The automated manual transmission (AMT) is a type of transmission for motor vehicles. It is essentially a conventional manual transmission equipped with automatic actuation to operate the clutch and/or shift gears.
Many early versions of these transmissions that are semi-automatic in operation, such as Autostick, which automatically control only the clutch — often using various forms of clutch actuation, such as electro-mechanical, hydraulic, pneumatic, or vacuum actuation — but still require the driver's manual input and full control to initiate gear changes by hand. These systems that require manual shifting are also referred to as clutchless manual systems. Modern versions of these systems that are fully automatic in operation, such as Selespeed and Easytronic, can control both the clutch operation and the gear shifts automatically, by means of an ECU, therefore requiring no manual intervention or driver input for gear changes.
The usage of modern computer-controlled AMTs in passenger cars increased during the mid-1990s, as a more sporting alternative to the traditional hydraulic automatic transmission. During the 2010s, AMTs were largely replaced by the increasingly widespread dual-clutch transmission, but remained popular for smaller cars in Europe and some developing markets, particularly India where it is notably favored over conventional automatic and CVT transmissions.
Automated manual transmissions can be semi-automatic or fully-automatic in operation. Several different system to automate the clutch and/or shifting have been used over the years, but they will generally use one of the following methods of actuation for the clutch and/or shifting:
hydraulic or electro-hydraulic actuation, electro-mechanical, pneumatic, electromagnetic, or even purely electrical by means of an electric motor.
Gear shifting, clutch actuation, shift-timing, and rev-matching are all under automated control via the electronic sensors, computers, and actuators.