Renault Powertrain Strategy: Focus on Electric Motor Development for EV Powertrains, New Technologies for Conventional Engines
Renault is currently working on the development of low-emission and zero-CO2 emissions vehicles in what it calls “a determined bid” to introduce as many effective technologies as possible at an affordable price. Its work on powertrains focuses on two main areas: the development of a range of electric motors for all-electric vehicles, and new technologies for conventional engines, including a new generation of turbocharged internal combustion engines as well as on new automatic transmissions.
Electric motors. Renault is aiming to become the industry leader in the realm of mass-market electric vehicles. The Renault-Nissan Alliance is consequently developing a comprehensive range of all-electric powertrains, with power outputs ranging from 50 to 100 kW (70 to 140 hp).
Renault says that its commitment to the development of zero-emission electric vehicles is due to a number of factors:
Awareness of the role CO2 emissions play in global warming;
Toughening legislation aimed at curbing CO2 emissions;
Oil price increases;
A growing need for urban mobility and the potentially significant market in Europe, due notably to motorists who primarily use their vehicle on a daily basis to get to and back from work—in other words urban commuters for whom electric vehicles are a workable solution;
Lithium-ion battery technology within the Renault-Nissan Alliance thanks to Automotive Electric Supply Corp (AESC), a joint venture involving Nissan and NEC; and
The development of new consumer patterns (monthly subscriptions, pay as you go schemes, etc.) which already operate in numerous sectors and which can be carried over to the automobile.
Renault is targeting its all-electric powertrains for a wide range of vehicle categories, from city cars and family sedans, to small and large vans. The first vehicles to feature all-electric powertrains will be a three-box sedan and a Kangoo-type van as early as 2011.
Conventional combustion engines. To achieve significant reductions in CO2 emissions from its conventional powertrains, Renault is working concurrently on:
Fundamental vehicle design parameters: mass, aerodynamics (CdA), rolling resistance;
Efficient management of electrical energy (battery recharging under braking and when decelerating) and thermal energy (to speed up the climb in engine temperature);
Transverse technologies, including stop & start which automatically cuts the engine when the vehicle is at a standstill;
Widespread downsizing of internal combustion engines (smaller turbocharged engines are more efficient). This work covers both gasoline and diesel powerplants, although the greatest scope for reducing CO2 emissions concerns gasoline engines; and
More efficient manual and automatic transmissions.
Renault is developing a new family of modular TCe gasoline engines. (The company introduced the TCe 100 in 2007 and the TCe 130 in 2008, earlier post.)
With the imminent switch to Euro 5 and Euro 6 legislation, Renault expects gasoline engines to become an increasingly attractive proposition in diesel-oriented Europe, a trend it is trying to anticipate with a new family of three- and four cylinder TCe engines.
Based on a range of cubic capacities extending from 0.9 to 1.2 liters, they will replace the current normally-aspirated engines in the 1.2- to 1.6-liter bracket. These new engines, which will feature a low inertia turbocharger, will focus on power outputs of between 65 and 85 kW (90 and 115 hp). Renault will go on to develop more powerful versions.
The basic design of these engines will permit the use of direct fuel injection and will enable even higher specific power outputs. CO2 emissions will be cut by between 30 and 40 g/km compared with the engines they replace, and certain vehicles will be able to claim CO2 emissions of less than 100 g/km.
The first of these engines will be launched within the next two-and-a-half years, and Renault estimates that these powerplants will go on to account for some 85% of the gasoline engines it markets in Europe.
This family of modular engines is being developed within the framework of the Renault-Nissan Alliance, an approach which permits capital outlay to be shared and economies of scale to be achieved, while also allowing the development of powertrains that meet the specific needs of different regions. Renault are bringing its understanding of the European market and experience of turbocharging to the table.
On the diesel side, Renault's engineers intend to maximize the benefits of its dCi technology with evolutionary technologies aimed at enabling them to comply with upcoming emissions standards and making them even more fuel efficient. Numerous vehicles powered by these new-generation dCi engines will be able to claim CO2 emissions of less than 100 g/km, according to Renault.
Renault plans to modify its mainstay 1.5 dCi (Type K9K)—currently the most commonly sold Renault engine—enabling a reduction of approximately 20 g/km less CO2 when the new version is introduced in 2012.
An all-new 1.6 dCi 130 engine will offer peak power of 96 kW (130 hp) from launch. The 1.6 dCi represents a 16% reduction in cubic capacity compared with a current 1.9-liter diesel engine of the same power output. Renault will go on to develop more powerful versions. CO2 emissions will be reduced by 25 g/km compared with an equivalent engine, independent of improvements made to the vehicles it equips in fields such as aerodynamic performance, rolling resistance, mass, etc. It will be Euro 6-ready and is covered by 15 Renault patents.
This engine will form the core of the brand’s C-segment line-up and will also play key roles in its D-segment and van ranges. Its launch is scheduled for 2011. This project, code-named R9M, is a Renault-Nissan Alliance joint development.
The new-generation 2.0 dCi engine (Type M9R) is due to be released in 2012. In the meantime, Renault will carry over its downsizing policy to cover utility vehicles with the replacement of its current 2.5-liter engines by a 2.3 dCi unit featuring the same genetic make-up as the 2.0 dCi.
The V6 dCi (Type V9X) will continue to equip the group’s upper-range models.
Automatic transmissions. Renault is pursuing two objectives through its development of new automatic transmissions:
Improved mechanical efficiency compared to that of a conventional automatic transmission (with hydraulic coupling) thanks to technologies carried over from manual gearboxes; and
Profit from the ability of automatic transmissions to permit an engine to run at the most energy-efficient revs.
Renault will release a twin-clutch transmission within the next year. Twin clutch transmissions enable gears to be changed without interrupting the transmission of torque. Twin clutch transmissions also combine ride comfort (no jarring during gearshifts, no loss of traction) with CO2 emissions identical to those of a manual gearbox (a reduction of 15% compared with conventional automatic transmissions).