How a dual clutch works
We’ve been talking quite a bit about dual-clutch gearboxes lately, especially when it comes to the higher end spectrum of motor vehicles, so we thought it about time to talk a bit about why they are becoming so widespread and how they actually work.
Porsche and Audi have been using the technology in their racecars since the 1980s, but it was only introduced in the road car considerably more recently, in 2003 by Volkswagen in the Golf R32.
The industry-wide move towards fuel efficiency has brought dual clutch gearboxes to the forefront thanks to their fast changes and superior fuel efficiency, nowadays being installed in a wide range of models from the likes of the Porsche 911 Turbo to the Ford Focus. Mitsubishi Fuso has also been using a dual clutch shifter for their Canter light truck range.
Porsche prefers dual clutch transmissions for their super fast pace shifts, while Volkswagen are much more interested in their improved fuel economy.
As far as differences between this and other technologies go, we should mention that a dual clutch transmission isn’t a regular automatic because there is no torque convertor to slur the gear change; it’s a special kind of manual transmission but with two automated clutches.
The major benefit of the technology is that the dual clutch system can select the next gear before releasing the current one, which means that there is no detectable interruption in power delivery; the absence of a torque convertor also means that far less fuel is used than a traditional automatic would.
How it’s actually made
The gears aren’t all located on a single shaft, they are instead spread across two in a dual clutch gearbox which means that you can select two gear at the same time.
One shaft houses three or four gears: 1, 3, 5, and occasionally 7, while the other houses the others: 2, 4, 6 and Reverse.
The two clutches are located at the front of the gearbox, one nestled behind the other, while one clutch is engaged the other one spins freely.
The transmission takes information from the engine computer and determines which gear should be selected next. For instance, if revs are rising it will select a higher gear, now obviously it doesn’t always predict the right gear and this can cause some problems with changes in stop-start conditions.
The feature that you will find most noticeable when driving a car with a dual clutch system is that there is no clutch pedal in the cabin because the clutches are controlled by electro-hydraulic actuators.
