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.
An efficient automatic transmission design that provides an infinite number of drive ratios Read more
Most transmissions, whether manual or automatic have a fixed number of forward gears (from 2 to 10 or more). Belt driven vehicles (like snowmobiles) have an infinite number of positions of engagement. The infinitely variable transmission is sensitive to the changes in the throttle position and adjusts the gear ratio accordingly. In this way, the most efficient gear ratio is selected thus improving fuel economy. Also called "continuously variable transmission".
Unlike regular automatic transmissions, a CVT doesn't have gears to be changed. Rather, depending on how fast a driver wants to accelerate it uses two variable diameter cone-shaped pulleys with a steel belt strung between them to provide a constantly variable transmission ratio that renders a hydraulic torque converter extraneous and improves power application and fuel economy, while assisting with reducing emissions.
The continuously variable transmission (CVT) is a transmission in which the ratio of the rotational speeds of two shafts, as the input shaft and output shaft of a vehicle or other machine, can be varied continuously within a given range, providing an infinite number of possible ratios.