Monday, November 11, 2013

AMT (Automated Manual Transmission)

Automated Manual Transmission (AMT, also called Freechoice) from Magneti Marelli is a electro-hydraulic mechanism for automating manual transmission which derives from Formula 1. It combines comfort of use with a reduction in consumption, and can be applied to any transmission, with production costs that are consequently lower compared to traditional automatic transmissions. AMT is based on an electronic control unit and a hydraulic system that supervise the use of the clutch and the gear shifting, allowing the driver to change gear without using the clutch, either sequentially or fully automatically. The device from Magneti Marelli operates on the manual transmission of a car in the same way as the driver would: it opens and closes the clutch, engages and disengages the gears and, when necessary, it also controls the choice of transmission (automatic or sequential mode for changing gear). These three control movements are ensured by three specific hydraulic actuators, controlled by hydraulic electro-valves. All the components in the hydraulic unit are gathered together in a single kit. It is delivered to the car manufacturer sealed and ready to be installed in the gearbox. Once assembled in the gearbox, the hydraulic kit mechanically interfaces with the gear drive shaft. The heart and intelligence of the gear control system is the TCU (Transmission Control Unit). Taking into account the driver’s requirements and the operating conditions of the vehicle, it manages the gear changes by controlling the clutch, the gears and the engine. Thanks to the electronic optimization of the gear change and the coupling with the engine control means the AMT is able to ensure less consumption than a car with manual transmission: lower consumption also means lower emissions, especially of CO2. In some of the best applications of the AMT on mass-production automobiles, a 5% reduction in fuel consumption was recorded compared to the automatic transmission version of the same automobiles, as well as a reduction in emissions equal to 5 g/km of CO2. The latest generation of AMT is known as “mechatronic”, as for the first time, it combines the electronic control part and the hydraulic actuation part of the transmission in a single kit. This allows considerable improvements to performance, both in terms of speed and comfort when changing gear. This is the latest step in the evolution of a product which was first introduced to the car market with the Ferrari 355 F1 in July 1997. The product is still undergoing “sharp” growth in performance. Automated manual transmissions combine the best features of manual and automatic transmissions. Manual transmissions are lighter than conventional automatic transmissions and suffer fewer energy losses. However, most drivers prefer the convenience of an automatic. AMT operates similarly to a manual transmission except that it does not require clutch actuation or shifting by the driver. Automatic shifting is controlled electronically (shift-by-wire) and performed by a hydraulic system or electric motor. In addition, technologies can be employed to make the shifting process smoother than conventional manual transmissions.

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