November 19, 2007 The Logan Renault eco² Concept has achieved emissions of 71g/km while traveling a distance of 172.2km on just 4.69 litres of biodiesel at the 2007 Challenge Bibendum in Shanghai – an event created by Michelin in 1998 that promotes sustainable transport and the development of fuel-efficient, clean automotive technology. In NEDC combined cycle homologation tests for the eco² it achieved a result of 97g CO2/km and finished second out of 74 vehicles in a combined criteria test involving an acceleration test, a slalom test, noise emissions and a regularity run. To put the emissions results in perspective, a compact diesel achieves around 130g CO2/km and the exceptionally green smart fortwo diesel comes in at 88 grams of CO2 per kilometer.

Renault's eco² appellation was released in May 2007 with vehicles that qualify for the tag being required to meet a three benchmarks: they must emit less than 140g of CO2/km (or alternatively run on biofuel); they must be manufactured at an ISO 14001-certified factory; and 95% end-of-life reusable (with at least 5% of the plastics used in their production must be sourced from recycling). Renault says that 40% of its current range qualify for the Renault eco2 label.

Powered by a 1.5 dCi 85hp engine running on B30 biofuel (a blend that contains 30% vegetable oil-derived methyl ester), the Logan Renault eco² Concept was manufactured at the ISO 14001-certified Pitesti plant in Romania and contains 8.3% of recycled plastics and is 95%-reusable by weight.

The Concept therefore meets the above criteria and its Challenge Bibendum performance (equivalent to an average fuel consumption of 2.72 litres/100km) relied on a number of technical enhancements including a lengthening of the final drive ratio, optimizing the use of low-viscosity lubricants, re-calibrating the injection system and widening the piston bowl for enhanced fuel spray and combustion.

Aerodynamics performance was also enhanced via the use of a flexible splitter under the front bumper to reduce underbody turbulence combined with a spare-wheel fairing to optimise the flow of air underneath the car. The front air intakes were modified to reduce the drag caused by air-cooling airflow and a rear lip spoiler was used to reduce the vehicle's overall drag performance. Another cost-effective solution employed was the “VORTEX” generators - small, drag-reducing, roof-mounted features that channel airflow to reduce rear drag. Combined with a slightly lower ride, the modifications cut the drag co-efficient by around 20%.

Other modifications included the use of Michelin Energy Saver 185/65R15 low rolling resistance tyres, low-friction rear bearings, reduced energy needs with an “active control alternator” that only charges the battery as required and a gearshift indicator on the dashboard that enables drivers to make an active contribution to the optimization of fuel consumption.

Visit the Challenge Bibendium site for full details of the event or see Renault for more on the eco².

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