CVT

[stegomon]

whats the difference between a cvt and an Ecvt transmission?? Thanks for the info

 

[RonD]

CVT uses belts or chains on conical drives, the belts/chains move in and out on the "cones" to change ratios
Picture here: https://cdn.jdpower.com/JDPA_Nissan Xtronic CVT.jpg
Cones squeeze together or farther apart to change ratio between them

Chain drive version here: https://cfx-wp-images.imgix.net/2017/11/cvt-subaru-1.jpg?auto=compress,format&fit=crop&h=620&ixlib=php-3.3.0&w=930&wpsize=neve-blog&s=51ca3a3a5fec624354d4d8e98aeab9cb


eCVT uses electric motor(s) to drive planetary gears to change ratios
Tough to find "pictures" that show how eCVT works
This slideshow shows some of the workings: https://slideplayer.com/slide/9965090/

Simplified picture here: https://i.ytimg.com/vi/ZmHpSyTsfm0/maxresdefault.jpg
And no that's not a clutch disc, and yes that IS a clutch disc, lol

So the two are quite different

Even using the planetary gears in the eCVT, similar to regular automatics, the driver won't feel the changes in ratios like they would in regular transmission

The CVT, of course, does not have "gears" just ratios so there would be no "feel" of gear changes


go-carts, mini-bikes, and snowmobiles have use CVTs for many many years, spinning "conical" device on the crank shaft, as RPMs increase the "cone" squeezes the drive belt to make it ride higher and higher in the drive changing its ratio to rear drive sprocket that doesn't change

 

[Dirtman]

CVT is a piece of garbage that uses a belt on cone shaped pulleys to vary the gear ratio. ECVT is a piece of garbage that uses electric motors and magical wizards to vary the gear ratio.

 

[RonD]

CVT has been around for years just not used in cars/trucks

eCVT is fairly new 2003 or so

If you thought an automatic transmission was tough to rebuild.......................I guess we will have to wait and see

 

[Ranger850]

So is a CVT something like a 12 speed bike chain? but not as clunky?

 

[Dirtman]

So is a CVT something like a 12 speed bike chain? but not as clunky?

Nope a 12 speed bike still has gears. There are no gears in a CVT just cones. As the cones move, the belt slides up one and down the other varying the ratio.


Simple image of the inside of a CVT.

Simple image of the inside of a ECVT

 

[Ranger850]

I don't see no cones, Kenny?

 

[fastpakr]

Nope a 12 speed bike still has gears. There are no gears in a CVT just cones. As the cones move, the belt slides up one and down the other varying the ratio.


Simple image of the inside of a CVT.

View attachment 63475


Simple image of the inside of a ECVT

View attachment 63477

CVT is a really cool concept that never -quite- pans out for higher output applications. The Fiesta and Justy go back to the late 80's, but that was behind anemic engines. And Audi jumped in with performance applications quite a while ago using a chain based system. It just doesn't hold up all that well so far outside of high efficiency/low output use.

A few years ago I got to see a whole different kind of CVT in a car at the Fountainhead museum. The 1907 Cartercar had a handle that the driver used to slide the friction surface across a flywheel with a pedal engaged to separate them. Release the pedal with the friction surface on one side of the flywheel and you're moving in reverse. Slide it across to the other side and you can progressively access higher speeds depending entirely on where you position the friction wheel.

 

[Dirtman]

I don't see no cones, Kenny?
View attachment 63481

That's cause the ECTV uses wizards not cones.

 

[Dirtman]

CVT is a really cool concept that never -quite- pans out for higher output applications. The Fiesta and Justy go back to the late 80's, but that was behind anemic engines. And Audi jumped in with performance applications quite a while ago using a chain based system. It just doesn't hold up all that well so far outside of high efficiency/low output use.

I have a CVT in my Polaris ranger and while I can't say I really like how it operates it has never let me down. There's also a CVT on the head of my Bridgeport mill which is awesome since you just turn a handle to move the cones and adjust the speed. The concept is solid, like you said though I have yet to meet one put in an actual car that isn't just a massive headache.

 

[fastpakr]

More info on the Cartercar system:

 

[Dirt Squirt]

CVT is a really cool concept that never -quite- pans out for higher output applications. The Fiesta and Justy go back to the late 80's, but that was behind anemic engines. And Audi jumped in with performance applications quite a while ago using a chain based system. It just doesn't hold up all that well so far outside of high efficiency/low output use.

A few years ago I got to see a whole different kind of CVT in a car at the Fountainhead museum. The 1907 Cartercar had a handle that the driver used to slide the friction surface across a flywheel with a pedal engaged to separate them. Release the pedal with the friction surface on one side of the flywheel and you're moving in reverse. Slide it across to the other side and you can progressively access higher speeds depending entirely on where you position the friction wheel.

View attachment 63485

Snapper has used this system on their lawnmowers since the 60's.

 

[Snoranger]

I’ve got a “Ford” with a CVT... it’s never had any issues.

 

[RonD]

"Few things are harder to put up with than the annoyance of a good example."- Pudd'nhead Wilson(AKA Mark Twain)

 

[Dirtman]

View attachment 63486

I’ve got a “Ford” with a CVT... it’s never had any issues.