longer periods of time. The operating strategy has also been optimized for the fans and the servo pump.
From October 1st to 6th, the new technology has to prove itself for the first time in competition at the Rallye du Maroc. All three Audi driver pairings will then contest the desert rally, starting and finishing in Agadir in the south-west of the North African country.