Semi-automatic transmission

A semi-automatic transmission is a multiple-speed transmission where part of its operation is automated (typically the actuation of the clutch), but the driver's input is still required to launch the vehicle from a standstill and to manually change gears. Semi-automatic transmissions were almost exclusively used in motorcycles and are based on conventional manual transmissions or sequential manual transmissions, but use an automatic clutch system. But some semi-automatic transmissions have also been based on standard hydraulic automatic transmissions with torque converters and planetary gearsets.[1][2]

Names for specific types of semi-automatic transmissions include clutchless manual,[3] auto-manual,[4][5] auto-clutch manual,[6][7] and paddle-shift transmissions.[8][9][10] These systems facilitate gear shifts for the driver by operating the clutch system automatically, usually via switches that trigger an actuator or servo, while still requiring the driver to manually shift gears. This contrasts with a preselector gearbox, in which the driver selects the next gear ratio and operates the pedal, but the gear change within the transmission is performed automatically.

The first usage of semi-automatic transmissions was in automobiles, increasing in popularity in the mid-1930s when they were offered by several American car manufacturers. Less common than traditional hydraulic automatic transmissions, semi-automatic transmissions have nonetheless been made available on various car and motorcycle models and have remained in production throughout the 21st century. Semi-automatic transmissions with paddle shift operation have been used in various racing cars, and were first introduced to control the electro-hydraulic gear shift mechanism of the Ferrari 640 Formula One car in 1989. These systems are currently used on a variety of top-tier racing car classes; including Formula One, IndyCar, and touring car racing. Other applications include motorcycles, trucks, buses, and railway vehicles.

  1. ^ Wan, Mark (2019). "AutoZine Technical School, Manual Transmission". autozine.org. Retrieved 17 November 2020.
  2. ^ "How to Shift Gears on a Motorcycle". wikiHow. 21 September 2020. Retrieved 17 November 2020.
  3. ^ "The next shift: The clutchless manual". autonews.com. 13 December 2005. Retrieved 29 February 2020.
  4. ^ "1993 Ferrari Mondial T Cabriolet Valeo". Bring a Trailer. October 2018. Retrieved 18 November 2020.
  5. ^ "1992 Ferrari Mondial T Cabriolet Valeo Transmission". 20 July 2023.
  6. ^ "2022 Yamaha TT-R110E Trail Motorcycle – Photo Gallery, Video, Specs, Features, Offers, Inventory and more". www.yamahamotorsports.com. Archived from the original on 29 September 2020. Retrieved 16 August 2020.
  7. ^ Archived at Ghostarchive and the Wayback Machine: "How to make any bike an AUTOMATIC". YouTube.
  8. ^ "Geartronics – Sequential gearbox electronic systems – Professional paddle shift system".
  9. ^ "Semi-Auto Systems".
  10. ^ "Control components for race series reduce cost, improve competition".