Although there are different parts of CVT transmission most commercial cars use a similar set up. Essentially a CVT Transmission operates by the working diameter of the two main pulleys in the transmission.
How it works it that the pulleys have a V-shaped grooves in which the connecting steel belt rides on. One side of the pulley is fixed while the other side is movable and is controlled by a hydraulic cylinder. The Cylinder can increase or decrease the amount of space between the two sides of the pulley. This allows the steel belt to ride higher or lower along the sides of the pulley wall, depending on the driving condition. This purpose is the same as a mountain bike shifting gears by going on the next sprocket except with a CVT transmission the gears are infinite with no steps in between.
The step-less nature of the design is CVT’s biggest Success for Automotive Engineers. Because of this a CVT transmission can work to keep the engine at its optimum power range therefore increasing power when needed and fuel efficient if you’re easy on the accelerator.
With these advantages its quite easy to understand why most manufacturers often use CVT Transmission in their car mostly because of its fewer internal components.