The drive for cleaner, more fuel-efficient vehicles has seen significant research and development of the diesel engine, whose CO2 emissions - given the engine is well maintained - are typically well below those of petrol.

Mitsubishi Motors is fast developing a new range of fuel-efficient diesel engines, with technologies like catalytic converters and particulate filters that are already incorporated into "show" vehicles like the concept cars CX, ZT and RA.

Concept-cX is a compact SUV – a ‘soft-roader’ for on-road use. Its 1.8-litre high-output diesel engine links to the highly efficient new Twin Clutch Sport Shift Transmission (TC-SST), and the car uses Outlander-style integrated vehicle dynamics. Green Plastic is used wherever possible for interior components.

This is Mitsubishi's ‘Ultimate Tourer’ showcase, a premium sedan centring on a newly developed fuel-efficient, 2.2-litre diesel engine.

Its multitude of passenger protection features include a radar-guided pre-crash safety system, lane-drift warning system, multi-monitors, parking assistance and a pop-up hood to minimise injury to pedestrians.

At the 2008 Detroit Motor Show the Concept-RA demonstrated Mitsubishi’s dedication to tackling emissions without curtailing driving pleasure.

This sporty, dynamic coupe packs a low-emission 2.2-litre turbo diesel engine producing over 150kW and 420Nm. Its diesel oxidation and NOx trap catalysts and particulate filter technologies combine to significantly reduce emissions.