DC plots twin-clutch gearbox

Spurred on by the worldwide acclaim that has been bestowed on Volkswagen's pioneering twin-clutch Dual Shift Gearbox (DSG), DaimlerChrysler has announced its intention to mass-produce its own version of the system.

A report by US publication Automotive News states that DaimlerChrysler plans to invest $US560 million in a new assembly plant in Indiana to manufacturer its own version of DSG.

Volkswagen had announced a few months ago that it plans to replace all its automatic transmission vehicles with DSG variants over the next five years -- hardly surprising, given the enthusiastic take-up rate of the twin-clutch gearbox.

Australian buyers have been among the early adopters of the technology, as evidenced by the high percentage of DSG-equipped Golfs, vis-à-vis their manual and automatic counterparts.

DaimlerChrysler plans on creating 700,000 units annually in partnership with Getrag, with production set to begin in 2009.

AN suggests the models that stand to benefit from the new transmission are primarily front-wheel drive vehicles, including the recently unveiled Avenger, Sebring and a variety of MPVs.

But, you might ask, what exactly is DSG, what are its advantages, and how does it work?

Glad you asked...

DSG is essentially a sequential manual gearbox in which electronic wizardry takes care of all clutch-related duties. This means it engages and disengages the clutch without the driver’s left leg coming into play.

However, most single-clutch sequential gearboxes have a propensity for clunky shifts at the best of times and aren’t really an ideal alternative to a conventional manual or auto transmission.

The beauty of DSG is that eliminates the lag and clunkiness of other sequential gearboxes by using two clutches -- it’s essentially two three-speed gearboxes with a pair of clutches.

When the driver starts out, transmission No 1 is in first gear and transmission No 2 is in second. The clutch engages and the car starts out in first. When it’s time to change gears, the DSG system instantaneously swaps transmissions.

Meanwhile, the No 1 transmission immediately shifts to third gear. At the next change the DSG swaps transmissions again, and No 2 shifts to fourth. The DSG’s computerised controller calculates the next likely gearchange and shifts the currently unused transmission into that gear.

The real beauty of all this is that the workings are completely invisible to the driver. For all intents and purposes, it functions just like an automatic gearbox -- it can be left to its own devices, or worked manually via steering wheel paddles -- yet it delivers greater efficiency and faster gearchanges.

Expect the system to feature in a number of marques (including Porsche) before the decade is out.