Ford has unveiled a new concept Fiesta passenger car that utilises Schaeffler’s innovative electric wheel hub drive system, the E-Wheel Drive. The highly integrated, liquid-cooled wheel hub drive has a total weight of just 53kg and is compact enough to fit inside a 16-inch wheel rim.
The E-Wheel Drive was presented at the recent ‘Auto, Motor und Sport’ congress in Germany. This novel co-development between Schaeffler and Ford was on display to in a new concept car based on a Ford Fiesta. This compact vehicle is driven by two Schaeffler E-Wheel Drives installed in the rear wheel arches. All components required for drive, deceleration and driving safety – including the electric motor, power electronics, controller, brake and cooling system – are installed inside the wheel rim in the highy integrated wheel hub drive.
The wheel hub drives provide an output of 40kW per drive, with a continuous output of 2 x 33kW, which is equivalent to 110hp and 90hp respectively. The wheel hub drive, now in its second (Beta) stage of development, delivers a torque of up to 700Nm. Compared to the first-generation (Alpha) wheel hub drive – first unveiled in Schaeffler’s Vauxhall Corsa-based ‘Schaeffler Hybrid’ concept car in 2010 – the E-Wheel Drive Beta version offers a 33% higher output, as well as a 75% increase in torque. The electrical voltage of the high-voltage drive is 360-420V.
“Overall, we were able to reduce the vehicle weight once again,” stated Dr. Raphael Fischer, Director of the Wheel Hub Drives Product Group in Schaeffler’s eMobility Systems Division. “This is because, as well as liquid cooling, the power electronics and controller are now also integrated to the wheel, which means that complex wiring in the vehicle can be omitted.”
At the Auto, Motor und Sport Congress, Prof. Peter Gutzmer, Member of the Executive Board and CTO at Schaeffler, gave his assessment of the new drive technology innovation: “The B-segment vehicle serves as a pre-production model. However, wheel hub drives have to be integrated into new vehicle concepts in order to demonstrate their strengths to the full.”
“Thanks to this highly integrated wheel hub drive, we can now re-think the city car without any restrictions. It will be a key factor in new vehicle concepts and automotive vehicle platforms in the future. For electric vehicles in urban environments – which may become obligatory in many densely populated areas – the wheel hub drive enables significant space savings to be made. In these new vehicle concepts, all components relating to propulsion, braking and driving safety are housed inside the wheel. The vehicle platform therefore provides maximum space for passengers, luggage and for the battery, electronics and communication systems. Vehicle manufacturers can also use this as a basis for creating a range of different body designs. Automotive vehicle manufacture originally started in just the same way.”
The unveiling of the Fiesta E-Wheel Drive development vehicle –designed in close cooperation with Ford Research & Advanced Engineering Europe – at the Auto, Motor und Sport Congress was a welcome break from the vehicle’s otherwise busy test schedule, which has included extensive test drives in the cold climate of Scandinavia. These winter tests were part of a comprehensive development, coordination and test programme in which driving dynamics also played a critical role. “Excellent driving dynamics are among the main attributes of Ford vehicles. Our expertise and experience in this area was also key during this project. The test drives have clearly shown that the driving behaviour of this test vehicle in terms of comfort and safety has remained at virtually the same level, despite the higher wheel-sprung masses compared to the conventional basic vehicle,” explained Roger Graaf, Project Manager at Ford Research & Advanced Engineering Europe.
What is more, the Fiesta E-Wheel Drive displays extraordinary dynamics. In addition to regulating the stability of the driving dynamics, the two wheel hub drives also enable ‘torque vectoring’ – the selective distribution of torque to the wheels. “In this way, highly integrated wheel hub drives also provide significant advantages in terms of maneuverability, driving dynamics and active safety, as well as perfect utilisation of space. This will play a significant role in the future, particularly in combination with independent driving,” commented Prof. Gutzmer.
“The electric wheel hub drive therefore has the potential to become one of the drives of the future and a valuable addition to the range of drives that, from a global point of view, will continue to be governed by increasingly electrified drive trains based on internal combustion engines,” he added.
Schaeffler’s E-Wheel Drive is now also part of a research project listed by the Federal Ministry of Economics and Technology.