Continuously Variable Transmission

A continuously variable transmission (CVT) is an automatic transmission that can change through a continuous range of gear ratios rather than the limited number of fixed steps of other transmissions, which typically gives better fuel economy in gasoline applications. With suitable control it can let the engine run at a constant angular velocity while the vehicle moves at varying speeds. The most common type uses a V-belt or chain running between two variable-diameter pulleys made of cone-shaped halves that move together and apart, while toroidal designs use discs and rollers and ratcheting designs use one-way clutches. In the United States in 1879 Milton Reeves invented a CVT, then called a variable-speed transmission, for use in sawmilling, and he began fitting it to his cars in 1896. In 1958 the Dutch DAF 600 became the first mass-production car to use a CVT, with its Variomatic transmission used in vehicles built by DAF and Volvo until the 1980s. CVTs are used in cars, tractors, side-by-sides, motor scooters, snowmobiles, bicycles and heavy equipment.