The dashboard energy monitor of a 2012 Buick Lacrosse, which comes with General Motors' new stop-start feature called eAssist. The system helps power a lithium-ion battery. (General Motors)
The stage is set for a relatively simple and inexpensive fuel-saving technology to proliferate on vehicles in North America.
So-called start-stop systems turn off a car when it is idling and reignite the engine when the driver releases the brake or engages the clutch.
The technology is widespread in Europe and in hybrids, and is poised to expand in the U.S. and Canada in the next five years as automakers look for every tool in the box to meet increasingly stringent fuel-economy and emissions requirements.
Estimates vary, but the consensus is that shutting off the engine at a stop can improve fuel economy as much as 15 percent. And its affordability should make it accessible to the car-buying masses.
Start-stop technology is available in the Porsche Panamera. (Porsche)
"Engineers kill for one-tenth of a mile per gallon," says Joe Phillippi of AutoTrends Consulting Inc. "In city driving, it would make a huge impact."
The technology already is prevalent in Europe on vehicles with manual transmissions. But because it must be adapted to work with automatics -- which account for 90 percent of North American sales -- it has been slower to catch on here.
General Motors is among the first to add the technology to U.S. vehicles. Its system, called eAssist, will be a standard feature on 2012 models of the full-size Buick LaCrosse sedan with a four-cylinder engine; it will be an option on the midsize 2012 Regal.
"We call this a 'light electrified' technology, and it provides a lot of bang for the buck in terms of overall cost compared with full hybrids," says Steve Poulos, chief engineer for eAssist. "It could become our base powertrain."
Behind eAssist
Automakers and suppliers are working on warning systems to reduce incidents of children being forgotten in hot cars.
- GM's eAssist engines are fitted with direct fuel injection, which enables their eye-blink restarts.
- The engine is complemented by a 115-volt lithium-ion battery and a 15-kilowatt motor-generator -- in place of the conventional alternator.
- In addition to fuel savings, the motor-generator of eAssist provides a 15-horsepower boost to the gasoline engine.
- Besides shutting down the engine when the vehicle stops, eAssist also can shut off fuel delivery while the car decelerates under certain conditions, an additional fuel-saving measure.
Poulos says a LaCrosse with the 2.4-liter eAssist engine and a six-speed automatic transmission would achieve 25 mpg in the city and 37 mpg on the highway, a 25 percent improvement over the 2011 model.
Other companies are working to add the feature as well. Ford says it intends to spread stop-start throughout its global product range in the next few years. The company plans to offer the technology as early as 2012 on U.S. vehicles with manual transmissions, says spokesman Richard Truett.
Chrysler offers start-stop in Europe and will introduce it in North America by 2014, according to the automaker's five-year plan.
"To bring it to the U.S. is more challenging to match it with an automatic transmission," says Chrysler powertrain chief Paolo Ferrero.
BMW made the technology standard on vehicles with manual transmissions in Europe, and says it will add the technology to a U.S. vehicle as early as this year. Mazda, Mercedes, Peugeot, Porsche and others are also using it in some European models, with Porsche offering start-stop in the Panamera in the U.S.
Start-stop is a draw because it's low-cost technology. Most of the components already are in the car; they may just need some modification. Suppliers and analysts estimate the cost to add it to be as low as $500.
"The cost will be considerably less than the least-expensive hybrid," Truett says.
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