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CVT is continuously variable transmission, it is one of the system of automatic power transduction which trend today. Basic Differences between CVT and other power transduction is like conventional automatic transmission and manual, is the way to continuing torsion from engine to wheels

CVT is not using wheel gear for increase and decrease the rotation to wheels. CVT use 2 puli and steel belt. Because no more wheels gear, so at CVT there is no gear comparison like conventional automatic transmission and manual. There is only rotating comparison from lower to higher. Gear change not drastically happen, likewise 1 to 2, 3 and others, and on the contrary

So if the gas pedal pushed and engine burden condition change, CVT will change the rotation compare which will continuously send to wheels automatically. Because of that it is named continuously variable transmission, so the transmission will do compare changing continuously

Basic system

At the CVT there is two puli which connected by belt. For car, because the power that transmitted is huge, so its made from steel [ for bike use belt from rubber]. Puli is the main component at CVT

Special character of two CVT puli is diameter path inside can change. For this, one of the puli side can be shifted, this side can move front and back close to another side which made still and cannot move

The first puli function like power accepter from engine or called rotater puli. After that, trough the belt, these puli continuing the engine power to second puli which is called rotater puli. From this last puli, power transferred to wheels

Power transfer from CVT to wheels cannot be direct, but using gear wheel or differential [last gear compare]

For step a side the puli which are moving, used hydraulic pressured. So this system have pump installed

With one of the side is slip, so the diameter puli path changes. And because the inside of the puli is tirus. Cause changes of diameter path, there is changes happen at the rotate comparison which is transferred fro, rotater puli to rotation puli

When both of puli closing, the path diameter increasing. Otherwise, if pull step away from inside side, the diameter will decrease, and because the differences of this diameter, the comparison of transferred rotation can be change or replace

Because of the  main component have only two puli and belt, the construction of CVT become more simple. The amount of the component is more less compare with conventional automatic transmission and manual. Because of that the size is became more compact. At every test which already done with CVT, the consumption of fuel became more efficient

Comparison changes

First time the car start, the first puli diameter is small and the second is bi. The result is engine rotation will decrease when transferred to second puli. And car runs slowly. This condition is using for the first run and for accelerate to. These conditions called low gear comparison

When the engine rotation increased, there is changes at the second puli diameter. Rotater puli, the diameter are increase. But the rotated puli diameter is decrease. And second puli rotation increase and so the car speed increase too. This condition called high gear comparison. Its use for high speed

Converter torque

The last version of CVT is completed with torque converter [TC] increaser or torque converters which like tun shape on its unit. The TC is used to increase the torque, mainly when the car starts. Even so, the engine rotation increase, TC is locked. The engine rotation directly transfers to puli. And power transfer can do in efficient way

CVT and TC now implement at Nissan [Xtrail] and soon Honda Odyssey. When using this TC, so the fluid for CVT same with ATF. And Nissan said, using ATF, the work of CVT to transfer the power will get increase about 30 percent compare if not using ATF

During the time, the CVT only for small cars use. This is because the ability of belt that connected two puli. But the developing of belt stuff and the technology, the car with big engine can start to use it.

For example, Nissan which called his CVT is X-tronic, already use for passenger car 3.5 liter engine. And Honda at odyssey, minivan 7 passenger with 2.4 liter engine. Honda have CVT factory too.

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