Gbaji, other engineers, car people, your opinions please...Follow

At the moment, sure, it's not really useful at all. In fact, you'd be better building a drainpipe on your roof and directing the falling water to spin a little wheel - but it's pretty cool!

Potential viability isn't the issue here.

Shhhh....

/hides hat

I skipped over the part about there being two motors for each rear wheel, so yes a conventional manual gearbox would not work for that setup. The paddleshifters they incorporated makes it a manual transmission without a clutch and the shifting as you said is probably electronic. Without some sort of gearbox the motor may take 10k RPMS to stay at a constant speed of 60mph. With a gearbox incorporated it may only take 2k RPMs in 5th gear. I'm sure the electricity it takes to spin the motor 8k more RPMS is way more than the 10-15% power loss found in usual drivetrains.

And there's no reason to have a gear shift, much less a manual one. It's for show.



Properly designed electric motors can do that all by themselves without needing an external gear system. Purely electronically controlled changes to the electric field driving the motor itself can effectively "shift gears" by changing from low speed/high torque to high speed/low torque modes automatically on a smooth curve. And it can do so far more effectively than any set of gears can.

What you're talking about is drag on the rotational system as speed gets high. Traditionally, a motor puts out a narrow range of rotational energy, and a gearing system allows for managing torque/speed changes through an acceleration/speed range. The motor requires a set amount of energy to "spin" at a given speed (RPM inside the engine). For an internal combustion engine this is a big deal, since that RPM means that crankshaft and pistons have to all move at that speed.


In an electric motor, the only part that is moving is the motor coil. It is spun as a result of alternating electro-magnetic fields around said coil. The amount of energy loss from having that component spinning "fast" at high speeds is going to be less than the amount lost by having the wheel spin that fast (it's almost certainly heavier), much less the added energy loss by including a set of gears to manage this. You don't spend 10x the energy spinning that coil at 10x the speed. Not strictly speaking you don't. You can adjust the frequency and intensity of the field in order to make exactly the kind of torque/RPM changes that a traditional gearbox does. Thus, it takes only the amount of power to keep the motor spinning at a "high" speed as is required to make up for the loss due to drag forces on the system. Trust me. Wind drag, and the wheel mass (ie: the stuff that the motor is driving against) are much more significant than the motor coil itself. Keeping that spinning is the smallest factor here.



Now, maybe there's some actual reason to do this, but everything I've ever heard from people who are very very heavy into electric cars is that one of the huge payoffs to using an all electric car is that you can run the wheels directly off electric motors and don't need a transmission or gears anymore (aside from perhaps a slip-differential just to prevent rotational energy from violently feeding back into the motor of course). And certainly, the idea of having a manually controlled gearbox is just absurd.

Only after the polar ice caps have fully melted.

Properly designed electric motors can do that all by themselves without needing an external gear system. Purely electronically controlled changes to the electric field driving the motor itself can effectively "shift gears" by changing from low speed/high torque to high speed/low torque modes automatically on a smooth curve. And it can do so far more effectively than any set of gears can.

Yeah, no.