just might be in the pipeline

[skippy41]

http://cars.uk.msn.c...x-for-road-cars

[hawkster]

CVT anyone - wait long enough and things come round again.

[Dodgy]

That's not CVT, it's 10 finite ratios.

[scottpcs]

That's not CVT, it's 10 finite ratios.

I don't think he was implying that it's a CVT box but that CVT boxes may become popular with engineers again. Remember the experimental Williams F1 car that DC drove back in the 90's?

[hawkster]

Yep - 10 today -then someone will decide that 15 is better etc etc and before long CVT will come back again - wasn't it Fiat that tried cvt for a while back in the 80s or so? Also didn't DAF experiment with it as well?

[Juniperz]

Yep - 10 today -then someone will decide that 15 is better etc etc and before long CVT will come back again - wasn't it Fiat that tried cvt for a while back in the 80s or so? Also didn't DAF experiment with it as well?

Audi use CVT currently (or at least recently) with the 2.7TDi Multitronic, though I think it had some preset "gears". Their name for DSG is S-tronic (or I might have those the wrong way round )

Edited 29 April, 2013 by Juniperz

[phsroberts]

Audi also use cvt on the 2.0 tdi lump too.

[Timoctav]

CVT is pretty poor. Double clutch technology is by far and away the best automatic transmission available. Can't quite work out why with petrol engines you get better performance and economy than with a manual transmission yet slower and less economical in a diesel.

I'm not sure that Audi or any VW Group car have used CVT, before DSG I think you will find they used conventional torque converter automatics. CVT tends to be used by Japanese manufacturers and hybrid cars where the transmission can adapt easily to the different characteristics of internal combustion engines and electric motors.

Edited 29 April, 2013 by Timoctav

[skippy41]

^{I'm thinking along the lines of the inners of the gearbox being shaped like a cone, the faster you go the further up the cone a rod slides, similar to changing cogs on a bike, this could be activated by hydraulics from a compressor built into or on the engine}, still trying to figure how to get this to work though, this is my idea of a gearbox that is a full on auto, with no clutch, or torque converter, something for the future

Edited 30 April, 2013 by skippy41

[reverse]

Audi multitronic is a CVT box. As there are many others on the market at the moment. As said above, mostly on Japanese cars. I've driven a few, not my cup of tea.

However given how smooth the DSG is on my car, I would mind the extra 4 gears - as I will mostly not notice it anyway

[Jockdooshbag]

In theory CVT is the best solution as it means your car engine is always running at the optimal speed. Getting it to work in practice is the problem. People didnt like it as it felt "weird". I would have one in a heartbeat myself as you get fixed ratios if you want when doing manual shifts so it feels like a normal gearbox when pressing on. When just cruising you leave it in full auto mode and the engine automatically revs at the optimal range to suit how your driving.

It feels slightly weird like a clutch is slipping but you get used to it. I certainly liked it when i tried it on a 2.0 petrol Audi years ago. They have torque limitations but if they became more popular i dare say they would engineer a solution to this.

The thing i liked was there was no torque interuption or hesitation when accelerating out of a corner etc as the engine never needs to be disengaged ever so you always have drive to the wheels.

Bring them on i say i would have one in preference to a DSG or a torque convertor myself.

[Timoctav]

Bring them on i say i would have one in preference to a DSG or a torque convertor myself.

With respect I cannot agree with you on this. CVT transmissions are invariably slow on pick up, the response to "kick down" is poor compared with a good double clutch gearbox and they are not as mechanically efficient. All the ones I have driven, or read road tests on, have a horrible drone at cruising speeds as well. It is barely - and only - tolerable in low powered town cars or hybrids. You would never, ever find such a transmission fitted to any car designed for an enthusiastic or sporting driver.

A good double clutch transmission responds in a fraction of a second to throttle inputs, kick down and initial start from rest is instant. Gear changes are also smooth and not detectable other than at full chat. They also "learn" very quickly with adaptive electronics.

Edited 30 April, 2013 by Timoctav

[Jockdooshbag]

With respect I cannot agree with you on this. CVT transmissions are invariably slow on pick up, the response to "kick down" is poor compared with a good double clutch gearbox and they are not as mechanically efficient. All the ones I have driven, or read road tests on, have a horrible drone at cruising speeds as well. It is barely - and only - tolerable in low powered town cars or hybrids. You would never, ever find such a transmission fitted to any car designed for an enthusiastic or sporting driver.

A good double clutch transmission responds in a fraction of a second to throttle inputs, kick down and initial start from rest is instant. Gear changes are also smooth and not detectable other than at full chat. They also "learn" very quickly with adaptive electronics.

I know how DSG works as i have one. Some of the issues you spek of relating to CVT transmissions would be engineered out as they got more common just as early DSG wasnt as good as the current version is just called development. This and the fact that the audi i drove displayed none of the characteristics you speak of. Audi used CVT in various cars and ive neve heard any bad words about it otherthan some people thought it was weird.

Everything is weird though untill you get used to it and then eventually it becomes the norm. Having pre-defined gears is always going to be a compromise whereas a CVT is the perfect solution. In theory. As said before fine tuning the actual design and manufacture and installation of a CVT takes time and i dare say these types of gearboxes would then surpass the likes of DSG and torque convertor. Especially once they offer improved performance and efficiency.

Why wouldnt you want your car engine always running in its sweet spot? Thats effectively what a CVT does, gets the best out of the engine at all times. Yes i dare say some current versions are not tremendous but thats because they need to become more popular so that they develop quicker.

Its like electric cars. The were terrible as no-one really invested in battery technology. Now there are becoming more popular the technology relating to batgtery life etc has improved remarkably. OK they are still a bit pants but you can see the engineering progression. The same can happen to CVT.

For me an auto with 10 gears seems nonsense as the thing will be swapping cogs constantly and the more gears you have the more times drive is not connected to the wheels i.e torque interuption. This is not desirable as no matter how quick th change its still interuption.

I like my DSG, its my second one and i like torque convertor autos, ive had numerous but i have to say that the one CVT i drove was better as it was silky smooth all the time and really got the best, which wasnt a lot, from the audi 2.0 130bhp petrol engine.

Tried editing but the something isnt working so excuse missing letters.

Edited 1 May, 2013 by Jockdooshbag

[Herschel]

I've had a CVT in my BMW 330d and it was great.

I currently have a DSG and I love it.

My wife has a 4-speed (plus overdrive) TC in her Nissan Note and it's also brilliant, with instant pick-up from standing start.

Overall, I prefer the DSG, but that's only because I can use the paddles and the changes are so quick.

If I wanted perfectly relaxed driving all the time, a CVT box is best as there is no delay in kickdown (like there is in my DSG as it selects the appropriate gear), it just goes like a rocket.

H

[Jockdooshbag]

Audi used the CVT with the 3.0 petrol engine as well i think along with the 2.7tdi so it must be able to handle a reasonable amount of torque. Was also used with the 130bhp PD engines and mayebe even the 140CR engines. Would be intersesting to see real facts as to why is wasnt more popular. Maybe it was. With the big focus on emmisions etc i would have thought it offered the best solution. Does anyone know how the economy and performance figures of the audi CVT cars compared with the manual equivilents??

[beneix]

Audi used the CVT with the 3.0 petrol engine as well i think along with the 2.7tdi so it must be able to handle a reasonable amount of torque.

I remember test driving a 3.0TDI Audi Multitronic a couple of years ago -- it was very nice... would have thought that size diesel had even more torque. CVT has matured and is not the awful thing it was back in the 80s when DAF CVT boxes even found their way into Volvos (!) in the form of "Variomatic".

[Herschel]

Audi used the CVT with the 3.0 petrol engine as well i think along with the 2.7tdi so it must be able to handle a reasonable amount of torque. Was also used with the 130bhp PD engines and mayebe even the 140CR engines. Would be intersesting to see real facts as to why is wasnt more popular. Maybe it was. With the big focus on emmisions etc i would have thought it offered the best solution. Does anyone know how the economy and performance figures of the audi CVT cars compared with the manual equivilents??

they aren't good on economy as they don't lock the gear in, so a small bit of fuel is constantly wasted

[auroan]

Eh !?!?!... Before DSG all Audi longitudinal based car (A4,A6 etc) auto boxes came in two flavours. Multitronic (nick named multispastic because of is tendency to break - alot and expensively) and Tiptronic.

Tiptronic only ever went on AWD vehicles and is a version of a manumatic system (http://en.wikipedia.org/wiki/Manumatic)

Multitronic only ever went on FWD vehicles (http://www.audiworld...c/content.shtml) and is not a pure version of CVT

http://www.audi.co.u...nsmissions.html

[Jockdooshbag]

Eh !?!?!... Before DSG all Audi longitudinal based car (A4,A6 etc) auto boxes came in two flavours. Multitronic (nick named multispastic because of is tendency to break - alot and expensively) and Tiptronic.

Tiptronic only ever went on AWD vehicles and is a version of a manumatic system (http://en.wikipedia.org/wiki/Manumatic)

Multitronic only ever went on FWD vehicles (http://www.audiworld...c/content.shtml) and is not a pure version of CVT

http://www.audi.co.u...nsmissions.html

Very interesting article on the multitronic transmission. Sounds almost perfect. You would hope the reliability issues could be designed out eventually as on paper it sounds like the ideal gearbox according to that article. It certainly felt very good in the audi i drove for few days when i had it in a courtesy car. Do audi still put this transmission in some cars? I would love to see it make a come back and become mainstream as i would specify it as long as it proved reliable.

[Huskoda]

What the need for this? What does it solve? I can't possibly see how you would use that many gears. Are the gaps between current 6/7 speeds so large? I suppose it might have made sense with a PD diesel that only had 500RPM of useful torque but really?

Its just more dickwaving.

[Jockdooshbag]

What the need for this? What does it solve? I can't possibly see how you would use that many gears. Are the gaps between current 6/7 speeds so large? I suppose it might have made sense with a PD diesel that only had 500RPM of useful torque but really?

Its just more dickwaving.

It seems they just want taller gears for motorway economy. Why not have a 6 sp DSG with a big 7th overdrive gear purely for motorway cruising? 10 gears seems ridiculous. Imagine using paddles with 10 gears??? You would never know what gear you where in.

[Huskoda]

Exactly. The DSG works because it doesn't have to hunt around many gears. With 5 on each clutch, kickdown could be horrendous. Plus it would be changing every second as you accelerate. I wonder if they will consider making it a triple clutch one so each has 3-4 cogs.

[Timoctav]

10 gears is daft, far too many. Seven is about right, six driving gears plus an overdrive 7th.

Both DSG and CVT have their places in life. CVT is ok in economy cars designed primarily for urban use but never in a performance car and maybe vice versa with DSG.

Edited 1 May, 2013 by Timoctav

[Dodgy]

Yeah, what do those engineers know.

[Huskoda]

Yeah, what do those engineers know.

Next you'll be saying those electronic handbrakes are better too Another bit of engineering for engineering's sake.

Yeah, I'm sure it will work mechanically, but it does just seem a bit like a ****ing contest.