Since the CVT allows for a free selection of the engine parameters torque and speed, the operation of the combustion engine can be optimized based on different criteria. When the optimum points on the engine map are combined over the entire performance area of the engine, a curve which is parametrized with respect to power, also called "control line", results. The figure above shows the control lines for the optimization criteria "noise", "fuel consumption", and "driving dynamics".
When realizing only one control line for transmission operation using a relatively simple mechanical control, the drawn-in curve "RL" also represents a good compromise. In the future, we can expect an increasing number of electronically regulated CVTs. In this case, control lines that correspond to the demand as well as the driver's needs can then be realized. This already implies that continuously variable transmissions can be exclusively realized as automatic transmissions.