Less is all set to mean more in a major move by Renault to clean up diesel power.

Development engineers at the French firm have won the race to build the first 1.6-litre heavy oil engine to deliver 1.9-litre performance.

Helped by a cocktail of technical advances and a unique engineering feature, the new dCi unit boasts 130bhp - an output that equals Renault’s current 1.9-litre diesel and makes it the most powerful motor of its size.

Due next year, the breakthrough will play a key role in strengthening the fleet credentials of the brand by delivering a 30g/km cut in tailpipe emissions and a fuel economy boost of more than 20% with no discernable change in driving performance.

"This is the first production engine in the world to offer this level of output and efficiency. We are proud to have raised the bar," said diesel engine performance supervisor Jerome Escullier.

Speaking as Fleet News put a prototype example of the engine through its paces, he added: "It should put us at the head of the class for quite some time."

The latest example of power unit downsizing will replace the current 1.9-litre unit across Megane and Scenic ranges to become Renault's core C-segment power source and will also be used in the Laguna.

Featuring a 16% cut in displacement, it will go under the bonnets of several models produced by alliance partner Nissan and looks likely to be adopted by Daimler, which has just agreed on a working co-operation deal with Renault-Nissan.

"We're using less fuel in each cycle because of the lower swept volume. Downsizing is a major driver in CO2 reduction and the effect of smaller cubic capacity alone is a 6% gain in efficiency. 

Renault’s fleet average emissions figure totaled 138g/km last year and executives claim a decade of downsizing experience has left the company well placed to take the emissions lead in the next five years. 

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