The automated manual transmission (AMT) is a type of transmission for

motor vehicles A motor vehicle, also known as motorized vehicle or automotive vehicle, is a self-propelled land vehicle, commonly wheeled, that does not operate on rails (such as trains or trams) and is used for the transportation of people or cargo. The veh ...

. It is essentially a conventional

manual transmission A manual transmission (MT), also known as manual gearbox, standard transmission (in Canada, the United Kingdom, and the United States), or stick shift (in the United States), is a multi-speed motor vehicle transmission system, where gear change ...

but uses automatic actuation to operate the clutch and/or shift between

gears A gear is a rotating circular machine part having cut teeth or, in the case of a cogwheel or gearwheel, inserted teeth (called ''cogs''), which mesh with another (compatible) toothed part to transmit (convert) torque and speed. The basic p ...

. 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 In engineering, electromechanics combines processes and procedures drawn from electrical engineering and mechanical engineering. Electromechanics focuses on the interaction of electrical and mechanical systems as a whole and how the two systems ...

hydraulic Hydraulics (from Greek: Υδραυλική) is a technology and applied science using engineering, chemistry, and other sciences involving the mechanical properties and use of liquids. At a very basic level, hydraulics is the liquid counte ...

, pneumatic, or

vacuum A vacuum is a space devoid of matter. The word is derived from the Latin adjective ''vacuus'' for "vacant" or " void". An approximation to such vacuum is a region with a gaseous pressure much less than atmospheric pressure. Physicists often di ...

actuationhttp://hudsonterraplane.com/tech/other/DrivemasterServiceInformation.pdf — 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 An automatic firearm is an auto-loading firearm that continuously chambers and fires rounds when the trigger mechanism is actuated. The action of an automatic firearm is capable of harvesting the excess energy released from a previous discha ...

in operation, such as ''

Selespeed Selespeed is the name of an automated manual transmission used in Alfa Romeo cars, developed by Italian company Magneti Marelli and made by Graziano Trasmissioni. The Selespeed is an automated manual gearbox with an electronic clutch. In its curre ...

'' 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 Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a subcontinent of Eurasia and it is located entirel ...

and some

developing market A developing country is a sovereign state with a lesser developed industrial base and a lower Human Development Index (HDI) relative to other countries. However, this definition is not universally agreed upon. There is also no clear agreeme ...

s, particularly

India India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...

where it is notably favored over conventional automatic and CVT transmissions.

Design and operation

Automated manual transmissions can be semi-automatic or

fully-automatic An automatic firearm is an auto-loading firearm that continuously chambers and fires rounds when the trigger mechanism is actuated. The action of an automatic firearm is capable of harvesting the excess energy released from a previous discha ...

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:

or electro-hydraulic actuation,

, pneumatic,

electromagnetic In physics, electromagnetism is an interaction that occurs between particles with electric charge. It is the second-strongest of the four fundamental interactions, after the strong force, and it is the dominant force in the interactions o ...

, or even purely

electrical Electricity is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described ...

by means of an

electric motor An electric motor is an electrical machine that converts electrical energy into mechanical energy. Most electric motors operate through the interaction between the motor's magnetic field and electric current in a wire winding to generate for ...

. Gear shifting, clutch actuation, shift-timing, and rev-matching are all under automated control via the electronic sensors, computers, and actuators. When shifting gears, the driver selects the desired gear with the transmission shift lever, while electronic sensors and actuators connected to a TCU (transmission computer) or

microprocessor A microprocessor is a computer processor where the data processing logic and control is included on a single integrated circuit, or a small number of integrated circuits. The microprocessor contains the arithmetic, logic, and control circ ...

will automatically operate the clutch and throttle to match revs and to re-engage the clutch in milliseconds. Torque and power transfer to the drive wheels will also be electronically controlled. Most modern implementations of this transmission function in a sequential mode, where the driver can upshift or downshift by only one gear at a time. However, this is not the case for all modern transmissions. For example, BMW's "SMG" and Ferrari's "F1" transmission can skip gears on both downshifts and upshifts, when selecting gears manually via the steering wheel-mounted paddle-shifters, as seen on most modern transmissions. Older clutchless manual transmissions (mostly prior to the 1990s) will retain H-pattern shifters, plus the shift gate, and will require the driver to select the required gear ratios manually. The clutch, however, will be a servo-controlled unit, connected to various actuators, a solenoid and sensors which control the clutch automatically. Another alternate means of clutch

automation Automation describes a wide range of technologies that reduce human intervention in processes, namely by predetermining decision criteria, subprocess relationships, and related actions, as well as embodying those predeterminations in machines ...

is the "clutch-by-wire" system. The system generally uses an

electric Electricity is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described by ...

actuator and electronic sensors, which replace the mechanical clutch linkage or hydraulic clutch connection, to monitor and control clutch positioning, completely replacing the hydraulic linkage between the mechanical clutch and pedal itself with a single electro-mechanical actuator. Depending on the mechanical build and design, some (mostly modern) automated manual transmissions will automatically shift gears at appropriate points (like a conventional

automatic transmission An automatic transmission (sometimes abbreviated to auto or AT) is a multi-speed transmission used in internal combustion engine-based motor vehicles that does not require any input from the driver to change forward gears under normal driving ...

), while traditional semi-automatic and clutchless manuals require the driver to manually select the gear even when the engine is at redline, since they automate only part of the transmission (namely the clutch), and will not shift gears by themselves. Despite the superficial similarity, automated manual transmissions differ significantly in internal operation and driver's "feel" from a

manumatic The modern usage of the automotive term manumatic denotes an automatic transmission that allows the driver to select a specific gear, typically using paddle-shifters, steering wheel-mounted push-buttons, or "+" and "-" controls on the gear sele ...

, the latter of which is an

(automatics use a

torque converter A torque converter is a type of fluid coupling that transfers rotating power from a prime mover, like an internal combustion engine, to a rotating driven load. In a vehicle with an automatic transmission, the torque converter connects the power ...

instead of a clutch like in an automated manual, to manage the mechanical linkage between the transmission and motor) with the ability to override the automatic transmission's computer, and actuate shifts manually. Add-on AMTs can also function as a regular manual gearbox (with a manual shift lever), whereas integrated AMTs do not need a "normal" shift layout, so they can be designed with an optimized AMT shifting layout (which would have an unusual pattern to manually shift). Integrated AMTs either have gear-selector drums (which allows only serial shifting and no gear-skipping, but this system is fairly inexpensive, because it needs only one actuator), or single actuators. Single-actuator systems require one actuator for each shifting sleeve (which is why this type of system is more expensive, but it also shifts faster). The actuators can either be electro-hydraulic (more expensive, but faster, well-suited for single-actuator systems, and allow for higher torque), or

(less expensive, but usually limited to 250 N·m (184.5 lb-ft) of gearbox input torque). This limit is because the clutch actuation force increases with higher torque, and short shifting times; electro-mechanical actuators are just

s – using larger motors reduces the motor dynamics due to the motors' higher mass moment of inertia (which is not good for fast shifting), and bigger motors also put more stress on the car's 12-volt electrical system. As a result, one can have either slow shifting and a very large lead-acid battery (not suitable for cars), or fast shifting and a smaller battery (works up to 250 N·m of torque). Modern AMTs, such as Suzuki ''Auto Gear Shift'' and Dacia/Renault '' Easy-R'', usually operate in conjunction with

electronic throttle control Electronic throttle control (ETC) is an automobile technology which electronically "connects" the accelerator pedal to the throttle, replacing a mechanical linkage. A typical ETC system consists of three major components: (i) an accelerator ped ...

to initiate gear shifts based on certain RPM and/or throttle position.

Usage in passenger cars

BMW M3 SMG Convertible - Flickr - The Car Spy (3)

The automated manual transmission has its origins in early

clutchless manual A semi-automatic transmission is a "theoretical" multiple-speed Transmission (mechanics), transmission where part of its operation is Automation, automated (typically the actuation of the clutch), but the driver's input would be required to launc ...

transmissions that began to appear on mass-production cars in the 1940s and 1950s. An early example of this transmission was introduced with the

Hudson Commodore The Hudson Commodore is an automobile that was produced by the Hudson Motor Car Company of Detroit, Michigan between 1941 and 1952. During its time in production, the Commodore was the largest and most luxurious Hudson model. First generation ...

in 1942, called ''Drive-Master''. This unit was an early

semi-automatic transmission A semi-automatic transmission is a "theoretical" multiple-speed transmission where part of its operation is automated (typically the actuation of the clutch), but the driver's input would be required to launch the vehicle from a standstill and t ...

, based on the design of a conventional manual transmission which used a servo-controlled vacuum-operated clutch system, with three different gear shifting modes, at the touch of a button; manual shifting and manual clutch operation (fully-manual), manual shifting with automated clutch operation (semi-automatic), and automatic shifting with automatic clutch operation (fully-automatic). Another early example is the 1955

Citroën DS The Citroën DS () is a front mid-engined, front-wheel drive executive car manufactured and marketed by Citroën from 1955 to 1975, in fastback/sedan, wagon/estate, and convertible body configurations, across three series of one generation. ...

, which used a 4-speed "BVH" transmission. This semi-automatic transmission used an automated clutch, which was actuated using

hydraulics Hydraulics (from Greek: Υδραυλική) is a technology and applied science using engineering, chemistry, and other sciences involving the mechanical properties and use of liquids. At a very basic level, hydraulics is the liquid counte ...

. Gear selection also used hydraulics, however, the gear ratio needs to be manually selected by the driver. The 1956

Renault Dauphine The Renault Dauphine () is a rear-engined economy car manufactured by Renault in a single body style – a three-box, 4-door sedan – as the successor to the Renault 4CV; more than two million were manufactured during its 1956–1967 ...

3-speed manual transmission was available with an optional ''Ferlec'' automated clutch, which used an electromagnetically-operated clutch system. Other clutchless manual transmissions included the 1967

NSU Ro 80 The NSU Ro 80 is a four-door, front-engine executive sedan manufactured and marketed by the West German firm NSU from 1967 until 1977. Noted for innovative, aerodynamic styling by Claus Luthe and a technologically advanced powertrain, the Ro ...

(3-speed ''Fichtel & Sachs'') and 1967 Porsche 911 (4-speed ''Sportomatic''), both of which used vacuum-actuated clutches and hydraulic torque converters. The 1968

Volkswagen Beetle The Volkswagen Beetle—officially the Volkswagen Type 1, informally in German (meaning "beetle"), in parts of the English-speaking world the Bug, and known by many other nicknames in other languages—is a two-door, rear-engine economy car, ...

and

Volkswagen Karmann Ghia The Volkswagen Karmann Ghia is a sports car marketed in 2+2 coupe (1955–1974) and 2+2 convertible (1957–1974) body styles by Volkswagen. Internally designated the Type 14, the Karmann Ghia combined the chassis and mechanicals of the Type 1 (B ...

offered a 3-speed ''Autostick'' transmission, which used an electric switch on the gear shifter connected to a solenoid, to operate the electro-pneumatic vacuum clutch

servo Servo may refer to: Mechanisms * Servomechanism, or servo, a device used to provide control of a desired operation through the use of feedback ** AI servo, an autofocus mode ** Electrohydraulic servo valve, an electrically operated valve that c ...

. In 1963, Renault switched from the automated clutch to a fully-automatic 3-speed Jager transmission, which consisted of an electro-mechanical control unit that operated both the clutch and shifting, effectively making it one of the earliest automated manual transmissions. The Jager transmission was controlled via dash-mounted electronic push-buttons. The Isuzu '' NAVi5'' 5-speed automatic transmission was introduced in the 1984

Isuzu Aska The Isuzu Aska was a nameplate used by Isuzu Motors Ltd. of Japan to denote their mid-size sedans from 1983 to 2002. Originally, the Aska was a version of GM's J-car produced by Isuzu, but later, after Isuzu pulled out of manufacturing passen ...

mid-size sedan (sold in the Japanese domestic market only). This transmission, originally designed for trucks, was based on a manual transmission with the addition of

hydraulic actuator A hydraulic cylinder (also called a linear hydraulic motor) is a mechanical actuator that is used to give a unidirectional force through a unidirectional stroke. It has many applications, notably in construction equipment ( engineering vehicles) ...

s for the gear shifter and the clutch. Initial versions did not allow direct selection of gear ratios, instead allowing drivers only to lock out higher gears (as per many traditional automatic transmissions). Later versions added a manual mode, allowing the driver to control the gear selection. Several companies owned by Fiat S.p.A. were influential in the development of automated manual transmissions. Ferrari's involvement with automated manual transmission began with the 7-speed semi-automatic ''paddle-shift'' transmission used in the 1989 Ferrari 640 Formula One racing car. In 1992, the Ferrari Mondial T introduced the option of a "Valeo" 5-speed semi-automatic transmission. This transmission used an electro-mechanical actuator to automatically operate the clutch, while the gearshift mechanism was a standard H-pattern shifter operated as per normal transmissions. In 1997, the

Ferrari F355 The Ferrari F355 (Type F129) is a sports car manufactured by Italian car manufacturer Ferrari produced from May 1994 until 1999. The car is a heavily revised Ferrari 348 with notable exterior and performance changes. The F355 was succeeded by th ...

became available with an "F1" 6-speed transmission, which uses paddle-shifters located behind the steering wheel or can be driven in a fully-automatic mode. The F355's successors offered similar transmissions, until the company switched to a dual-clutch transmission for the Ferrari 458 in 2009. Red Ferrari F430 Spider steering wheel

Sister company Alfa Romeo introduced the related ''

'' 5-speed automatic transmission for the Alfa Romeo 156 in 1999. This was followed by Maserati's 2001 introduction of the related ''Cambiocorsa'' 6-speed automatic transmission in the

Maserati Coupé The Maserati Coupé and Spyder (''Tipo M138'') are a series of grand tourers produced by Italian automaker Maserati from 2001 to 2007. The two nameplates refer to the four-seater coupé and two-seater convertible models, respectively. The design ...

. Selespeed was also used in the

Fiat Punto The Fiat Punto is a supermini car (B-segment) produced by the Italian manufacturer Fiat from 1993 to 2018, spanning over three generations. The third generation of the car was marketed between 2005 and 2009 as the Grande Punto, and between 2009 a ...

and

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models. BMW's involvement with automated manual transmissions began in 1993, when the "Shift-tronic" 6-speed semi-automatic was offered on the Alpina B12 coupe (based on the E31 850CSi). Using an automated clutch paired to a standard H-pattern shifter (as per the Ferrari Mondial T), the transmission was supplied by LuK and fitted to less than 40 cars. Mass-production of automated manual transmissions began for BMW in 1997 with the introduction of the "SMG" 6-speed automatic transmission in the BMW E36 M3 coupe. Although the name "SMG" was an abbreviation of "Sequential Manual Gearbox", the transmission internal were as per a typical (synchromesh-equipped) manual transmission, not a true

sequential manual transmission A sequential manual transmission, also known as a sequential gearbox, or a sequential transmission, is a type of non-synchronous manual transmission used mostly for motorcycles and racing cars. It produces faster shift times than traditional ...

. The SMG was replaced by the SMG-II when the E46 M3 was introduced in 2000. BMW's final AMT (before being replaced by a dual-clutch transmission) was the 7-speed SMG-III used in the 2004-2010 BMW E60 M5 and related BMW E63 M6. The SMG-III could achieve a shift time of 65 milliseconds in its most aggressive mode From 2002 to 2007, the Toyota MR2 (3rd generation) was available with an "SMT" 6-speed automated manual transmission. The SMT system utilized an electro-hydraulic activation system for both the clutch and shifting, but no H-pattern shifter like with the standard transmission. Instead, there was a shift lever that could be pulled and pushed forward or backward to upshift and downshift, as well as the addition of electronic steering-wheel-mounted shift buttons. Brands within the Volkswagen Group have typically used dual-clutch transmissions instead of automated manual transmissions, however a 6-speed "E-gear" automated manual transmission was introduced for the 2004

Lamborghini Murciélago The Lamborghini Murciélago is a sports car produced by Italian automotive manufacturer Lamborghini between 2001 and 2010. Successor to the Diablo and flagship V12 of the automaker's lineup, the Murciélago was introduced as a coupé in 2001. ...

. and

Lamborghini Gallardo The Lamborghini Gallardo (; ) is a sports car built by the Italian automotive manufacturer Lamborghini from 2003 to 2013. It is Lamborghini's second car released under parent company Audi, and best-selling model with 14,022 built throughout its ...

. The E-gear was used on the successors to the Murciélago and Gallardo, and it was also available on the 2007-2012

Audi R8 (Type 42) The Audi R8 (Type 42) is the first generation of the R8 sports car developed and manufactured by German automobile manufacturer Audi. Conceived in 2003 in concept form, the R8 was put into production in June 2006. The Type 42 is based on the L ...

, marketed as the "R-tronic" transmission.

Applications

Usage in semi-trucks /
tractors A tractor is an engineering vehicle specifically designed to deliver a high tractive effort (or torque) at slow speeds, for the purposes of hauling a trailer or machinery such as that used in agriculture, mining or construction. Most common ...

* Volvo I-Shift: an automated manual transmission; introduced in 2001 and used in trucks and buses. This system is an add-on for the conventional unsynchronized manual transmission. * ZF ''AS Tronic'': an automated manual transmission; introduced in 2003, and used in trucks, buses, and coaches. * Eaton ''AutoShift'': introduced in the early 2000s as an add-on to traditional non-synchromesh manual transmission for heavy trucks. * Isuzu ''Smoother'': Successor of the Japan-only NAVi5, primarily aimed at developing markets. * Mack ''mDRIVE'' and ''mDRIVE HD'': an automated manual transmission with synchronizers; introduced in 2010, and used in ''Mack'' semi-trucks. *

Renault Groupe Renault ( , , , also known as the Renault Group in English; legally Renault S.A.) is a French multinational automobile manufacturer established in 1899. The company produces a range of cars and vans, and in the past has manufacture ...

''Optidriver'': an automated manual transmission; introduced in 2004, and used in Renault heavy-duty commercial semi-trucks. * Daimler Trucks ''DT12'': an automated manual transmission; introduced in 2012, and used in the ''

Freightliner Cascadia Freightliner Cascadia is a heavy-duty semi-trailer truck and the flagship model of Freightliner. Its design took fuel efficiency into great consideration, As well as having improved upon several other features including the powertrain offering ...

'' semi-truck, and the '' Western Star 49X'' line of commercial semi-, crane, and dump trucks. *

Mercedes-Benz Mercedes-Benz (), commonly referred to as Mercedes and sometimes as Benz, is a German luxury and commercial vehicle automotive brand established in 1926. Mercedes-Benz AG (a Mercedes-Benz Group subsidiary established in 2019) is headquartere ...

''PowerShift'': A non-synchronous automated manual transmission, used in ''Mercedes-Benz'' heavy-duty semi-trucks. *

UD Trucks UD Trucks Corporation (UDトラックス株式会社, ''UD Torakkusu Kabushikigaisha'') is a Japanese company whose principal business is the manufacturing and sales of diesel trucks, buses, bus chassis and special-purpose vehicles. Its headquarte ...

''ESCOT'': An add-on for non-synchronized and synchronized manual transmission; introduced in 1995. Six different versions of this transmission have been made: ''ESCOT'', ''ESCOT-II'', ''ESCOT-III'', ''ESCOT-IV'', ''ESCOT-V'', and ''ESCOT-VI''. Used in UD Trucks' range of commercial vehicles.

References

{{DEFAULTSORT:Automated Manual Transmission Automotive transmission technologies

Design and operation

Usage in passenger cars

Applications

Usage in semi-trucks / tractors A tractor is an engineering vehicle specifically designed to deliver a high tractive effort (or torque) at slow speeds, for the purposes of hauling a trailer or machinery such as that used in agriculture, mining or construction. Most common ...

See also

References

Usage in semi-trucks /
tractors A tractor is an engineering vehicle specifically designed to deliver a high tractive effort (or torque) at slow speeds, for the purposes of hauling a trailer or machinery such as that used in agriculture, mining or construction. Most common ...