The most recent agenda from the Society of Automotive Engineers' Powertrain & Fluid Systems Conference & Exhibition demonstrates how serious engineers are about studying renewable fuels and incorporating alternatives into the automotive mainstream. More than 400 people attended the conference held in Rosemount, Ill., where several technical presentations focused on biodiesel, renewable diesel and ethanol in various fashions.

According to SAE Program Engineer Colette Wright, the 2007 lineup included 27 presentations classified under "Alternative Fuels." She told Biodiesel Magazine that most of those specifically addressed alcohols, biodiesel, dimethyl ethers and natural gas. She also said there were stand-alone sessions involving engines and fuels of the future. "The program has addressed alternative fuels for at least 15 years, but of course the subjects were reflections of the industry," she said. "For instance, I pulled a program from 1996 that featured nine presentations almost exclusively on natural gas. In 2002, there were 17 presentations that included hydrogen, ethanol, methanol [and] natural gas."

At the October event, DuPont Performance Elastomers presented results from a study matching up various grades of DuPont fluoroelastomers with different types of biodiesel to ascertain compatibility and recommend best-in-class offering. Speaker Eric Thomas of DuPont's elastomer division said six DuPont materials with varying compositions and fluorine contents were used in the study. All of the B100 and biodiesel blends for the study were transesterified from rapeseed oil and met SAE-designated specifications. The petroleum diesel was on-spec No. 2 ultra-low sulfur diesel. Six fuels-including B100, B20 and B5-were tested with the DuPont materials. The other three fuels were B100, B20 and B5 blended with 0.5 percent distilled water. Thomas concluded that fresh, presumably pure rapeseed methyl ester isn't aggressive toward fluoroelastomer compounds and doesn't swell the material, even conventionally formulated fluoroelastomers containing metal oxide. The study also concluded that biodiesel containing water and/or acid can be very aggressive toward conventionally formulated fluoroelastomers, causing those containing metal oxides to swell-in some cases, severely. Peroxide-cured fluoroelastomers without metal oxides were resistant to wet acidified B100 and biodiesel blends. Thomas noted that all the metal-oxide-free fluoroelastomers performed well under all conditions with all fuel blends.

Another presentation, according to an abstract submitted by Monica Larsson of Chalmers University of Technology, compared emissions from Swedish low-sulfur diesel, Fischer-Tropsch diesel synthesized from natural gas and biodiesel transesterified from rapeseed oil. Using a single-cylinder, heavy-duty engine at 25 percent and 100 percent loads, and a constant engine speed of 1,200 revolutions per minute, results showed soot emissions from Fischer-Tropsch diesel and biodiesel were up to 40 percent and 80 percent lower, respectively, compared with low-sulfur Swedish diesel. The Fischer-Tropsch diesel gave off slightly lower nitrogen oxide emissions than the Swedish diesel but the nitrogen oxide produced from biodiesel was slightly higher. Fischer-Tropsch fuel consumption matched Swedish petroleum fuel consumption, but biodiesel displayed a 10 percent increase in fuel consumption due to its lower energy content.

"For 2008, I would expect similar subjects as were given in 2007," Wright said. The deadline for 2008 abstract submissions was in February, but 2008 program information won't be available until this summer. Until then, for more information on presentations given during the 2007 meeting, visit www.sae.org.