The Toyota Prius uses Hybrid Synergy Drive technology.
Hybrid Synergy Drive, (HSD) is a set of technologies for hybrid vehicles developed by Toyota and used in Toyota Prius, Toyota Auris HSD, Highlander Hybrid, Camry Hybrid, Lexus RX 400h, Lexus GS 450h and Lexus LS 600h / LS 600hL. The technology is also used in the Nissan Altima Hybrid. It combines electric propulsion with continuous variable transmission. Synergy Drive technology is an electronic control system without mechanical connections between the engine and the engine controls, both the throttle and the shift lever, since in an HSD vehicle the computerized control only receives electrical signals.
wiki
