Combine this breakthrough with what Michigan State is doing in gas powered engines and battery powered cars dominance is delayed for at least another decade.
http://www.wkar.org/post/reworking-michigan-msu-develops-lig...
On the other hand as long as batteries are heavy, ICE's will have a place in aircraft, and I would think the OP's technology could be huge for helicopters.
1 http://www.electric-vehiclenews.com/2017/06/hondas-all-elect...
You can't just eliminate the driveshaft because the wheel must be on a suspension. Remove the driveshaft and you have to put the motor on the wheel, increasing unsprung weight, exposing the motor and making high voltage parts subject to damage.
4 motors is more complex than 2 and doesn't buy you much except in niche packaging applications (like buses). As far as torque vectoring, you can achieve the same effect with differential braking (the duty cycle of torque vectoring is very short, so you don't lose any efficiency). A 2-motor Tesla is probably already the optimal passenger car configuration.
Agreed on everything else though.
I actually helped a mechanical engineer to create a simulator for car dynamics in software.
Today's cars are over engineered mechanically in order to support and resist the forces and torques from the motor to the wheels.
When you put the motors in wheel you basically reduce the required rigidity and the weight of the car substantially.
You point out some disadvantage of the approach. The biggest disadvantage of all is that is not a proven technology, like 100 years old driveshaft. That means the company that commercializes it will eat all the risk, like what happens when people exposes the motor-wheels to wet surfaces and some part of it is damaged. The lawsuits could bankrupt even the biggest company.
I don't think we'll see in-wheel motors any time soon for the reasons you and I mentioned. (Also, in high performance applications (anything but econoboxes) won't you need to strengthen the suspension/chassis in some places even as you get to lighten it in others, since the motor is now torquing the rest of your suspension?)
Why not 2 on one axle? Do you really need all wheel drive?
Two words: unsprung weight.
CV shafts are gong nowhere for the foreseeable future.
Especially with liquid cooling, you could get a 100hp peak (20 hp continuous) motor inside 30 lbs if that was a design goal.
Motors for cars will get lighter as price competition pushes for designs involving less mass of raw materials.
The future of ICEs for aircraft is turbines, not piston engines with digital valves. Most commercial aircraft are already turbines; the only thing holding them back for light aircraft is cost.
> Nobody's ever done variable valve timing on the exhausts, so the benefits are less well understood.
BMW's been doing this for twenty years. Honda's been at it for over thirty years. On. The. Exhaust. Valves.