Composition, working principle and characteristics of DCT (powershift)

DCT (powershift), also known as DSG (Direct Shift Gearbox), is an advanced transmission system of power shift. The biggest feature of the transmission is the use of double clutches. It is different from the ordinary transmission system, based on the traditional manual transmission (MT), and consists of double clutch, three-axis gear transmission, automatic gear shifting mechanism and electronically controlled hydraulic system. When DCT is working, there are two automatic clutches. When the odd gears are selected, the clutch 1 is engaged, and a group of gears are engaged to output power. Before the next gear shift, the next set of meshing gears has been selected, and the clutch 2 associated with it is still in the disengaged state. When shifting into the next gear, the working clutch 1 is disengaged, and the gear in use is out of power. At the same time, the clutch 2 is engaged, and the next gear starts to transmit power and enter the next gear. During gear shifting, two groups of clutches work in turn to ensure that at least one group of gears outputs power, thus avoiding power interruption. In the working process of DCT transmission, there are always two gears combined, one is working and the other is ready. As a very advanced transmission mode, DCT has the following advantages: no hydraulic torque converter, the speed change part is the same as the traditional MT, and the efficiency is high; The energy consumption of power transmission is very small, which greatly improves the fuel economy; There is no power interruption in the acceleration process, which makes the acceleration smoother and more powerful; Double clutch and its control are the key to achieve superior shift quality. DCT is being used more and more, such as Volkswagen's DSG powershift (DQ25 and DQ2), Porsche's PDK powershift and Mitsubishi's TC-SST powershift. Ford's powershift6DCT25 powershift and GAC's C725 power shift are also typical examples of applying powershift. So far, DCT has become one of the most advanced transmission modes in modern automobile field.