What is the principle of a CVT transmission?
2 Answers
The principle of a CVT transmission is that the CVT uses a transmission belt and a variable-width pulley for power transmission. When the pulley changes its groove width, it correspondingly alters the contact radius of the driving wheel and the driven wheel on the transmission belt to achieve speed variation. The transmission belt is generally made of rubber belts, metal belts, or metal chains. Below is some information about CVT transmissions: CVT usually refers to a type of automotive transmission, also known as a continuously variable transmission. The difference between a CVT and a stepped transmission is that its gear ratio is not a series of discrete points but a continuous range of values, thereby achieving good fuel economy, power performance, and smooth driving, while also reducing emissions and costs. For example, it can vary continuously from 3.455 to 0.85. The structure of a CVT is simpler and more compact than that of a traditional transmission. It does not have the numerous gear pairs of a manual transmission or the complex planetary gear sets of an automatic transmission. It mainly relies on the primary and secondary pulleys and a metal belt to achieve continuously variable gear ratios.
The core principle of a CVT transmission is to achieve continuously variable speed through a system consisting of two conical pulleys and a metal belt or chain. Unlike traditional automatic transmissions with fixed gears, the engine power is connected to the input cone pulley and then transmitted to the drive wheels. A hydraulic or electronic control system moves the pulleys to change the diameter ratio, while the belt's sliding operation maintains a constant speed ratio. For example, when you press the accelerator to speed up, the input pulley's diameter decreases while the output pulley's diameter increases, allowing seamless power transfer without any jerking sensation. This is thanks to a microcomputer optimizing engine load in real-time, improving fuel efficiency—especially noticeable during smooth driving. However, prolonged use may lead to metal belt wear and increased noise, with higher maintenance costs. Personally, I find this design highly intelligent, showcasing the ingenuity of modern automotive engineering.
