Definitions for "Continuously Variable Transmission"
Keywords:  cvt, pulleys, murano, honda, nissan
Continuously Variable Transmission (CVT) shares some components and principles to a conventional automatic transmission - it has a torque converter and operated by the transmission fluid pressure. The difference is that it has no gears. Instead there are two pulleys connected by a special belt. The size of the pulleys can be varied and as a result the gear ratio can be changed continuously. It drives like conventional automatic transmission with the difference that there is no shifting - gear ration changes continuously according to the driving conditions. Nissan Murano, Saturn Vue, Audi A4, Honda Civic Hybrid are among the few models featuring the CVT.
Absence of gears clearly sets continuously variable transmissions (CVTs) apart from automatic transmissions (ATs). ATs change the ratio of power transmission from the engine to the drive mechanism by changing gears. But CVTs vary the power transmission ratio by using two pairs of cone-shaped pulleys and a metal belt as well as electronically controlling the distance between each pair of pulleys. For example, the metal belt rides higher on the pulleys when the distance between them is reduced, thus creating the same effect as switching to a larger gear. The opposite effect is produced when the distance is increased and the metal belt rides lower. In addition to a smoother power transmission ratio shift, CVTs bring the additional benefit of a higher power transmission efficiency, which results in better fuel economy. Among Japanese automakers, Toyota Motor Corp. (7203) uses a CVT in the Vitz subcompact. Honda Motor Co. (7267) uses a CVT also in a subcompact, the Fit. But Nissan Motor Co. (7201) equips its sport utility vehicle Murano with a CVT.
A form of automatic transmission that uses belts and pulleys instead of gear wheels to allow an infinite number of gears.