The vehicle of choice is a Mercedes-AMG GLA 45 to promote the one-off GKN Technology Demonstrator 2018 vehicle (GTD18).
The standard road car has been modified to become a petrol-electric plug-in hybrid with a zero-emissions pure-electric drive mode, and axle-split eAWD functionality that is independent of the combustion engine. Torque vectoring by GKN’s Twinster system is available on all four wheels, which is a world first.
Following initial testing at GKN Driveline’s Lohmar R&D centre in Germany, the GTD18 begins more extensive validation and proof-of-concept demonstrations this month at the company’s Wintertest facility in northern Sweden.
This year marks the 30th anniversary since GKN first started testing and demonstrating technologies at its dedicated vehicle development facility near the Arctic Circle.
For the front axle drive, GKN’s technical showcase harnesses the donor car’s 381 PS four-cylinder powertrain, and integrates a mechanical Twinster unit directly to the gearbox, replacing the final drive and differential. This allows GKN’s software to have complete control of torque distribution through the unique twin-clutch system that can make rapid and precise adjustments between the front left and right wheels by application of torque vectoring.
As part of the complete tear-down of the brand-new donor vehicle, the front Power Transfer Unit, propshaft and rear axle were all removed. In their place, at the rear of the car, GKN has integrated its new two-speed eAxle – ‘eTwinsterX’ and a high-performance battery.
Despite a high output of 163 PS and 210Nm of torque, the integrated e-motor’s coaxial format means that the electric drive (eDrive) unit is smaller than other systems with equivalent power outputs. This allows it to easily integrate within existing vehicle platforms, providing ‘bolt on’ eAWD hybridisation.
The eTwinsterX system also features a GKN-designed two-speed transmission, as well as full torque vectoring capability.
The unique ‘All Twinster Hybrid System’ setup of the demonstrator car means that GKN can precisely control the distribution of torque to all four wheels.
New electronic control units (ECUs) were installed to govern the dynamics of the one-of-a-kind driveline, and all software was developed and calibrated by GKN engineers. This also extended to the integration of GKN’s hardware and software with the standard car’s systems, to ensure that the electric drive at the rear runs in harmony with the petrol powertrain at the front.
GKN’s eTwinsterX system promises the GTD18 a high level of agility, with all-wheel torque vectoring capabilities, including the capability to over-speed the outside wheel in a corner to induce a yaw moment, helping to bring the car into a tighter line when turning.
The driving modes – which are switchable ‘on-the-fly’ – can be selected via a touch pad inside the car. The eTwinsterX system allows for a pure-electric, zero-emissions drive mode through the rear wheels. Conversely it can also operate in solely front-wheel drive mode. The combination of the two delivers a hybrid eAWD mode with the two powertrains working together.
In total, 99 assemblies needed significant mechanical or electrical modifications, resulting in 1,340 new parts being added to the vehicle.
