A CVT, or a continuously variable transmission, is an automatic transmission that replaces conventional gears with variable-diameter pulleys, thus avoiding the need to shift between gears, since the transmission is able to continuously vary its ratio.
In a CVT, one pulley is connected to the engine and another pulley is connected to the drive wheels. A drive belt connects both pulleys. A combination of a larger wheel-side pulley and a smaller drive-side pulley results in better low-speed acceleration. As the speed rises during acceleration, the ratio changes. A CVT uses higher RPMs for better acceleration and lower RPMs for better fuel economy.