The ETM is a rear axle differential with an integrated active coupling that provides vehicle traction and stability through high speed optimal torque allocation to the powered wheels. Its integrated electronically controlled direct actuation makes it a highly suited module for improving dynamic performance in sports cars such as the new XKR and XFR.
Key to the ETM's performance are a smooth and immediate engagement (mechanically pre-emptive), high control accuracy and the exceptional release response time, all of which are ensured by the ETM's 'smart' actuator. An electronic control unit with GKN's proprietary IPM software constantly monitors torque requirements and manages an electric motor that directly rotates the cam gear of a unidirectional ball-ramp mechanism. The rotational torque causes the balls to roll up the opposing ramps, which pushes the front cam forward and activates the clutch. Without intervention from the driver, the system continuously adapts to both the driver's demands and the amount of grip available at each individual wheel.
The decision to introduce the GKN Driveline product represents two firsts – Jaguar's first fitment of an eLSD for volume production cars and the first time that GKN Driveline has supplied its ETM for a high performance car. GKN Driveline also supplies the propshafts which transfer power from the engine to the rear axle and sideshafts, which transfer power from the rear axle differential to the wheels.
Graeme Walford, engineering & commercial director of GKN Driveline, said: "Our ETM technology has proved itself in premium SUVs where it delivers greatly improved traction in both on and off-road conditions. The superior performance of this product in terms of response time, control accuracy and low drag torque, is attracting significant interest from manufacturers of high performance cars. I am proud that working with Jaguar we have tailored our versatile ETM eLSD to be part of the overall high performance driving dynamics package of the XKR and XFR".