Renault plans DCT
French automaker Renault, already one of Europe's top performers in terms of emissions
and CO2 reduction, has committed itself to becoming the top environmental brand
in the market. The brand "is now setting its sights on moving to the top of the order," said Renault
in a statement last month (February).
As well as an "unprecedented commitment" to the development of electric motors, Renault also stated that it would introduce as many effective technologies as possible at an affordable price in the sphere of conventional engines.
In an unusually revealing move the company has publicly divulged its powertrain strategy for the next three to four years, when Euro 5 and Euro 6 emissions regulations will come into force. Included for the first time in the strategy are dual clutch transmissions: this is a significant step as with the launch of the new-generation Mégane sports hatch and coupé last year Renault had indicated a preference for the CVT technology used by its partner Nissan, which owns a significant stake in transmissions supplier Jatco that providers units to both companies.
Renault says that during the course of next year it will "be in a position to release" a new seven-speed twin-clutch gearbox combining exemplary gearshift quality with lower CO2 emissions for the same fuel consumption as that of a manual gearbox – or 15 percent less than that of a conventional automatic transmission.
"Conventional automatic transmissions tend to place the emphasis on gearshift quality rather than fuel consumption," says the company. "The development of new automatic transmissions sees Renault pursue two objectives: improved mechanical efficiency compared to that of a conventional torque converter automatic transmission (thanks to technologies carried over from manual gearboxes), and the ability of automatic transmissions to permit an engine to run at the most energy-efficient revs with a view to obtaining fuel consumption performance on a par with that of manual gearboxes. Twin-clutch transmissions also offer ride comfort, with no jarring during gearshifts and no loss of traction, says the automaker."
Renault did not say who would be the supplier of the twin-clutch transmissions, nor did it state production volumes or which models in the range the DCT transmissions would be fitted to.
On the engine side, Renault says electric powertrains between 50 and 100kW will power everything from small city cars to big vans and will appear in 2011: Renault intends to become the leader in battery vehicles.
Euro 6 standards will mean costly aftertreatment systems for diesel engines, making downsized gasoline engines more attractive. From 2012 modular three and four cylinder units from 0.9 to 1.2 liters will replace current 1.2 to 1.6 liter engines; many will be turbocharged and with direct injection, while some will give over 115 hp and others less than 100 g/km CO2 emissions.
In-depth modifications to Renault's best-selling engine, the 1.5 liter dCi diesel, will see its emissions drop by 25 g/km by 2011 compared with the already good current unit; this will be the main powerplant for Mégane-sized models and vans, while larger vans will downsize from 2.5 to 2.3 liters. In 2012 a new-generation 2.0 dCi will be launched, says the company.
Story Filed: 3/9/2009
By Tony Lewin, managing editor DCTfacts.com