Automakers testing new GKN electric torque vectoring technology; “eTwinster”
18 February 2016
Automakers are test-driving a new torque-vectoring electric drive system by GKN Automotive. The “eTwinster” technology is part of a range of new hybrid electric technologies GKN is showcasing to customers at its Wintertest proving ground in Arjeplog, Northern Sweden.
The eTwinster is a plug-in hybrid module that makes it simpler for vehicle platforms to offer electric all-wheel drive and torque vectoring. The driveline combines eAxle technologies proven in the Volvo XC90 T8 Twin Engine, Porsche 918 Spyder and BMW i8 plug-in hybrids and the twin-clutch torque vectoring technology that features in the Ford Focus RS and Range Rover Evoque.
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| GKN eTwinster Torque vectoring eAxle. Click to enlarge. |
Automakers’ vehicle dynamics experts are test-driving the technology in a premium SUV prototype. In the vehicle, a 60 kW, 240 N·m electric motor drives an electric axle with a transmission ratio of 1:10. A dual-clutch Twinster system then vectors the resulting 2,400 N·m of torque between the rear wheels, significantly improving dynamic response and handling.
GKN is the industry leader in eAxle technology with all our core eAxle and torque vectoring technologies now in production and proven expertise in integrating complete driveline systems. We have been building the momentum towards electric torque vectoring for some time. We believe our prototype torque-vectoring eAxle system represents the next step forward for the industry: a production-ready way to create higher performance hybrids that are more rewarding to drive.
The success of our eAxle systems in cars for Porsche, BMW and Volvo demonstrated how the right kind of hybridization creates new value propositions for the driver. Torque vectoring is the next step and we are excited to be demonstrating this technology during Wintertest.
—Peter Moelgg, GKN Automotive President of Technology
By 2025, GKN forecasts that 40-50% of vehicles will have some level of electrification, with a greater proportion hybrids’ power delivered from the electric motor. The eTwinster could be programmed and integrated into a vehicle platform for production within the next three years.
The eTwinster is part of a range of new eDrive technologies that GKN is developing to help shift the balance of power from engines to batteries in the next decade. Current mass-production vehicle platforms can only draw around 30% of their energy from a battery. GKN expects small, powerful, torque-vectoring electric axles could deliver 60-70% of the power in future vehicles.
Looking at their mechanism with the 2-pass gear reduction and the double clutches, it seems that it would be easier to just have 2 electric motors with their own gear reductions and get rid of the clutches. It should be easier to control the motor torques rather than to use clutches to control the axle torques.
Posted by: sd | 18 February 2016 at 11:17 AM
I agree, two motors and controllers would seem better.
Posted by: SJC | 18 February 2016 at 11:40 AM
I agree two motors offers much including redundancy and ability to use smaller paralleled components.
It may not be so important to drive one forward an done backwards in conventional twin axle vehicles but there are some application for that.
The reason for the described solution likely involves the electrical motor control power limitations as well as motor design that currently constrains the limits for reverse torque application.
Those limitations should be solvable but could involve motor design solutions that are unavailable.
This clutched axle design is definitely old school transmission solution but seems to satisfy the need to integrate dynamic control to market ready components.
I suspect the energy efficiency of this axle is very high despite the weight penalty.
It would meet plug and play requirements.
If anyone finds a way to achieve practical two motor alternative that would be a fantastic achievement and sit alongside practical in wheel motor technology.
have lower stressed
Posted by: Arnold | 18 February 2016 at 12:44 PM
"If anyone finds a way to achieve practical two motor alternative that would be a fantastic achievement and sit alongside practical in wheel motor technology".
Koenigsegg Regara's direct drive system has two YASA motors for drive. There is no gear reduction or differential...
http://koenigsegg.com/regera/
The Koenigsegg website states:
"To supplement the energy from the combustion engine and to allow for torque vectoring, regenerative braking, extreme drivers response, reverse and energy conversion, there are three YASA developed electric motors. YASA´s axial flux motors are extremely power dense and allow for direct drive, making them a key-ingredient for the KDD. One YASA for each rear wheel, giving direct drive – this time electric – and one on the crankshaft, giving torque-fill, electrical generation and starter motor functionality.
The three electric motors constitute the most powerful electrical motor set-up in production car history, replacing the gears of a normal transmission while adding; power, torque, torque vectoring and yet still able to remove weight".
Posted by: Jon Francis | 19 February 2016 at 09:10 AM
Mercedes SLS and Audi R8e both have a motor for each wheel.
Posted by: SJC | 19 February 2016 at 12:00 PM
The Acura RLX Sport Hybrid SH-AWD has two 36 hp dual rear motors. The 2017 Acura NSX also has two electric motors in the front.
Posted by: Account Deleted | 19 February 2016 at 06:27 PM