CVT

Continuously Variable Transmission, also known as CVT, is a kind of automatic transmission that produces more useable power, improves fuel economy, and gives a smoother ride than the usual automatic transmission.

CVTs and automatics both have the same controls: No clutch pedal and P-R-N-D-L style shift pattern. The difference is that an automatic has a set number of gear ratios, or speeds, usually 4, 5 or 6. With a CVT, the transmission is constantly changing with the engine speed using a pulley system. You will never feel or hear a CVT shift when driving. CVT simply raises and lowers with the engine’s speed as needed, calling up higher engine speeds (or RPMs) for better acceleration and lower RPMs for better fuel economy while cruising.

When people first drive a vehicle with a CVT, they feel unease because of the way the CVT sounds. When you step on the accelerator, the engine races as it would with a slipping clutch in a manual or a failing automatic transmission. This is typical for a CVT, it’s adjusting the engine speed to offer the best possible power the acceleration.

How it Works
Automatic and manual transmissions both use a gear set that uses a number of ratio, or speeds. Both transmissions have: low gears for starting out, middle gears for accelerating and passing, and high gears for fuel-efficient cruising that can be shifted by the transmission itself or the driver.

There are many different styles of CVTs. Most CVTs operate on a pair of variable-diameter, that are shaped like opposing cone, with a metal belt or chain running between them. One pulley is connected to the engine (input shaft), the other to the drive wheels (output shaft). The halves of each pulley are moveable; as the pulley halves come closer together the belt is forced to ride higher on the pulley, effectively making the pulley's diameter larger. Changing the diameter of the pulleys varies the transmission's ratio (the number of times the output shaft revolves for revolution of the engine), in the same way that a 10-speed bike routes the chain over larger or smaller gears to change the ratio. Making the input pulley smaller and the output pulley larger gives a low ratio (a large number of engine revolutions producing a small number of output revolutions) for better low-speed acceleration. As the car accelerates, the pulleys vary their diameter to lower the engine speed as car speed rises. This is the same thing a conventional automatic or manual transmission does, but while a conventional transmission changes the ratio in stages by shifting gears, the CVT continuously varies the ratio; therefore it’s named "continuously variable transmission".