A double clutch transmission (DCT) (sometimes called double clutch transmission or double clutch transmission), is a type of automatic transmission or automated automotive transmission. It uses two separate clutches for even and odd gear sets. It can be described essentially as two separate manual transmissions with their respective clutches contained within a housing and operating as a unit. Although generally operated in a fully automatic mode, many also have the ability to allow the driver to manually change the gears in semi-automatic mode, although still using the electro-hydraulic transmission.
This type of transmission was invented by the French Adolphe Kégresse just before the Second World War, although never developed a functional model. The first development of the double clutch or double clutch transmission began in the early 1980s under the guidance of Harry Webster in Automotive Products (AP), Leamington Spa, with prototypes built into the Ford Fiesta Mk1, Ford Ranger and Peugeot. 205. Initially, the control systems were based on purely analog / discrete digital circuits with patents filed in July 1981. All of these early dual-clutch AP installations featured a single dry clutch and a multiplate wet clutch. After discussions with VW / Porsche, DCT's work continued from Porsche's in-house development for the Audi and Porsche racing cars in the 1980s, when the computers to control the transmission became compact enough: the Porsche Doppelkupplungsgetriebe (PDK) used in the Porsche 956 and 962 Le Mans racing cars since 1983, and the Audi Sport Quattro S1.
A double clutch transmission eliminates the torque converter used in automatic transmissions with conventional epicyclic gear. In contrast, the dual-clutch transmissions currently on the market mainly use two wet, oil-dipped multipole clutches, similar to the clutches used on most motorcycles, although dry clutch versions are also available. The first mass production road car with a DCT was the 2003 Volkswagen Golf Mk4 R32.
As of 2009, DCT's largest Western European sales are made by several brands of the German Volkswagen Group, although this is expected to change as other transmission manufacturers and vehicle manufacturers put DCTs available in mass-production cars. In 2010, on the BMW Canada website for the 3 Series Coupé, it is described as a seven-speed double clutch transmission and as a seven-speed automatic transmission. It is a double clutch automatic.