Volkswagen has introduced a new generation of drive units for the MEB modular electric building kit. The APP550 rear axle drive features a fully developed power unit, which is supposed to deliver more power with improved efficiency at the same time.
Attentive readers will already be familiar with the APP550: this drive unit has been manufactured by VW Group Components in Kassel since mid-March. Since then, the key data is also known: the drive unit must deliver up to 210 kW and the namesake 550 Nm of torque. As is known, the engine variant used in most MEB models so far has an output of 150 kW and 310 Nm. When VW released footage of the ID.7’s latest test drives ahead of its world premiere in early April, the efficiency of the new electric drive system was particularly highlighted.
Now the Wolfsburg-based company has revealed some more details. The familiar design is retained with the pulse inverter integrated into the motor housing, rotor, stator, cooling jacket, gearbox and gearbox housing. However, all components have been further developed. The APP550 achieves the high torque of the electric drive through an improved stator with a large effective number of windings and a larger cable cross-section; at the same time, thin and optimized laminated plate packages increase efficiency.
The rotor is equipped as a counterpart with a stronger and larger capacity permanent magnet. The drive has been strengthened to cope with the resulting torque. To improve performance and efficiency, the pulse inverter (or inverter) has also been adapted, according to VW, with the aim of “providing high phase currents”.
Another lever to increase efficiency is thermal management. In the cooling system of the drive unit, the engineers have completely dispensed with an electrically driven oil pump (which, of course, would have consumed electricity). Instead, according to the press release, the system can be “cooled through transmission gear wheels, as well as specially shaped components to transfer and distribute the oil.” In addition, the stator has a water cooling jacket. Combining these two systems as needed is said to be the basis for further efficiency improvement, but this is not precisely quantified in the communication.
In addition, there are optimizations in classic mechanical engineering: polished and specially shaped helical gears are to further reduce losses in the gearbox, and there is also a friction-optimized bearing in the gearbox housing of changes
“Since the available space has not changed, we were forced to develop a new unit that achieves significant improvements in performance and efficiency, despite being subject to the same limitations,” says Karsten Bennewitz, head of Drive and Energy Systems in Technical Development. “This was a great challenge for the Group’s Technical Development and Components team. The result shows that we were able to reduce the use of raw materials, while achieving a considerable increase in vehicle efficiency.”
As a result, the ID The models (and also MEB vehicles from the rest of the Group’s brands) should be able to achieve a higher range with the same battery size. VW only confirms that it will deliver “the first vehicles with the new drive generation in a 210 kW (286 hp) variant” probably from the end of the year. No specific models are mentioned, but the new ID.7 is likely to be among the first series; possibly a rear-wheel-drive ID.3 GTX will also receive this variant at a later date.
volkswagen-newsroom.com
