The 2015 Detroit Auto Show opens next week and so far it's not looking like an especially noteworthy show for green cars.

While Detroit is one of the biggest stops on the global auto-show circuit, there don't seem to be many plug-in electric, hybrid, or other efficient-car debuts lined up.

That doesn't mean there won't be any important green-car news coming out of the Motor City next week. But perhaps it would be best to describe this year's Detroit show as a case of quality over quantity.

As always, we'll be on the ground to bring you live coverage--including updates on any surprise debuts not included in this preview.

Head over to our Detroit Auto Show page for the latest news. In the meantime, here are the significant green cars expected to debut in Detroit so far.

2016 Audi Q7

2016 Audi Q7 e-tron

Unveiled last month, the 2016 Audi Q7 e-tron features a diesel plug-in hybrid powertrain with all-wheel drive, and is part of a redesigned Q7 SUV lineup that sheds around 700 pounds compared to the previous generation.

The e-tron's 3.0-liter V-6 diesel engine and electric motor (integrated into an eight-speed automatic transmission) have a combined output of 373 horsepower and 516 pound-feet of torque.

DON'T MISS: 2016 Audi Q7 To Offer e-Tron Quattro Diesel Plug-In Hybrid Model

Audi says the 17.3-kilowatt-hour lithium-ion battery pack can provide 35 miles of electric range (albeit on the gentle European testing cycle), while both power sources can propel the Q7 e-tron from 0 to 62 mph in 6.0 seconds, and on to a top speed of 140 mph.

The e-tron will go on sale following the launch of the rest of the 2016 Q7 range next year.

Teaser for 2016 Chevrolet Volt

2016 Chevrolet Volt

Easily the biggest green-car news at Detroit will be the unveiling of the 2016 Chevrolet Volt extended-range electric car. Already teased numerous times, the new Volt will retain the compact hatchback layout of the current model, but will feature a long list of powertrain and styling updates.

Those updates include a new 1.5-liter four-cylinder gasoline range extender, a bigger battery pack, and on-demand regenerative braking. The new Volt also features a GPS-based charging-control system, and convenience-focused tweaks like a new charging cord that stows in a dedicated bin in the cargo area.

ALSO SEE: UPDATED: 2016 Chevrolet Volt To Launch In January: What We Know So Far

While overall efficiency will likely increase, the new Volt will probably have the same 38-mile electric-only range as the outgoing version.

Teaser images of the front end show what appears to be a lower nose and some added aerodynamic aids, and the overall shape will likely be a bit sleeker than before.

Since it shares the Volt's platform, an updated version of the Cadillac ELR coupe is also expected soon. However, the luxury brand hasn't confirmed that model for Detroit yet.

2016 Hyundai Sonata Hybrid

2016 Hyundai Sonata Hybrid

The 2016 Hyundai Sonata Hybrid was unveiled last month in Korea. It gets the same restyled body introduced on the rest of the Sonata lineup for the 2015 model year, and an upgraded powertrain.

The current model's 2.4-liter Atkinson-cycle four-cylinder engine is replaced by a 2.0-liter direct-injected four, along with an updated six-speed automatic transmission.

Hyundai also says it's improved the hybrid's battery pack--making it 13 percent lighter while adding more storage capacity.

RELATED: New Hyundai Sonata Hybrid Unveiled In Korea; U.S. Sales In 2016?

While there are some hybrid-specific changes, styling remains fairly close to the standard gasoline Sonata--much more so than the previous-generation model.

The Sonata Hybrid is expected to be joined shortly after launch by a plug-in hybrid version, which Hyundai will also discuss in Detroit.

The Korean automaker will also provide details of an ambitious green-car strategy intended to make it--and partner Kia--the number two producer of green cars by 2020.

That strategy will include Hyundai's first dedicated hybrid model, as well as additional plug-in electric cars.

Audi R8 e-tron track drive, Berlin Tempelhof Airport

Audi R8 e-tron

This is still more than a bit speculative, but it has been suggested that Audi will unveil the second generation of its R8 supercar this year--and one journalist claims it was confirmed to him for the Detroit Auto Show. (We're at least somewhat skeptical.)

If so, previous reports suggest an all-electric e-tron model will finally join the lineup.

MORE: Audi Confirms Electric R8 e-Tron, Also 280-Mile Family Electric Car In 2017

The e-tron has been in development limbo for years, but Audi technical chief Ulrich Hackenberg has said it will see production, perhaps sporting a 250-mile range.

That's a significant improvement over the 130 miles of the first prototype cars.

A plug-in hybrid version is also reportedly under consideration, although its unclear if it would also get "e-tron" badging.

The R8 e-tron could also lay the groundwork for an electric Audi "family car" with 280 miles of range--a vehicle that would appear to have the Tesla Model S (or Model X) in its sights.

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