Don’t expect General Motors Co. vehicles to join the increasing number of automakers shifting to dual-clutch transmissions (DCTs) anytime soon.
Other automakers have been offering DCTs for several years in Europe. But Tom Stephens, who heads the company’s global product operations, tells Wards.com that recent cash constraints make it unlikely GM will meet earlier plans to introduce the technology in 2012.
In a separate roundtable meeting with journalists at this week’s North American International Auto Show in Detroit, Vice Chairman Bob Lutz says only that GM will introduce dual-clutch systems “in due time.”
Cost isn’t the only issue. GM also wants to use a dry-clutch design that is less expensive and lighter than current wet-clutch DCTs. But to date, Lutz points out, dry-clutch designs cannot be used with engines displacing more than about 1.8 liters. GM aims to develop a dry system that can be used with its 2.0- and 2.4-liter four-cylinder engines, but Lutz concedes the company may have to switch to a wet-clutch design.
DCTs, which can be shifted automatically or manually without a foot pedal, allow motorists to achieve almost the same fuel efficiency as a traditional manual gearbox. Until it launches its own DCT, GM will continue to offer six-speed manual systems in its performance vehicles.
Whether wet or dry, a DCT uses one clutch to shift odd-number gears and another clutch to shift the even-number gears and reverse. The clutch not currently engaged is connected to the next pre-selected gear to enable faster shifting.
Volkswagen AG was first to market with a dual-clutch transmission when it debuted a BorgWarner Inc. system in European versions of the Golf R32 and Audi TT seven years ago. Since then, several other suppliers and automakers have developed and launched their own DCTs.
Ford Motor Co., working with Germany’s Getrag GmbH, offers a wet dual-clutch transmission mated to a 2.0-liter diesel in its European Focus car. In North America, Ford will introduce a six-speed dry system in the upcoming Fiesta and Focus small cars.