FRANKFURT -- Audi's best-selling model, the A4, is getting a significant makeover whose success will play a key part in the automaker's goal to topple BMW as the top-selling luxury brand globally and fend off a growing challenge from a resurgent Mercedes-Benz.
The redesigned A4, a rival to the BMW 3 series and Mercedes C class, is slightly larger than the current model with a bigger, revamped interior.
It retains conservative styling to appeal to business fleet customers whose purchase choices are based more on rational than emotional decisions.
The A4 will be offered with three gasoline and four diesel engine choices in Europe, ranging from 150 hp to 272 hp. The most efficient engine is a 150-hp, 2.0-liter diesel.
Engine details for the U.S. market are still being finalized but Audi will make available a diesel variant for the first time in the A4, a spokeswoman for Audi of America said. An updated 2.0-liter TFSI engine will also be offered in the U.S., Audi says.
The A4 is the second Audi after the Q7 large SUV to adopt Volkswagen Group's second-generation MLB modular architecture. The A4 has the best drag coefficient in its class at 0.23, Audi said in a statement.
It is up to 265 pounds lighter than the current car despite growing in length to nearly 15.5 feet. Its wheelbase has been widened to 9.3 feet, boosting cabin space and rear passenger legroom.
Fuel consumption, reflecting improved aerodynamics and lighter weight, will fall as much as 21 percent while performance output will increase by 25 percent, Audi said.
The new A4 offers Audi’s fully digital instrument cluster dubbed a “virtual cockpit” as an option. It has a 12.3-inch liquid crystal display. Additionally the top-end infotainment system, MMI Navigation plus, offers a high-speed LTE connection, Wi-Fi hotspot and an 8.3-inch screen with a new voice-control system.
Soon after launch, customers will be able to order a detachable Audi tablet for rear seat entertainment or navigation. The Android-based device has a high-resolution 10.1 inch display and connects to MMI Navigation plus through the car’s Wi-Fi.
Audi claims the A4's handling has dramatically improved with re-engineered, forged aluminum five-link front and rear axles and all-new electromechanical power steering. For the first time, adjustable shock absorbers and variable damping will allow drivers to select between two suspension settings -- sport or comfort. Audi said the feature will be standard on models with 190 horsepower and more.
Starting in late 2016, Audi plans to offer an A4 Avant g-tron variant that can run either on natural gas or the brand’s own sustainably produced e-gas, the second such model after the A3 Sportback g-tron. A plug-in hybrid version is also expected, although not confirmed by Audi.
Pricing for the new A4 has not been released.
The A4 is the last Audi model styled by Wolfgang Egger, who moved to Italdesign Giugario in early 2014. It will go on sale shortly after its public debut at the Frankfurt auto show in September.
U.S. deliveries of the redesigned 2017 Audi A4 will begin in the second quarter of 2016, the company said.
Audi sold 327,500 units of the A4 sedan, Avant station wagon and A4 allroad quattro worldwide last year, down just 3.8 percent even though the model is approaching the end of its life cycle. That means nearly one out of every five Audis sold in 2014 was an A4.
In the U.S., A4 sales fell 24 percent to 10,684 units through May.
BMW generated 480,000 deliveries of the 3 series, which is the best-selling premium midsize car globally.
Audi is spending 24 billion euros on technology and production in the next five years as it seeks to topple BMW from the No. 1 spot in the luxury-car market by 2020, an ambition also shared by current No. 3 Mercedes. Audi ranked No. 2 in luxury sales last year.
BMW remained the luxury leader in the first five months of 2015 with global sales of 759,609, an increase of 5.2 percent. Audi's volume rose 4.3 percent to 744,900, while Mercedes, boosted by new products, saw deliveries increase by 14 percent to 728,809.
Ryan Beene contributed to this report.