Considering the savings involved in building transmissions with only three moving parts, you’ll understand why car companies have become very thinking about CVTs lately.
All of this may sound complicated, nonetheless it isn’t. In theory, a CVT is much less complex when compared to a normal automated transmission. A planetary equipment automatic transmission – sold in the tens of millions this past year – has a huge selection of finely machined moving parts. It provides wearable friction bands and elaborate electronic and hydraulic settings. A CVT just like the one defined above has three simple moving parts: the belt and both pulleys.
There’s another benefit: The Variable Speed Transmission lowest and highest ratios are also additional apart than they would be in a conventional step-gear transmitting, giving the transmission a greater “ratio spread” This means it is even more flexible.
The engine can always run at the optimum speed for power or for fuel economy, whatever the wheel speed, which means no revving up or down with each gear change, and just the right rpm for the right speed all the time.
As a result, rather than five or six ratios, you get thousands of ratios between the lowest (smallest-diameter pulley environment) and highest (largest-diameter pulley setting).
Here’s a good example: When you start from an end, the control pc de-clamps the input pulley so the belt turns the smallest diameter while the output pulley (which goes to the 
tires) clamps tighter to make the belt change its largest diameter. This produces the cheapest gear ratio (say, 3.0-to-1) for the quickest acceleration. As acceleration builds, the pc varies the pulley diameters, as conditions dictate, to get the best balance of fuel economic climate and power.