With the focus now shifting towards Automatic cars, there are different technologies now available in the market. All the different technologies(AMT,CVT,DSG) have different mechanisms and have their own set of advantages and disadvantages.
Comparing the technologies on different parameters to help make a buying decision basis performance, fuel efficiency & cost.
I) Full form of Acronyms:
a) AMT: Automatic Manual Transmission
b) CVT: Continuous Variable Transmission
c) DSG: Direct Shift Gearbox
II) Transmission technology:
a) AMT: Automation of conventional manual transmission system
b) CVT: Single speed transmission
c) DSG: Dual clutch transmission
III) No. of Gears:
a) AMT: Fixed number of gear speed ratios
b) CVT: Infinite set of gear ratios. Single unique gear that can change through a continuous range of effective gear ratios
c) DSG: Fixed number of gear speed ratios
IV) Operational Mechanism:
a) AMT: Clutch and gear shifter-selector mechanism is operated by a hydraulic actuator system and an electronic control unit.
b) CVT: Gears with two variable-diameter pulleys(one connected to engine and the other to wheels), each shaped like a pair of opposing cones, with a metal belt or chain running between them.
c) DSG: Two clutches(with one clutch each dedicated to odd & even gears) working in tandem with one clutch disengaging the gear and the other one engaging the next gear through mechatronic module comprising of electronic control unit, sensors & hydraulic control elements.
a) AMT: Not smooth; Jerks on gear shift
b) CVT: Smooth gear shift compared to AMT
c) DSG: Smoothest gear shift
VI) Acceleration & power delivery:
a) AMT: Acceleration & power delivery is not very smooth and seamless.
b) CVT: Acceleration & power delivery is sluggish due to rubber band response due to which there is lag in power delivery even at high RPM.
c) DSG: Acceleration & power delivery is the best.
VII) Fuel efficiency:
a) AMT: Fuel efficiency as good as manual transmission
b) CVT: Not that fuel efficient; it is 5-10% lower than that of manual transmission
c) DSG: Fuel efficient
a) AMT: Least expensive
b) CVT: More expensive than AMT
c) DSG: Most expensive
a) AMT: Suited for city traffic
b) CVT: Suited for city traffic
c) DSG: Suited for offdrives
X) Examples of cars:
a) AMT: Maruti Celerio, Tata Tigor, Tata Nexon
b) CVT: Nissan Micra, Honda City,Honda Jazz
c) DSG: Skoda Rapid, Volkswagen Vento
a) AMT: This is the most affordable automatic option without compromising much on the performance. AMT gives reasonable performance in both city & highway driving conditions.
b) CVT: This is ideally suited for city driving conditions where high/instant acceleration is not required and car needs to be run at standard speeds. Not a good option for driving enthusiasts.
c)DSG: This is ideally suited for driving enthusiasts who want instant power delivery along with fuel efficiency. High initial costs is a big let down though.