Ford Motor Co. said Monday that it plans to include its fuel-saving Auto Start-Stop technology — originally designed for and used in its gas-electric hybrid — in a wider range of vehicles sold in North America starting in 2012.

The technology automatically shuts off the engine when a vehicle stops, which Ford says improves fuel economy at least 4 percent. A light on the dashboard confirms that the engine is off, but all accessories like heat and air conditioning remain on, and drivers don't have to change their behavior for the technology to work.

Ford says the system, already used in the Fusion Hybrid and Escape Hybrid in the U.S. and in some Ford cards sold in Europe, doesn't require additional maintenance.

The company plans to install it in cars, crossovers and sports utility vehicles sold in North America starting in 2012. Eventually, Ford will install the technology in vehicles sold worldwide.

Ford said that in 2011 it will be the only auto maker in North America offering four vehicles that get 40 miles per gallon or more. Those vehicles are the Ford Fiesta, Ford Focus, Ford Fusion and Lincoln MKZ Hybrid.

Ford's other energy-saving technologies including two kinds of energy-efficient engines; electric power steering, as opposed to hydraulic; six-speed transmissions, which select the best gear for the fuel economy; and dual-clutch automatic transmission, which efficiently sends the engine's power through the transmission.

Shares of the Dearborn, Mich. company fell 12 cents to $16.66 in morning trading.