French automaker Renault is expected to show a concept vehicle at the upcoming Paris Auto Show capable of hitting 117 mpg combined.

Not one to be left out, rival Peugeot will also show a 117 mpg concept at Paris--albeit one that may not be too far from production.

It stems from a French government target that requires automakers to produce a 117 mpg production vehicle by 2020.

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The number isn't as arbitrary as it sounds, as it equates to 2 liters of fuel per 100 kilometers, the measure of fuel economy used across most of Europe.

According to Autocar, the 208 Hybrid Air is based on the regular 1.2-liter PureTech production model, but incorporates Peugeot-Citroen's 'Hybrid Air' technology.

This compresses and stores air using hydraulic pumps as the car drives along or decelerates, air which can then be used to assist the 208 under acceleration.

In effect, it works very much like a regular hybrid drivetrain, without resorting to a bank of heavy batteries. Power from the engine and hydraulic pumps is sent through an epicyclic transmission, similar to the 'e-CVT' you'd find in a Toyota Prius.

To help it work to best effect, Peugeot has sliced 220 lbs from the 208's mass by replacing some of its structure with composites and aluminum. The doors and tailgate are also formed from carbon composites.

Peugeot 208 Hybrid Air concept

Peugeot 208 Hybrid Air concept

The upshot is a curb weight of just under 1,900 lbs, far lighter than any other similarly-sized car.

It also sits on lower suspension than the standard car, and aero tweaks to the 208's body help it slip through the air a little easier--though Peugeot has resisted changes as dramatic as those on its last 117 mpg concept, the 208 FE.

That car featured an extended tailgate, an even more dramatic weight reduction to 1,719 lbs, and a more conventional hybrid drivetrain assisted by a 40-horsepower electric motor to hit the French target.

Hybrid Air is remarkably effective though, boosting the standard 208 1.2's economy from 52 mpg to the magic 117 mpg figure. CO2 emissions drop by a similarly large margin, from 104 g/km to just over 46 g/km.

If the promised cost reduction of Hybrid Air is as significant as its economy performance, it could be the next big thing for the small car sector.


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