Last month, Mercedes-Benz officially started mass series production of the new electric axial engine at the Berlin-Marienfelde plant. With this step, the oldest factory of this company, founded in 1902, opens a new chapter in its history of more than 120 years. This compact, high-performance engine will make its market debut in the recently announced new 4-door Mercedes-AMG GT Coupe, but will also find its place in the CLA 45 4MATIC+ and could mark a whole new era for electric sports cars.
Preko 30 patents
Mercedes says that the project of industrial realization of this drive system is an extremely complex undertaking. The production area covers about 30,000 square meters, in three halls and on seven production lines. The entire process consists of 98 steps, of which as many as 65 are being used for the first time at Mercedes-Benz, while 35 of them are completely new at the global level. Due to the development of new technologies required for this project, the company has filed more than 30 patent applications.
Axial motor production places extremely high demands on automation and precision processes, which required the development of completely new methods. An example of this is the manufacture of copper windings in the stator, where rectangular instead of round copper wire is used to maximize space and achieve higher power density. In order to bend this wire at high speeds and with small radii – without creating creases, damaging the insulation or reducing the cross-section – Mercedes-Benz has developed and protected a special technological process in cooperation with partners.
A particularly demanding part of the production takes place during the final connection, when the stator is positioned and permanently connected between two rotating discs equipped with magnets. During this process, magnetic forces of up to 9 kN (about 900 kilograms) act on the components, while the stator must remain within the magnetic central plane with a deviation of less than 0.1 millimeter. The position in the last half second of the process is corrected by a computer algorithm via high-frequency control pulses, which relies on sensitive sensors and intelligent control instead of pure force.
What are axial flow motors anyway?
The new axial flow technology brings exceptional power in a compact electric motor design, as evidenced by the Mercedes-AMG GT with acceleration to 100 km/h in 2.1 seconds and broken 25 endurance records. Mercedes-Benz was the first to successfully introduce this revolutionary technology into serial production.
The foundations of the innovative drive were laid by British electric motor specialist YASA, developing an advanced prototype that redefined traditional design postulates. After YASA was transferred to the ownership of Mercedes-Benz in 2021, it began intensive work on adapting the technology to the requirements of mass car production, ensuring at the same time top performance and the ability to withstand continuous loads.
Unlike conventional radial flux motors, where the magnetic field flows perpendicular to the shaft, the electromagnetic flux in an axial flux motor moves parallel to the axis of rotation. The key components are arranged in the form of a disk, where two rotors like a sandwich enclose the stator on the left and right. Such an arrangement enables an extremely compact architecture, high power and torque density, and opens up completely new possibilities in structuring the powertrain inside the vehicle. For example, in the aforementioned AMG GT model, the width of the front engine is only slightly less than nine centimeters, while the two rear engines measure only about eight centimeters.
The technological demonstrator CONCEPT AMG GT XX also proved that it is not just about theoretical performance on short tracks. During rigorous testing on the Nardò track in Italy, this prototype was exposed to an extreme endurance test last year. In a continuous drive that lasted seven days and 13 hours, this model covered more than 40,000 kilometers. With this, he successfully set as many as 25 records on long tracks, confirming the long-term stability, thermal resistance and durability of the new drive system under constant maximum load.