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Renault has applied an interesting range of CO2 saving techniques to its Logan saloon and entered it into the Challenge Bibendum in Shanghai, an event designed to demonstrate such technology. The Logan can appear as a Renault or Dacia depending on the country of sale, and the Dacia brand comes to the UK in early 2009.
Known as the Logan Renault eco2 Concept, a range of technical enhancements enabled the car to cover the 172.2km route of the 2007 Challenge Bibendum on 4.69 litres of B30 biodiesel. This gave an average fuel consumption of 2.72 litres per 100km and CO2 emissions of just 71g/km.
During combined cycle homologation tests for the vehicle, it achieved a result of 97g CO2/km, equivalent to fuel consumption of 3.8 litres/100km.
After the Challenge, competing vehicles were judged on an acceleration test, a slalom test, noise emissions and a regularity run. Out of a total field of 74 vehicles, the Logan Renault eco² Concept finished second.
Renault says that its eco² symbol illustrates the brand’s commitment to offering a line-up of ecological, economical vehicles that show measurable results throughout their life cycles, as well as new technologies at prices which most customers can afford.
To qualify for the Renault eco² symbol, vehicles must comply with all three of the following criteria:
– They must emit less than 140g of CO2/km, or run on biofuel
– They must be manufactured in an ISO 14001-certified factory
– They must be 95% end-of-life reusable, and at least 5% of the plastics used in their production must be sourced from recycling.
Today, 40% of the versions in the Renault range qualify.
The Logan Renault eco² Concept is manufactured at the Pitesti plant in Romania, which has been ISO 14001-certified since 2005, while the finished vehicle contains 8.3% of recycled plastics and is 95%-reusable by weight. And special attention has been paid to bringing its CO2 emissions below the 100g/km threshold.
Powered by a 1.5 dCi 85hp engine running on B30 biofuel, it incorporates a variety of technical enhancements and innovations, all of which are paths for future vehicle development at Renault.
The Engine is based on the 1.5 dCi (85hp) engine launched at the end of 2007 and normally emitting 120g CO2/km. The final drive ratio has been lengthened 8% to reduce fuel consumption while ensuring a level of mid-range acceleration that is suitable for normal use. This enhancement gave a saving of 4g CO2/km. The injection system has also been re-calibrated by introducing seven-hole nozzles (instead of five as is the case with production models) and widening the piston bowl for enhanced fuel spray and combustion. This modification produced a further saving of 5g of CO2/km. Finally, by optimising the balance between certain moving parts and using low-viscosity lubricants (5W20 plus additives instead of the standard 5W30), internal engine friction has been reduced. The gear oil is also less viscous. This work helped cut CO2 emissions by a further 2g/km. Powertrain adjustments led to a total CO2 emissions improvements of 11g/km.
Aerodynamic performance was also improved by the following:
– 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
– Wheel fairings to reduce lateral turbulence
– A rear lip spoiler to reduce the vehicle’s overall drag performance
– VORTEX generators – small, drag-reducing, roof-mounted features that channel airflow to reduce rear drag, a particularly effective solution on three-box cars
– A slightly lower ride-height.
Altogether, the drag co-efficient was cut by some 20%, from 0.36 for the production Logan to 0.29. This gave a CO2 improvement of 5g/km.
With running gear, the aim was to reduce mechanical friction with solutions such as:
– Logan Renault eco² Concept is equipped with new Michelin Energy Saver 185/65R15 low rolling resistance tyres. This brought a CO2 gain of 2g/km (NEDC homologation cycle).
– The use of low-friction rear bearings led to an emission gain of around 1g of CO2/km. The camber and toe settings were also optimised.
Work on the running gear helped to achieve CO2 emission gains of 3g/km.
The car also has lower energy needs, such as the active control alternator which ensures that the battery is charged only as required (12.8V instead of 13.5V). The battery consequently doesn’t have to be charged as frequently, which leads to lower fuel consumption. Measures taken to reduce the effect of energy-hungry parts helped reduce CO2 emissions by 4g/km.
The sum of all the work that went into Logan Renault eco² Concept achieved record low CO2 emissions of just 97g/km (NEDC combined cycle) equivalent to fuel consumption of 3.8 litres/100km. The extra-urban phase of the driving cycle returned fuel consumption of just 3.4 litres/100km, equivalent to CO2 emissions of 88g/km.
