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Old 13th March 2011, 22:30   #1
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Default Why aren't CVTs preferred to regular autos in india?

IMHO, i'd expect CVTs to be a lot more popular than regular autoboxes in india. Yet, we see very few CVTs. I have made a few assumptions about this, so please correct me if i'm wrong.


1. CVTs are cheaper to manufacture when compared to regular complex autoboxes. Should reduce the price diff between manuals and autos - meaning more uptake in cities.

2. Fewer moving parts means fewer breakdowns and easier repairs when compared to the hydraulics and planetary mechanisms of autoboxes.

3. The main obstacle to their adoption abroad has been the rubberband effect and that it's a little strange to not hear the engine rev up and a lot of people are resistant to change. We, in india, don't have that problem. Traditional Autoboxes are rare and everyone knows a CVT. (i'm talking about the scootys, dios and activas)

4. FE and performance. I club them two together as it all depends on how the manufacturer tunes their engine. If the engine's set rpm is the engine's max torque point, then the CVT will outaccelerate manuals, sportshifts and traditional autos. If tuned to run at a lower rpm, FE will be good. Either way, CVT typically give better fe then regular autos.

So, you'd think it makes more economical and logistical sense to put CVTs on more cars. So, where's the problem? What am i missing? Is it the lack of tech? I not sure about that. I think most companies have access to CVTs now.
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Old 13th March 2011, 23:40   #2
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Default Re: Why aren't CVTs preferred to regular autos in india?

I agree with you and I wonder, too. Why don't we have more CVTs than conventional auto boxes? AFAIK, only Old Honda Citys had CVTs. CVTs offer infinite ratios which means stepless transmission, as opposed to 4-speed or 5-speed boxes which shift up or down with a jerk which can be felt and which can also be a bit annoying.

And, will we ever see a diesel hatchback with auto box? CVT or otherwise, I don't care. Somebody please give us an auto.
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Old 14th March 2011, 14:25   #3
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Default Re: Why aren't CVTs preferred to regular autos in india?

I always prefered a conventional auto-box to the CVT; now, with the advent of dual clutch autoboxes, the CVTs feel completed outdated. Here's what I don't like about CVTs:

- The annoying rubber band effect. Not only when starting off, but frequent running up & down the revv counter.

- CVTs are slower! Period. Their response time, under full throttle, just isn't good enough. All you see is the engine rpm climbing (without the expected increase in speed).

- If the NHC & OHC are anything to go by (both models are old enough to warrant repairs), the CVT costs a heck of a lot more in upkeep in the longer run. There are 5X the number of failures in NHC CVTs than OHC ATs.

I will add that CVTs are much smoother than conventional auto-boxes though. Maybe, we should ask Honda why they switched from CVT -> conventional AT for the new Honda City. Surely, there must be a solid reason?

Last edited by GTO : 14th March 2011 at 14:27.
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Old 14th March 2011, 14:51   #4
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Default Re: Why aren't CVTs preferred to regular autos in india?

GTO: One reason you left out was the rubber banding, i.e. car will accelerate with no change in the engine note. very disconcerting for the user, and quite unpopular.
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Old 14th March 2011, 15:01   #5
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Default Re: Why aren't CVTs preferred to regular autos in india?

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Originally Posted by sgiitk View Post
GTO: One reason you left out was the rubber banding, i.e. car will accelerate with no change in the engine note. very disconcerting for the user, and quite unpopular.
Aint it the first point that GTO mentioned? or are you talking about something totally different and ??
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Old 14th March 2011, 15:07   #6
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Default Re: Why aren't CVTs preferred to regular autos in india?

There was an earlier Nano CVT project in TATA which never saw the light of the day. Reason was something related to reliability. It had lower FE too. But they may still come up with one.

Last edited by clevermax : 14th March 2011 at 15:09.
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Old 14th March 2011, 15:25   #7
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Default Re: Why aren't CVTs preferred to regular autos in india?

here is an interesting article....about CVT and why they failed...

CVT - what the Continuously Variable Transmission is and how CVT works
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Old 14th March 2011, 15:28   #8
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Default Re: Why aren't CVTs preferred to regular autos in india?

Quote:
Originally Posted by Archish View Post
Aint it the first point that GTO mentioned? or are you talking about something totally different and ??
I think two things can happen (as part of rubber band effect)

-Engine revs go up but without expected increase in the vehicle speed
-You accelerate, the engine revs stay where it is but the car goes faster

This is because the computer decides which point in the rev range and which ratio on the CVT gives the optimum performance for the given input/running condition

Last edited by Guna : 14th March 2011 at 15:29.
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Old 14th March 2011, 15:32   #9
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Default Re: Why aren't CVTs preferred to regular autos in india?

@mindgrinder: Yes and no. I was more bothered by the minimal change in engine note as the speed goes up or down. This audio clue is critical to many drivers. Going up and down will depend a lot on the terrain - if you go up the ratio will go down and more revs for the same speed. At least you will notice that you are on an upslope.

These days you are seeing the CVT make a comeback in many ATs with manual over-ride. The manual mode simply uses some predefined ratios.
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Old 14th March 2011, 16:55   #10
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Default Re: Why aren't CVTs preferred to regular autos in india?

I don't understand the performance aspect. CVTs are designed to run at a constant engine speed. The change in the car's speed is due to gear ratio change. So, if you designed a cvt engine to run at an rpm equal to it's max torque point, the engine would be making the most possible torque at any given speed meaning as far acceleration goes, the engine is working at max possible efficiency. Isn't this why cvts was banned in F1? And if fuel economy was important, it could be tuned to run at an rpm giving the best possible fe. IMO it would be very easy to have an economy mode and a performance mode and still get the best of both worlds.



And as far as acceptance goes, other than the rubber band effect, the lack of change in rpms bothers many seasoned drivers. But i daresay that it wouldn't bother an indian driver as automatics on the road are still rare and most of us have our first automatic experience on the cvt of a scooty or an activa. The main reason why traditional autos don't sell in india is the price and the fe. CVTs can help with both and i'd expect heavy uptake in the cities.
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Old 14th March 2011, 16:58   #11
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Default Re: Why aren't CVTs preferred to regular autos in india?

The latest car to be launched with CVT is the Suzuki Kizashi. It's time Suzuki start making some decent 4+ speed Auto transmissions, Dual clutch auto will be asking too much.
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Old 14th March 2011, 18:02   #12
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Default Re: Why aren't CVTs preferred to regular autos in india?

I don't remember ever driving a car with CVT but my wifey's scooterette annoys me no end because of that bland engine note. If that ever happened in my car 'd hate it myself!

The Vento AT that I drive has a manual (tiptronic) mode that I love. But even in D or S, I take my cues from the engine note and cannot imagine not doing that.

edit: Can someone explain what the rubberband effect is and why it's called that? Sorry if I sound stupid, but I did search the forums and googled it as well, but couldn't get the concept.

Last edited by noopster : 14th March 2011 at 18:04.
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Old 14th March 2011, 18:25   #13
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Default Re: Why aren't CVTs preferred to regular autos in india?

Quote:
Originally Posted by .anshuman View Post
The latest car to be launched with CVT is the Suzuki Kizashi. It's time Suzuki start making some decent 4+ speed Auto transmissions, Dual clutch auto will be asking too much.
I think the Teana might be a CVT too. Nissan is betting really high on CVTs and also make some of the best CVTs in the world.

I test drove a Murano V6 with CVT auto and was simply blown away by the performance and refinement. There is absolutely no rubberband effect and throttle response was really good as well. My opinion on CVT has completely changed after that drive.
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Old 14th March 2011, 18:46   #14
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Default Re: Why aren't CVTs preferred to regular autos in india?

^^ A variant of current Audi A6 too comes with a CVT, the next gen is likely to have the 8 speed ZF.
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Old 15th March 2011, 21:18   #15
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Default Re: Why aren't CVTs preferred to regular autos in india?

I would prefer a CVT anyday over a MT or AMT or DCT.
As already said the engine can produce Max Torque,Max Power and Max Fuel efficiency at certain rpms only. The CVT keeps the engine at these rpm's so you get either the best torque,or the best power or the best fuel efficiency.
A properly designed CVT would anyday outaccelerate the regular MT. I feel the CVT technology at present is still in the nascent stage. Reliable,Efficient CVT's have not yet been designed for high torque and power requirements other than passenger cars like trucks,buses etc. Many of the CVT's are friction driven like Torroidal CVT's or Belt and pulley types. Positive steel belt CVT's have been designed but it still have lot of relative movement between the parts in contact leading to higher wear and other problems.
As we are accustomed to MT and the engine acceleration we feel its the right way but once we get accustomed to a CVT, technically speaking it would be best solution.You need not change gears,you get the perfect gear ration depending upon the requirement at the wheels,engine operates perfectly at the right rpm it should. But achieveing all the above things although theoretically the best solution is not yet been possible due to load limitations,reliability, lag in changing the gear ratio's etc.Also the CVT's have infinite gear ratios within a band say 1 to 8. But what if we want a CVT whose gear ratios vary from say 1 to 16, so a lot of design still needs to be done to make the CVT perfect. I dream of a day when there will be no MT's all CVT's giving the perfect Torque,power and fuel efficiency in the coming years. No hassle of changing gears,smooth acceleration,no discontinuinity in power while changing gears.
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