When buying a car, one of the most important questions is the type of transmission. In the past, this meant choosing one of the two types: a manual transmission or an automatic. An automatic meant no ‘pressing the clutch and changing the gear’, and a much higher price.
And only those who could afford to spare the extra few lakhs would buy an automatic. The rest of us, while coveting the ease of driving an automatic on the crowded roads, would pretend disdain. How many people have you heard saying ‘I love the power the stick shaft gives me, I would not drive an automatic even if it was free’!
Times have changed however. Automatic transmissions are slowly getting popular across India, with more manufacturers offering them. And the price difference between manual and automatic cars has reduced drastically, making the automatic seem more attractive, and more affordable.
Types of Automatic Cars
There are 4 types of automatic transmission cars.
-Fully automatic Transmission
-Dual-clutch Transmission (DCT)
-Automated Manual Transmission
-Continuously Variable Transmission (CVT)
Fully Automatic Transmission
These fully automatic vehicles use automated gearboxes with the capability to change gear rations automatically according to driving environments. The automated gearbox moves the vehicle efficiently by integrating three major components – fluid/hydraulic coupling, hydraulic controls and planetary gears train. The planetary gears train provides a variety of gear ratios.
The fluid/hydraulic coupling changes the gear automatically by locking and unlocking a system of planetary gears. At the same time, the hydraulic controls are designed as gear pump to control the clutches and bands according to the driving environment and running condition. The mechanism makes the car change the gear ratios constantly without requiring the driver to shift gears manually.
These semi-automatic automobiles integrate manual and automated transmission seamlessly. The dual-clutch transmission (DCT) features a conventional mechanical layout. But it changes gears through a system of pneumatics and actuators. Also, it comes with separate clutches for odd and even gears. When the clutch engages an odd number gear, the computer decides the even number gear required by the clutch according to precise driving environments.
The mechanism enables drivers to operate the vehicle’s gear box in a number of modes – fully automatic and manually shifted. Unlike manual transmission, DCTs enable drivers to change gears instantaneously. But the mechanism is currently used only by certain sporting car models. Also, the mechanism makes the DCT expensive. The complex mechanism even makes the owner incur frequent and expensive repair cost.
Automated Manual Transmission
It is the most common type of automatic cars found in various countries. Many drivers prefer automated manual transmission due to its simple learning curve and driving experience. These vehicles convert power to energy through complex torque converters. Also, automatic gear box moves the vehicle automatically with self-change gear ratios.
The vehicle’s gear shifts are further controlled by a computer through a set of clutches and brakes and a planetary gear set. Unlike other automatic car types, automated manual transmission has a more complex mechanism. The complex mechanism makes the automobile fuel-hungry and prone to frequent repairs.
Continuously Variable Transmission
Despite delivering simple driving experience like automated manual transmission, the continuously variable transmission (CVT) uses a completely different mechanism. Unlike other automatic vehicles, CVS does not use gears. It is designed to generate a wide variety of ratios using a system of belts and pulleys.
Also, it is designed with a built-in computer which creates optimal ratio for varying driving environments by adjusting the pulleys. The mechanism makes CVT more energy efficient than other types of automated cars. But the absence of gears makes the learning curve of such automobile complex. However, the owner can drive his CVT smoothly without any frequent and expensive repairs.
With the growing range of automatic cars in the market, take a moment to really consider what the humble automatic is trying to do: shift for you. Amazing, right!!