How the 2016 Acura NSX works as posted on Jalopnik...

[stuntman]

A lot of cars use brake torque vectoring. Heck, I just tracked an AWD Ford Flex and it was actively braking the inside front and rear wheels to minimize understeer. I didn't know a run-of-the-mill Flex had this function and was actually really impressed at how well it mitigated the understeer and helped turn the car. While it still eventually settled on a final understeer balance, entering corners and mid-corner, its programming of braking various wheels did help the car turn...

McLaren's 12C and 650 rely on hit heavily to brake the inside rear wheel to help turn the car when entering corners, as well as they get away with using NO LIMITED SLIP DIFF (an open diff) by using the brakes on the inside rear wheel to limit slip and distribute torque evenly (or more on the outer wheel) when putting power down.

Yes having individual electric motors can open a whole new level of potential for making a car go through a corner - as well as understeer mitigation! BUT as you start having active suspension, active diffs, active torque vectoring, and electric motors; it's a TALL order to get all the programs to work together in sync, feel natural, and contribute to the overall performance of the car. Remember how long the 918 took to develop and the hurdles they had to overcome? The NSX 2.0 has a ton of techology which could make it really good, or very disconnected, unnatural, and outright bad. It all depends on the engineers' execution. Like i said before, even McLaren is behind the ball to Ferrari with integrating their systems and they are some pretty smart people over there...

You can read my review on the McLaren 12C, and this systems integration issue here: (click the image)

 

[seaeyes]

Actively redistribute the torque between inner/outer wheels and 'awd torque vectoring using brakes' are totally different stories.

.

Nothing new or revolutionary in the concept of AWD torque vectoring .

What makes the NSX 2.0 different is that it will use the motors on the front axles to apply and control the amount of torque that is delivered to the outside wheel as well as applying deceleration to the inside wheel instead of using an ediff or a regular diff with brakes to slow the inside wheel on a non hybrid AWD setup. Because the car will apply torque to the front wheel it will slip, thus causing the understeer as well as the tire noise.

A Huracan, 2nd Gen R8, R35 GT-R, 991.1 Turbo(S), they all do the same when pushed (cars mentioned have AWD torque vectoring), the hybrid 918 does the same as well, nothing new or surprising about it.

 

[Adamantium]

I don't consider brake distribution to be torque vectoring.

First of all it can only be negative torque and second of all it is a function of the brake torque which will be related to weight transfer and probably vehicle speed.

With electric motor based torque vectoring, the control circuitry can add or take away torque independently from each front wheel as a function of anything it likes. You could be cornering hard without braking at all, you could be accelerating through the bend but the electric motors could still be slowing an inside wheel and accelerating the outside. That to me is torque vectoring.

Even the 918 can't do that as it doesn't have individual motors on each of the front wheels, nor does the 4wd Tesla model S.

The only car I can think of that does do this is the Electric MB SLS which had a motor at each corner.

I think this set up is going to be game changing.

 

[2slow2speed]

I don't consider brake distribution to be torque vectoring.

First of all it can only be negative torque and second of all it is a function of the brake torque which will be related to weight transfer and probably vehicle speed.

With electric motor based torque vectoring, the control circuitry can add or take away torque independently from each front wheel as a function of anything it likes. You could be cornering hard without braking at all, you could be accelerating through the bend but the electric motors could still be slowing an inside wheel and accelerating the outside. That to me is torque vectoring.

Even the 918 can't do that as it doesn't have individual motors on each of the front wheels, nor does the 4wd Tesla model S.

The only car I can think of that does do this is the Electric MB SLS which had a motor at each corner.

I think this set up is going to be game changing.

Just because the 918 has a single electric motor on the front axle it does not automatically imply that it can't implement torque vectoring. After all Porsche learned quite a bit about how to apply torque vectoring at the front wheels on the GT3RHybrid race car that had been running around way before Honda/Acura announced the NSX2.0. Just in case you are not aware, the GT3RHybrid also had 2 electric motors on the front axle, one for each front wheel.

There are a lot of details of the 918 that most common folks don't know about because Porsche discloses only as much as they want to disclose and not a cent more. The engineering details can be glimpsed by reading various articles.

http://www.edmunds.com/car-reviews/features/riding-shotgun-in-the-2014-porsche-918-hybrid.html

The front electric motor runs a direct-drive unit, and an electronic torque-vectoring function apportions torque between the front wheels to benefit handling. The Porsche engineers tell us that drive to the front wheels is disengaged at 146 mph to improve high-speed stability.

This was a rare case of Porsche engineers disclosing a bit more information than usual. BTW: You can't find this information in the 918 official brochures. But anyone who follows Porsche cars probably knows this already.

 

[Adamantium]

I didn't know this about the gt3 hybrid so thanks for that.

i know the 918 has torque vectoring I just don't consider its potential in that regard to be as pure as that available from the twin motor set up on the NSX.

 

[2slow2speed]

I didn't know this about the gt3 hybrid so thanks for that.

You are welcomed.

i know the 918 has torque vectoring I just don't consider its potential in that regard to be as pure as that available from the twin motor set up on the NSX.

In regards to the 918 implementation I can think of some scenarios that might play out differently between the 918 and the NSX 2.0.

For example:

The 918 has a front e-motor that is rated at 129hp. The control system on the 918 can divide the amount of power/torque that is available to the front axle as FRTorque + FLTorque = front e-motor torque output at any given time. In the worst case the control system might be able to apply close to 129hp worth of power to one wheel and almost zero to the other.

In contrast each of the front e-motors of the NSX2.0 is rated to X amount of HP, in the worst case the maximum amount of power/torque that the control system might be able to apply to one wheel is limited to X.

Even if X comes out to be 64.5hp, resulting in a combined front axle HP of 129HP like the 918. In the worst case scenario the control system on the NSX2.0 would only be able to apply 64.5HP to a single wheel.

 

[seaeyes]

“an electronic torque-vectoring function" for front axle (in 918 spyder) doesn't necessarily mean it can achieve a torque distribution range all the way from 0:100 to 100:0, but two electric motors definitely can.

The 918 has a front e-motor that is rated at 129hp. The control system on the 918 can divide the amount of power/torque that is available to the front axle as FRTorque + FLTorque = front e-motor torque output at any given time. In the worst case the control system might be able to apply close to 129hp worth of power to one wheel and almost zero to the other.

In contrast each of the front e-motors of the NSX2.0 is rated to X amount of HP, in the worst case the maximum amount of power/torque that the control system might be able to apply to one wheel is limited to X.

Even if X comes out to be 64.5hp, resulting in a combined front axle HP of 129HP like the 918. In the worst case scenario the control system on the NSX2.0 would only be able to apply 64.5HP to a single wheel.

 

[Adamantium]

It's an interesting hypothesis but surely it the delta between the wheels that matters. In this case the NSX could output X of one side and -X on the other and crucially -X requires no brake pedal application.

 

[Valkyrie Pilot]

It's an interesting hypothesis but surely it the delta between the wheels that matters. In this case the NSX could output X of one side and -X on the other and crucially -X requires no brake pedal application.

Another interesting concept though I am not sure that you would want to use the batteries to accomplish what the brakes can do by themselves (unless you are referring to a regen function)

- - - Updated - - -

You are welcomed.




In regards to the 918 implementation I can think of some scenarios that might play out differently between the 918 and the NSX 2.0.

For example:

The 918 has a front e-motor that is rated at 129hp. The control system on the 918 can divide the amount of power/torque that is available to the front axle as FRTorque + FLTorque = front e-motor torque output at any given time. In the worst case the control system might be able to apply close to 129hp worth of power to one wheel and almost zero to the other.

In contrast each of the front e-motors of the NSX2.0 is rated to X amount of HP, in the worst case the maximum amount of power/torque that the control system might be able to apply to one wheel is limited to X.

Even if X comes out to be 64.5hp, resulting in a combined front axle HP of 129HP like the 918. In the worst case scenario the control system on the NSX2.0 would only be able to apply 64.5HP to a single wheel.

If having both motors work together on one wheel is desirable, why couldn't they link them together on either the left or right axle momentarily?

Also, I believe that an additional benefit of having two motors is that you can have one motor regenerating the battery while the other motor is powering the other wheel.

 

[Adamantium]

Yes am talking about regen.