Marelli’s AMT (Automated Manual Transmission), known as Selespeed, is a form of automation for the manual gearbox originating from the Formula 1 world that combines ease of use and a reduction in fuel consumption. A hydraulic servo system operating clutch and gear changes that allows a combination of all the benefits of a dry clutch and manual transmission (reduced weight, sturdiness and reliability, as well as low energy consumption).
At the same time it simplifies operations and reduces effort when driving in traffic or in situations when frequent gear changes are required.
Thanks to the use of the hydraulic servo systems and interfacing with the engine control unit, the AMT is capable of providing either sportive or relaxed gear changes according to the requirements of the driver and their driving style. There is no clutch pedal in the foot well.
The servo system basically consists of a hydraulic actuator fitted directly onto the gearbox which, via a series of pistons, manages the selection and engagement of the gears. The pistons are controlled by a set of solenoid valves provided with the required hydraulic power from an electric pump and an accumulator.
An electronic control unit, having identified the request from the driver and assessed the operational conditions of the vehicle via a series of sensors, autonomously manages gear changes, directly controlling clutch, gearbox and engine torque (hence the definition of robotised gearbox).
The interfacing between the control of the gearbox and the engine significantly improves the performance of the system and frees the driver from any need to synchronise clutch and acceleration during gear changes (which can even take place with the accelerator to the floor).
The robotised gearbox also serves a role of tutoring and driving assistance, inhibiting erroneous gear change requests and avoiding engine stalls or wheel locking on slippery surfaces. In terms of driving assistance, it also ensures the immediate availability of first gear when the vehicle comes to a halt, and automatic downshifting in the event of sudden deceleration. These aspects all represent an increase in driving safety as the possibilities of erroneous actions by the driver are reduced to a minimum.
Thanks to the electronic optimisation of gear changes and the positive combination with engine control, this technology is capable of ensuring lower consumption in comparison with a vehicle with manual transmission, leading to lower pollution emissions, particularly of CO₂ (carbonic anhydride, also known as carbon dioxide).
With over 90 items, the Magneti Marelli Parts & Services AMT range offers a comprehensive repair service, covering a large proportion of Stellantis models equipped with the increasingly popular robotised gearbox (including: 500, 500L, Doblò, Ducato, Fiorino, Giulietta Ypsilon, Panda, Punto, Qubo). Access to products manufactured in the relative dedicated factories results in a portfolio of high-quality spare parts that is constantly updated with the latest production developments. Catalogues, related information and after-sales services allow precise and rapid identification of the necessary products, as well as assistance for their correct installation.