Gears are not compatible with the concept of a CVT. However, that belt is more reliable than you think; the CVT pulleys actually push the links of the belt instead of pulling them. (It has to do with how the links of the belt nest with each other.) The steel bands that the links attach to just keep the links in line; they do not actually propel the car, so they are under much less tension than you'd think.

 

Gears are everything but variable. Regular transmissions are full of gears.

 

As stated, gears are not possible in a CVT type trans.

I suggest that you check out a youtube video on the concept/function/operation of a CVT. It's a total trip to watch. Like nothing you've ever seen where transmissions are concerned.

 

 

To the OP, the CVT has cone pulleys on the engine driver shaft and the transmission driven shaft. The cone points are pointed to each other. As speed increases the driver cones move closer to together and the belt moves up higher on the circumference of the cones, while in the driven cones they start moving farther apart so the belt moves to a smaller circumference.
the driving force is the friction of the belt to the cones.

 

Here is the best demonstration I've seen, as noted by @sirwired above.

Sent from my Samsung Tab A using Tapatalk

 

A very good presentation, and one that clearly demonstrates that CVTs are a marvel of engineering design.

The only thing holding back CVTs in their early years of introduction were poor torque characteristics of the engines they were mated to... particularly at lower rpms. Honda has completely turned this challenge into a non-issue with their latest generation small turbo engines (both 1.5T and 2.0T), which very much appear to be purpose designed to feed a wide and rich torque band to a CVT. THAT is a marvel of engineering in engine design by Honda .. to deliver a flat and rich level of torque to the CVT from 1500-5000 rpm.

 

For those who don't understand the CVT concept, Find a golf cart shop that sells Gas golf carts. Have a look at the drive system .It is a CVT in it's most basic form. It may help in understanding the Honda.

 

The very first car with CVT gearbox was a dutch Daf variomatic. Here you can clearly see the reasoning for drive belt usage. Daf (later bought by Volvo) used consumable rubber belts

 

The very first car with CVT gearbox was a dutch Daf variomatic. Here you can clearly see the reasoning for drive belt usage. Daf (later bought by Volvo) used consumable rubber belts[/MEDIA]

Once knew a girl who had a 300-series Volvo with a CVT. She said there was no ratio limitation in reverse. It went as hard backwards as you pushed it.

 

The current gen Toyota Corolla uses a CVT, but has a physical first gear designed to make the Corolla feel more energetic when taking off from a standstill. It is above my level of understanding how this would even be designed. The Honda CVT in the CR-V would seem to be a much simpler design.

 

Toyota does this to deal with the poor torque performance at low rpm of their engines. An interesting approach, and probably cost effective for Toyota, but not very elegant. I have no clue how well it works or how reliable it is though.

The proper engineering approach though is what Honda did..... designing engines that deliver very strong torque that is essentially flat over the useful rpm range of the engine. This is allows the engine to consistently feed what makes CVTs so good..... torque. And CVTs are simpler designs to produce.. it's just that for many vehicles with bell curve torque characteristics force the driver to push the engine to higher rpms for the same results.

The Honda approach is a marvel of engineering in my view and speaks well of Honda's expertise in engine design. I'm still amazed that they pulled this off so well in their new small turbo engines. I doubt it could be done well with a normally aspirated engine.. which may be why Toyota went the route they did.

 

It took awhile for me to learn how to drive using the CVT on my 18 Touring. I work the gas pedal like I would as if the car was a manual transmission. It works near perfectly now. I had a 17 EX-L before my current 18 Touring. That 17 EX-L had every single problem I have read online.

The interior of the 17 stank of gasoline. The battery died with less than 2000 miles on it and left me stranded. The CVT of that 17 EX-L took a solid 3-5 seconds to go from reverse to drive.

The 18 I have now has NONE of the issues I have read so much about. It does not blow gas into the crankcase...for now. It is perfectly sorted now. Next step is to put better tires than the stock Hankook Kinergy GT on it.

 

Toyota does this to deal with the poor torque performance at low rpm of their engines. An interesting approach, and probably cost effective for Toyota, but not very elegant. I have no clue how well it works or how reliable it is though.

The reason why Toyota does this is because CVT transmissions do not have the gear ratio spread of a modern multi speed transmission. The engineers need to pick: either low ratio for quick acceleration off the line, or higher ratio for interstate/freeway. The engineers always pick higher ratio, since the vehicle spends very little time at low speeds. This is why the CRV feels weak off the line, even though it is one of the fastest compact SUVs in acceleration tests.

Toyota elegantly gets around this with their CVT, which is essentially a two speed transmission. It has a conventional fixed low speed gear ratio for quick acceleration and low speed driving, then shifts to the CVT for everything else.

 

While my V isn't a rocket ship off the line, it surges forward nicely once it hits 2K RPMs (which is nearly instantaneously) and the turbo takes over. It does not have the dead feeling many modern cars have (emissions control) at the moment you step into the gas pedal unless it's in ECO. One of the biggest compliments by the critics about the Gen 5 V is that the CVT is about the best there is where this type of trans is concerned. That was one of the factors that sold me on buying one.

Furthermore, I feel that the 0-60 figures supplied for the V are incorrect. Mine feels quicker than that to me.

 

CVT and smaller engines is why I bought a 2012

 

 

to agentl074 : Perhaps you don't understand how a CVT transmission works. Its design with two variable pulleys allows for smooth acceleration without discernible shifts. A variable pulley has a smaller effective diameter at lower speeds and larger effective diameter at higher speeds. There is one pulley (the drive pulley) attached to the motor and a driven pulley attached to the wheels. As engine speed increases the drive pulley diameter increases, changing the ratio in rpm between the drive and driven pulleys, thus changing the wheel speed. This type of drive has been used in tractors and agricultural equipment since AT LEAST the early 20th century. It's also used in recreational vehicle, snowmobiles, and machine tool for years. It is a well proven means of power transfer, is actually simpler than a geared transmission, and some wouldargue that it is more reliable than a geared transmission.

 

The most important feature and the reason for shift (see what I did here) towards CVT is also fuel economy. Current emission limits require car manufacturers to squeeze out every last drop.

 

After speaking with an ASE tech friend of mine, and by watching the cool educational videos shared here, I have a better understanding of why they don't use timing gears; however, there is another CVT transmission called a toroidal CVT which allows for a higher torque application without needing to add like 20 rings to the ring packs lol.

 

OK my take from engineering thoughts. CVT as above^ Continues Variable because it gives much better gas millage as the computer keeps the transmission to the wheels at the best torque from the engine. They are used with smaller engines (as in less than 200 hp.) You will see that Honda and other MFG. use 6, 7, 8 or more gear transmissions with engines over 200 hp. all the way up. These are shifted by the Computer as well to keep at the best performance. Note: that they use Gears to accept the enormous power? Alos, the CVT are less expensive and well as efficient

 

The Nissan Murano uses a CVT...260 HP
Murano takes on the road with a 260-horsepower, 3.5-liter V6 engine. Aerodynamics achieve a drag coefficient of 0.31 – comparable to some sports cars. Along with the Xtronic® CVT (Continuously Variable Transmission), it all adds up to an impressive 28 MPG on the highway.
[*]