Renault EOLAB and DuPont™ Vizilon® TPC
What’s the secret to building an ultra-low emissions car? For French automaker Renault, the answer has three parts: innovation, innovation, and innovation. Unveiled at the 2014 Paris Motor Show to wide acclaim, Renault’s ultralight EOLAB vehicle is the fruit of two years of concentrated engineering research, all pointing to one goal: creating an affordable consumer vehicle with a drastically lower carbon footprint.
With its sleek, meticulously crafted appearance, EOLAB got high marks from those who attended the Paris event, but the car is much more than just a pretty face. Unlike many “concept” vehicles that are doomed to live out their days as mere curiosities, EOLAB serves as a roadmap toward a more sustainable future. From bumper to bumper, EOLAB cradles no less than 100 reproducible technological advances, all developed to help lessen the environmental impact of subsequent generations of vehicles.
A National Focus
Renault launched its EOLAB project in response to the French government’s New Industrial Plan, in particular the Minister for the Economy, Industrial Renewal and Digital Affairs’ initiative to encourage widespread adoption of vehicles with fuel consumption of less than two litres/100km (141 mpg). The plan, which involves the entire French auto industry for a total of more than 160 businesses and groups, promotes the development of technological ‘building bricks’ for curbing CO2 emissions—critically, at a price-point consumers can afford.
The challenge for EOLAB was to offer a level of performance and cost representative of a B-segment (“supermini”) vehicle that could be produced on an industrial scale within the decade.
EOLAB’s designers focused their efforts on three main areas:
- Employing zero-emissions technology
- Improving aerodynamics
- Minimizing weight
Through careful modeling, Renault managed to reduce EOLAB’s drag coefficient by 30%. That, combined with a modified version of Renault’s hybrid Z.E. (“zero emission”) powertrain, served to boost the car’s fuel efficiency significantly. But aerodynamics and improved mechanics are a well-trod path to low-emissions vehicle design. A more ambitious goal would be getting EOLAB’s weight down.
DuPont at the Drafting Table
DuPont Performance Materials was on the short list of partners selected to participate in the EOLAB project. With the industry’s most extensive portfolio of advanced materials, DuPont was a natural choice when it came to the task of lightweighting the Renault prototype. For EOLAB, Renault selected DuPont™ Vizilon® TPC, a family of lightweighting composite solutions all supported by DuPont’s advanced simulation and production capabilities.
Unlike most of today’s car bodies, EOLAB’s multi-material shell combined steel, aluminum, magnesium, and thermoplastic composites that were hand-selected according to their weight, cost, and production readiness.
Keeping materials costs down was the number-one driver for the EOLAB team. “You can always save weight if you’re prepared to pay the price, but that would be contrary to Renault’s philosophy,” said EOLAB project leader Laurent Taupin. “Our strategy is to reduce weight in a way that benefits everybody. That means finding economically viable solutions that our customers can afford. Our approach can be summed up by the phrase: ‘the right material for a given job.’”
By that standard, DuPont™ Vizilon® TPC was a clear success. The EOLAB car included four structural parts designed with Vizilon® TPC (shown in the figure below as light green parts): its B-pillars, a lower cross member, and its front, central, and rear, floor pans.
Taken on their own, the floor pans manufactured with Vizilon® TPC offered:
- Weight reduction of 16.5kg (36.3 pounds)
- Parts integration (reduced the number of parts by >50%)
- Outstanding crash performance
- Dimensional stability
- Excellent part stiffness from -40°C to 90°C
- Electrocoating suitability
- High damping coefficient
When its incremental weight savings were added up, EOLAB tipped the scales at just 955kg (2,105 pounds), 20% (881 pounds) lighter than Renault’s baseline vehicle, the popular five-door Renault Clio.
The environmental benefits of all that lost weight are hard to ignore. For every 10kg (22 lbs.) of weight shed, the EOLAB produced a predicted 1g/km less CO2. “Saving weight is a ‘virtuous circle’” said Taupin. “The savings from the materials choices we made in designing EOLAB allowed us to use more expensive features where they would make the greatest impact.”
As anyone in the car business knows, consumer acceptance drives sales, a fact that was no less important in EOLAB’s case. Renault had proven to the world that it could build a car that gets 100km/l (235 mpg). But a more pressing question lingered: Would anyone actually want to buy one?
If initial reports are any gauge, the answer is a resounding “yes.” Close on the heels of EOLAB’s 2014 debut, UK-based Auto Express enthused that EOLAB “looks fantastic” and didn’t “compromise on performance despite the remarkable efficiency gains.” Test drivers from BBC’s popular “Top Gear” program were equally convinced, describing EOLAB’s ride as “supple” and its body as “impressively tight and rigid.”
“But the main thing is, it drives like a normal car,” the “Top Gear” team reported at their website. “If this is the supermini of the next generation, we’re in.”
With lessons learned from EOLAB, by 2020 Renault expects to market its first vehicles boasting a fuel consumption of less than two litres/100km (117 mpg), a goal that now looks very achievable, thanks in part to DuPont Performance Materials.
“EOLAB is a statement of our company’s environmental strategy, which strives to reduce the carbon footprint of its vehicles across successive generations,” said Taupin. “Everything is geared towards frugality. It demonstrates that Renault is able to add a touch of dream-like magic to a prototype whose fundamental mission is to achieve ultra-low fuel consumption.”