What is a DSG Gearbox?
The Direct-Shift Gearbox (German: DirektSchaltGetriebe), or DSG, is an electronically controlled, twin-shaft dual-clutch manual gearbox, without a conventional clutch pedal, with full automatic, or semi-manual control. In simple terms, it is two separate manual gearboxes, contained within one housing, and working as one unit. It was designed by BorgWarner and initially licensed to Volkswagen Group (which owns the Volkswagen, Audi, SEAT, Bentley, Bugatti, Lamborghini, and Škoda brands), with support by IAV GmbH. By using two clutches, fast shifts can be achieved, and the torque converter of a conventional epicyclic automatic transmission is eliminated.
At the present time, the DSG transmission is only available in transaxle-mounted front engine, front-wheel drive or four-wheel drive. The Bugatti Veyron is a notable exception, due to its Ricardo-developed transmission.
The first DSG gearbox that went into production had 6 speeds and wet/submerged clutch packs, which can desipate more heat but requires regular oilchanges. The new 7 speed DSG Gearbox uses dry clutches, which does not require changing oil. It is used in the 1.4 TSI and in cars such as the new Skoda Superb and the new Seat Ibiza
The engine drives two clutch packs. The outer clutch pack drives gears 1, 3, 5 and reverse. The inner clutch pack drives gears 2, 4, and 6. Instead of a standard large dry single-plate clutch, each clutch pack is a collection of four small wet interleaved clutch plates (similar to a motorcycle wet multi-plate clutch). Due to space constraints, the two clutch assemblies are concentric. Because the alternate clutch pack's gear-sets can be pre-selected (predictive shifts taking place while the other section is in use), un-powered time while shifting is avoided because the transmission of torque is simply switched from one clutch-pack to the other. This means that the DSG takes only about 8 milliseconds to upshift. In comparison, the sequential manual transmission (SMT) in the Enzo Ferrari takes 150 milliseconds to upshift. The quoted time for upshifts is the time the wheels are completely non-powered.
How does it work?
There are five positions for the gearbox selector.
- P - Park
- R - Reverse
- N - Neutral
- D - Drive
- S - Sport
This is for when the car is stationary and the engine off.
Make it go backwards!
For use at traffic lights etc so you can take your foot off the brake to stop the 'automatic creep'.
There are three ways to use this mode. With the selector just in D mode the car will drive like a regular automatic, making up and down shifts at optimum revs for smooth passage. You can also override that by using the steering wheel gear selector paddles. If you do not use the paddles for a set period of time it will revert back to regular automatic mode.
There is also a built in sensor that will detect if you apply more vigorous pressure to the throttle and automatically down change for you.
If you push the selector over to the +/- side you can use the paddles to change gear. Up on the right, down on the left. You can also use the gear selector itself. To change up a gear, the lever is pushed forwards (against a spring pressure) towards the "+", and to change down, the lever is pulled rearwards towards the "−". This is similar to the Porsche tiptronic system.
Sport mode still functions as a fully automatic mode, identical in operation to "D" mode, but upshifts and downshifts are made much higher up the engine rev-range. This aids a more sporty driving manner, by utilising considerably more of the available engine power, and also maximising engine braking. However, this mode does have a worsening effect on the vehicle fuel consumption, when compared to D mode.