# Torque Vectoring



## m3_4_wifey (Jul 26, 2016)

I was watching some videos about the Rimrac Concept1. Rather than dual electric motors, they have a motor for each wheel allowing some real torque vector control per wheel. 
On Tesla's dual motor cars, the software to decide if more power should placed to the forward or rear wheels seem straight forward, but it's not clear to me how things work side to side. Is there something in between the electric motor and the wheel to deal with the 
inside wheel moving slower than the outside wheel on a turn problem? Apply regenerative breaking per wheel?

While I don't plan to drift my Model 3, it does seem like having a motor per wheel would supply superior control. Probably nothing I would notice most of the time, but would be interesting to find out how Tesla solved this problem. 
Anybody have any ideas?


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## Badback (Apr 7, 2016)

Not sure what 'problem' you are referring to.

The Tesla has a differential gear set for each pair of powered wheels. Brakes can be applied individually for stability control just like in any ICE car.


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## Ron Miller (Jul 31, 2016)

m3_4_wifey is talking about torque vectoring. A differential is not a device for applying torque vectoring, is it?


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## m3_4_wifey (Jul 26, 2016)

Badback said:


> The Tesla has a differential gear set for each pair of powered wheels. Brakes can be applied individually for stability control just like in any ICE car.


In the dual motor launch a couple years back Elon talks about the system being digital for applying power in the first 5 minutes.




The Rimrac will give feedback to each wheel 100 times per second making it much faster than a mechanical differential. I haven't heard any equivalent numbers for Tesla or found any good pictures of the Telsa's drivetrain that helps answer things.


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## Badback (Apr 7, 2016)

Ron Miller said:


> m3_4_wifey is talking about torque vectoring. A differential is not a device for applying torque vectoring, is it?


A differential gear set is a device that allows the two powered wheels to turn at different speeds, like when you go around a corner.

If each wheel had its own motor, then this could be done electronically, but there is one motor driving two wheels in the Tesla.

Torque vectoring refers to changing the vehicles yaw by varying the torque difference to the powered wheels.


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## Paul Spiers (Apr 11, 2016)

I watched a video the other day of the Mercedes SLR, I think, and it had the torque vectoring. It seems to me that would only be useful for very high end super cars. Too much complexity and added cost to be practical for a daily driver EV.


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## garsh (Apr 4, 2016)

Paul Spiers said:


> It seems to me that would only be useful for very high end super cars. Too much complexity and added cost to be practical for a daily driver EV.


It could also be considered a safety feature, since it can help to keep a vehicle under control when a driver takes a corner too quickly. These have been under development for quite a while, and like most technology, it will keep getting less expensive and will eventually make its way into cheaper vehicles. Like the Ford Focus, for instance.


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## Paul Spiers (Apr 11, 2016)

garsh said:


> It could also be considered a safety feature, since it can help to keep a vehicle under control when a driver takes a corner too quickly. These have been under development for quite a while, and like most technology, it will keep getting less expensive and will eventually make its way into cheaper vehicles. Like the Ford Focus, for instance.


Oh, I wasn't aware that Ford had made it available. I was, incorrectly, under the impression that it was found mostly in high performance cars. I wonder why Tesla didn't think to make this an option on the Model S, maybe at the time it was just too expensive and doesn't help with range?


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## m3_4_wifey (Jul 26, 2016)

Ford is transferring power to the outside wheels rather than just breaking to get the difference. There's some pictures here to explain the innards. Would love to get a similar picture of the Tesla drivetrain of a Model 3.
http://drivingspirit.com/ford-focus-rs-dynamic-torque-vectoring-explained/

When are they going to have rally car circuit for electric cars?


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## Jayc (May 19, 2016)

I've noticed it's mostly the Audi click at office going on and on about torque vectoring, the rest of us don't really see the point to it in day to day driving. If you get it into your head that you really cannot do without, then it will haunt you. EV will give you a much better driving experience in day-to-day driving IMHO.


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## m3_4_wifey (Jul 26, 2016)

Jayc said:


> I've noticed it's mostly the Audi click at office going on and on about torque vectoring, the rest of us don't really see the point to it in day to day driving. If you get it into your head that you really cannot do without, then it will haunt you. EV will give you a much better driving experience in day-to-day driving IMHO.


I agree that agree the torque vectoring in the way of drifting is not needed for day to day driving. 
Of course, if there is some part of torque vectoring that makes a car more safe, I could Tesla moving in that direction. Going to dual motor improved the efficiency and performance at the same time.
Cars will continue to advance, so if it can be packaged without adding too much weight or cost, I imagine Tesla will add it.

Hopefully the next reveal will start to give us more details. There's plenty of time to wait, so we might as well study up on how it is put together.


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## AutoMcD (Nov 8, 2016)

The Nissan GTR accomplishes this via mechanical means.. a highly complicated transmission. Reviews say it feels like it uses magic to corner, very exciting.
I hope in the future we can get true vectoring by having a motor on each wheel. It would have some side benefits, dumping the power steering and perhaps some tank-steer stunts for parking and rock climbing.


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