Scheme of operation of a CVT Subaru.
automatic transmission-type CVT are the most unknown to the majority of users. Facing the average driver, there are only two types of transmission available, manual or automatic, but it is certain that of these latter we can find different types, and the CVT is the least well known.
This transmission is different because it does not use gears which directly connect the engine to the wheels. As a general rule, to transfer the rotational motion from the engine to the wheels using a variety of gears, each one of them (which we call commonly marches) has a different size, allowing the rotation of the motor to match the rotation necessary on the driving wheels depending on the speed of the vehicle.
These gears disappear in the transmissions CVT and in its place we find a simple mechanism consisting of two pulleys and a belt or a chain that binds them, these pulleys are formed by two truncated cones facing and have the ability to modify the distance that separates them, so that the strap that passes through them changes its travel, as you can see in the video below.
To change the route of the belt through the idler to simulate the different sizes of the gears featureless and as this effect is imperceptible for the user, the sensation that it offers is that of no gear change never, due to disappear, jump, or vacuum of power that we find when changing gear, although ironically, many boxes simulate these jumps so that the driver can feel the usual jump. This allows the feeling of acceleration is continuous, and hence its name, since the initials CVT mean Continuous Variable Transmission (continuously variable Transmission).
The advantages are obvious, lost in the jumps between gears and so the engine is constantly in the regime of money most optimal pair, moreover, contrary to any transmission, is not limited to a certain number of gears, and therefore gear, but any minimum change in the path of the strap alters the relationship of the change, so you can create any development within the boundaries of the pulleys.
despite its advantages in use, this type of transmission do not have a widespread use in the world of 4-wheel and are quite a rarity, however, is the type of transmission par excellence for the scooters.