Honda watchers counting on a restyled 2013 Accord to reignite the Japanese automaker's sales spark in the United States may be disappointed by the first spy images emerging of the sedan.

Photographs captured this week show the mid-sized sedan with only evolutionary changes from its previous design. In a segment that will be filled with several bold redesigns by next spring -- the Toyota Camry, Volkswagen Passat, Nissan Altima, Chevrolet Malibu, Ford Fusion and Mazda6 -- the Accord could find itself fighting for a seat at the head of the table.

In engineering the new Accord, Honda executives say they learned their lesson when they removed too much content on the redesigned 2012 Civic.

"You're going to find that Accord is a very well-balanced product that is the best overall product in everything, whether we're talking about interior packaging, content of the vehicle, the fuel economy of the vehicle," Erik Berkman, head of research and development for Honda Americas, told Bloomberg News in a recent interview.

It "will be one of the most feature-rich vehicles we've ever made," Berkman added, without elaborating.

The new Accord is expected to go on sale early this fall.

A merely evolutionary design change to the Accord could spell trouble when the competition is making huge jumps in styling, especially the Ford Fusion with its Aston Martin-like lines.

Hyundai and Kia have also gained ground in the U.S. market with radically designed mid-sized sedans.

The 2013 Accord is the last of four core models Honda will introduce over a 24-month period. An all-new Odyssey minivan went on sale in late 2010, followed by the new Civic compact last spring and the revamped CR-V in late 2011.

The four models accounted for nearly 80 percent of the Honda brand's U.S. sales last year.

Accord sales last year fell to 235,625 units, representing a 17 percent decline, although a big chunk of the decline was tied to earthquake-related parts shortages.

But it's still a long way from previous years when the Accord produced annual sales of nearly 400,000 units.

Last year, the rival Nissan Altima became the second-best selling car in the United States after the Toyota Camry.

So far in 2012, the Accord is the fourth best-selling car in America, after the Camry, Altima and Honda Civic.

The revamped Accord will feature Honda's new "Earth Dreams" family of engines and related technology, including continuously variable transmissions, the automaker's first such powertrain change in a decade.

Honda previously used CVTs only on small cars made in Japan.

Starting with the 2013 Accord, the new transmission, with an infinite number of gear ratios, will replace the current five-speed automatic to aid fuel-economy and performance.

The CVT will be the only automatic offered in the Accord four-cylinder, but the V-6 will come with a traditional geared transmission.

The engine line, with displacement ranges from 660 cubic centimeters to 3.5 liters, is being added to every new Honda model starting with the Accord.

Mark Rechtin and Bloomberg News contributed to this report