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.
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