Autumn is here, and so is auto-show season.

The 2014 Paris Motor Show this week kicked off the annual global parade of new production cars and concepts, and several notable green cars made their debuts.

They include both concept and production models with hybrid, plug-in electric, and diesel powertrains.

Demonstrating the breadth of green-car technology--and carmakers' need to meet tightening global emissions standards--those powertrains would be found in everything from luxury sedans to small utility vehicles.

All of the significant debuts are listed here. For complete coverage, visit our Paris Motor Show page.

Citroen Cactus Airflow 2L Concept, 2014 Paris Motor Show Citroen C4 CactusAIRFLOW 2L concept

This quirky French utility vehicle uses compressed air instead of electricity in its hybrid system.

PSA Peugeot Citroën has been experimenting with compressed-air hybrids, and applied the technology to the Citroen C4 Cactus, a vehicle somewhere between a wagon and a crossover, one with funky "Airbumps" on its sides meant to lessen parking-lot dings.

The Airflow concept's powertrain marries a 1.2-liter three-cylinder engine that powers the front wheels with a hydraulic pump/motor that operates from compressed air stored in two high-pressure tanks under the rear load deck.

The Cactus can operate on gasoline only, compressed air only (at low speeds) or both, and Citroën estimates a 30-percent reduction in overall fuel consumption.

While the compressed-air hybrid Cactus itself isn't slated for production right now, PSA plans to introduce the system on a subcompact vehicle during 2016.



Updated Ford C-Max (European market) for 2015, shown at 2014 Paris Motor Show 2016 Ford C-Max

The European version of the Ford C-Max debuted in Paris with revised styling and feature updates.

It now features a sleek front end that matches the faces of the Focus and Fiesta, as well as a full suite of electronic driver aids, including Active Park Assist, Perpendicular Parking, and Cross-Traffic Alert.

While it's only offered as a Hybrid and Energi plug-in hybrid in the U.S., the European C-Max is offered with conventional gasoline and diesel engines as well, and as the longer 7-seat Grand C-Max.

Those models will remain for Europe only, but versions of the C-Max Hybrid and C-Max Energi with similar updates are expected to arrive here next spring, likely as 2016 models.



Infiniti Q80 Inspiration concept, 2014 Paris Auto Show Infiniti Q80 Inspiration concept

This rakish four-door hatchback previews a future flagship luxury model from Infiniti, but also features a hybrid powertrain. A 3.0-liter twin-turbocharged V-6 is paired with an electric motor, and the combination produces 550 hp and 553 lb-ft of torque.

A production car with some of the concept's styling will likely appear in a few years, while the hybrid system could represent an evolution of the one currently used in the Q50 and Q70 sedans.

2017 Jaguar XE 2017 Jaguar XE diesel

The Jaguar XE won't arrive in the U.S. for two years, but Jaguar released more details on the aluminum-bodied small luxury sedan in Paris.

Base models will be offered with a 163-hp 2.0-liter turbodiesel four-cylinder engine from the new Ingenium family--giving Jaguar a competitor to the BMW 328d--while an expanded engine lineup will follow.

Buyers will also get to choose between rear-wheel drive and all-wheel drive.

Content could change significantly before the XE becomes available in the U.S., but with diesel power and a lightweight aluminum chassis, it could be Jaguar's most fuel-efficient production car to date.

Mitsubishi Outlander PHEV Concept-S, 2014 Paris Auto Show 2016 Mitsubishi Outlander Plug-In Hybrid (PHEV Concept-S)

While Mitsubishi calls this a concept, what you're looking at is most likely the facelifted 2016 Outlander Plug-In Hybrid that is expected to go on sale in the U.S. in the fall of 2015.

The Outlander Plug-In Hybrid has been on sale in Europe and Asia for almost two years, but multiple delays have kept it out of the U.S.

When it finally does arrive here, the plug-in crossover will likely feature the revised styling seen on this show vehicle, which will be a nice change of pace from the rather boring current version.



Renault Eolab Concept for future plug-in hybrid vehicle, 2014 Paris Motor Show Renault Eolab concept

This plug-in hybrid concept somewhat resembles a sleeker Toyota Prius C, but has three doors like a Hyundai Veloster. Its powertrain consists of a 67-hp electric motor that produces 150 lb-ft of torque--and is powered by a 6.7-kWh lithium-ion battery pack--paired with a 1.0-liter three-cylinder engine with output of 75 hp and 75 lb-ft.

Designers also focused on saving weight, employing light materials--including a magnesium roof panel that weighs just 9 pounds--to cut 880 pounds compared to an average vehicle, according to Renault.

While Renault hasn't sold cars in the U.S. in almost 30 years, the Eolab could preview future plug-in cars from global-alliance partner Nissan, which is looking to offer plug-in hybrids beginning in 2015.

2015 Volkswagen Passat GTE (European spec) Volkswagen Passat GTE Plug-In Hybrid



The Volkswagen Passat GTE plug-in hybrid uses the same powertrain as the smaller Golf GTE, which is already on sale in Europe. Its 1.4-liter four-cylinder gasoline engine and electric motor produce a combined 215 hp, while the 9.9-kWh lithium ion battery pack provides 31 miles of electric range, albeit on the optimistic European testing cycle.

The Passat GTE is based on the European version of VW's mid-size sedan--which differs from the larger U.S. version--and while it will go on sale there next year.

However, U.S. buyers won't get the plug-in hybrid powertrain in any Volkswagen model, although it will be offered in the 2016 Audi A3 e-tron Sportback hatchback.



Volkswagen XL Sport concept Volkswagen XL Sport

To create this minimalist performance car, Volkswagen added a Ducati V-twin motorcycle engine to its XL1 diesel plug-in hybrid.

That results in a vehicle that's less efficient than the original carbon-fiber reinforced plastic-bodied two seater, but also capable of reaching 168 mph with less than 200 hp.

The basic XL body was also modified to accommodate wider tires, aid cooling, and produce enough downforce to keep the car from behaving like an aircraft wing at speed.

The XL Sport isn't slated for production, but it does demonstrate how efficiency-improving design elements can also have a positive affect on performance.

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