Schaeffler recently presented its ACTIVeDRIVE concept vehicle for electric mobility to the European media.
The ACTIVeDRIVE is a purely electric vehicle (BEV: battery electric vehicle) with four-wheel drive, based on a Skoda Octavia Scout.
The major innovation of the Schaeffler ACTIVeDRIVE is its active electric differential (eDifferential) which is installed both on the front and on the rear axles. This component combines the electric drive with the option of wheel-selective drive power control. This enables torque vectoring (torque distribution between the right and the left wheel), which enhances driving dynamics, driving safety and driving comfort.
“The eDifferential permits active intervening in driving dynamics through well-aimed power supply – instead of braking intervention and thus power reduction, as is the case with the ESP. The active electric differential significantly improves power transmission when driving on surfaces with different friction coefficients. Moreover it assists the steering and has a clearly positive effect on driving dynamics, driving safety and driving comfort. In addition, the use of two eDifferentials enables the longitudinal distribution of drive torques,” says Schaeffler Automotive manager Prof. Dr.-Ing. Gutzmer. “The possibility of active longitudinal and lateral distribution of drive torques makes the eDifferential an ideal platform for innovative vehicle dynamics control systems. With the solution shown in the ACTIVeDRIVE, Schaeffler is a pioneer in such electric concepts for vehicle drives.“
The actively controllable torque distribution enables torque vectoring, which means that the vehicle can be controlled virtually without the use of steering and braking by means of a wheel-selective flow of forces.
“So the potential fields of application for the eDifferential range from sports cars with extremely high driving dynamics and vehicles of classic automobile categories to agricultural machines,” says Schaeffler Automotive senior manager Dr. Tomas Smetana.
The eDifferential system integrates two water-cooled permanent magnet synchronous machines (PMSM) of different dimensions, a planetary gear, a gearbox for active torque distribution and – a central element – a Schaeffler lightweight differential. The electric machines come from Schaeffler’s brand IDAM. The larger PMSM, which delivers up to 105 kW and 170 Nm, is responsible for the drive. The second PMSM, which controls the torque distribution, must deliver merely 5 kW output to generate up to 2000 Nm of torque difference to the axle. Other innovations shown in conjunction with the ACTIVeDRIVE include an integrated electromechanical parking lock, a new forced lubrication system without oil pump for the gearbox, sheet metal planetary carriers and various high-speed and friction-optimized bearing solutions. The electronic control is supplied by AFT and thus comes from Schaeffler as well.
Due to the use of two active electric differentials, the concept car has an overall output of up to 210 kW. Fitted in the cardan tunnel and in front of the rear axle, Li-ion batteries with a capacity of 18 kWh function as energy storage devices. Thanks to its performance and traction capacity, the 1,900-kilogram test platform accelerates from a standstill to 100 km/h in merely 8.5 seconds. There is an electronic top speed regulation at 150 km/h. The vehicle’s cruise range in this configuration amounts to up to 100 kilometers.