Renault and sustainable mobility

In the spring, Renault ran an ‘environment workshop’ to publicise its work in the area of whole-life sustainability for its vehicles. Following the workshop, the Company has issued a substantial document detailing the Renault-Nissan Alliance’s present view of all matters connected with sustaintable private transport.

Renault’s document is not a vague expression of intent or a puffing-up of achievements. If it were no more than an advertisement for the brand it would be the longest ever published. The Company discusses specific technologies that are being deployed now and that will be incorporated into vehicles designed in the short term — say, the next five years.

As Renault and Nissan are among the leaders in developing electric powertrains, and Renault’s diesel (particularly) and petrol engines are among the more accomplished presently on the market, the Company’s views are worth reading. While the document is principally a promoitional device, a number of important issues are discussed and explained, and above all it represents a view of the road ahead by a major international motor manufacturer.

We present an edited version of the document here.

Renault believes it is essential to make the most effective technologies available to as many motorists as possible, at prices they can afford.

Design: Renault is working on two fronts in its bid to become the highest-placed European car manufacturer in terms of CO2 emissions:

  • The introduction of new technologies for internal combustion engines and conventional transmissions.
  • An unprecedented commitment to electric powertrains. Renault estimates that electric vehicles will account for 10 per cent. of the world market by 2020. The Alliance is investing 4bn Euro in its zero emissions programme, and a 2000-strong team (1000 at Renault and 1000 at Nissan) is already working on electric vehicles.

The technology used in Renault’s prototype electric vehicles is very similar to that employed for the upcoming production electric cars currently under development. The sale of these electric vehicles — which represent a clean break solution aimed at putting zero emission mobility within the reach off all motorists — will start in 2011.

Production: In addition to the ISO 14001-certification of its factories, new avenues are constantly being explored to achieve even further water and energy consumption savings, and also to cut waste.

On-road use: Renault is about to launch an extensive eco-driving tuition programme for fleet operators and private motorists.

End-of-life: Renault has become a major player in France for recycling and the recoverability of plastics, metals, etc.

Designing sustainable mobility

The key challenge today resides in the ability of a group such as Renault to put vehicle technologies capable of achieving real emissions savings within the reach of all motorists and to enable people across the world to benefit from a wide range of mobility solutions.

To permit widespread access to more ecological forms of mobility, it is necessary to have a thorough understanding of the issue. And that is the mission, for example, of the Lifecycle Management scheme which has been in place since the Mégane II project, as well as of the Sustainable Mobility Institute which was founded by Renault in 2009.

Lifecycle management

Protecting the environment calls for the impact that new services and products make into account from the design stage. This includes the environmental and economic situations of the different markets. To balance the different environmental impacts without losing sight of other key factors (such as selling price, safety performance, comfort, cost per tonne of CO2avoided, etc.), Renault bases its work on an approach known as lifecycle management. This permits the full environmental impact of a vehicle — from the mining of ores, to the sourcing of fossil fuel and the landfill treatment of waste resulting from its crushing at the end of life — to be taken into consideration.

Comparisons are systematically carried out between different generations of vehicle belonging to the same segment. This global view of complete lifecycles enables Renault to focus on a broad spectrum of technologies (electric vehicles, hybridisation, fuel cells), as well as on the potential of alternative fuels such as LPG (liquefied petroleum gas), compressed natural gas (CNG — methane) and biofuels, both now and in the future. These alternative sources of energy are deployed taking local resources and market demand into account.

The Renault eco² and Dacia eco² signatures have permitted both brands to raise the issue of lifecycle management with their customers.

Renault Foundation and ParisTech have joined forces in 2009 to create the Sustainable Mobility Institute to conduct research into the future of personal transportation. The aim of the cooperation between Renault’s engineers and the teacher-researchers and students from ParisTech is to promote research into the conception of innovative mobility systems and to provide future executives and scientists with the educational background they need to meet the needs of manufacturers in the transport world of tomorrow. The Sustainable Mobility Institute is more than happy to strike up partnerships with other businesses and university institutes that wish to take part in this research.

Eco-design

Economics and ecology must come together to deliver products that can be used by as many motorists as possible.

To reduce effectively the pollutants generated at the different stages of a vehicle’s life-cycle, it is essential to start at the earliest design stage: i.e., between three and five years before the vehicle is brought to market. Some years ago, Renault adopted an approach based on eco-design, both for its products and its industrial processes. This approach covers the choice of materials, fluid extractability, dismantling operations for recycling, pollutant emissions, fuel consumption, CO2 emissions and the environmental impact of production.

At the same time, Renault’s engineering centres are developing in-house eco-design processes. Renault aims to include 20 per cent. of recycled plastic in all new vehicles by 2015.

The virtuous circle of recycling

Renault anticipated the recycling type-approval imperatives specified in Directive 2005/64, which sets a 2015 deadline for carmakers to demonstrate that the vehicles they sell are designed to be 85 per cent. recyclable. In May 2008, the Mégane III Hatchback became the first vehicle to obtain global homologation. This was made possible by many years’ work on improving the recovery of fluids and materials at the end of a vehicle’s life, while careful choice of materials plays a key role in eco-design for end-of-life recycling. For example, the Mégane III Hatchback contains 23kg of recycled material (11.5%) against 16kg for Mégane II. The result is even more striking for the New Scénic, which contains 34kg (14%) of recycled plastic, compared with 18kg for Scénic II. Laguna III includes 33kg (16%).

Ongoing reductions to the environmental impact of production sites

Since 1997, environmental management policies at production plants have cut:

  • energy consumption by 30% (kW/vehicle);
  • water consumption by 65% (m³/vehicle), equivalent to 10m m³;
  • waste by 64% (kg/vehicle);
  • volatile organic compounds (VOC) by 40% (kg/vehicle).

Protecting natural resources and limiting global warming

Cutting greenhouse gas emissions

Renault is pursuing four main objectives in this area, to:

  • increase energy efficiency;
  • reduce energy consumption;
  • switch to alternative fuels;
  • develop renewable energies.

Total direct greenhouse gas emissions fell from 755kt (CO2 equivalent) in 2003 to 508kt in 2009, a fall of 32 per cent.

Combating emissions of volatile organic compounds (VOC)

The volatile organic compounds released by solvents used in paint shops are the major source of atmospheric emissions generated by Renault’s activities. Reducing VOC emissions is a top priority for bodywork assembly plants. In 2009, VOC emissions fell by 10 per cent. over the previous year. As a result, the target of 419g/m² set for 2012 was reached in 2009.

Reduce, reuse, recycle and recover

Renault has adopted a global approach to waste management. The '4R' approach introduced in 2008 set ambitious targets to reduce the residual impact of Renault plants and cut the quantity of waste sent to landfill by 2015. The plant waste recovery rate rose by 20 per cent. in 2009 compared with 2003, largely through more extensive recycling of plastic parts.

Protecting water resources

On a like-for-like basis, the Group has halved its water consumption over the past 10 years. Withdrawals totalled 10.6 million cubic metres in 2009, while residual waste (organic matter, suspended solids and metals) has also been halved in 10 years on a like-for-like basis. By gradually deploying ‘reduce, reuse, recycle’ best practices, and by continuing its efforts to cut residual waste, the Group is expected to reduce water withdrawals by a further 15 per cent. by 2012 compared with 2007.

All factories ISO 14001-certified

All the manufacturing facilities that come under Renault’s responsibility are ISO 14001-certified.

The Somaca facility in Morocco received ISO 14001 certification in early 2008. Renault has invested heavily in personnel and equipment to reduce the plant’s environmental impact. Meanwhile, a total waste management system that meets European standards was put into place in 2007. In terms of energy consumption, action plans on the manufacturing side have yielded important savings: between 2002 and 2008, the saving per vehicle produced reached 15 per cent.

The Avto Framos facility in Russia obtained ISO 14001 certification in April 2008, the last of the Group’s industrial facilities to do so. Significant attention was paid to raising the environmental awareness of all employees in the facility.

Eco-driving

The aim is a sustainable 10 per cent. reduction in real vehicle fuel consumption.

One of the challenges facing the Renault eco² programme is adapting individual driving behaviours to make the most of the potential offered by the latest vehicle technologies. Renault has been running eco-driving awareness operations since 2008 in various countries. These are aimed at the public at large and involve free tuition, tests on simulators, fun activities for the family and a family eco-driving challenge. Building on the success encountered by these operations, Renault has decided to launch a Driving eco² programme which will initially be reserved for fleet customers, before being extended to private motorists. Through its subsidiary Renault Environnement, Renault has joined forces with Key Driving Competences to develop on-road and simulator training programmes in Europe for drivers of small vehicles and heavy goods vehicles alike. Local partnerships are being explored with a view to expanding this innovative approach to changing attitudes.

Giving a second lease of life to end-of-life vehicles

In 2008, Renault’s subsidiary Renault Environnement joined forces with the SITA / Suez Environnement Group to develop end-of-life vehicle recycling in France. Along with SITA, the group has taken a majority stake in Indra, a vehicle management / distribution firm, working with 350 dismantlers across France.

In 2009, more than 350,000 vehicles were processed. Renault and SITA are developing vehicle dismantling processes aimed at the extraction and recycling of materials that will subsequently be used to produce new automotive parts. These new end-of-life recycling tools and processes are developed and tested at dismantling sites (including two centres in France’s Sologne and Nord regions). The combined efforts of the three companies and their partners will contribute to meeting the vehicle end-of-life recoverability target of 95 per cent. by 2015.

The Renault eco² signature is a pledge of Renault’s commitment to protecting the environment and enables customers to identify those models of the Renault range that are the most respectful of the environment throughout their full lifecycle, since it indicates that they comply with the three following criteria:

  • Production: Renault eco² vehicles must be manufactured in ISO 14001-certified factories. This certification testifies to a plant’s ongoing efforts to reduce the impact of its activity on the environment.
  • On-road use: CO2 emissions must be equal to or less than 140g/km for cars or 195g/km for light commercial vehicles, or the vehicle must run on bio-fuels.
  • Recycling: Five per cent. of the plastics that Renault eco² vehicles contain must be sourced from recycling. Vehicles must also be 95 per cent. end-of-life recoverable.
Examples of eco² cars
Twingo
dCi 86
Clio
dCi 86
Mégane
dCi 110
Scénic
dCi 110
Factory
(ISO 14001)
Novo Mesto
SLO
Flins/Bursa
F/TR
Palencia
E
Douai
F
CO2
g/km
94 98 114 130
Recycled
plastic
15kg
9%
15.5kg
10%
23kg
11.5%
34kg
14%
Recoverability >95% >95% >95% >95%

Renault’s powertrain strategy

Renault’s efforts have seen the brand achieve significant savings of the CO2 emissions of its vehicles.

Renault’s ambition for the future is to be a driving force in the field of sustainable mobility for all to ensure that the automobile continues to represent a means of freedom for as many people as possible. To achieve this, Renault has set itself the target of becoming Europe’s leading carmaker in terms of CO2 emissions thanks to the following work:

  • Ongoing improvements to fundamental vehicle characteristics such as weight, aerodynamic performance and friction;
  • The introduction of new technologies for internal combustion engines and conventional transmissions;
  • An unprecedented commitment to all-electric ‘zero-emission’ vehicles.

It is expected that nine vehicles in 10 will be powered by an internal combustion engine in 2020. [If one tenth are not, this represents a huge uptake of electric power by car buyers. — Ed.]

Renault is continuing to make ongoing reductions to the ecological footprint of the vehicles that make up its current and forthcoming ranges. This is being achieved through the increasingly widespread downsizing of its diesel and petrol engines thanks to the introduction of new technologies which stand to make significant contributions to reducing CO2 emissions.

As part of its Renault eco² environmental programme, the brand believes it is vital to put the most effective technologies within the reach of as many people as possible, at affordable prices.

Improving fundamental vehicle characteristics

One way to reduce CO2 emissions is to continue working on the fundamental characteristics of all the vehicles that make up the Renault range. For example:

Vehicle weight

This has the greatest influence on CO2 emissions. Over the past 20 years, vehicle weights have been rising gradually as a result of several factors:

  • Increasingly strict standards and safety-rating procedures;
  • More comprehensively equipped vehicles;
  • Improvements to comfort and soundproofing performance.

Together, these three factors have led to an average increase from one generation of a given car to the next of between 10 and 20 per cent., depending on model.

Yet the relationship between the CO2 emissions of a vehicle and its weight is a factor of 1 to 10; that is, a 10kg reduction in a vehicle’s weight will result in a corresponding 1g/km decrease in CO2 emissions on the road. [More in town, less at constant speed. — Ed.]

Since 2000, vehicle project teams have paid particular attention to reducing the weight of new cars. Laguna III was the first Renault model to benefit from this work, with weight savings compared with Laguna II amounting to between 15kg and 65kg, depending on version.

Ways in which vehicles can be made lighter include:

  • Work on the body structure. For example, optimisation of the gauge of steel panels, laser brazing of the body sides, and the use of High Elastic Limit steels.
  • Reducing the weight of individual components: e.g., thinner glass, thinner-walled exhaust pipes, etc.
  • The use of lightweight materials: e.g., aluminium bonnets, Noryl front wings, plastic composite headlights, thermoplastic tailgates.
  • The doubling-up of functions, minimising the number of parts and fittings required.

It is expected that it will be possible to shave between 100kg and 200kg off the weight of forthcoming generations of vehicle, which is equivalent to a potential CO2 emissions saving of between 10 and 20g/km.

Enhanced vehicle aerodynamics

The aim here is to minimise drag in a number of different ways:

  • Work on the vehicle’s basic forms — frontal area, roofline, etc.
  • Exterior fitments: rear lip spoiler, profiled exterior mirror housings, flexible front bumper lips.
  • Lower ride height.
  • Front wheel arch liner extension flaps.
  • Specific underbody and rear suspension shielding.
  • Blocking of the passage of air into the engine compartment thanks to fixed or pivoting flaps.

The combination of all these techniques can improve CdA by up to 10 per cent. It is estimated that a CdA improvement of 0.02 saves 1g of CO2 per kilometre.

Reduced rolling resistance

This is essentially achieved by reducing brake rub after the driver has lifted off the pedal and the fitment of low rolling resistance tyres.

The introduction of new technologies for conventional engines and transmissions

Renault’s ongoing downsizing strategy is aimed at reducing the cubic capacity of its engines in order to bring down fuel consumption and CO2 emissions, without detracting from performance.

The optimisation of conventional petrol and diesel engines continues to be one of the most economical means of lowering fuel consumption and, consequently, greenhouse gas emissions. Smaller, turbocharged engines, whether petrol or diesel, are more efficient and allow significant CO2 emissions savings to be achieved — approximately six per cent.

The downsizing of engines has two benefits. To begin with, smaller engines reduce CO2 emissions by improving their volumetric efficiency (torque and power per litre). This can be achieved through turbocharging. Part of the energy contained in the exhaust gases is used to compress intake air. Recovering energy in this way, plus the fact that smaller engines function efficiently across broader zones (on a given vehicle), enables fuel consumption and consequently CO2 emissions to be reduced.

In the case of Laguna, for example, the 2.2-litre diesel engine that delivered 115PS in 1996 has today been superseded by a 100PS 1.5 dCi powerplant. This has achieved a saving of almost 70g of CO2 per kilometre, as well as a 35 per cent. reduction in fuel consumption (over 20mpg) over a period of less than 15 years.

Laguna diesel
1996 2001 2007 2010
2.2 dT 1.9 dCi 1.5 dCi 1.5 dCi
PS 115 110 110 110
MPG 39.2 50.4 57.7 60.1
CO2 190 150 130 122

The benefits of dCi technology

Turbocharged diesel engines equipped with direct common-rail fuel injection represent the most energy-efficient solution today. On average, diesel vehicles consume between 20 and 30 per cent. less fuel than a petrol-powered vehicle of equivalent performance.

New-generation 1.5 dCi engines

The 1.5 dCi (type K9K) is the brand’s best-selling engine, with almost 900,000 units manufactured in 2009, in Valladolid (Spain) and Bursa (Turkey). It is available with several power outputs (currently from 65 to 110PS) and powers numerous Renault (from Twingo to Laguna) and Dacia models. Its simple design and low levels of friction make it particularly competitive in terms of the performance it delivers for its price.

Renault worked particularly hard on tuning the 86hp and 106hp dCi engines to optimise CO2 emissions without detracting from performance.

  • Taller ratios for all gears: the torque and response inherent in the dCi engine have enabled these changes to be introduced without affecting its performance.
  • Reduced transmission friction thanks to the use of low viscosity oils.
  • Specific engine-mapping aimed at reducing fuel consumption and CO2 emissions.

Renault is in the process of introducing significant changes to this four-cylinder 1.5-litre engine. The latest evolution will become available in 2012 and will cut CO2 emissions by approximately 20g/km.

Downsizing the engines of light commercial vehicles

Renault’s large van range incorporates a new diesel engine: the 2.3 dCi. For the new Master, this unit is available in a choice of three power outputs — 100PS or 125PS, with a fixed geometry turbocharger, and 150PS, with a variable geometry blower. It will go on to be available for other Renault-Nissan Alliance vehicles.

Derived from the 2.0 dCi (M9R), which features in the Laguna and Espace, this new engine supersedes the 2.5 dCi (G9U) and the four-cylinder 3.0 dCi diesel (ZD30). Under the bonnet of the new Master, this 2.3 dCi diesel powerplant returns lower fuel consumption — an average saving of one litre per 100km, and as much as 2.7l/100km in the case of the range’s rear-wheel drive versions. CO2 emissions are down 10 per cent. on average; torque is up 30Nm.

This has been achieved thanks to the new block’s smaller cubic capacity and the use of a new fuel injection system incorporating latest-generation seven-hole injectors.

This new, versatile 2.3 dCi engine is available for all the different versions of the new Master in either front- (transversely-mounted) or rear-wheel drive (longitudinal) form.

The future 1.6 dCi 130 engine

When it reaches the marketplace, this all-new 1.6-litre engine will deliver a power output of 130PS. This is equivalent to a reduction in cubic capacity of 16 per cent compared with a current 1.9-litre diesel engine of equivalent power.

The downsizing process involved shortening the piston stroke by reducing the size of the crank pin and conrod assembly. Downsizing alone results in a saving of six per cent. compared with the engine it replaces.

The forthcoming dCi 130 (R9M) will be ready for Euro 6 compliance. It is covered by 15 Renault patents and will be the core C-segment engine, in addition to playing a key role in the brand’s D-segment and van ranges. It is a Renault-Nissan Alliance joint development and is due to be introduced in 2011. It will be manufactured at the Cléon plant in France. Combined with the improvements to the forthcoming vehicles themselves — in the areas of weight, aerodynamics and friction — this engine will enable CO2 emissions to be reduced by 30g/km, while fuel consumption will come down by more than 20 per cent. compared with the current dCi 130.

Downsizing applied to petrol engines

Renault was one of the first manufacturers to apply the principle of downsizing to petrol engines, and the TCe 100 — which has been available for Twingo, Clio and Modus since 2007 — stood out as a groundbreaking product in its class.

This 1149cc unit delivers 100PS and moderate fuel consumption. It is equipped with a low inertia turbocharger and was engineered to provide standard-setting performance and fuel economy for its class. The latest Euro 5-compliant version was introduced at the beginning of the year under the bonnet of Clio. The Clio TCe 100 emits 129g/km of CO2, which is a reduction of 8g/km over the previous version.

Meanwhile, the new Mégane range saw the introduction of the new TCe 130 in 2009. This engine develops 130PS and 190 Nm from 1397cc.

TCe 100 TCe 130
D4Ft H4Jt
Swept volume 1149cc 1397cc
Bore/stroke 69.0/76.8 78.0/73.1
Cylinders 4 4
Valves 4 4
Compression
ratio
9.5:1 9.2:1
PS/rpm 100/5500 130/5500
Nm/rpm 152/3500 190/2250
Fuelling Port Port
Emissions EU4 / EU5 EU5

Future modular TCe engines will be introduced, with power outputs ranging from 90PS to 115PS.

Scheduled for launch in 2012, the new TCe family it is expected to account for 85 per cent. of Renault’s petrol engine sales in 2015. These ‘modular’ engines will have a cubic capacity of between 0.9 and 1.2 litres and will be available in three- and four-cylinder form. A number of vehicles equipped with these engines will emit less than 100g/km of CO2.

New technologies to reduce the CO2 emissions of internal combustion engines

Downsizing will continue, and the technique is entering a new phase thanks to the advent of new petrol and diesel engine technologies that will deliver unprecedented performance in terms of low CO2 emissions.

Six new technologies will significantly reduce the CO2 emissions of future engines:

  • Thermal management
  • Low pressure EGR (exhaust gas recirculation)
  • Variable swirl technology
  • Variable flow oil pump
  • Triple post-injection strategy
  • Stop-start technology
Fuel-saving technologies
Technology CO2 saving
Downsizing 5.5%
Low-pressure EGR 3%
Stop-start 3%
Variable swirl 0.5%
Variable flow oil pump 1%
Thermal management 1%

Thermal management

The efficiency of a cold-running engine (below 80°C) is penalised in two ways:

1. When the combustion chamber is cold (and the cooling fluid that surrounds it is cold), the combustion process is poor and incomplete, and produces a high quantity of unburned hydrocarbons and carbon monoxide. Fuel consumption is poor.

2. When the lubricant is cold, it is more viscous, which increases the energy required to pump it around the engine. Along with mechanical friction, this phenomenon increases fuel consumption.

Thermal management speeds up the warming of the engine. It uses a solenoid valve located in the cooling circuit upstream of the cylinder head and cylinder block; when the engine starts from cold, the valve is closed and prevents coolant from circulating around the combustion chambers. Hence the cylinders warm up more quickly.

Once the optimal temperature has been reached, the solenoid valve opens and coolant flows through the cooling circuit as normal, with the thermostat controlling access to the coolant radiator.

Thermal management ensures enhanced combustion and reduced friction inside the engine while it is warming up. It is estimated that this technology delivers a CO2 emissions saving of one per cent.

See bottom of page for graphics.

Lower pressure EGR (exhaust gas recirculation)

The use of EGR cuts emissions by recycling exhaust gases into the combustion chamber. This reduces combustion temperatures and the oxygen content of the charge air, both factors which favour the production of nitrogen oxides.

With a conventional (high pressure) EGR, exhaust gases are recovered as they exit the combustion chamber and are still hot as they are ducted directly into the air intake, mixed with fresh air. Although this minimises the production of nitrogen oxides during combustion, it raises the intake temperature and reduces air mass, two factors which have a negative impact on energy efficiency.

With low-pressure EGR technology, the exhaust gases are recovered further downstream, once they have been through the primary turbine of the turbocharger and the particulate filter. They are cooled in a low pressure intercooler which enables them to be recirculated through the turbo, mixed with air. They are then cooled by air in the intercooler and used for combustion a second time. This cold loop enables the recirculation rate to be increased, while at the same time lowering the temperature and pressure. Emissions of nitrogen oxides are cut more efficiently than is the case with a high pressure EGR, and engine efficiency is improved. The combustion is of a higher quality and CO2 emissions are reduced.

Low-pressure EGR technology calls for an engine architecture that minimises the distance between the catalytic converter / particulate filter and the air intake, an arrangement known as a post-turbo after-treatment system.

This proximity enables the catalytic converter and particulate filter to function at higher temperatures and therefore more efficiently, and it also permits the fitment of a compact and efficient low-pressure EGR circuit.

Use of this technology reduces CO2 emissions by three per cent.

Variable swirl technology

‘Swirl’ is the horizontal rotation of air inside the cylinder. The swirl is produced during the intake stroke and is amplified during compression. Although swirl favours efficient combustion, its properties need to be adapted as a function of engine speed and load if performance is to be optimised.

Variable swirl technology consists of controlling the amount of swirl by means of a flap situated in the upper duct of the air intake. When the flap is in the closed position, gas flows unhindered through the ports that remain open; this increases turbulence.

This technology delivers CO2 emissions savings of 0.5 per cent.

Variable displacement oil pump

This technology allows the capacity of the oil pump to be adjusted as a function of the engine’s needs, which vary as a function of engine speed. This minimises the pump’s energy consumption.

The capacity of a conventional oil pump is fixed and oil pressure is capped by a relief valve. Pumping the oil the engine doesn’t need through the relief valve wastes energy. Variable flow pumps do away with the need for a relief valve and avoid the unnecessary consumption of energy that this sort of valve requires. The CO2 emissions saving achieved in this way is approximately one per cent.

Variable displacement oil pump. For detailed graphics, see bottom of page.

Triple post-injection strategy

As its name implies, post-injection consists of injecting fuel during the combustion phase of the four-stroke cycle. Fuel is injected into the combustion chamber at periodic intervals in the form of three very short post-injections. The fuel used for the last two post-injections produces a reaction in the exhaust line, inside the catalytic converter, thanks to the prior increase in the exhaust’s temperature resulting from the combustion of the first post-injection. This enables the necessary temperature for regeneration of the particulate filter to be reached, however the engine is being used.

The triple post-injection strategy is employed to optimise the amount of fuel used to regenerate the particulate filter and to limit dilution of engine oil with fuel. It combats CO2 emissions and permits extended oil change intervals.

Stop-start technology

Stop-start technology involves automatically cutting the engine when the vehicle is at a standstill. This system comes into its own in built-up areas and congested traffic.

The system uses a controller which instructs the ECU to cut the engine when three conditions are met: the transmission is in neutral, the clutch pedal released and the car’s speed is zero.

When the driver presses on the clutch pedal to select first gear to pull away again, the ECU is instructed to re-start the engine, allowing the vehicle to move away. To cope with the engine’s repeated starting, the specification of the starter motor is uprated.

This technology permits a CO2 emissions saving of three per cent.

EDC automatic transmission

This is Renault’s dual-clutch transmission. It marks a significant step forward compared with conventional automatic transmissions — a gain of up to 17 per cent, or approximately 30g of CO2 per kilometre.

The EDC uses the following technologies:

  • The use of a dual dry clutch combined with electric actuators — a world first.
  • Calibration focused on minimising fuel consumption.
  • This EDC transmission will be introduced in the first quarter of 2010 and will initially be available for core-range versions of the new Mégane (dCi 110 FAP). Thanks to their lower CO2 emissions, these Méganes will be the brand’s first automatic cars to qualify for the Renault eco² signature.

In recent years, several new types of automatic transmission have arrived on the market, delivering a steady improvement to performance, driving comfort, fuel consumption and CO2 emissions. Dual clutch automatic transmissions are an example of this progress.

The advantages of EDC automatic transmission

Renault’s EDC dual clutch transmission dispenses with the need for a clutch pedal, while gearshift control is of the ‘P-R-N-D’ type, plus an ‘up/down’ shift mode. The ideal gear is selected by an electronic control unit and gearshifts are both automatic and comfortable.

To optimise efficiency and minimise fuel consumption, Renault has chosen a dual dry-clutch system for its EDC transmission. The first of the two clutches looks after the odd-number gears (1st, 3rd and 5th), while the second covers the even-number gears (2nd, 4th and 6th) as well as reverse. The gears are carried by four shafts: two concentric primary shafts (each of which is connected to a clutch) and two secondary shafts. Gears are matched by means of synchronisers, as is the case with a manual gearbox. These synchronisers, like the clutches, are operated by electric actuators which are in turn controlled by a control unit.

The aim was fuel consumption and CO2 emissions comparable with that of vehicles equipped with a manual gearbox.

  • Dual dry clutch technology was chosen to minimise the parasitic friction associated with wet clutches and the converters of conventional automatic transmissions.
  • The two clutches and synchronisers use energy-efficient electric actuators.
  • Gearshift calibration has been optimised to achieve low fuel consumption: the system ensures a swift climb up through the gears in order to select the highest gear possible for a given speed, thereby minimising fuel consumption and CO2 emissions.
  • Renault’s EDC transmission delivers a level of efficiency similar to that of a manual gearbox.

As with any automatic transmission, gearshifts are carried out under load: i.e., the transmission of torque from the engine to the wheels is not interrupted.

When the vehicle is moving, one clutch is engaged and transmits engine torque via the selected gear, while the other clutch remains disengaged but connected to the next, pre-selected gear. At a predetermined moment, the gearshift takes place by switching from one clutch to the other: the first clutch becomes disengaged at the same time as the second clutch engages, ensuring that traction is not uninterrupted during the shift (under load).

With its six speeds and ultrafast shift time (290ms), the new EDC automatic dual clutch transmission is extremely responsive and is as enjoyable to drive as a manual gearbox, whether in automatic or ‘up/down’ shift mode.

In automatic mode, the electronic control unit takes on board a number of parameters to select the ideal gear. The system adapts instantaneously to the driver’s demands.

Optimised ‘creep’ has been built in. As with conventional automatic transmissions, the vehicle pulls away gradually when the brake pedal is released. This feature is particularly welcome in stop/start traffic or when parking.

Hill-start assist

When starting on a slope, the system continues to apply pressure to the brakes to keep the vehicle stationary for a few seconds as the driver lifts off the brake pedal. Coupled with the creep control system, this prevents rearward movement to ensure safe hill starts.

Equipped with this automatic transmission, Mégane Hatch, Coupé and Sport Tourer emit 114g/km of CO2 or 130g in the case of Scénic, Grand Scénic and Mégane Cabriolet.

Renault EDC transmission
Maximum torque 240Nm
Mass 82kg †
Length 384mm
Primary shaft
between centres
(differential)
188mm
Lubricant 1.7l
Gear ratio spread 6.6
Control unit Incorporated
Parking brake Rear, mechanical
Gearshift actuators Electromechanical
Clutch actuators Electromechanical
† Including dual-mass flywheel

These reductions in CO2 emissions have been achieved thanks to a range of engine and vehicle design improvements.

Powertrain: Taller ratios for all gears; reduced engine and transmission friction thanks to low-viscosity lubricants, and work on the geometry and finish of reciprocating and timing components. These developments will be extended to all EU5-compliant 1.5 dCi engines.

Vehicle design: Enhanced aerodynamic efficiency (flexible lip under front bumper, wheel arch extension shields, rear underbody shielding in certain cases) and reduced rolling resistance (low fuel consumption tyres).

All-electric vehicles from 2011

  • Electric vehicles represent the clean-break solution that can put ‘zero-emission’ mobility within everybody’s reach. [Zero local emissions. — Ed.] Renault Z.E. electric vehicles are poised to be marketed on a large scale.
  • This clean break already enjoys significant political support around the world, notably in the form of tax incentives based on CO2 emission savings, as well as the development of the infrastructures necessary for electricity-based mobility.
  • Renault will begin selling affordable mass-production electric vehicles in 2011.
  • The Renault-Nissan Alliance is aiming to be the market leader in sales of mass market Zero-Emission (during road use) vehicles.

Renault’s electric vehicles will offer customers a spacious interior, comfort, quality and safety. Renault is also working on the development of battery charging infrastructures that will be operational when the Renault Z.E. models are rolled out.

To develop these solutions, the Renault-Nissan Alliance has entered into a long list of partnerships with governments, energy companies and other organisations, such as Better Place, so that mass-market electric vehicles can become a reality.

The Alliance’s commitment to electric vehicles

In the 2009 edition of its World Energy Outlook, the International Energy Agency (IEA) explained that, without the implementation of new policies, the global demand for energy is expected to rise by 40 per cent. by 2030.

Three-quarters of new demand will be catered for by fossil fuels which, in this scenario, will lead to a one-third increase in greenhouse gas emissions. This would double the concentration of greenhouse gases by the end of the century (equivalent to 1,000ppm) and produce an increase in average temperature of 6°C.

As far as vehicles are concerned, switching to electric vehicles stands out as a clean break solution likely to bring down CO2 emissions, both at source (by removing the carbon factor involved in the production of electricity) and during road use. This represents a major shift and is notably highlighted in the EV/PHEV roadmap, another document published by the International Energy Agency in November 2009.

The Renault-Nissan Alliance is to market a comprehensive range of high-quality, reliable and innovative electrical vehicles at affordable prices. Renault Z.E. electric vehicles will be particularly quiet-running and generate zero emissions during road use. As such, they will mark an environmental clean-break that is within the budget of the majority of motorists.

This commitment to the electric vehicle is founded on a single, underlying principle: unlike all other technologies (internal combustion engines, hybrids), electric vehicles are genuine zero-emission vehicles regarding their use on the road. They also permit a reduction in oil-dependency.

Although the well-to-wheel emissions of greenhouse gases (expressed as equivalent CO2) can vary significantly depending on how the electricity they use is produced in the different countries where they are driven, electric vehicles still account for a smaller quantity of greenhouse gases than equivalent internal combustion vehicles.

When the electricity is produced by nuclear or renewable sources (hydro-electric, wind-generated, photovoltaic), the well-to-wheel performance of electric vehicles is indisputably superior. With the electricity generation methods currently employed in Europe, the results are still compelling, since CO2 emissions are halved compared to those produced by an internal combustion engine.

When the car is charged at night, customers can:

  • benefit from appreciable savings by profiting from off-peak tariffs offered by energy companies;
  • use the cleanest forms of electricity (nuclear, hydro-electric, wind power), since thermal power plants are usually on stand-by at night.

The Renault-Nissan Alliance’s battery production strategy

Battery production is poised to become a core activity for the Renault-Nissan Alliance. Renault and Nissan will manufacture lithium-ion batteries on three continents — America, Asia and Europe — with a view to supplying the body assembly factories where the forthcoming E.V.s will be produced from a local source.

This multi-locality arrangement will permit a secure supply flow and ensure logistics-related cost-savings, while at the same time enabling significant production volumes to be turned over. In the longer term, this set-up will allow the Alliance to produce more than 500,000 batteries annually.

Latest-generation lithium-ion batteries

All of Renault’s electric vehicles are powered by a latest-generation lithium-ion battery. The battery comprises 48 power modules, positioned in two rows, side by side. A module is similar in size to a laptop computer, and each one incorporates four elementary cells. In turn, each cell looks (on the outside) a bit like a Jiffy bag. It is inside these cells that the electrochemical reactions take place to producing a voltage. Each cell has a voltage of 8.4V, making a combined total of 400V for the 48 modules that are connected in series to make up the battery. This design offers superior cooling to cylindrical cells and is known unflatteringly as the ‘coffee-bag type’.

These compact, innovative lithium-ion batteries are produced by AESC (Automotive Electric Supply Corporation), a Nissan-NEC joint venture founded in April 2007.

The performance of these batteries compared with the older nickel hydride batteries is superior in every domain, including range, performance, reliability and safety.

  • Lithium-ion batteries do not suffer from the ‘memory effect’ that results from incomplete charge cycles and leads to a fall-off in capacity.
  • The battery is maintenance-free.
  • Eighty per cent. of its original capacity is available after six years.
  • The battery is cooled by ambient airflow thanks to the heat-dissipation properties of its aluminium casing.
  • The energy density is superior to that of nickel hydride units: 100Wh/kg against 63 for a NiMh battery.

Finally, lithium-ion batteries are recyclable and the Renault-Nissan Alliance is actively working on establishing recycling processes and infrastructures suited to automotive batteries.

The Alliance’s AESC 250kg batteries contain 3kg of lithium. According to the mining companies Chemetall and SQM, worldwide lithium reserves are currently estimated to be between 14 and 17 million tonnes.

A specific MMI (Man Machine Interface) has been developed to keep the driver informed about the vehicle’s current state of charge and remaining range.

A gauge alongside the speedometer displays the battery’s level of charge. An ‘econo-meter’ uses a new a new colour-coded system to tell the driver how economical his or her driving is in terms of energy consumption.

The trip computer is adapted to the needs of an electric vehicle, and indicates the number of kWh remaining, average and instantaneous energy consumption, and remaining range.

There are three battery-charging techniques:

  • A standard charge using a conventional plug via the household mains supply or at the workplace (between six and eight hours).
  • Fast charge: permits batteries to be charged to 80 per cent. of their capacity in 30 minutes.
  • Battery exchange stations: rapid battery exchange in bespoke exchange stations. In Israel, Better Place is currently putting a network of such stations into place. Around 100 will be operational in 2011 and they will be compatible with Renault’s first three-volume all-electric saloon car, the Fluence Z.E. Other stations will be opened progressively in other countries.

Battery exchange stations are being developed by different partners in different countries. The more electric vehicles there are on the road, the more partners there will be to put this concept into place. The Renault network is ideally qualified to develop this type of facility.

Renault’s electric vehicles will be equipped with smart navigation systems that will permanently indicate the battery’s remaining range, as well as the nearest charging or battery exchange station.

Use and maintenance

Owners of electric vehicles may carry out everyday servicing work in compliance with the instructions provided in the user’s manual. Safeguards have been put into place to prevent accidents such as electrocution when working around the motor.

As is the case with all types of vehicle, the insulation and waterproofing of the vehicle’s electrics have been designed to cover foreseeable driving situations in complete safety (e.g., water crossings).

In exceptional circumstances, such as flooding or immersion, the damage caused by water will not pose any particular risks, either for people or for the environment.

At speeds of less than 30kph, electric vehicles are extremely quiet, although it should be noted that electric vehicles can be heard beyond this speed — if only because of the road-noise generated by the tyres, in addition to the sound of displaced air. In response to this apprehension, Renault is currently working on the artificial generation of noise that would be audible; for example, thanks to a loudspeaker located in the motor compartment. Renault’s work in this domain anticipates possible forthcoming legislation.

About the customers

The four electric cars which make up the range of models that will begin to be introduced from mid-2011 are aimed at distinct types of customer:

  • To begin with, Twizy Z.E. Concept is an innovative two-seater vehicle which targets city dwellers looking for a safer, more comfortable, zero-emission (during road use) alternative to a scooter.
  • Zoe Z.E. Concept is a versatile, Clio-sized city car. It is the core model of the electric vehicle range.
  • Fluence Z.E. is an electric version of the Fluence saloon car, this spacious five-seater is ideal for single-car families and packs all the features expected of a D-segment vehicle. It is built on Renault’s C-segment (Mégane) platform.
  • Kangoo Van Z.E. is aimed at fleet operators and business customers. It combines the acclaimed strengths of Kangoo, including the same impressive load capacity, with the advantages of zero-emission motoring (during road use). Its missions include serving as a quiet, pollution-free final link in the supply chain for deliveries in built-up areas.

Potential electric vehicle customers

Surveys reveal that 50 per cent. of versatile, Clio-type hatchbacks are never used for long trips. Instead, they tend to serve essentially for short journeys, although half of owners cover 30 miles each day (i.e., 7,500 miles per year based on 240 days' use). In addition to the pleasure owners will derive from driving a Z.E. range car, they will clearly gain financially, too.

Since 2007, more than half of the world’s population lives in a built-up area, and the curve continues to rise.

Electric cars do not seek to fit in with all types of use, but they do have a natural role to play, especially as the second car of multi-car families in larger towns and cities.

Text and design copyright © Under the Skin 2010. We recommend Firefox.