The Renault Group has been on the road to sustainability for a long time. One of the first "green" concept experiments dates back to 2007, when the Dacia Logan ECO2 was presented, an interesting prototype that was heavily modified compared to the production model in order to maximise efficiency.

And no, we are not talking about a purely electric concept, but a model that runs on biodiesel. Some of you may remember the 3L versions of the VW Lupo and Audi A2 or the Opel Astra Eco4. The Dacia Logan presented in 2004 was certainly not a boozer, but there was still room for manoeuvre.

Gallery: Dacia Logan ECO2 Concept (2007)

Modifications to the engine and aerodynamics

In 2007, a total of 74 vehicles from numerous car manufacturers took part in Michelin's "Challenge Bibendum" environmental rally over 172 kilometres. The competition included an acceleration and slalom test, a regularity drive and a test of noise emissions.

The "Logan Renault eco2 Concept" (the official name) was based on the Dacia Logan saloon and was powered by the proven 1.5 dCi engine with 86 PS, which was adapted to run on biodiesel (B30). The engine differed from the standard engine in a number of ways, including modified pistons and a modified injection system. The new gear ratios and optimised lubrication, which reduced friction losses, also contributed to the low fuel consumption.

Dacia Logan ECO2 Concept (2007)

Dacia Logan Eco2 Concept (2007)

The aerodynamics package with rear spoiler, flexible front spoiler and a vortex generator on the roof also contributed to this. These are small air guiding elements that direct the airflow in a targeted manner and reduce disruptive turbulence. Low rolling resistance Michelin Pure tyres in 185/65 R 15 format rounded off the equipment.

Better than the approval values

During the approval tests for the Challenge Bibendum, the Logan achieved an average fuel consumption of 3.8 litres of diesel per 100 kilometres and CO2 emissions of 97 grams per kilometre. The further improvement in the values was mainly due to the gearshift indicator, which alerts the driver to change to the most fuel-efficient gear: Just 2.72 litres of diesel per 100 km and 71 g of CO2 per kilometre.

Dacia Logan ECO2 Concept (2007)

Dacia Logan eco2 Concept (2007)

As the name suggests, this particular version of the Logan was part of Renault's ECO2 project, which at the time identified the models with the lowest environmental impact.

These vehicles had to be manufactured in ISO 14001-certified factories, emit less than 140 g/km of CO2 or run on biodiesel and be made from 95% recyclable materials, with at least 5% of the plastics coming from recycled material.

Gallery: Dacia Logan ECO2 Concept (2007)