@kupfernigk wrote:
A CVT is normally a transmission in which a belt runs between two sets of conical pulleys which can be set to different separations to change the effective gear ratio. It is mechanical and the actual transmission itself changes to suit conditions.
The Prius transmission has a gasoline engine, a constant direction electric motor, and a motor that can run in both directions, all linked by a planetary gear. Very complicated algorithms then allow a variety of combinations (in one the gasoline engine drives the reversible motor as a generator which then drives the forward engine, acting as a torque multiplier.)
There is no constantly variable gear ratio; the gears are fixed. What is variable is the algorithm.There are other hybrid designs which use an actual CVT. Calling the Prius a CVT is simply to adopt confusing terminology, because it works on a totally different principle.