Delivering power to Porsche

The targets for the Porsche 918 Spyder programme were simple: be the fastest road car ever around the Nürburgring and achieve fuel economy of 70mpg. To meet them Porsche engineers chose GKN Automotive and its eAxle technology. 

The targets for the Porsche 918 Spyder programme were simple: be the fastest road car ever around the Nürburgring and achieve fuel economy of 70mpg. To meet them Porsche engineers chose GKN Automotive and its eAxle technology.

Designed to deliver performance and efficiency without compromise, GKN Automotive’s electric drive system powers the front wheels, supplementing the 918’s 4.6 litre V8 engine on the rear axle with 95kW of power and 1500Nm of torque. Its seamless integration gives the 918 optimum power distribution at all times.

Successful partnership

Being selected as Porsche’s Technology Partner was the perfect opportunity for GKN Automotive’s global electric drive systems team to demonstrate how putting the right technology on board can improve both fuel efficiency and dynamic performance. The award cements the company’s position as the industry leader in e-drive systems.

2015 Porsche 918 Spyder

GKN Automotive’s electric axle technology continues to evolve. Already in demand for front-wheel drive platforms, other automakers are integrating versions of the same system.

Unconventional thinking

A key target of the Porsche 918 Spyder was to have the lowest weight and lowest possible centre of gravity and ground clearance. Achieving this required an original and innovative engineering solution – GKN Automotive positioned the output shaft overhead, devising an innovative lubrication concept to manage the oil flow and maximise efficiency.

Oil was gravity-fed onto the bearings and gears, circulating back up when it reached the high speed input at the bottom. This design minimised the amount of oil on the input shaft, keeping churning losses to a minimum. Even when in disconnect mode, the motor is driven for brief, intermittent intervals to maintain a constant flow of oil.

Porsche 918 eAxle

The 918 Spyder’s tight packaging also means there is almost no airflow around the eDrive unit, so water cooling was required to manage the heat generated by the module’s high power density.

Targets met

The 918 Spyder presented challenging targets for power density, noise and durability, which also required an innovative approach. GKN Automotive’s global development team met the challenge with state-of-the-art simulation and analysis tools developed in-house.

Porsche 918 Spyder

A specially developed compact differential engages the torque seamlessly, giving the 918 optimum power distribution at all times. The differential also disengages the module to minimise drag losses and maximise efficiency. At speeds above 225kmh (146mph), a clutch isolates the electric motor to prevent it from over-spinning.

The 918 Spyder is a remarkable achievement. Delivering such a level of vehicle dynamics, stability and efficiency drew on the full capability of GKN Automotive’s technology and its systems engineering. A technology that meets the demands of Porsche – and the Nürburgring – can deliver in any situation.