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Audi e-tron FE07, a super-efficient powertrain for Formula E

17.12.2020
Audi e-tron FE07, a super-efficient powertrain for Formula E

Audi’s new Formula E racing car uses an electric drivetrain that was developed in-house for the first time by Audi Sport. Named MGU05, it combines efficiency of up to 97 percent with an extremely compact size.

From zero to one hundred in 2.8 seconds and more than 95 percent efficiency – these two details alone demonstrate how advanced the Audi e-tron FE07 is; the new Audi Sport Formula E racing car is ready to make its debut with Lucas di Grassi and René Rast at the wheel. And the centrepiece of this evolution is the new MGU05 electric drivetrain.

The 2021 season starts in Chile in mid-January, with Formula E being held as an official FIA World Championship for the first time. For Audi, its commitment to the electric car racing series is not just about participating in a sporting competition at the highest international level – it also perfectly supports the brand’s transformation towards sustainable and digital premium mobility.

‘Vorsprung durch Technik’

Motorsport has always been of decisive importance for Audi and its technology development. That is also where our most famous slogan ‘Vorsprung durch Technik’ comes from,” says Team Principal Allan McNish. The electric powertrain for the Audi e-tron FE07 was developed entirely in-house by Audi Sport for the first time, marking a shift from recent years when a continually optimized version of the unit, jointly developed with technology partner Schaeffler, was used.

“Work on the new MGU (Motor Generator Unit) started from scratch and we went to the limits in all areas of this project,” comments Stefan Aicher, Head of Development e-Drive at Audi Sport.

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The Audi MGU05 drivetrain

The result of their work is the Audi MGU05: a new electric one-speed drivetrain with an internal rotor and external magnets, a highly efficient cooling system and six separate electrical phases.

Moreover, the engineers have managed to save weight compared to the previous unit by using lightweight materials and intelligent integration inside the vehicle. “The new MGU inverter unit weighs less than 35 kilograms. This was an exceptional achievement,” says Aicher. This is echoed by Tristan Summerscale, Formula E Project Leader at Audi Sport: “Efficiency is key in Formula E. That is why we are leaving no stone unturned to reduce the energy loss within the system to an absolute minimum.”

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Exceptional efficiency

The extensive work done on in-house test benches was a decisive factor in achieving the objectives for the unit. In numerous tough testing cycles, the entire powertrain was stressed to the limits in order to raise the system to its maximum performance level. “We have achieved an overall efficiency of more than 95 percent for our powertrain. The new MGU inverter unit has an efficiency of up 97 percent in all relevant driving conditions,” continues Summerscale, who goes on to emphasize how the high performance is combined with its compact size: “If you compare our MGU with an internal combustion engine delivering a comparable power output of 250 kW, our efficiency is not only twice as high, but our weight is also much lighter.”

SourceAUDI AG

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