Multitronic

Multitronic is a stepless transmission launched by AUDI AG in late 1999, jointly developed and manufactured by LuK, a division of the Schaeffler Group. The capitalization used is multitronic (spelled by Audi with a lower-case leading 'm') and is a registered trademark of AUDI AG.

Based on the principles of continuously variable transmission (CVT) popularised by DAF, Multitronic offers a stepless automatic transmission in which the ratio between the input shaft and output shaft can be varied continuously within a given range, providing virtually an infinite number of possible ratios. The Multitronic system uses a link-plate chain drive, an oil-cooled multi-plate clutch (initially of six parts, later of seven to enable it to cope better with the high torque outputs of larger turbodiesel engines), and complex electronics, to overcome the traditional shortcomings of CVTs.

The transmission is monitored and regulated by Audi's "Dynamic Regulating Programme" (DRP), which tracks the driver's inputs (from how the driver applies the throttle pedal), driving conditions, and engine load - to compute the optimal gear ratio for fuel efficiency or maximum performance, as mandated by the user. The transmission can select pre-programmed underdrive to increase performance, or overdrive to improve economy. From 2004, Multitronic transmissions offered manual selection of a 'sport mode' to pre-select the performance mapping. The electronic system also includes sensors to detect whether the vehicle is traveling downhill, and provides additional engine braking in such circumstances. Multitronic also offers a number of driver-selectable fixed ratios, selectable from either the gear-lever in a sequential style, or via (optional) steering wheel-mounted fingertip paddle-shift controls.

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