Comment Two problems with this (Score 1) 88
Vehicles have sprung weight and unsprung weight. Sprung weight is weight which is insulated from the road by the springs and other suspension elements. Your engine and vehicle body are part of the sprung weight. Your wheels and brakes are part of the unsprung weight (no springs isolating them from the road).
For a smooth ride, you want your ratio of sprung : unsprung to be as high as possible. That way, the weight of the vehicle keeps the wheels stuck to the road and the wheels bouncing up and down on the road transmit less motion through the suspension to the body. Adding a motor to each hub is going to boost the unsprung weight, meaning you vehicle will have a rougher ride. That's problem #1.
You want as few moving parts, as possible, as part of the unsprung weight because they take a genuine beating driving over the road. Putting the motors in the unsprung weight means the motors will take a beating, which means they're going to have a shorter lifespan than you might hope. That's problem #2.
If you could remove a vehicle's differential and replace that with one containing one or more electric motors, such that the motors are part of the sprung weight, that would help to fix both issues. That, however, would add considerably to the weight and price tag, especially when you consider most front-wheel-drive vehicles already have a very crowded engine bay.
I admire his thought about retrofitting existing vehicles and turning them into Plug-In Hybrid Vehicles (PHEVs). I agree that, if 90+% of your daily driving could be done on electricity, you would seriously diminish the amount of fossil fuels needed. I agree that, if you are only adding 20 miles or so of range, you don't need such a large battery. I agree that retrofitting an existing vehicle into a PHEV, without spending 5 figures doing it, could go a LONG way toward diminishing fuel usage (mod your existing vehicle, rather than acquiring a completely different one). I agree with his motivations, and I've pondered what he suggests, some time ago. Unfortunately, I just don't see such an easy way to reach the goal.