Considering the savings involved in building transmissions with only three shifting parts, you’ll understand why car companies have become very interested in CVTs lately.
All this may audio complicated, nonetheless it isn’t. In theory, a CVT is much less complex than a normal automatic transmission. A planetary gear automatic transmission – offered in the tens of millions last year – has a huge selection of finely machined moving parts. It has wearable friction bands and elaborate electronic and hydraulic settings. A CVT like the one described above has three fundamental shifting parts: the belt and the two pulleys.
There’s another advantage: The lowest and maximum ratios are also further apart than they would be in a conventional step-gear transmitting, giving the Variable Speed Transmission transmitting a greater “ratio spread” This means it is a lot 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 the ideal rpm for the proper speed on a regular basis.
As a result, instead of five or six ratios, you get thousands of ratios between your lowest (smallest-diameter pulley environment) and highest (largest-diameter pulley setting).
Here’s a good example: When you begin from a stop, the control computer de-clamps the insight pulley so the belt turns the smallest diameter while the output pulley (which would go to the tires) clamps tighter to help make the belt switch its largest diameter. This creates the cheapest gear ratio (say, 3.0-to-1) for the quickest acceleration. As quickness builds, the computer varies the pulley diameters, as conditions dictate, to get the best balance of fuel economy and power.