What does 7-speed dual-clutch mean?

[LaneAnn]

A 7-speed dual-clutch transmission (DCT) is a dual-clutch transmission with 7 forward gears. It can be divided into dry and wet types. Dual-clutch, or dual-clutch transmission (Dual-Clutch-Transmission), differs from conventional automatic transmission systems. It belongs to both manual and automatic transmissions, offering the flexibility of a manual transmission and the comfort of an automatic transmission while providing uninterrupted power output. Traditional manual transmissions use a single clutch. When shifting gears, the driver must press the clutch pedal to engage different gears, causing a power interruption during the shift, resulting in intermittent power output. Working Principle: The dual-clutch automatic transmission is based on a manual transmission. Unlike a manual transmission, the DCT has two clutches connected to two input shafts. Gear shifting and clutch operations are achieved through an integrated electro-hydraulic mechanical module rather than a clutch pedal. Similar to a tiptronic hydraulic automatic transmission, the driver can manually shift gears or place the gear lever in fully automatic D or S mode. In this mode, gear shifts are typically performed by gear and clutch actuators. The dual-clutch transmission is an automatic transmission developed from a manual transmission. Its structure is similar to that of a manual transmission, but it includes an additional clutch and a set of gear-shifting control mechanisms. One clutch controls the odd-numbered gears (1, 3, 5, 7), while the other controls the even-numbered gears (2, 4, 6). Each clutch is connected to a different input shaft. For example, clutch 1 is connected to gears 1, 3, 5, and 7 via a solid shaft, while clutch 2 is connected to gears 2, 4, and 6. The intermediate disc moves between them, engaging or disengaging the two clutch plates to shift gears. In simple terms, this transmission has two clutches: one for odd gears and one for even gears. When using first gear, second gear is already prepared, significantly reducing shift time with no delay. The difference between dry and wet dual-clutch transmissions lies in whether the clutch plates are immersed in transmission fluid. Dry dual-clutch transmissions have clutch plates that are not immersed in fluid, offering faster shift speeds and higher transmission efficiency. Wet dual-clutch transmissions have clutch plates immersed in fluid, allowing them to handle higher torque and providing better reliability and stability. However, wet dual-clutch transmissions are more expensive. Most high-performance vehicles use wet dual-clutch transmissions, including supercars and sports cars. Cars equipped with dual-clutch transmissions offer an exhilarating driving experience. Many family cars also use dual-clutch transmissions because they are cheaper than AT transmissions. There are two other common types of transmissions in cars: the AT transmission and the CVT transmission. The AT transmission is the most mature and widely used automatic transmission. The CVT transmission is the simplest in terms of internal structure among automatic transmissions.

[McKyle]

A 7-speed dual-clutch transmission refers to a type of car transmission with 7 forward gears and a dual-clutch system. Imagine it like two people working in relay—one managing odd gears like 1st, 3rd, 5th, and 7th, and the other handling even gears 2nd, 4th, and 6th. While driving, it anticipates the next move and prepares in advance, shifting gears as fast as a blink, almost without any jerkiness, and even saves some fuel. It's particularly common in Volkswagen cars. From driving such a car, I've found it combines the convenience of an automatic transmission with the sporty feel of a manual. In traffic jams, it prevents any flustered moments, though the higher cost might make it pricier. If you often drive on mountain roads, it smoothly helps you navigate winding paths, feeling incredibly satisfying. However, new drivers might need some time to adapt to the initial acceleration.