FRANKFURT (Bloomberg) -- Audi plans to double its lineup of SUVs by 2020 to close the sales gap behind BMW as more customers seek high-riding vehicles with the cachet of a luxury brand.

The Volkswagen Group unit is developing the Q2, Q4 and Q6 as a sportier alternative to its current range of three SUVs, according to a person familiar with the strategy, who asked not to be identified because the plans aren't public.

"Audi is really the first with a grand plan to mirror" its car offerings with corresponding SUVs, said Christoph Stuermer, an analyst with researcher IHS Automotive in Frankfurt. "The SUV package, with its high seating position, is similar to those beautiful, upright cars from the 1920s. This could become the normal car in the premium segment."

The push into SUVs, once a quirky add-on for sedan-heavy upscale brands, reflects the expanding definition of a luxury car. Sales of high-end SUVs are forecast to advance 36 percent by 2018, according to IHS Automotive.

The acceptance of SUVs among wealthy consumers has made it one of the fastest-growing segments, fueling a wave of new models as Audi, BMW and Mercedes-Benz vie for the sales lead.

Audi, the world's second-largest luxury-car brand, and No. 3 Mercedes are both seeking to topple BMW as the market leader by the end of the decade.

For Volkswagen, the development of Audi is critical as it aims to become the world's biggest carmaker by 2018. Audi accounted for 48 percent of VW's operating profit in the first nine months of 2012, even though it sold just 14 percent of the group's cars.

Decisive brand

"Audi is decisive for VW," said Juergen Pieper, an analyst with Bankhaus Metzler in Frankfurt. "You could say that Audi's the most important part of VW in terms of profit, technology and branding."

After increasing sales 12 percent to 1.46 million cars last year, Audi's profit may have helped Volkswagen post record profit in 2012. The automaker is expected to report 11.5 billion euros in operating profit, beating the previous year's 11.3 billion euros, according to the average of 14 analyst estimates compiled by Bloomberg.

VW is scheduled to release detailed results for 2012 on March 14. The new offerings mean Audi, which only moved into SUVs in 2005 with the Q7, will have six such models, roughly matching up with its sedan and coupe lineup in a bid to catch up with BMW and keep Mercedes at bay.

Mexican plant

The compact Q2 will be based on the Crosslane Coupe concept car shown at the Paris auto show last year, the person said. The larger Q6 could be built at a new plant in Mexico alongside the mid-sized Q5.

Audi expects the new offerings, along with performance versions of its existing models such as the SQ5, to boost SUVs to about 40 percent of the brand's sales from about 25 percent in 2012, the person said.

"We see a lot of potential in the SUV segment," said Audi Sales and Marketing Chief Luca de Meo. "We're right in the middle of our development," he said, declining to give details of specific model plans.

To keep pace, BMW is developing the X4, which would be its fifth SUV. Mercedes plans to introduce a compact model to add to the GLK, M-Class, GL and G-Class off-roader. The upscale SUV segment is expected to grow to 3 million vehicles in 2018 from 2.2 million last year, according to IHS.

"SUV growth will continue and the manufacturers are reacting to that with new models," said Uwe Lexa, managing director of AVG Rosier, a dealer group that sells Audi, Mercedes, and other brands at 16 locations in northern Germany. SUV buyers "span horsepower fans to moms with small kids."

Fuel economy

Automakers have moved to dilute concerns about the gas-guzzling image of SUVs by adding hybrid versions and cleaner engines. The Audi Q5 uses about 10.2 liters of fuel per 100km (23 U.S: mpg), compared with 9.8 l/100km for the similar-sized A4 sedan.

Audi will reduce the weight of the next generation of the Q7 SUV by as much as 400 kilograms (882 pounds) -- or about 15 percent -- next year to improve fuel efficiency from the current 13 l/100km (18 mpg), the person said.

The brand kicked off 2013 by beating BMW in monthly sales, propelled by a 39 percent jump in deliveries in China, where Audi is the top-selling luxury marque.

Audi sold 111,750 vehicles worldwide in January, a 16 percent increase from a year earlier. Deliveries of the BMW brand rose 12 percent to 107,276 autos.

For the full year, BMW is expected to recover, thanks in part to its lead in SUVs, with the Munich-based carmaker's sales rising to 1.58 million versus Audi's 1.45 million, IHS Automotive predicts.

The researcher expects Audi to drop back to third in 2014 as Mercedes expands with the new SUV, revamps the S-Class luxury sedan, and adds the CLA four-door coupe.

"Product proliferation continues to grow for the premium brands," said Jonathon Poskitt, an analyst with LMC Automotive in Oxford, England. "They're all going after that incremental market share."

Mercedes-Benz USA has announced that it plans to introduce 30 new models to the market in the next seven years.

It will be the biggest growth for the German automaker in the U.S. in its history with the launch of the redesigned S-Class and the new CLA kicking off the product onslaught this year.

As for details on the other models Mercedes plans on redesigning or launching, the German automaker is keeping it vague. What we do know is that Mercedes plans on reinventing and reinvigorating the brand over the next few years, hoping to bring it to new places in the market. Though 30 models may seems like a lot, with the combination of AMG products, we could just be seeing a thorough refresh of its entire lineup in addition to a couple of new models.

“We just had the highest sales year in our history and carried that over to our best January on record. And, according to just released registration data, more customers put a Mercedes-Benz in their driveway last year than any other luxury make,” said Steve Cannon, President and CEO of Mercedes-Benz USA. “We’re going to take this forward with a continuing influx of innovative new products for our current owners and we’ll enter other segments to bring new buyers to the brand.” Cannon estimated that the product offensive would average out to a new vehicle every quarter for the next seven years.”

hell about froze over when PORSCHE launched cayenne, but it's been hugely successful for them.

since big luxury car makers have 6+ sedan types, having as many cuv/suv's doesn't seem out of line.