# Torque Vectoring - any solution on the market ?



## Hugues (Jul 13, 2014)

Sorry to reply to my own post....

Borg Warner seem to have developed something for torque vectoring for an electric drive:
https://www.youtube.com/watch?v=0DqPmACIeKA

not sure if it's only for hybrid or also pure electric. I sent them a mail to learn more as i cannot find it on their website, it was there last week i'm pretty sure, i saw this hardware on their website:
https://www.pinterest.com/pin/93027548530358281/


----------



## Nuts&Volts (Dec 20, 2011)

Buy the electric differential from an Acura RLX hybrid. Two electric motors with separate reduction gearing 


Sent from my iPhone using Tapatalk


----------



## dcb (Dec 5, 2009)

I guess I'm confused, if rwd torque vectoring is the solution, what is the problem?


----------



## Hugues (Jul 13, 2014)

Nuts&Volts said:


> Buy the electric differential from an Acura RLX hybrid. Two electric motors with separate reduction gearing
> 
> 
> Sent from my iPhone using Tapatalk


Thanks N&V for the lead.
From this article we can read:
_At the rear, Honda installs what it calls a 'Twin Motor Unit'. As the name suggests, this comprises two more electric motors--one per wheel--each developing 27 kW and 54 lb-ft._

That is not very powerful and "torquy". 2x27 kw = 54 kw and 2 x 54 lb-ft = 108 lb-ft or 146 N-m.

I forgot to mention, sorry, that my requirements are closer to 300 kw and 500 N-m, details in my thread here.

I don't know if there is a hybrid drive train with torque vectoring that is powerful enough for my needs, although i think i read that the Borg Warner eAWD package could develop a rather high torque but i forgot the figure


----------



## dcb (Dec 5, 2009)

I think dual motors and controllers is basically the rwd torque vectoring setup. What do you want it to do? keep the car straight or help it turn, or both and under what specific circumstances? Or traction control or what?

FWIW it won't help much as long as the front wheels have some weight on them. But if you take the default of each wheel gets the same torque (controllers share a throttle) then it'll go pretty straight with the fronts unloaded.

500nm is axle torqe? x2?


----------



## Duncan (Dec 8, 2008)

To dcb's point

What exactly are you trying to achieve?
Why do you want to apply a different torque to each wheel?

And what is wrong with the current solutions to that problem?
One motor
One reduction gear
One differential - anything from an "open diff" like 99% of all cars to any number of "limited slip" diffs
With individual control of the rear brakes for fine tuning

Two motors will require two reduction gears for a substantial increase in weight and no real gain

The only vehicles that use motors for an individual wheel are things like those monster dump truck in mines


----------



## Hugues (Jul 13, 2014)

Fair enough.
My original intent (which is not all that clear from my first post I agree) is:
Is there anything in Torque Vectoring that could be useful for my project ? If no, then fine and I go on the traditional way with 1 motor and 1 transaxle.

I just don't want to regret it one year from now and say "shoot, i should have investigated torque vectoring further". So that's what i want to do now, investigate torque vectoring.

Now, it's a little difficult for me to say why i want torque vectoring as i don't know enough about it. So part of my initial post was to get the feed-back from people who have actually used it and are able to share their experience.

What do I *think *i can achieve with torque vectoring ?
Well, i find this article interesting, there is a good explanation of the benefits and their conclusion is positive, although it's a purely mechanical torque vectoring differential for an ICE:
_"There’s no question that torque vectoring improves objective performance, yet the strongest selling point for this differential is how the car feels from behind the wheel. Whether it’s at the limit on the track or winding down country roads, torque vectoring makes the car livelier and more controllable. Without it, limit cornering is a trying exercise in traction management, load transfer, and other subtle variables. The torque-vectoring differential feels like a subtle push from behind. Turn the wheel and the car dives in so eagerly and effortlessly that you’ll want to attribute its behavior to magnetic forces or supernatural powers. Or, you might just tell passengers that it’s all due to your peerless driving technique. And isn’t that worth the money?"_

I would like to get the same kind of traction control, when cornering, entering and going out of a curve. Seems to make sense that the system can put more torque on the exterior rear wheel to help turning the car. I do not think a traditional differential or one with LSD does this kind of action, but i may be wrong.

Now, as we're talking about electric drive here, are there any more advanced ? torque vectoring systems designed specifically for electric, potentially making good use of 2 electric motors ?

Just want to explore and understand at this stage.


----------



## Hugues (Jul 13, 2014)

Duncan said:


> ...
> With individual control of the rear brakes for fine tuning
> ...


Interesting. Do you have a good link about this topic ?


----------



## Duncan (Dec 8, 2008)

Real basic explanation of the topic
ABS, ESC and Traction control all essentially use computer control of individual wheel brakes to do their magic

http://jalopnik.com/this-is-how-abs-esc-and-traction-control-work-513807036

It could be slightly more efficient to apply power differently BUT
It will not be a lot of the time so a lesser efficiency will not be noticed
And you won't get more performance because it will normally be working when grip is lower

You need the brakes anyway - and the control system for the ABS
So you get your "stability Control" AKA Torque Vectoring with just some software and some yaw sensors

I'm glad you asked me about this I had not realized it was as common or as effective - Electronic Stability Control - Mandatory in 2012!


----------



## Karter2 (Nov 17, 2011)

The only car i can recall that has true torque vectoring ( on all 4wheels) is the AMG SLS-E, which uses a inboard mounted motor for each wheel....
http://www.mercedes-amg.com/webspecial/sls_e-drive/eng.php
....incidentally, Merc hybrid "Citago" busses also have 4wheel hub motors.


----------



## Hollie Maea (Dec 9, 2009)

Our UTV has torque vectoring. Implementing it wasn't trivial or cheap...

https://youtu.be/7-HEXF_2pas


----------



## Karter2 (Nov 17, 2011)

> One differential - anything from an "open diff" like 99% of all cars to any number of "limited slip" diffs
> With individual control of the rear brakes for fine tuning
> u


 hey Duncan !,
You just made me realise i was using "torque vectoring". Way back in Norfolk in the '60s on that Massey Fergy tractor, to spin it in its own length....
....its just that we knew it as "Diff brakes" back then...( separate brake operation on each rear wheel ) 
Is this a case of "The names have been changed to protect the innocent" ..?
https://youtu.be/HmcbKcf9VIc


----------



## riba2233 (Apr 29, 2015)

Karter2 said:


> The only car i can recall that has true torque vectoring ( on all 4wheels) is the AMG SLS-E, which uses a inboard mounted motor for each wheel....
> http://www.mercedes-amg.com/webspecial/sls_e-drive/eng.php
> ....incidentally, Merc hybrid "Citago" busses also have 4wheel hub motors.



Rimac Concept One had it even before Mercedes, so there are at least two of them


----------

