Fast forward to now and torque vectoring is such a natural fi t with the electrification of cars, it would be rude not to. GKN Driveline is no stranger to the technology and produced the hardware (based on a Prodrive Engineering concept) for the torque vectoring rear axle of the original BMW X6. In February, GKN demonstrated its latest e-Twinster technology on the front axle of its Jeep Renegade-based EV, codenamed GTD19. Last year, a similar system was trialled on the rear axle of a GTD18 Mercedes-AMG GLA 45 test car.
The e-Twinster unit incorporates a 120kW, 2360lb ft GKN e-motor, a Twinster system with two wet clutch packs replacing the geared differential, and can vary the torque between rear wheels by up to 1475lb ft. A two-speed planetary gear set combined with a third clutch pack provides seamless gearshifting necessary with the high-speed, high-power motor and the third clutch can also slip to prevent wheel spin during launch due to the motor’s brutal torque.
Purists may question the need for torque vectoring, but it can improve safety and drivability and can banish understeer to the point of controlled drifting with the right foot hard in. On electric cars with heavy batteries, it’s useful tech to have in the back pocket – and, let’s face it, those Mitsubishi Evos were pretty cool, so why not?
The latest twist
A kind of poor man’s torque vectoring, torque vectoring by braking is being adopted by a few manufacturers. By applying the brake on one wheel of the axle using a plain ‘open’ differential (no clutches or limited-slip technology), more torque can be forced towards the opposite wheel. Its use has limitations because of brake wear, but brake temperature is monitored by algorithms in a car’s chassis software.