No, I might be behind the times on this but usually you power axles, do you not (really naively asking)?
I would imagines any disruptions only affecting one wheel instead of axle being rather catastrophic. The brakes are also always set up in a way that you don’t brake on one wheel only even if it’s damaged.
So uncoupling all 4 wheels seems like a really really bad idea. Of course you can compensate this electronically, but that will work about sd well as the Boeing 737 max with its issues. There are physical things you should not mess with.
But maybe as I said I am behind the times and with electric cars that’s normal now to power wheels (l/r) separately?
It’s not uncommon. Rivian, Rimac, and various Chinese cars all have IWD (Individual Wheel Drive.) For a rather longer time, trams have been running with stub-axles and individual motors for decades.
You are behind the times. This is a pretty well-studied and implemented thing. It is expensive, though, which is why you don’t see if more often. If a motor stops working, you can still drive the car with the other three motors. That’s SUPER simple with modern computing and software.
Now, the part where the motors are Ferrari-made… let’s see how that turns out.
What risk? There is way less risk than a traditional setup due to not having a differential. And it is being done literally all day every day by existing cars that have this setup. Rimac and Rivian both have 4 motor configs. BMW releases theirs this year. Audi and Tesla have versions with 3 instead of 4. Controlling things is software is so much easier than with hardware.
The ONLY ONLY reason more cars don’t do this is the cost. That’s it.
The risk of one of the motors not behaving as expected. Yes I am aware they’re very reliable but I have also been close to software development and that’s where my doubts come from.
But maybe they’re unfounded, that’s why I am asking and also being surprised in trying to update my foundation with knowledge and people downvote on that.
All the super-fast EVs from the Model S Plaid and Lucid Air Sapphire to the Rimac Nevera have used separate L/R motors in the rear for some time now, and some have been separate motors for all four wheels. I think that includes some Rivians, and definitely the Nevera.
Keep in mind that having an electric motor per wheel would be nothing like having a gasoline engine per wheel. Not only can an electric motor change its thrust thousands of times per second for good traction control, it can also apply regenerative braking or even just let the motor spin freely.
I assume the cars are at least monitoring the current to each motor constantly, so it’s just a programming decision when the LR motor fails whether to go into limp mode vs still sending 500hp to the right rear wheel to see what happens.
Good to hear and I understand electric motors but being in IT I have a special perspective on failures. And I’d rather have an axle suddenly accelerate /decelerate instead of one wheel.
No, I might be behind the times on this but usually you power axles, do you not (really naively asking)?
I would imagines any disruptions only affecting one wheel instead of axle being rather catastrophic. The brakes are also always set up in a way that you don’t brake on one wheel only even if it’s damaged.
So uncoupling all 4 wheels seems like a really really bad idea. Of course you can compensate this electronically, but that will work about sd well as the Boeing 737 max with its issues. There are physical things you should not mess with.
But maybe as I said I am behind the times and with electric cars that’s normal now to power wheels (l/r) separately?
It’s not uncommon. Rivian, Rimac, and various Chinese cars all have IWD (Individual Wheel Drive.) For a rather longer time, trams have been running with stub-axles and individual motors for decades.
You are behind the times. This is a pretty well-studied and implemented thing. It is expensive, though, which is why you don’t see if more often. If a motor stops working, you can still drive the car with the other three motors. That’s SUPER simple with modern computing and software.
Now, the part where the motors are Ferrari-made… let’s see how that turns out.
Interesting to hear and yes of course it’s possible and I believe the simple thing but not it being worth the risk. Yet at least.
What risk? There is way less risk than a traditional setup due to not having a differential. And it is being done literally all day every day by existing cars that have this setup. Rimac and Rivian both have 4 motor configs. BMW releases theirs this year. Audi and Tesla have versions with 3 instead of 4. Controlling things is software is so much easier than with hardware.
The ONLY ONLY reason more cars don’t do this is the cost. That’s it.
The risk of one of the motors not behaving as expected. Yes I am aware they’re very reliable but I have also been close to software development and that’s where my doubts come from.
But maybe they’re unfounded, that’s why I am asking and also being surprised in trying to update my foundation with knowledge and people downvote on that.
When a car turns, one side’s wheels have to rotate faster than the other side as it needs to travel further.
Thus, it’s advantageous to be able to power wheels independently.
Of course you can do neat things but I’ve seen so much technical failure in my life that I believe I would not want to risk this setup.
Sure but it’s not a new thing, either.
All the super-fast EVs from the Model S Plaid and Lucid Air Sapphire to the Rimac Nevera have used separate L/R motors in the rear for some time now, and some have been separate motors for all four wheels. I think that includes some Rivians, and definitely the Nevera.
Keep in mind that having an electric motor per wheel would be nothing like having a gasoline engine per wheel. Not only can an electric motor change its thrust thousands of times per second for good traction control, it can also apply regenerative braking or even just let the motor spin freely.
I assume the cars are at least monitoring the current to each motor constantly, so it’s just a programming decision when the LR motor fails whether to go into limp mode vs still sending 500hp to the right rear wheel to see what happens.
Good to hear and I understand electric motors but being in IT I have a special perspective on failures. And I’d rather have an axle suddenly accelerate /decelerate instead of one wheel.