GKN Tests ‘Bolt-On’ eAWD

LONDON – U.K. drivetrain specialist GKN Driveline is developing a “bolt-on” system that could allow automakers to add all-wheel-drive systems to existing models at much reduced cost.

The company, based in Redditch, Worcestershire, some 110 miles (177 km) northwest of London, is doing final shakedown testing on a new mechanical and electric hybrid drive system in extreme weather conditions at the company’s Wintertest facility near the Arctic Circle in northern Sweden.

The system operates on the front axle by integrating a mechanical Twinster unit directly to the gearbox, replacing the final drive and differential. This allows GKN’s software complete control of torque distribution through a twinclutch, adjusting torque vectoring between the front wheels.

Its test mule has the front power-transfer unit, prop shaft and rear axle removed and replaced at the rear of the car by a 2-speed electronic “eTwinsterX” axle and a high-performance battery.

Producing 161 hp and 155 lb.-ft. (210 Nm) of torque, the integrated e-motor’s coaxial format means that the electric-drive unit is significantly smaller than other systems with equivalent power outputs.

This allows it to easily and inexpensively integrate within existing vehicle platforms, providing “bolt-on” eAWD hybridization capability. The eTwinsterX system also features a GKN-designed 2-speed transmission, as well as full torque-vectoring capability. GKN claims its All Twinster Hybrid System enables precise distribution of torque to all four wheels via new electronic control units.

Drive modes, switchable on the move, can be selected via a touchpad inside the car. The system also allows for a pure-electric, zero-emissions drive mode through the rear wheels. It also can operate in solely front-wheel-drive mode. The combination of the two claims to deliver a hybrid eAWD mode with the two powertrains working together.