DETROIT -- Mention Nissan to most car drivers and they think of the Altima, and not much else.

The sedan is America's second-best selling car and Nissan's top seller by far. When the new version goes on sale in July, it will likely be a hit.

But Nissan's other models -- such as the Sentra small car and the boxy Cube -- are struggling to win buyers, even as auto sales surge. They're old, inefficient, or just plain odd. And their designs are inconsistent, which keeps customers from sticking with the brand when they move up or down a car size. That's making it hard for Nissan to hang on to customers or woo new ones in the U.S.

Nissan is hoping to win over U.S. buyers with some new models in key segments. In addition to the Altima, Nissan will roll out new versions of the Versa hatchback, Sentra, and Pathfinder and Rogue SUVs over the next 15 months. The company promises more emphasis on fuel economy, more luxurious interiors, handsome and consistent styling and updated dashboard technology. The new Pathfinder, for example, will be lighter and nimbler, which will improve fuel economy and make it a smoother ride.

The new vehicles should help Nissan step out of the shadow of its Japanese competitors, Toyota and Honda, who have outsold Nissan in the U.S. nearly every year since the late 1980s. Toyota commanded a 14 percent share of the U.S. market in the first three months of this year, compared with 9 percent for Nissan. Nissan outsold Honda by 2,000 cars in that time, but to do that it resorted to some of its worst habits, including high incentive spending and low-profit sales to rental fleets.

Nissan lost U.S. customers in the 1990s, when it was faltering financially and producing bland cars. CEO Carlos Ghosn brought the company back to profitability in the early 2000s, after joining forces with French carmaker Renault in 1999 and embarking on a multi-year restructuring. Ghosn's feat is so celebrated in Japan that he is the hero of a comic book series there.

The profits have let Nissan invest in innovative products like the Nissan Leaf, which was the first all-electric car sold in the U.S., and the Murano CrossCabriolet, which is the only convertible SUV on the market.

But Ghosn wants more. He says Nissan's improved quality and broad lineup justifies a 10-percent share of the U.S. market. That would require Nissan to sell up to 400,000 more cars and trucks than the 1 million it sold last year. Increasing U.S. sales is part of Ghosn's plan to command 8 percent of worldwide market share by 2016, up from 6 percent in 2011. The current leader, General Motors, holds an 11.9 percent share.

More marketing will help. One of the highest-profile efforts will be the opening next month of a seven-story Nissan and Infiniti dealership in San Francisco, which was designed as a regional hub for people interested in the Leaf and future electric cars.

The new products will also help. The Altima is expected to get 38 miles per gallon on the highway, up 20 percent from the old model and the best fuel economy of any gas-powered midsize car.