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I wonder why I don't see more about electric hub motors. I remember seeing Protean Electric get 937 hybrid miles to a charge in 2006 on a converted Mini Cooper

I wonder why I don't see more about electric hub motors. I remember seeing Protean Electric get 937 hybrid miles to a charge in 2006 on a converted Mini Cooper (http://www.autoblog.com/2006/07/21/pml-s-mini-qed-boasts-640-in-wheel-electric-horsepower/ http://www.autoblog.com/2006/07/21/pml-s-mini-qed-boasts-640...), and they later showed that you can use this on a pickup truck (http://inhabitat.com/protean-demonstrates-that-its-electric-motors-can-drive-an-f150-from-the-wheels/protean-in-wheel-electric-motor http://inhabitat.com/protean-demonstrates-that-its-electric-...), and they were supposed to bring this technology to mass market in 2014 (https://cleantechnica.com/2013/04/17/proteans-in-wheel-electric-motors-coming-to-market-in-2014/ https://cleantechnica.com/2013/04/17/proteans-in-wheel-elect...), but I haven't really heard anything from them.

rtkwe 9y ago
It moves a lot of mass out the the end of the suspension system that comes with a lot of problems for handling. Also with the motor on the hub all of the shocks directly hit the electric motors where they don't in a normal car setup with motors and drive shafts and the bearings in the motor have to directly bear the weight of the vehicle.
jasonwatkinspdx 9y ago
Because in hub motors are generally a bad idea. The more weight you shift to the unsprung portion of the suspension, the worse handling, ride quality over rough surfaces, and energy economy gets. Even worse, the geometry of an efficient induction motor is a cylinder, and you can add torque by lengthening the cylinder. With an in hub motor you need either axial flux or to bond in permanent magnets, both of which complicate manufacturing. On the other hand, a universal joint and a drive shaft are about as straightforward and reliable as it gets. You can still have a motor per wheel and size is not as restricted. Long story short: in hub motors don't make sense unless you're very space constrained, like on an e-bike. You can build a good enough demo to get press. Once the vehicles are out there as a product for a couple years the flaws will be clear.

rtkwe 9y ago

It moves a lot of mass out the the end of the suspension system that comes with a lot of problems for handling. Also with the motor on the hub all of the shocks directly hit the electric motors where they don't in a normal car setup with motors and drive shafts and the bearings in the motor have to directly bear the weight of the vehicle.

jasonwatkinspdx 9y ago

Because in hub motors are generally a bad idea. The more weight you shift to the unsprung portion of the suspension, the worse handling, ride quality over rough surfaces, and energy economy gets. Even worse, the geometry of an efficient induction motor is a cylinder, and you can add torque by lengthening the cylinder. With an in hub motor you need either axial flux or to bond in permanent magnets, both of which complicate manufacturing. On the other hand, a universal joint and a drive shaft are about as straightforward and reliable as it gets. You can still have a motor per wheel and size is not as restricted. Long story short: in hub motors don't make sense unless you're very space constrained, like on an e-bike. You can build a good enough demo to get press. Once the vehicles are out there as a product for a couple years the flaws will be clear.