[amulu10]

I am blessed to work in the North american automotive industry so I thought why not share some information to clear confusion here regarding the difference between this (AMT) , DSG , CVT regular old style automatic transmission, triptronic.
Firstly the main difference between a conventional automatic and these newer automated manuals/DSG is the way the power is transmitted from the engine to the transmission/gearbox.
(A)In a conventional automatic there is a torque converter that transfers power from engine to gearbox(Read:http://auto.howstuffworks.com/auto-p...-converter.htm). And additionally they have a planetary gearset (read http://auto.howstuffworks.com/automa...nsmission3.htm) which is different from a conventional manual gearbox.The low and higher gears in these are usually controlled with hydraulics wheres in a triptronic you use electronics to control the hydraulic valves.
Advantage and Disadvantage ?
There is no clutch to replace which makes it relatively inexpensive to maintain.The units are sealed and would require very little oil change for a long time. They are quite slow to respond and inefficient
(B)On the other hand in automated manuals there is a clutch or rather 2 clutches ( in DSG there is one for even gears and another for odd gears. Read:http://auto.howstuffworks.com/dual-c...ansmission.htm). The way the power( torque actually) is transmitted is the same as it would in a manual gearbox with the one differnce being that the computer does the clutch/de-clutch and shifting action for you based on a algorithm. Some examples of the AMT or single clutch automated gearbox(they are the same) would be the gearbox in older Ferrari of the 90s to early 2000s, Bmw's SMG , Lexus LFA , All Paganis, Lamborghini Aventedor and formula 1 !
Advantage and disadvantage??
The advantage of this being the light weight ( at times 50 kgs lighter than dual clutch) but you do get the jerky shift which is why more and more companies are going over to the heavier and complicated but much smoother dual clutch.
(C)Talking about the dual clutch now the examples would be the DSG( VW) , Nissan GTR , new Ferrari , the new Lambo Hurracan, ford fiesta DCT( in india)
Advantage and disadvantage:
As mentioned , they are more expensive to produce and add weight but are the best in terms of driveablity and performance(fastest shifts)
(D)Now the third type would be CVT which does not have gears at all !(technically speaking they have infinite gear ratio).The gear reduction in this case is with a set of belt drives.(read http://auto.howstuffworks.com/cvt.htm) They may or may not have a torque converter to transfer torque. This in theory would be the most efficient transmission as they help keep the engine at the RPM in which produces the most FE or the most power, atleast that's the theory anyway!

So that's pretty much the "high level" differences out there ! To talk about this particular car , it has a single clutch like I mentioned in (B) . It would in theory be just as efficient as a manual but smoothness and driveability depends a lot on the calibration performed by the company. My experience with them are that while they work brilliant in a track and while driving fast , they are quite jerky in city bumper to bumper traffic !
PS: I if you have anymore questions then please do post them !

[katpasin]

If anyone has been to the showrooms, can you tell whats the waiting period now? and how much is the Vxi AT price coming to(on road?)

[Jeroen]

Originally Posted by amulu10

I am blessed to work in the North american automotive industry so


Advantage and Disadvantage ?

There is no clutch to replace which makes it relatively inexpensive to maintain.The units are sealed and would require very little oil change for a long time. They are quite slow to respond and inefficient

!

I don't think you can call a modern auto box slow to respond and inefficient. Maybe American ones, but not the European and Japanese ones. Please check the link I provided in my earlier post. Slow to respond and inefficient are largely a thing of the past and if you take your Joe average driver the difference becomes smaller, in fact the autobox might actually have the advantage. Two identical cars, one manual and one auto, the first one is likely to be of the line quicker, but in most cases as soon as the manual car needs to shift the auto will start gaining.

Now the one thing that is probably true is that on smaller cars, i.e. Less power, the manual might have the advantage, but the more power the more likely the auto box has the edge.

We need to face the fact that 99.9% of drivers are simply incapable of outperforming some very simple automated stuff, let alone some of the more advanced stuff.

In my experience, having lived in the USA, Americans are lazy drivers compared to European or Indian. I don't mean that in a put down or negative way. But they they have a different environment in which they drive and different expectations on what a car should do. Only a few months ago I was back in the USA for a week or so and I rented a car. It was the newest Buick or GM, i cant tell them apart. Of course, an autobox. Acceleration was absolutely glacier like. You stomp on the "gas", push the pedal to the metal, into the kick down and through the firewall and still nothing happens. If you would take the smallest BMW, with an autobox and you so much think about pushing the accelerator you end up with whiplash. Its just two completely different approaches to what a car and or auto box should be doing.

BTW, curious to know what your involvement in the NA automative industry is?

Jeroen

[Mpower]

Technology is changing so fast that you cannot really generalize and say that all conventional auto are slow shifting

Originally Posted by Jeroen

I don't think you can call a modern auto box slow to respond and inefficient. Maybe American ones, but not the European and Japanese ones.

HaHa..nice try. Not all ....as it turns out the fastest responding box in the world is American. The new Corvette can shift faster than Porsche's PDK dual-clutch

http://www.motorauthority.com/news/1...-pdk-heres-how

[Jeroen]

Originally Posted by Mpower

Technology is changing so fast that you cannot really generalize and say that all conventional auto are slow shifting

HaHa..nice try. Not all ....as it turns out the fastest responding box in the world is American. The new Corvette can shift faster than Porsche's PDK dual-clutch

http://www.motorauthority.com/news/1...-pdk-heres-how

Interesting concept! Ok, so the Americans have one autobox thats not slow to respond.

[Mpower]

There is no such thing as 'the Americans' anymore.

Chrysler uses the ZF-9speed, Ford uses Getrag DCTs and GM has had a transmission design center & plant in Strasbourg France for a long time. The new Caddy CTS uses an Aisin 8AT

[Jeroen]

Originally Posted by Mpower

There is no such thing as 'the Americans' anymore.



Chrysler uses the ZF-9speed, Ford uses Getrag DCTs and GM has had a transmission design center & plant in Strasbourg France for a long time. The new Caddy CTS uses an Aisin 8AT

Even more amazing how they are still able to crank out some awful cars.
At the end of the day its just preference. I'm just not a big fan of American cars. I don't like the way they look inside or outside and I don't like the way they handle.

Having said that, if you ever find yourself in the USA renting a car, make sure you get the biggest American model you can get. It is just very cool to drive on the American Highways, wallowing along, one hand on the wheel, a huge coffee or soft drink in you hand, Bob Seger on the radio, 18 wheeler in you rear view mirror.

American cars are just very functional, with little effort made on style and finesse. Lets face it, most of America and the Americans are like that. Makes it a great place to be, and you can still buy proper European cars there too if you want. When we lived there we owned three cars. Two European and one American, the last one a 1998 Jeep Cherokee. Talk about functionality over finesses and style! Loved my truck.

Jeroen

[volkman10]

Encashing on the AMT - the next big thing expected in Indian auto scene, the Celerio amasses a whopping 14000 orders since its launch ( 2 weeks ago).

AMT variant accounts for half of the total volume.

http://blogs.wsj.com/indiarealtime/2...elerio-surges/

[Sutripta]

What is the system used in F1 cars? What is the shift time like?

Regards
Sutripta

[Rahul Rao]

Originally Posted by amulu10

I am blessed to work in the North american automotive industry so I thought why not share some information to clear confusion here regarding the difference between this (AMT) , DSG , CVT ................

Good to see some one knowledgeable from the industry providing information.

Originally Posted by amulu10

(A)In a conventional automatic there is a torque converter that transfers power from engine to gearbox(Read:..................................... .... Advantage and Disadvantage ?
There is no clutch to replace which makes it relatively inexpensive to maintain.The units are sealed and would require very little oil change for a long time. They are quite slow to respond and inefficient

Very true. But Torque converter and auto boxes in commercial vehicles are having decent efficiency as well as response.
The main difference is the operation of a converter lock.
A Cars with this type of transmission starts in first with converter operational, as converter slip reduces it shifts to second, and so on till it reaches top gear. If provided with a lock the converter lock ups only then giving fuel efficiency close to a manuals.
In a ZF or Allison gearbox meant for trucks or buses. It starts in second gear with converter in operation, (if load is too much to start, only then it down shifts to first) as the converter slip reduces, the converter locks up, and the lock releases only for a fraction of a second while upshifting. You have no converter slip in 3rd to 6th gear. In such operation, there is loss of efficiency only while crawling at low speed in traffic and starting off from a dead halt, and many times it is preferable to burn fuel than a clutch plate and flywheel.

Originally Posted by amulu10

(C)Talking about the dual clutch now the examples would be the DSG( VW) , Nissan GTR , new Ferrari , the new Lambo Hurracan, ford fiesta DCT( in india)
Advantage and disadvantage:
As mentioned , they are more expensive to produce and add weight but are the best in terms of driveablity and performance(fastest shifts)

What are your views of the DCI developed by Renault and used in their Megan the engine is the same 110BHP K(K as used in Duster here.
In the Renault DCI the two sets of gearboxes are adjacent to each other and not co axial as in DSG.

Originally Posted by amulu10

(D)Now the third type would be CVT which does not have gears at all !(technically speaking they have infinite gear ratio).The gear reduction in this case is with a set of belt drives.(read http://auto.howstuffworks.com/cvt.htm) They may or may not have a torque converter to transfer torque.

The CVT in India currently only by Honda Toyota and Nissan. (The Altis has a CVT but a restricted steps one, and not a free ratio one like the Nissan one.)
How early dose the converter lock up, driving a Sunny with a light foot you do notice that the drive is positive (no converter slip) at as low as 30 kph.

Rahul

PS Dear Moderators, I have searched but not found any thread discussing torque converters and its modification.
If we play with the wiring I believe that we can add on a trigger switch for the converter lock in vehicles like Fortuner, Captiva and Endeavour. The purple wire between ECU and Gearbox in Endavours wiring loom controls the lock up clutch.

[Mpower]

Originally Posted by Sutripta

What is the system used in F1 cars? What is the shift time like?

Regards
Sutripta

Basically AMTs but much faster shifting. Ferrari offered it on its road cars too (F355, 360, 430) Lambo via Graziano as well

[VeyronSuperSprt]

Originally Posted by Sutripta

What is the system used in F1 cars? What is the shift time like?

Regards
Sutripta

Current F1 gear shift times are in the region of 0.05 - 0.06 seconds.

[Sutripta]

Originally Posted by Mpower

Basically AMTs

Originally Posted by VeyronSuperSprt

Current F1 gear shift times are in the region of 0.05 - 0.06 seconds.

Thanks.
Actually the deeper question is why F1 uses this system instead of any other.
A side question would be how the F1 system differs from the plebian AMTs.

Does anyone know the shift times achieved with a sequential shifter on drag cars?

Regards
Sutripta

[Jeroen]

Originally Posted by Rahul Rao

Very true. But Torque converter and auto boxes in commercial vehicles are having decent efficiency as well as response.

The main difference is the operation of a converter lock.

A Cars with this type of transmission starts in first with converter operational, as converter slip reduces it shifts to second, and so on till it reaches top gear. If provided with a lock the converter lock ups only then giving fuel efficiency close to a manuals.

In a ZF or Allison gearbox meant for trucks or buses. It starts in second gear with converter in operation, (if load is too much to start, only then it down shifts to first) as the converter slip reduces, the converter locks up, and the lock releases only for a fraction of a second while upshifting. You have no converter slip in 3rd to 6th gear. In such operation, there is loss of efficiency only while crawling at low speed in traffic and starting off from a dead halt, and many times it is preferable to burn fuel than a clutch plate and flywheel.

.

My Jaguar when in Drive mode will also pull away in second gear. Only by putting it in Sports mode will it uses first gear. Interesting anorak fact. In reverse, with Sports mode engaged you will get first and second gear. Only car. i know that does that.
These Jaguars have ZF or Mercedes auto boxes.

Jeroen

[man_and_machine]

How does one slip the clutch in such a gear box? Would there even be a need to do it in such a box? If the electronics just takes care of doing the manual work of shifting the gear in the manual mode, does it also slip the clutch in a gear if need be? In a manual when you stall the engine if you can't slip in a higher gear (say at times you need to half clutch, slip clutch etc). There will be a way for such a situation, curious, does it behave like it does a traditional AT in the manual mode too?