Continuously variable transmission (CVT) refers to a continuously variable transmission system that can continuously obtain any gear ratio within a variable speed range. Its internal gear transmission structure does not have the traditional transmission, but with two diameters can change the drive wheel, the middle set of drive transmission. The basic principle is that the two sides of the transmission belt are wound on a taper pulley, and the outer diameter of the pulley is changed steplessly by the size of the oil pressure. At the start, the diameter of the active pulley becomes the maximum diameter, and the passive pulley becomes the minimum, achieving a higher gear ratio. With the increase of the vehicle speed and the change of each sensor signal, the computer control system determines the control of the hydraulic pressure of the two pulleys, and finally changes the continuous change of the pulley diameter so as to achieve stepless speed change during the entire shifting process.
The biggest feature of CVT is the stepless control of the speed ratio of the output, which makes it possible to achieve the feeling of running through the water, thus eliminating the feeling of shifting. The occupants did not feel the impact of the gear shift and the power connection continued. This increases the comfort of the CVT while driving, and accelerates faster than the automatic transmission. Compared with stepped transmissions, continuously variable transmissions can reduce harmful emissions, increase driving power and fuel economy (ie, keep the engine running in the lowest oil consumption area).