A series of new C-segment vehicles, beginning with the BMW 2 Series Active Tourer PHEV model, will offer buyers the option of adding plug-in electric all-wheel drive. The option is based on GKN Driveline’s electric axle drive (eAxle) technology, which is said by GKN to be an evolution of systems developed for hybrid supercars that use electric all-wheel drive to boost performance and efficiency.
The technology, production of which is now underway at the company’s eDrive production facility in Bruneck, Italy, has been optimized for compact car applications. The lightweight single-speed design has a transmission ratio of 12.5:1, reducing the electric motor speed in two stages. The system generates up to 2,000Nm and 70kW of additional torque and power – enough for a vehicle’s pure electric mode to achieve speeds of up to 78mph (125km/h) – and has an all-wheel drive (AWD) mode that accelerates considerably faster than conventional mechanical AWD systems.
The entire unit weighs 44.5 lbs (20.2kg) and has a length of 18in (457mm), a width of 9in (229mm) and a height of 10in (259mm), facilitating packaging and installation in confined spaces
When hybrid operation is not required, the eAxle can be disconnected from the driveline by an integrated disconnect device, which uses an electromechanically actuated dog clutch. This arrangement minimizes rotating losses at higher vehicle speeds when disengaged. Gear and bearing arrangements have also been optimized for efficiency, NVH and durability. Precision engineering throughout the system, including a low backlash, high-performance transmission differential and case ensures transitions between pure electric, hybrid and ICE modes are transparent to the driver.
GKN Automotive’s president of engineering, Peter Moelgg, stated, “GKN’s eAxle technology is passing a key milestone in its evolution at a time when the demand for all-wheel drive and plug-in hybrids is strengthening. This latest system advances the business case for electric all-wheel drive capability in hybrids. A number of automakers are introducing our technology on their premium models and starting to transfer eAxle hybrid versions of higher volume models.”