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Continuous Variable Transmission


Normal_aspirated
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Simply put, the CVT uses belts and pulleys to create the gear ratios instead of using individual gears. So basically there's 2 pulleys connected by a belt. The pulleys will move away/towards each other to create different ratios. This effectively means that there is an infinite amount of ratios within a range. This is just a simple explanation, perhaps other bros can give you a better and more detailed explanation.

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Neutral Newbie

well said. But i think current CVT uses chain instead of belts, as it frails and breaks easily. CVT gives you that seamless shift that most conventional automatic cars which still has that slight jerk. CVT will be smooth through out.

 

In the Fiat back in 90s they came up with this similar transmission. Not sure if the Japs have perfected it, the movement of the belts or chain depends on an armature (motor). If the armature is fried due to overheating, the transmission will be stuck at that ratio and no shifting is possible. Changing the armature is just as good as changing transmission and no rebuild or recon ones are available. As the armature cannot be re-conditioned. That's why there is a sharp drop in the Fiat Punto population esp the ELX and SX versions.

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That's what Subaru Justy J10 used, and was not very successful. [:/]

Now Japs are making it a come back, what further improvements? Better torgue transfers or just to cut production cost? CVT is not new, just an old tech revived. [dizzy][dizzy][:/]

 

What about Opel's Tiptronic gearbox in their Corsa models? [rolleyes]

Edited by Normal_aspirated
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The CVT will theoratically have better fuel consumption than even the manual transmission since it can choose the best ratio... that's one of the reasons... anyway, the CVTs now are more reliable than the past, but it's not completely problem-free... maybe it is cheaper to make CVTs. Another reason is that with a CVT, you can preset something like 7 gear ratios, to come up with a 7-speed gearbox, like the Fit/Jazz. If you try to make a 7-speed auto or manual gearbox, the gearbox will be too big and take up too much space, unless the car is very big.

 

For the Opel Corsa, if I'm not wrong, they are using a sequential manual, rather than a Tiptronic gearbox. The difference is that sequential manuals uses dry clutches to transfer power, like the normal manual transmission. These clutches are operated automatically, so the Corsa can still be driven like an auto. Tiptronic transmissions uses the torque converter like the normal auto transmission. Hence, it will still suffer poorer fuel consumption even though it can be driven like a manual.

Edited by Car_guru
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Aiyah, wait till it is perfected & then introduce it into the market.

Why make consumers be "Guinea Pig" and also pay for it.

 

i also say but research needs $$, so they can only test it up to a certain extend.. [shakehead][shakehead]

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Imagine trying to sell yr car with this kinda gearbox with faulty design?

 

there are still ppl buying cars with CVT ler, think should be ok bah [sweatdrop][sweatdrop]

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Neutral Newbie

just like what the Alfa and YRV uses. Whatever it is, CVT is something that still has a long way to go before it can safely say that its good. By far i think the best auto would still be the dry clutch system like what Alfa is using. Power is there and the reliability is ther. However, being a manual gear box, the car tends to roll backwards on a slope.

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Neutral Newbie

wait until perfect, nobody will be able to afford the car liao. The R&D cost would be so high that its going to cost an arm or leg for a Sunny. Think about it, paying maybe 250K for a 1.6 Sunny. Would you want to be that goon goon to buy it?

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I like the sequential manual gearboxes... can enjoy the power and fuel consumption of a manual but don't need to mess with the clutch pedal...thumbsup.gif much more convinient for some drivers... but too bad, this kind of transmission is not widely available for affordable cars yet.. thumbsdown.gif

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