Audi’s engineering team has achieved a technical breakthrough with the new A2 e-tron, making it the most economical electric model ever to roll out of the brand’s factories. In its base version with an output of 140 kW, the German hatchback recorded an exceptionally low consumption of just 12.8 kWh per 100 km in WLTP cycle testing. Depending on the equipment selected and the specific version, the figure ranges up to 15.7 kWh per 100 km. This phenomenal result is the product of a comprehensive revision of the powertrain, aimed at radically reducing internal energy losses in the power electronics, power unit and transmission mechanism.
The model’s technical architecture is based on a heavily upgraded APP350 electric motor, specially adapted for the MEB platform concept. All available versions of the A2 e-tron rely on a permanent-magnet synchronous motor positioned parallel to the rear axle. The drive unit operates at a voltage of 400 volts and generates maximum torque of 350 Nm, ensuring dynamic power delivery.
A major contribution to the record efficiency comes from the power inverter, which converts direct current from the battery into alternating current for the motor. Ingolstadt’s engineers have introduced advanced silicon-carbide semiconductor transistors that reduce thermal and switching losses to a minimum. As a result, the inverter’s efficiency exceeds an impressive 97%.
The integrated software control dynamically modulates the switching frequency according to the instantaneous load and speed. When driving in urban environments or on country roads at a moderate pace, switching is reduced, preserving precious charge. An additional advantage of the electronics is their ability to maintain maximum capacity even when the battery’s energy level is critically low.
The electric motor itself has also undergone a major design change compared with the previous-generation APP310. The thickness of the steel laminations in the rotor has been reduced by more than a third, dramatically cutting losses caused by cyclic remagnetization. The stator windings are arranged in a “delta” configuration with a reduced number of parallel branches—a change whose effect is felt most strongly under partial loads during everyday driving.
Attention to detail is also evident in the management of acoustic comfort. To eliminate the characteristic high-frequency humming noise when pulling away, the individual rotor segments are arranged with precise geometric offsets relative to one another. This neutralizes background vibrations, while the remaining acoustic oscillations are suppressed by the inverter through fine modulation of the current supplied to the stator.
The transmission ratios have also been precisely calibrated to match the potential of the different versions. The 125 kW and 140 kW variants use a 10.21:1 reduction ratio, while the top version with 170 kW has a fixed ratio of 11.53:1. This allows the drive unit to operate in its most efficient operating range as often as possible. Mechanical losses are further reduced through ultra-smooth finishing of the gear pairs, the use of rare low-viscosity transmission oils and fully optimized lubrication while the gears are rotating.