Putting Green in Gear
Globally sustainable mobility, the theme of this year's Society of Automotive Engineers' World Congress, reflects the growing importance of green design to the automotive industry. As general chair of...
Globally sustainable mobility, the theme of this year’s Society of Automotive Engineers’ World Congress, reflects the growing importance of green design to the automotive industry. As general chair of the Congress and managing officer of Toyota Yasuhiko Ichihashi observed, “If current mobility trends were to continue, social, economic and environmental costs would be unacceptably high; we must now plan for the next generation.”
Yet, green design encompasses a diverse range of strategies and technologies, some of them feasible today, some of them futuristic. One thing is certain: automotive OEMs are in the mood to push the envelope and eager to partner with companies with innovative approaches to improving automotive sustainability.
THE LIGHTER SIDE
Perhaps the most pragmatic, simplest approach to green design is reducing the weight of the automobile. Lighter cars and trucks go further on a litre of gas, reducing overall emissions. Today’s car and trucks are indeed much lighter per unit of horsepower than their heavy-metal cousins of thirty or forty years ago, and much of the credit goes to plastic. Equipped with higher performance resins and complimentary technologies, engineers and suppliers continue to find fresh ways of infusing more plastic into production vehicles.
InoPlastic Omnium Auto Exterior LLC, which has offices in Troy, Mich., has developed a new, all-plastic design for a rear liftgate or “hatchback” for cars, minivans and SUVs. Called Higate, the part is comprised of a SMC inner panel and a thermoplastic outer panel. The tailgate is 15 to 20 per cent lighter compared to metal-based design, but Higate’s main innovation is the use of a combination of thermoset and thermoplastic materials.
According to Andrew Novak, the company’s senior product manager, composites, the SMC panel provides rigidity, geometry and good high temperature performance, while the outer thermoplastic panel has a low coefficient of thermal expansion and superior paint characteristics. Paintability is crucial, as the part has to meet stringent Class A surface requirements and match colour exactly to the rear fascia. Meeting those appearance requirements is more difficult with a tailgate made entirely of SMC, which is more challenging to paint.
The key to the mating of thermoplastic and thermoset panels was the in-house development of a new adhesive, according to Chuck Saito, the company’s sales and marketing director, Japanese OEMs. “We developed a unique adhesive that binds two different materials,” Saito said. “The key is to control the thermal expansion of two different materials.”
InoPlastic Omnium is working with a European OEM to introduce the Higate tailgate on a production vehicle in the near future.
Plastic is also making inroads into components in the powertrain, an area conventional wisdom once deemed an all-metal domain. Saint-Gobain Performance Plastics, headquartered in Sugarland, Tex., supplies materials for a part used in automotive transmissions. The part, called a gerotor, is a component of positive displacement oil pumps that supply hydraulic oil pressure vital to transmissions. Composed of an inner and outer ring, the part is made of two grades of the company’s Meldin line of polyimide resins, Meldin 5330 and Meldin 1003. The parts, which replace a part usually made of powdered metal, provide a weight savings of about 75 per cent, according to Ken Smith, Saint-Gobain product manager, Meldin series.
According to Smith, the two Meldin grades used in the gerotor have different base resins, as well as a proprietary package of fillers and additives. “We developed these materials specifically for these types of parts,” he said. “The weight savings give an increase in output horsepower by itself.”
Smith also noted that the thermoplastic parts have better resistance to cracking than powdered metal, as well superior vibration dampening characteristics at high rpms. Saint-Gobain also injection molds the parts, which have very tight tolerance requirements. The parts are currently used in motor-sport cars, but Smith said automotive OEMs are showing high interest in transferring the technology to mass-produced consumer vehicles.
The specific gravity of polycarbonate (PC) is 50 per cent less than that of glass, which is why automotive OEMs have always been willing, in theory, to consider PC glazing as a replacement for glass. The challenge for suppliers has been to demonstrate that PC can perform as well as glass, while at the same time meeting all the safety and legal requirements. In that respect, according to Bayer’s David Loren, PC glazing has made great technological strides, evident by the rapid growth of commercial applications over the past five to 10 years.
Loren, Bayer program manager, future business group and leader of PC glazing technology in North America, says innovations in coating technology and chemistry has driven up the performance of the Exatec (the joint technology venture between Bayer and GE Plastics) PC glazing system. The PC produced by it can now pass the AS2 application requirement for hazing. The AS2 is the second most demanding rating, just below the AS1 rating required for front windshields. Simply put, there is now no technical material performance barrier preventing the replacement of glass with PC in all automotive window applications other than the windshield.
“Automotive OEMs seem satisfied with plaque (test) data,” Loren said. “They are moving on to auto applications studies, for example what happens to the thermal expansion of a window at 85 Celsius.”
Loren says one significant growth area for PC glazing is panoramic roofs, which are larger than sunroofs and generally not required to move. The 2006 Mercedes GL Class launched with a 1.1 m2 (square) PC roof panel and Daimler-Chrysler’s new 2008 Smart fortwo model, which is coming to North America, has a 1.2 m2 PC roof. The Chevrolet Corvette C5 and C6 models also have PC roof panels.
“The move to larger, panoramic roofs is definitely a styling trend as it allows more light into the vehicle,” Loren noted. The lightness of PC is a distinct advantage in these applications, he continued, because it doesn’t top load the car with extra weight, helping to prevent rollovers. According to Loren, a number of North American OEMs are seriously considering using PC glazing in roof applications that could be commercial “by the end of this year.”
GREEN IS IN THE DETAILS
Environmental proficiency does not begin and end at the tailpipe. Modern environmental science is keen on the concept of “lifecycle” impact of a product — i.e., the sum of the total energy, emissions and waste generated and consumed in the course of a product’s manufacture, use and disposal. OEMs and suppliers are looking at everything from materials to processes to improve the lifecycle rating of automobiles.
Solvay Engineered Polymers Inc. has developed a new line of pre-coloured TPO compounds. The Indure series is targeted to replace painted plastic parts in high-gloss exterior applications. Using pre-coloured parts eliminates VOC emissions associated with painting. Pre-coloured materials are also a boon for recycling.
“Usually, if a part is painted, recycling becomes much more complex,” Mitesh Shah, technical manager, automotive operations, said. “Recovery requires separation of the painted material which adds cost.”
Solvay currently has three pre-coloured grades of Indure commercialized: X76, X210 and X225. Indure X210 is designed to replace ABS and is currently used to injection mold a transition panel that fits into the body of a school bus. The two other grades will be used to mold two automotive trim parts in four different metallic colours. The parts are expected to be in production in the 4th quarter of 2007.
According to Shah, the Indure line has been in development for four to five years and brings a step-change improvement in pre-coloured resins for high-gloss applications with Class A finish requirements. “O
ther pre-coloured products and blends that have been on the market do not show good weatherability,” he said. “Our material provides the same weathering performance as paint.”
Engineers are still a long way from achieving the goal of building a completely recyclable automobile. While most of the metal is readily recovered at the end of a vehicle’s life, the mixture of plastics, fabrics, electronic components and other materials left over still defy an efficient, clear-cut method of recovery and reuse. The most common approach is to reduce this grab bag of materials, using any one of a variety of technologies, into generic mush, called automotive shredder residue (ASR). Other technologies attempt to make some use of ASR, for example as a fuel or feedstock. While some inroads have been made to improve the process, ASR production and use is nonetheless unwieldy and inefficient.
One alternative is to build a vehicle that is easy to disassemble so that relatively homogeneous systems can be recovered intact. Ford’s Vehicle Recycling Partnership is an initiative that brings together suppliers and recyclers to look for innovative ways of separating plastics, foams and metal from ASR. Another research project has described an alternative method for recycling plastic fuel tanks (PFT) from scrapped vehicles. The study, led by David Raney at American Honda Motor Co., found that PFTs could be economically used as an alternative, high-BTU fuel source in cement kilns, with the possible additional benefit of reducing air pollution during cement production.
Another route to building greener vehicles is by increasing the amount of recycled and bio-based plastics in the design. Ford uses post-consumer and post-industrial recycled plastics in components such as air ventilation ducts, battery trays, trunk linings and housings.
GE Plastics recently introduced two resins made primarily from post-consumer polyethylene terephthalate (PET), Valox iQ and Xenoy iQ. Valox iQ PBT resins are made from 85 per cent recycled PET. As they are upcycled from PET, the resins offer virgin thermoplastic properties with an extremely low carbon footprint. According to GE Plastics, Valox iQ uses 80 per cent less energy and carbon dioxide emissions than standard nylon 6/6, and 50 per cent less energy and carbon dioxide than bio-based polylactic acid. Xenoy iQ, meanwhile, is an alloy of PBT and PC polymers, also derived from 85 per cent post-consumer plastic. The resin is being used to make the hood and doors on General Motors’ electric-hybrid concept vehicle, the Chevrolet Volt.
DuPont Engineering Polymers launched two new biopolymers at last year’s National Plastics Exhibition (NPE): a bio-based version of its workhorse thermoplastic polyester elastomer Hytrel, and a totally new biopolymer called Sorona. DuPont manufactures the monomer 1,3 propanediol (PDO), the base ingredient used in both biopolymers, using a fermentation process based on corn sugar and genetically engineered bacteria. The production process uses 40 per cent less energy than its petroleum-based counterpart. According to Dupont, Sorona has performance and molding characteristics similar to PBT, making it ideal for automotive parts and electronic systems. Preliminary testing on Hytrel made with Bio-PDO shows improvements in temperature resistance and elasticity. It too is targeted for automotive applications. Both polymers are expected to be fully commercial by the end of this year.
Taking a cue from life itself, it seems, automotive engineers are discovering there are many shades of green.
Auto biomaterials move full speed ahead in Ontario
The greening of the automotive sector has recently put a spotlight on two automotive biomaterial initiatives in Ontario.
In March 2007, the Ontario Ministry of Research and Innovation invested $5.9 million in the Ontario BioCar Initiative, a multi-university research project helmed by University of Toronto chemical engineering professor Dr. Mohini Sain. Sain is very active in the plastics industry, and also acts as the director for the University of Toronto’s Centre for Biocomposites and Biomaterials Processing.
“We integrate three different declining industries, the forestry sector, agricultural sector and automotive sector,” explained Sain.
The Ontario BioCar Initiative — consisting of 24 experts from the Universities of Guelph, Toronto, Waterloo and Windsor — is trying to use bio-based feedstocks such as corn, wheat, soybeans and wood fiber in usable automotive applications.
In addition, the Ontario ministry announced $255,000 of funding for the Ontario BioAuto Council, a coalition that was formed in July 2006. The council also received $6 million as part of the province’s environment-related budgetary spending.
Headquartered in Guelph, Ont., the council aims to move emerging auto-related bioplastic technologies into the marketplace and attract jobs and investment. Former Canada Colors and Chemicals Limited president Bernard West is chair of the council, which brings together more than 20 key players in the province’s automotive assembly and manufacturing companies, agriculture, forestry, chemical and plastic manufacturing, public research and several Ontario ministries.
The council plans on creating a Sector Innovation Network (SIN) that will facilitate linkages and build a network that includes science, industry and capital focused on creating a bioplastics industry in Ontario.
“We will ensure Ontario is positioned to capture a substantial share of what is projected to be a $50-billion global market for bioplastics by the year 2015,” said council executive director Terry Daynard.
Michael R. LeGault is a former editor of Canadian Plastics magazine
Bayer Inc. – Div. of Bayer AG (Toronto); www.bayer.ca; 866-770-1102
Detroit Engineered Products (Troy, Mich.); www.depusa.com; 248-269-7130
E.I. DuPont Canada Company (Mississauga, Ont.); www.plastics.dupont.com; 800-387-2122
GE Plastics Canada (Mississauga, Ont.); www.geplastics.com; 800-845-0600 Ext. 1
InoPlastic Omnium Auto Exterior LLC (Troy, Mich.); www.plasticomnium.com; 248-458-0785
Saint-Gobain Performance Plastics (Sugarland, Tex.); www.plastics.saint-gobain.com; 281-565-6071
Solvay Engineered Polymers (Canada) Inc. (Concord, Ont.); www.solvay.com; 905-738-6433