The gasoline-powered engines of many gas-electric hybrids turn off when the vehicles stop -- at a traffic light, for example -- and then instantly restart when the driver accelerates. This feature helps hybrids achieve some of the eye-popping fuel economy figures that well exceed those passenger cars powered by conventional gasoline engines.
Ford Motor (F) currently sells two hybrid models -- the Fusion sedan and Escape compact SUV -- that use start-stop technology. But the auto giant said Monday it plans to extend the feature to conventional gasoline-powered passenger cars and SUVs sold in North America by 2012, as it seeks ways to boost its corporate average fuel-economy (CAFE) rating.
Cycling conventional gasoline engines on and off can improve fuel economy by 4% to 10%, depending on driving habits, and vehicle size and usage, Ford said. The technology works the same way as it does on hybrid vehicles, seamlessly stopping and starting the engine as needed, and requires no changes in driving behavior. In city driving, when the vehicle is stopped, the engine restarts as soon as the driver's foot leaves the brake pedal. When the engine is off, all of the vehicle's accessories function normally, Ford said.
"Extra Fuel Efficiency Without Inconvenience"
"For the driver, [the technology] provides extra fuel efficiency without inconvenience, as it works completely automatically," said Barb Samardzich, Ford vice president of powertrain engineering. "And, just like in our hybrid vehicles, the heater and air conditioner work as normal so drivers will not sacrifice comfort."
Auto start-stop is just one of several recently introduced technologies Ford and other automakers have deployed in recent years, which also include electric-power steering and six-speed automatic transmissions. The new technology is aimed at boosting fuel economy to meet new federal standards unveiled by the Obama administration earlier this year and taking effect beginning in 2012.
The standard requires that manufacturers achieve a corporate average fuel economy rating of 35.5 mpg by 2016, up from the current 27.5 mpg, across automakers' car and truck fleets. The legislation is expected to save 1.8 billion barrels of oil over the life of cars and trucks sold between the 2012 and 2016 model years through improved efficiency, in addition to reducing greenhouse gas emissions.
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