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Making the case for IN-WHEEL MOTORS

  • Magazine Article
  • 21AUTP08_01
Published August 01, 2021 by SAE International in United States
  • English

IWMs can improve EV efficiency, dynamics, safety, and manufacturability - when unsprung mass is addressed in their design.

Much of an IC engine-powered vehicle's ride, handling, sound and overall character derives from the engine. Some believe that electric vehicles (EVs), propelled by electric motors with no intake or exhaust sound and less gearing and NVH, limit the opportunity for vehicle differentiation. They argue that the powertrain will become a commodity and that competitive advantage will need to be achieved through other areas, such as styling and infotainment.

I contend that the exception to this view is the in-wheel motor (IWM), a technology that enables quantum improvements in propulsion efficiency, ride dynamics, active safety, and vehicle design. IWMs enable “turn-on-a-dime” operation, a relevant feature for dense urban environments and safe vehicle entry/egress from the sidewalk. Moreover, the IWM has the potential to extend the revolution - started by the now-ubiquitous EV “skateboard” architecture - in how vehicles are developed, manufactured and serviced.