* EPA deems C-Max plug-in more efficient than Prius
* Ford eyes "optimizers" to drive C-Max sales
* Winglets boost C-Max fuel efficiency
By Deepa Seetharaman
DETROIT, Oct 11 (Reuters) - Ford Motor Co , vying to challenge Toyota Motor Corp's dominance in the hybrid market, said on Thursday that its 2013 C-Max Energi plug-in hybrid gets 100 miles per gallon, beating the 2012 Prius by about 5 percent.
The mileage rating given by the U.S. Environmental Protection Agency means the C-Max plug-in's fuel efficiency both in the city and on the highway is five miles better than the Toyota Prius plug-in and two miles ahead of General Motors Co's 2013 Chevrolet Volt .
Ford, the second-largest U.S. automaker, has been vocal in its desire to take on Toyota, which has had a stronghold over the hybrid market for more than a decade with the Prius.
Last year, the Prius made up 54 percent of U.S. sales of alternative powertrain vehicles, according to market research firm Strategic Vision. Ten other brands divided the rest.
Still far more people consider green cars than buy them, experts say. Ford aims to attract U.S. buyers by offering more power, space and efficiency than the Prius at a lower cost with its hybrid-only C-Max nameplate.
Internally, Ford calls potential C-Max buyers "optimizers," said Michael O'Brien, Ford's electrification marketing manager.
"They're looking for their dollar to go as far as possible and as smart a way as possible," O'Brien said in an interview. "The notion of having MPGe (miles per gallon equivalent) that's best in class is a terrific advantage."
Ford did not provide an estimate for the size of this group, but O'Brien said Ford's emphasis on improving fuel economy and lower costs in recent years has piqued their interest.
"Five years ago, the optimizers may not have even had us on their radar screen," O'Brien said.
Toyota's missteps over the last few years with a series of recalls also provide a boost for Ford, said Alexander Edwards, president of Strategic Vision. "Toyota buyers are not destined to be Toyota buyers anymore," he said.
Ford recently began selling the C-Max hybrid and the Energi goes on sale later this year. A plug-in version of the Fusion midsize sedan will go on sale in 2013.
To beat the Prius on fuel economy, Ford engineers used a lithium-ion battery instead of a heavier, but less expensive, nickel-metal hydride battery. Ford offset the higher cost partly by assembling those batteries and transmissions in house.
Designers also sought to eke out gains through small changes to the C-Max's European design. For example, Ford added "winglets" to the rear corners of the C-Max to improve aerodynamics, John Davis, the chief C-Max engineer, said.
The plug-in versions of the C-Max and Fusion share powertrain technology. Ford also uses the same primary engine, a similar transmission and method for mounting the battery pack in both the C-Max plug-in and hybrids.
Keeping engineering costs low was crucial for the C-Max, which also seeks to beat the Prius on price. The C-Max plug-in hybrid, which sells for nearly $30,000 after a federal tax credit, compared to Toyota's Prius plug-in, which costs $32,000.
Strategic Vision estimates that nearly 20 percent of vehicle owners are considering a hybrid and 12 percent are researching plug-in hybrids. But advanced powertrain vehicles have accounted for just 2 percent of U.S. auto sales during the first nine months of this year, Edmunds.com said.
Higher prices, a lack of charging infrastructure and fewer features have stymied demand for green cars, experts say. The average annual income of people who buy the Prius is around $98,000, according to Strategic Vision. But incomes for those who consider, but do not buy, the Prius is about $85,000.
"The clear difference comes down to price," Edwards said.
(Reporting By Deepa Seetharaman; Editing by Matt Driskill)
Keywords: FORD CMAX/