When Volvo was looking for a driveline partner for all variants of its all-new XC90, it needed to ensure its supplier had expertise across both conventional and electrified hybrid drivelines. GKN was the logical answer.
Volvo’s requirements were particularly clear for the plug-in hybrid (PHEV) T8 Twin Engine XC90. To produce a vehicle with the refined drive dynamics and performance associated with a top end Volvo - and the off-road capabilities of a premium SUV - but with great fuel efficiency and low CO2 emissions levels required to satisfy Volvo’s environmentally-conscious target customer.
High density, high efficiency
GKN developed an all-new high torque density co-axial electric axle (eAxle) that met these requirements, helping to intelligently transform power from the electric motor on the rear axle to torque on the road, providing the driver with pure electric drive or electric all-wheel drive as required.
The technology had to be lightweight and set new standards regarding performance and package, ensuring the module was small enough to fit into the space occupied by the Rear Drive Module on the conventional XC90 AWD models, enabling Volvo to alter production requirements based on demand.
GKN’s answer was a semi-integrated concept of the entire electric drive module, where the eAxle and electric motor shared a common housing and combined the electric motor shaft with the geartrain.
Adopting a co-axial layout - meaning that transmission input and output are on the same axis - with a layshaft design, as opposed to the standard offset layout, provided excellent Noise, Vibration and Harshness (NVH)-behaviour, together with high efficiency and cost-effectiveness. GKN’s system managed to package a helical gear set, leading to greater efficiency compared to previous systems.
GKN’s eAxle system incorporates an intelligent disconnect clutch technology that not only provides a more efficient eDrive mode, but also gives the vehicle a powerful all-wheel drive function. Working seamlessly with the vehicle’s own control system, the electric motor can be decoupled from the drivetrain when electric power is not required to minimise losses and prevent the overspeeding of the motor at higher speeds.
Ease of assembly
To ease assembly and guarantee serviceability to the requested degree, a new radial sensor was developed. The characteristic of the newly developed radial sensor eliminated the sensor shimming operation during assembly, resulting in a simplified mounting process.
The XC90’s eAxle delivers nominal output torque of 2400Nm in a package that measures 263mm x 310mm x 293mm and weighs just 15kg, without oil. Delivering efficiency of more than 97.5%, the small footprint of this higher output new eAxle saves space, making integration into global vehicle platforms simpler while also enhancing driveability.