All the technical hurdles aside, as was already mentioned the material cost of 2 or 4 electric drive motors, and necessary batteries, control systems, etc. (Not to mention the R&D costs) would be huge in comparison to a traditional setup. If a volt is estimated to be around 45k, imagine a car with this system?

 

Also;
FWIW It would make an interesting technology to see on Bikes/ATV's/etc

 

We're of course talking long term here, after battery systems have come down in price and when fossil fuels are almost extinguished. Furthermore, just what is "traditional"? Electric and steam powered automobiles existed long before today's ICE powered cars.

 

As modern cars have often over a dozen controllers on-board, it makes the task easier. A single controller to do this would indeed be a nightmare.

Regardless, the systems and software to control such a "4 motor vehicle" already exist and work quite well when integrated with stability control systems. The harder part was the stability control side of things- which is a carryover from work already done over the past 20 years.

Controlling a motor at each wheel is *easier* to throttle up/down/brake/freespin/regen than trying to control a single engine and then approximately distribute power with electronic differentials - which will never deliver the same precise output at each wheel.

It isnt simple, cheap, or easy. But it has been done already.

Other advantage - ground clearance.

Other advantage - having transmissions to handle 400tq are large and tough. 4 transmissions handling 100tq would be overall heavier but the shafts/axles/gears could be lighter and/or made of lower grade alloys.

There are plenty of other advantages and disadvantages. Think of it from an assembly point of view - "engine set" is often one of the most dangerous and complicated steps during a vehicle's assembly. Putting 4 smaller and lightweight packages (which might be able to be lifted BY HAND) could be advantageous.

Or Fuel Cells

2WD electric bike? Already been done. I'll have to go find it though...

The cost of the batteries is a *huge* portion of that cost. The next major part is the car itself. The motors and controllers are indeed expensive, but *much* cheaper and smaller than the batteries.

 

Why couldn't the motors be mounted inside the wheels? It's not because they are mounted there that the motor also has to be spinning.

Also, they wouldn't all have to be working all the time. You could have it work as a RWD for summer and a front wheel drive for winter with AWD only when spinning or in performance mode.

I would think not all 4 would run at the same time... the trick would be to have the least amount running for it to drain the less energy possible. So most likely just one running during normal driving.

 

From what I wrote in the other thread ...

 

The mention of brakes makes me wonder... how does the torque that can be created by an electric motor compare to the torque that can be created by a brake rotor and pad?

I'm not talking about regenerative drag -- I'm talking about applying a reversed-polarity current to the motor.

I suspect you'd want a mechanical backup system so that you still had braking ability in the case of an electrical failure (and that might even make this entirely impractical), but what I'm really wondering about is whether an electric motor in the 50-75hp range would even be up to the task (assuming one at each wheel).

 

A manufacturer would never be able to pass FMVSS (federal safety regs) without the mechanical backup. Too dangerous.

Motors in the chassis, brake rotors and calipers just like they are today in the wheel.

 

That's what I'd wait for.

 

Ehhh... what about unsprung weight? I don't know what a good electric motor might add in terms of weight, but its still extra wegitht that has to be offset or simply delt with.

I imagine the simplest setup would be replace the wheel hub with the drive motor and sandwhich the brakes between the wheel and the motor (but what about heat?) and possibly offesting some of the weight gain by going to a composite brake (I imagine CF brakes for the average car is still some time off pending a breakthrough in manufacturing so a two-piece rotor would be the immediate choice).

 

Did you actually read the thread, or just the thread title?

 

About 2 seconds of it, gawd dang my Hogwaller blood

 

Boy, you should have just r u n n o f t. BTW, you wouldn't happen to have a hairnet would you?

 

Packaging issues on a model by model basis as opposed to electric motor's encased in a package which be mounted in a traditional area of a vehicle and fit multiple applications as opposed to engineering on a platform by platform basis. I have been advised that electric motors are most efficient when running at a set rpm, and some form of gearing helps make that happen in the case of how cars and trucks are operated.

Warranty expense and Vehicle hard cost wil be higher with 4 motors that have to be mounted separately, controlled spearately, and engineered to be isolated from exposure to the elements or shock such as potholes.

 

You forget that electric motors need service far less often than ICEs. In fact with electric cars the majority of servicing over the life of the vehicle is brakes and tires. (And of course batteries when their usuable life runs its course.) If electric cars take over the industry, many dealers will see a huge decrease in their most profitable asset, the service bay.