Alfa Romeo Giulietta TCT
Detail optimisation makes the difference in Alfa’s C-car dual-clutch transmission application, not the number of gears. Comfort goes up; fuel consumption goes down
- Published in Vehicle Development.
White hot: Two clutches make the Giulietta quicker
Think Alfa Romeo and it may bring to mind wailing V6 engines redlined in every gear by drivers keen to get from point to point as quickly – and as stylishly – as possible. And the cars would, of course, all be red ones.
But the reality is a little different. Like most other brands, the majority of Alfas sold in Europe are diesel – the 156 sedan was, after all, the world’s first passenger car with a commonrail engine – and most have only four cylinders.
And volume is much more important than niches – in particular, the C-segment which defines the European market. Since its launch in 2010, the Alfa Giulietta has become the brand’s most successful hatchback model, and white – not red – is the most popular colour; 35% versus 6%.
Now consumers have the option of a dual-clutch transmission (DCT). Designed by Fiat Powertrain, it first appeared in the smaller Alfa MiTo, and has been further developed for the Giulietta. Europe is still dominated by manuals but two-pedal transmissions are gaining in popularity. OEMs including Volkswagen, Ford, Volvo and Renault already offer DCTs in their C-segment products.
But not being first to market has advantages – the opportunity to benchmark and to learn, just as other OEMs did with the Alfa 156’s diesels and its automated manual transmission.
“The introduction of DCTs is a benefit for the industry so the more we do all together to promote this technology, the more we all have,” says Constantinos Vafidis, Fiat Powertrain’s director of transmissions and hybrids. “It’s like commonrail – you don't have to keep it a secret. You have to spread it so that technology takes hold and is better exploited.”
The transmission is, mechanically, much the same as it is in the MiTo – a six-speed dry-clutch unit – but control and calibration have been adapted for the bigger, heavier Giulietta application, and to suit the higher ratings: the 2.0 diesel, not available in the MiTo, develops more torque – up to 350Nm.
Evolution of any technology tends to be asymptotic – over time the potential left decreases and the effort goes up, but Vafidis says that you always keep going: “The more you do, the more you expect it to do. There’s no breakthrough, so at this stage of refinement you need to go into details.
Wide ratio spread and better control make this dual-clutch transmission more efficient
