#NewsBytesExplainer: Types of car transmissions and how do they work
All vehicles with an internal combustion engine require a transmission aka a gearbox. There are two main types of gearboxes, namely manual and automatic. However, they branch out into different versions like manual, torque converter automatic, CVT, DCT, AMT, and iMT. Each one of them has its own set of advantages and disadvantages. Let's take a closer look.
What is transmission and what does it do?
A gearbox is a device that can change the engine's speed based on the power requirement. It aids in sending the power from the mill to the wheels in an efficient way. Without a gearbox, a vehicle will move as per the engine's crankshaft revolution, offering poor performance and consuming a lot of fuel. Drivers will have to switch off the engine to stop.
Manual transmission
The manual transmission uses a clutch so that the drivers can change gears by themselves. To engage the clutch, the foot pedal has to be pressed, followed by selecting a proper gear ratio via the gear selector lever. This gearbox is better for off-road usage and easier to maintain as well as repair. However, driving requires more effort and some skill for smooth operation.
Torque converter automatic gearbox
In vehicles with a torque converter automatic gearbox, drivers don't have to manually shift the gears. Even if the output rotational speed is low, this type of transmission can increase the torque by deflecting the fluid coming from the turbine. It is easy to use and ensures good driving as well as mileage. However, maintenance costs are high.
Continuously variable transmission
Continuously variable transmission (CVT) uses four pulleys connected by rubber belts instead of gears. CVT is not torque-dependent and the diameter of its pulleys can be increased as per the requirement to ensure the engine's efficiency is not compromised. It responds quickly to changes in driving and provides good fuel efficiency as well as riding experience. However, it is not suited for off-road conditions.
Dual-clutch transmission
Dual-clutch transmission (DCT) is an automatic gearbox with two separate clutches for a set of even and odd gear ratios. The outer clutch is larger and drives the even-numbered gears, while the smaller clutch drives odd-numbered ones. DCT is of two types: wet multi-plate and dry single-plate. The former is suitable for engines with high torque output, while the latter provides better fuel efficiency.
Automated manual transmission
Automated manual transmission (AMT) is also called auto gear-shift transmission. It is a manual gearbox with an electronically or hydraulically controlled actuator that shifts the gears automatically. Vehicular speed and throttle input determine the gear transitions. AMTs are cheap and fuel-efficient but don't offer a very pleasant driving experience since their response to throttle inputs is slow.
Intelligent manual transmission
Intelligent manual transmission (iMT) is a manual gearbox sans a clutch pedal. The driver has to manually shift gears, while the clutch is operated by software and actuators. Thanks to fewer parts, it costs similar to a regular manual unit. However, its drawback is that the shifting of gears is not smooth as the transmission relies solely on one clutch.
