Various makers use different names for the technology, including micro-hybrids and idle-stop. But industry experts agree that whatever it's called, the system could be critical for manufacturers hoping to meet the tough new U.S. fuel economy standards of 35.5 mpg taking effect in 2016, and then jumping to 54.5 mpg by 2025.
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The exact payoff from using the technology is a matter of debate. Manufacturers quote numbers ranging anywhere from 2 percent to 5 percent savings. Motorists will likely see a big difference depending upon how and where they drive, as stop-start is most effective when a vehicle is driven in urban settings where it is likely to be idled more frequently.
"The whole auto industry is moving to start-stop to improve fuel economy," said Dave Sargent, vice president of J.D. Power and Associate's automotive research group, though he did note "there's some risk" to using the technology.
It adds to a vehicle's cost, for one thing, especially the more sophisticated versions that are likely to be the most transparent to a motorist. Manufacturers have been struggling to find ways to reduce costs, but that can create problems. BMW, for example, has been faulted for the stop-start system on several models, such as the 3-Series, because of its roughness and the starter-like whine when the engine fires back up.
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General Motors is another maker that expects to rapidly expand the use of the technology, introducing it on the 2014 update of its Chevrolet Malibu. The technology is a simpler and lower-cost version of what's already available on several GM hybrids, though "there's no sacrifice in drivability," contended Todd Pawlik, the chief engineer on the Malibu program.
American motorists are just beginning to see stop-start technology roll out, and on many models, such as the Porsche Panamera, they can hit a switch to shut it off. But as fuel costs rise and mileage standards increase, experts anticipate it will become nearly as commonplace as in Europe, where fuel now runs as high as $9 a gallon and stop-start is already found on 45 percent of the latest models.
—By CNBC Contributor Paul A. Eisenstein. Follow him on Twitter @DetroitBureau or at thedetroitbureau.com.