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Renault Introduces Logan Renault Eco2 Concept at Challenge Bibendum; Taking a Production Car from 120g CO2/km to 97g

Some of the elements and attributes contributing to the enhanced fuel economy of the Logan Renault eco2 concept. Click to enlarge. Illustration: Hubert Vincent

Renault is introducing the Logan Renault eco2 concept, which will contest the 2007 Michelin-organized Challenge Bibendum in Shanghai, China running from 14-17 November.

In May, Renault introduced the Renault eco2 appelation for its most fuel-efficient and “ecological” products. Renault eco2 vehicles meet three global standards: they are produced in an ISO-14001-certified plant, their CO2 emissions do not exceed 140 g/km (or are biofuel-compatible) and, in addition to being 95% reusable at the end of their life, at least 5% of the plastics they contain have been recycled. (Earlier post.)

The Logan Renault eco2 Concept was 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. The vehicle has a low CO2 emissions rating of 97 g/km.

Powered by a 1.5 dCi (63kW/85hp) engine which runs on B30 biofue1, Logan Renault eco2 Concept incorporates a variety of technical enhancements and innovations, all of which are paths for future vehicle development at Renault.

The powertrain is based on the 1.5 dCi (85hp) engine launched at the end of 2007 and homologated at 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 ordinary use. This enhancement enabled a saving of 4g of CO2/km.

Renault also re-calibrated the injection system 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 saving of 5g of CO2/km.

Finally, by optimizing the play between certain moving parts and using low-viscosity lubricants (5W20 plus additives instead of the standard 5W30), Renault reduced internal engine friction. The gear oil is also less viscous. This work helped cut CO2 emissions by a further 2g/km.

Analysis of the most cost-effective solutions enabled Renault to identify six points which, together, produced significant aerodynamic gains.

  • A flexible splitter under the front bumper to reduce underbody turbulence combined with a spare-wheel fairing to optimize 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, Renault reduced the drag coefficient by some 20%, from 0.36 for the production Logan to 0.29, a score that makes Logan Renault eco2 Concept one of the most aerodynamically efficient three-box sedans. All the work aimed at reducing drag produced a CO2 gain of 5g/km.

Logan Renault eco2 Concept is equipped with new Michelin Energy Saver 185/65R15 low rolling resistance tires. 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 optimized. Work on the running gear helped us make CO2 emission gains of 3g/km.

The active control alternator ensures that the battery is charged only as required (12.8 Volts instead of 13.5 Volts). The battery consequently doesn’t have to be charged so 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 liters/100km (62 mpg US).

Furthermore, the extra-urban phase of the NEDC driving cycle returned UTAC homologated fuel consumption of just 3.4 liters/100km (69 mpg US), equivalent to CO2 emissions of 88g/km.

Driving style can also play a significant role when it comes to curbing fuel consumption and CO2 emissions. The dashboard of Logan Renault eco2 Concept features a gearshift indicator which enables drivers to make an active contribution to the optimization of fuel consumption.

By taking full advantage of this aid, drivers can bring Logan Renault eco2 Concept’s CO2 emissions performance below the homologated score of 97g/km.


daniel billinton

This renault is definitely the way to go to reduce emissions in the most cost effective way.

All of these small refinements in aerodynamics, rolling resistance, engine friction and gearing produce a 20% reduction in CO2 emissions - and most notably without altering the performance of the car or adding any significant cost by resorting to expensive hybridisation

This car proves that the industry's claims that they cannot meet the 130g by 2012 wanted by the EC are nonsense. If these simple modifications were made to all the cars in the European fleet then the current 160g CO2/km fleet average would already be 128g CO2/km

The only question is why is the car still a concept ?

I believe there is evidence that car manufacturers have been withholding these simple changes to overstate the cost of meeting emissions targets for political reasons.

There is no technical reason why these simple changes should not be use on the whole range right now. Low rollign resistance tyres should be fitted as standard


It sounds fantastic - what do the changes do to the cost of ownership and robustness ?
How many of them could be rolled across the range ?
Do lower rolling resistance tyres have smaller amounts of grip ?
Even so, you can have a "green" model which is known to have lower grip than the standard, the same way as sport models are known to have higher grip and performance.
Also, what does the lower CD do to the top speed ?


"record low CO2 emissions of just 97g/km"

This is better than the Prius's 104 g/km!

daniel billinton

I agree, this again demonstartes how the Prius is a very expensive way of achieveing low emissions.

this car would have much lower cost of owneership ANd higher speed - top speed would increase by around 5mph by my estimates.

The measures used in the Renault would not add any significant cost to the car which makes you wonder why they haven't done this sooner. The only question mark is over the use of low visocity fluids and the effect on long term wear and reliability.

Michelin have reassured customers that their low rolling resistance energy saver tyre have the same grip (and improved wear) as normal tyres thanks to the use of Silica in the compound. These Michelin tyres are currently licensed for exclusive use on the new Peugeot 308 until next year but after that they should become commonplace.

Harvey D


I fully agree with you. All those improvements have been known for years. Renault has demonstrated that it can be easily done, most probably at very little extra cost.

Most car manufacturer's on-going reluctance seems to be just another resistance to change or part of a scheme to burn more fuel and create more pollutants than neccessary.

Of course, we could be driving 4-5 passenger cars with less than 100 g/Km CO2 and more than 60 mpg in 2008. All other units, not meeting those goals, could be progressively but very heavily taxed, to (conveniently) drive them out of the market place or reduce their number to a few thousand a year.


Vehicles between 100 and 130 could be taxed $100/g/Km.
Vehicles between 130 and 160 could be taxed an extra $200/g/Km.
Vehicles between above 160 could be taxed an extra $500/g/Km.

Vehicles below 100g/Km could receive a $100/g/Km sales taxe reduction or purchase bonus.

The 100 g/Km pivot point could be lowered as technology progresses.

Rafael Seidl

@ Harvey D -

the German federal government is actually proposing to eliminate the annual license fee for vehicles that emit less than 100gCO2/km (in the NEDC). Right now, only the smart fortwo Cdi and the VW Polo Bluemotion would qualify but others - like this eco2 Logan - would surely follow. The snag is that this particular tax is collected by the individual states who say they will only support the idea if the feds give them a higher share of other tax revenue to compensate.

Btw, by your calculation, a vehicle emitting 130gCO2/km would be taxed at $3000 per year. I think your proposal is interesting but the numbers are a factor 10 too high. Also, the overhead of collecting any tax is non-negligible, so anything below e.g. $100 probably isn't worth chasing after.

Bear in mind that Europeans already pay the highest fuel taxes in the world. A number of countries (e.g. Switzerland, AUstria, Czech Republic) also require vignettes for using the freeways, while others have congestion charges and/or are considering distance-based road pricing.

Harvey D


I know that Europeans already pay a lot of road/vehicle/fuel taxes. The idea of a progressive carbon applied as purchase taxes is to discourage the purchase of large polluting gas guzzlers and promote the purchase of cleaner units via lower purchase taxes or bonus. Such scheme could be revenue neutral or other associated taxes could be progressively reduced or removed.

In other words, tax the polluters and compensate those making an effort to reduce pollution and fuel consumption.


Well, these changes are for sure cheaper than sticking a parallel hybrid system on it, but you can still do it and obtain further reduction in fuel consumption/co2 emission (though a lot of work on the Prius was already on optimizing the aerodynamic efficiency). With regenerative braking it would score even better on a test which is more oriented to urban driving.


As for the switch to lower viscosity engine oil, Ford and Honda switched to 5W20 (at least for most US-spec models) several years ago. I know my 2001 Ford Focus specified 5W20, and at this point almost all new Ford products use it.

Motor oils have advanced tremendously in the last 10-15 years. Viscosity in itself isn't a defining factor now that we have so much better control over the other properties of the oil.

GM has been using flexible under-bumper fairings since the early 1980s. They have to be flexible because they drag pretty regularly on irregular surfaces. The scraping noise tends to freak customers out though!

As for comparison with the Prius, it has a lot of these low-cost features incorporated. This concept can't approach the Prius net power spec of 110 hp, though, and I can't imagine it can approach its acceleration specs either.

I think the big-issue that nobody really wants to talk about is that one of the best ways to make cars more fuel efficient is to reduce power and performance. We will discuss how much mass vehicles have gained in the last 20 years, but tend to ignore how acceleration times have dropped by 50-100% in many classes, and now consumers demand that level of performance in everything. The average ho-hum sedan today can post performance numbers that only exotic sportscars could touch in the 1980s. If you want stellar efficiency AND that kind of performance in the same vehicle, it's going to add a lot of cost.

Anybody have a 0-100 km/h time for this version of the Logan? I'm betting 14-16 seconds.


While this car could certainly be improved with varying degrees of hybridisation, this would push the cost too high for most people.
It would be better to pack it and sell it as is, rather than further tweek it.

A possible idea would be to offer a hybridised version as a sort of "show" car which is mainly a marketing tool for the rest of the range.

This one could have regen brakes, PHEV capability, whatever, and might cost twice the "eco2" version.

It could be purchased - Renault would probably lose money on it, but it would be for a marketing aura rather than mass sales.

I absolutely agree with you - as long as people require very fast acceleration times, we are going nowhere (fast!)
If you give a bit on 0-60, you make it much easier to improve the CO2.
The problem is to get people to buy slower, greener cars. People have to feel that they are doing the right thing, rather than compromising on performance.
So much of this problem is a marketing problem.
If people accepted that 0-60 in 15 seconds was OK, rather than 10 seconds, the problem gets much simpler.


Very cost-effective approach. I'd love to know what the cost/benefit of adding idle-stop to this package would be.


To the point about diesels being a cheaper alternative to hybridization. That's not necessarily the case. The fuel systems on diesels are very expensive compared to their gasoline equivalents, adding thousand$ per engine. For example the rotary fuel pump on my VW TDI is a $3500 oem part. Ugh! This is why you're not seeing the best of both worlds (ie. diesel hybrid electric passenger cars). The engine cost would be prohibitive.


Don't forget air quality! A typical Euro 4 diesel (eg Astra 1.7) will produce at much as ten times the NO2 as the equivalent Euro 4 petrol car and 20 times as much as the Prius. About 95% of the UK's 260+ Air Quality Management Areas (AQMAs) are due to high NOx levels - from diesel engines. The UK's Air Quality Expert Group reported in 2006 "a dramatic rise" in roadside NO2 and the cause - particulate abatement technology on Euro 3+ diesel engines! Research suggest that in the UK there are four times as many premature deaths from transport emissions as from transport collisions... The petrol/gas hybrid not only delivers low CO2 it also delivers cleaner air! I'd still like to see this Renault in production...maybe they could do all this and deliver Euro 5 emissions!

Rafael Seidl

@ Marshall -

all of the VW TDIs on US roads today feature unit injectors. That means the rotary fuel pump is a cheap *low* pressure device. A quote for $3500 is a total rip-off. For the 1998-2005 Bora (cp. US Jetta), a used replacement sells for EUR 90, incl. 19% sales tax in Germany.


All other brands have long used common rail injection which features a much more expensive *high* pressure pump. VW is now switching to common rail as well in order to meet tightening toxic and noise emissions regs in Europe.

The markup on a new T2B5-compliant VW Jetta TDI will likely be quite hefty compared to a similarly powerful gasoline model. This is partly due to the higher cost of the engine. However, the exhaust gas aftertreatment systems are also much pricier than a three-way catalyst. The purchase will make sense only if you drive a lot of miles annually, with most on the highway and freeway at speed (i.e. not stuck in traffic jams). For an SUV or pick-up, the break-even point shifts to lower mileage.

A single-mode full hybrid like the Prius will make more sense only if your annual mileage is moderate and most of it in stop-and-go traffic.

Note that qualifying diesel vehicles through MY 2010 will be eligible for federal income tax credits, just as electric hybrids and CNG already are.


While 0-60 times don't need to be 8 seconds and under (as most V-6 powered sedans are) but you do need some capability for a burst of speed.
0-60 in 15 seconds means you'd traverse almost a 1/4 mile before getting to highway speed. On-ramps are far less than a 1/4 mile and typically on an upward slope (meaning underpowered vehicles would have even less speed when they merge onto the highway) so you are causing everyone in the right lane of a highway to have to slam on the brakes for on-coming traffic or merge left and increase the congestion on the highways due to one less useable lane.
If cars were lighter weight we could have good 0-60 times (say 10sec) without excessive top speeds and modest engine power. My 24hp motorcycle will do 0-60 in around 7 seconds but the top speed is under 95mph and it typically gets 55-60mpg in modest driving.


so you are causing everyone in the right lane of a highway to have to slam on the brakes for on-coming traffic or merge left and increase the congestion on the highways due to one less useable lane

patrick, the
highway speed isn't 60mph,
and it surely isn't it on the right side

there usually it is ~80-90 kmh,

and when the highway is prone to congestion then the speed on the right side is even much less ...

think about it

fred schumacher

The safety benefit of fast acceleration is generally overstated, especially by the autopress. The fact is that most cars, even when merging on to a high speed highway, are operating at a small fraction of their capability. Most car engines will never experience reaching redline. If a 0-60 time of less than 10 seconds were essential, then nearly all commercial trucks on the road would have to be considered unsafe.

The auto manufacturers got themselves caught in a horsepower race and they don't know how to get out of it.

The great benefit of Renault's project is that it is doable. Nearly every vehicle on the road, diesel or gas powered, would benefit by this type of action. If the Renault were gas engined, it should be able to get about 55 mpg on the highway. Not shabby.

If 80% of our driving were done in a car like this Renault, we would not need to import any oil. The U.S. would actually become an oil exporter.


And, if people did not have to merge as often and slow down for slower merging traffic there would be less congestion: think about it.

Regardless of the speed limits in the country of origin I was speaking to the people who believe such a vehicle and vehicles with less power are suitable for the US highway system where 60mph highway speeds are only typical in urban areas (and extra urban areas have higher speeds depending on state).

A large truck slowly merging onto the highway is far more visible and less prevalent than passenger vehicles merging on to the highway. Those who are not using the speed would be far more likely to have to redline the engine if the 0-60 time were in the 15 second range. Think of the distance travelled in 5 seconds while accelerating from 45mph to 60mph (looks like somewhere in the neighborhood of 400 feet at MAXIMUM acceleration).

A modern sedan is capable of 0-60 in closer to 8 seconds. There is a world of difference in this acceleration and a vehicle which takes 12 seconds to accelerate to 60mph and the guy in the 8 second car is unlikely to ever have a need to redline the engine to reach cruising speed while the guy in the 12 second or slower car will probably be redlining to merge safely (which they most likely won't do for fear of hurting their engine). Just sit on an overpass near a busy merging section of a highway and observe the "ripple" effect caused whenever you have someone merging lazily at a relatively slow speed onto a highway flowing freely at the speed limit and you quickly see the problems associated.

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