I was wondering, if you were planning to design an electric vehicle, would it be more efficient to have multiple smaller motors, one for each power-driven wheel, or one big electric motor that divides power to the wheels via a transmission? Or does it not really matter?
More details: If each wheel had it's own motor, each motor's current could be controlled more accurately to make sure all wheels are rotating at the proper speed when turning and such. This seems better to me, compared to using differentials to split the power from one, large motor. Additionally, you could possibly save on weight, since with smaller motors you could attach them directly to the wheel and wouldn't need any differentials or half-axles to adjust for the suspension or the wheels turning.
Just curious, as this difference would significantly impact my idea for a vehicle.
Answers & Comments
Verified answer
In wheel motors is where any electric vehicle wants to be, however there is a problem with what is called unsprung weight. A heavier wheel wants to go bouncing up and down, requiring more work from a shock absorber than a lighter wheel. Also wheels that turn must have some heavy duty electrical connections that are flexible enough but not subject to damage from the road. The advantage is electrically operated 4 wheel drive that requires fewer moving parts and is likely more efficient than an electric car with a single motor. Some electric cars compromise by having two electric motors located on the rear axle.
A car with a central motor is simpler to build and design, but it requires more moving parts. No electric vehicle requires a transmission that changes gears. A vehicle with one motor driving both rear or front wheels does require a differential to move wheels at a different speed while going around a corner.
I think there is a reason that no body has came out with a car like this. It theory it sounds good but in practice it could be much harder to achieve. Think about suspension.