E-four

E-Four is an all-wheel drive (AWD) system developed by Toyota Motor Corporation for hybrid vehicles. Front wheels are powered directly by the hybrid powertrain, rear wheels are powered by a dedicated electric motor with its own power control unit, reduction gear and differential. Amount of torque transferred to the rear wheels is automatically adjusted by the vehicle's electronic control unit according to driving conditions.

E-Four was first implemented in the 2001 Toyota Estima Hybrid and is used in several Toyota and Lexus cars, e.g. 2016 Toyota RAV4,Lexus NX 300h and Lexus RX 450h, and in the future may be used in the fifth generation Toyota Prius.

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