Porsche awards GKN with 'Technology Partner' status

Porsche has awarded GKN Driveline the 'Technology Partner' status for its development of a high-performance eAxle for the 918 Spyder, an advanced plug-in hybrid supercar. GKN Driveline's eAxle module supports full-electric mode, all-wheel drive and provides a boost function.

The eAxle that supplements the 918 Spyder's hybridised 4.6-litre V8 is an evolution of the company's innovative eAxle drive. The module has maximum power of 127bhp and can deliver up to 1,500Nm of torque to the front wheels via a fixed gear ratio.

A specially developed compact differential engages the torque seamlessly, giving the 918 Spyder optimum power distribution at all times. The differential also disengages the module to minimise drag losses and maximise efficiency. At speeds above 265km/h, a clutch isolates the electric motor to prevent it from over-spinning.

A key target for the 918 Spyder was to have the lowest possible centre of gravity and ground clearance. To achieve this, an original engineering solution was required: GKN Driveline positioned the output overhead, using an innovative lubrication concept to manage the oil flow.

The oil reservoir is positioned above, not below, the geartrain. Oil is gravity-fed down onto the bearings and gears until it reaches the high-speed input at the bottom where it is then circulated back to the oil reservoir at the top. This design minimises the amount of oil on the input shaft, keeping churning losses to a minimum. To ensure the critical areas remain lubricated even in disconnect mode, the motor is driven for brief, intermittent intervals to maintain a constant flow of oil.