AUTOMATIC TRANSMISSION EXPLAINED

AUTOMATIC TRANSMISSION EXPLAINED

According to ICRA(Information and Credit Rating Agency of India Limited),the demand in the Indian car market will move towards automatic transmission in the next 4-5 years.Currently  upto  5 percent cars in the mass market segment are equipped with automatic transmission .The relatively lower proportion of the automatic transmission is due to customers fear about long term reliability and relatively lower fuel efficiency.

Automatic transmissions are relatively new for the Indian customers especially in the mass market .Lets have a look at the the concept and different variants of automatic transmission.

Concept:

A transmission is a connection between the engine and the drive wheels of a vehicle.It transforms torque and horsepower to various  speed limits.

In other words it sends power from the first part to the second part to make the car move forward and backward.

The automatic version of the gearbox can change gears with the movement of the vehicle,the driver does not need to do anything except for selecting different modes.

Alfred Horner Munro a Canadian was the first person who patended the concept  of automatic transmission.His concept was developed into first automatic transmission by American Oscar H Banker.General Motors introduced the first modern and mass produced self-shifting  gear called Hydramatic in 1940.

Types of Automatic Transmission

1.Torque Converter

Torque Convertor is the most common type of automatic transmission.Unlike the manual gearbox,it does not use a clutch to change gears.The torque convertor uses thick hydrullic fluid to transfer drive from the engine to the gearbox.Because of this fluid link,torque convertor automatics are usually able to change the gears smoothly.

The drawbacks of the torque convertor is that it is not the most efficient way of transferring the engine’s power.So this type of transmission can be a little heavier on the fuel consumption and is very slow to respond during gear changes.

The gearbox is used in many BMW,Jaguar and Mercedez models like ZF-8-F,ZF 8HP,ZF-9 speed,9G Tronic,Geartronic.

Among Indian cars it is used in current generation Hyundai Verna,Mahindra XUV 500,Tata Hexa andFord Ecosport .

                                             Torque Converter

2.Automated Manual  Transmission

As the name suggests a car with an automated manual gearbox has a manual gearbox that is operated electronically.It is also known by other names like AGS,AMT,SAT,etc

This transmission uses a regular clutch and gear setup but the automation is done with the help of sensors,actuators,processors and pneumatics.Sensing the throttle output,it disengages the clutch automatically,selects a new gear and then re-engages the clutch.

The disadvantages of this gearbox is that it is quite a big task for the gearbox is that it is quite a big task for the gearbox to do all that both quickly and smoothly.That is why this gearbox is jerky in action

The AMT is used in the cars like Alto K10 AGS,Dzire/Swift AGS,Tata Zest Ftronic and Renault Duster AMT.

AMT GEARBOX 

3.Continuous Variable Transmission (CVT) .

 Continuous Variable Transmission  is also called single speed transmission or pulley transmission.It is the twist and go type of transmission  present in scooters like Honda Activa.

In CVT automatic transmission there are two pulleys connected by a belt.The advantages of CVT is that the size of the pulleys can change from small to large and infinite sizes in between.

The engine’s pulley will be small when you start your car.But as the car gathers  speed,there is reduction in the size upto top speed.Inbetween the pulleys can change from small to large and thus there are infinite sizes.

The drawback of CVT is that the energy loses due to friction are greater with a CVT.Moreover the engine note will become coarse in action as soon as you rev hard the throttle.This is called Rubber Band Effect.

CVT TRANSMISSION

4.Dual Clutch Transmission

This transmission is also called DSG(VAG),PDK(Porsche),DCT(Ford,FCA)

A dual clutch automatic transmission has two clutches but it does not mean that there are two clutch pedals in the car.

The whole process is controlled by car’s ECU.There are two shafts for gear changing,one for the odd numbered and another for the even numbered gears.Both of these shafts have their own clutch.One clutch controls the odd numbered gears and the other controls even numbered gears.

With the help of this gear box the shift from lower to upper gear or vice versa takes place in a fraction of a second.It disengages one clutch and engages another clutch for changing of gears.This  transmission offers faster gear changing and seamless pulling power.DCT offers faster gear changing and seamless pulling power.DCT offers higher efficiency than traditional transmissions.

DCT GEARBOX

5.Tiptronic Transmission
AUTOMATIC TRANSMISSION EXPLAINED

Tiptronic is the registered trademark owned by Porsche.Many other car manufacturers like Land Rover and the full Volkswagen Group used this gearbox under liscene.

This transmission is also called ‘manumatics’.This system allow drivers to choose whether they want to drive automatics,where the computer does gear  shifting or manual mode where the driver has the opportunity to change the gears.This type of transmission employs an additional gate.In most of the cars  the gear lever  when  moved  towards left activates the mode.If the driver fails to shift in proper time,the gearbox shifts to automatic mode once again.

TIPTRONIC GEARBOX

Which transmission should you use?

Well it all depends on the make ,model and the type of performance you are looking for.Besides  the budget is an issue too.With increased congestion in our cities and advancement  in technology will make automatic transmission affordable and reliable.The Indian automotive industry is definitely going towards automation.