CVTs (Continuously Variable Transmissions) are hardly a new technology, but modern advancements in materials, science and engineering have made them more useful for automotive applications. Still, the benefits at this point may be more academic than practical.
CVTs of one type or another have been used in lawnmowers, golf carts, ATVs and other small-engine vehicles for more than 80 years.
CVTs were originally designed to help less powerful engines stay in their "powerband" (ideal RPM range) at all speeds, but modern engines have wider powerbands than older ones. This negates a certain amount of the CVT's advantage in the modern age.
The CVT's ability to keep an engine at its most efficient RPM is a huge theoretical advantage, but internal losses created by the CVT's drive mechanism often off-set this effect.
A CVT allows an engine to stay at its peak power production point when called for, giving it an enormous advantage in acceleration. However, its lack of a torque converter can make low-speed acceleration less than impressive.
Most CVT transmissions are fairly weak when compared to conventional units, but some hydrostatic and variable-tooth CVTs can handle tremendous amounts of power without breaking. Some manufacturers that use such designs are Porsche, Mercedes and Audi.
