The development of Continously Variable
Transmissions (CVT) is currently a major focus in
the automotive industry. The advantage of this
transmission concept compared to manual or
automated shift transmissions is the simple
mechanical design and the reduced work load on the
human driver. By utilizing the continously variable
gear ratio the engine and transmission can be easily
optimized for the desired behaviour, for example fuel
consumption or power. Out of many mechanical
designs to realize a continously gear ratio, e.g.
hydraulic acts or friction gears, the looping principle
is now commonly used for the small and medium
power range (see figure 1). This design is well
developed and combines the advantages of low
noise and acceptable mechanical efficiency.
Fig. 1