When Fuel Economy Matters, Hyundai Chooses Dual-Clutch Transmissions over CVTs

By Jacob Brown | October 31, 2012
There's a growing debate among automakers over how to eke out more and more miles per gallon. Until some new engine breakthrough comes out, they'll be stuck refining their transmission options. Not too long ago, four-speed automatic were par for the course; now six, seven, and eight speeds are commonplace. Chrysler is coming out with a nine-speed auto for its next midsize sedans, and there's rumor of Hyundai even making a 10-speed for its next fleet of luxury cars. But then there are companies like Nissan and Subaru that are bucking the trend with continuously variable automatics. Essentially, they work like a rubber band being pulled across a cone. When there needs to be more low-end power, the metal belt that connects the transmission and engine pulleys goes to the small end of the cone to get the most direct power from the engine. When it's cruising on the highway, the engine doesn't need as much power, so the belt travels to the large end of the cone for higher speeds without the duress. It's a compact design that can house a wider ratio for which the transmission to follow, from bottom to top, allowing the engine to work more efficiently. The problem with it is that up until recently with the V-6-powered Nissans on which it's now employed, a CVT hasn't been able to handle that kind of force from the engine. Also, there are parasitic losses stemming from the friction of the band moving up and down the cone. A solution, which Hyundai believes is better, is the dual-clutch gearbox, which essentially mimics the fast-acting efficiency of a manual transmission, but it's completely automatic. There are two clutches to ensure quick, smooth shifting in theory—one for the even gears and one for the odd ones—but it's not been implemented too smoothly by any automaker outside Volkswagen/Audi and high-price automakers like Porsche. "Dual-clutch has a better future with us. It has better fuel-economy advantages. It's better for the enthusiast driver. It matches [our product philosophy] better," said Mike O'Brien, the vice president of product planning for Hyundai North America in an interview with Automotive News. Already, Hyundai has implemented its first dual-clutch setup in the Veloster, but it opted to go with a conventional automatic transmission for the turbocharged version of the car, better able to cope with the added 63 horsepower. Still, Hyundai has hinted at a future portfolio shod with dual-clutch transmission options. As of late, the only other mainstream automaker to dabble with dual-clutch setups has been Ford with the Focus and Fiesta. Both cars' automatics have been lambasted—including by us—for jerky shifts, despite their efficiencies. Will Hyundai be able to reverse the course and make a smooth-shifting dual-clutch transmission? It'll have to if it wants to keep moving forward in the precarious game of ever-farther-reaching fuel economy numbers. Source: Automotive News (Subscription required)