We're starting to see the first concept cars due at December's Tokyo Motor Show filtering through, and while many are excited for the design, the choice of powertrain is important too.

The 2011 Mazda Takeri Concept certainly looks striking, with Mazda's new KODO "Soul of Motion" design language making its influence felt. However, it's the brand new SKYACTIV-D clean diesel engine under the hood that caught our attention.

Mazda's SKYACTIV range of engines is designed to reduce emissions and fuel consumption to a minimum without resorting to expensive and complicated hybrid technology, instead taking the efficiency of internal combustion to a new level.

A light weight and aerodynamic body helps the diesel engine extract maximum economy from a modest size unit. A stop start system ensures no diesel is wasted when at a standstill.

The Takeri introduces regenerative braking too. Rather than putting power back into the batteries of a hybrid system, the Takeri's brake regeneration to store energy in capacitors which goes to power the car's electrical gadgets, meaning less of the engine's power is devoted to spinning an alternator, saving fuel in the process.

Central to the Takeri's philosophy is that saving fuel need not be a chore, and Mazda aims to make all its SKYACTIV cars fun to drive and comfortable to travel in.

We like the sound of that. The 2011 Tokyo Motor Show runs from November 30 until December 11, 2011.

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