DETROIT — The past few years have seen auto manufacturers stratify their brands to the high and low ends of the market. The disappearance of mid-market brands such as Oldsmobile and Mercury has left a hole that is being filled at the low-end by well-equipped midsize cars, which top out in the low $30,000 range, and on the high end by compact luxury vehicles, which start at or below that threshold.

In addition, luxury automakers are adding compact luxury SUVs at the bottom of their lineup to bolster fuel economy in the face of stiffening EPA fuel economy regulations. Many of these vehicles price close to those of lesser brands.

This is one of the key trends seen at this year’s North American International Auto Show, which runs through Sunday in Detroit.

Here’s what’s coming in this hotly contested part of the market.

—BMW 3 Series: The sixth-generation 3 Series — BMW’s most popular model — goes on sale next month as the 328i with a 240-hp twin-turbocharged four-cylinder and the 335i with a 300-hp six-cylinder engine with a six-speed manual or eight-speed automatic transmission. Look for a 335-hp hybrid that returns 37 mpg later in the year.

—Cadillac ATS: Cadillac is challenging the Mercedes-Benz C Class, Audi A4 and BMW 3 Series with the compact ATS. Engines include a new 270-hp, 2.0-liter turbocharged four-cylinder, a 200-hp 2.5-liter four-cylinder, and a 320-hp 3.6-liter V6 engine mated to a six-speed manual or automatic transmission. Both rear-wheel- and all-wheel-drive will be offered. It goes on sale later this year.

—Acura ILX: This luxury compact is scheduled to replace the Acura TSX in the spring. The new sedan is based on the Civic platform and will come with a 2.0-liter inline 4-cylinder engine; a high-performance model with a 2.4-liter inline 4-cylinder engine paired with a six-speed manual transmission; or a 1.5-liter gasoline-electric hybrid powertrain, Acura’s first-ever hybrid.

—Lincoln MKZ: Lincoln’s front-drive concept previews the next midsize MKZ sedan. A more refined interpretation of the split-wing grille, introduced on the 1938 Lincoln Zephyr, fronts a sweeping roofline that gives the MKZ a more sporting athletic look. The interior features include push-button transmission, which frees up space on the center console. Look for front-wheel-drive and all-wheel-drive configurations.

—Ford Fusion: The 2013 boasts a stunning new shape and a host of new safety systems, such as lane monitoring and adaptive cruise control. Two four-cylinder engines will be offered that deliver up to 37 mpg. The standard hybrid model is anticipated to deliver fuel economy of 47 mpg, while the Fusion’s plug-in hybrid, the Energi, is expected to return more than 100 mpg equivalent.

—Honda Accord Coupe Concept: This previews styling direction of the 2013 Accord, which will offer three all-new powertrains: a 181-hp 2.4-liter four-cylinder engine, a 3.5-liter SOHC V6 or a gas-electric plug-in hybrid with an all-electric range of approximately 10-15 miles in city driving up to 62 mph. Fully recharging the battery will take less than four hours using a 120-volt outlet.

—Audi A4 allroad quattro: Audi’s luxury wagon returns for 2013 riding atop the A4 platform. Audi’s familiar 211-hp turbocharged 2.0-liter four-cylinder engine, eight-speed automatic and quattro all-wheel drive is under the hood. The new allroad has 27 cubic feet of cargo space, 50 cubic feet of cargo space with the seats folded down. An optional power tailgate is available.

—Acura RDX: The second generation of Acura’s five-passenger crossover SUV, the 2013 Acura RDX, benefits from cleaner, more refined styling. A 3.5-liter V-6 engine produces 273 horsepower — 33 more than the 2012 model’s four-cylinder engine. A six-speed automatic transmission is standard. Both front-wheel- and all-wheel-drive models will be offered.

—Audi Q3 Vail: This compact crossover concept would slot below the midsize Q5 in Audi’s line-up and serve as its entry-level SUV. The Q3 Vail is powered by a 2.5-liter five-cylinder turbocharged engine developing 314 hp and employs quattro all-wheel drive. However, its stubby length and tall ride height is reminiscent of a potato topped with ski racks.

—Buick Encore: Looking to compete with the Audi A3 and the BMW X1 (which isn’t sold in the U.S.), the 2013 Buick Encore 18.8 cubic feet of cargo space; 48.4 cubic feet of cargo space with the seats folded down. A 140-hp 1.4-liter turbocharged four-cylinder engine and six-speed automatic transmission are standard. Unlike the larger Buick Enclave, the Encore has no Chevrolet equivalent.

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