Like it or not, ethanol blend fuels are here to stay. Because some remain unconvinced of the biofuel, automotive engineering consultant Ricardo has attached its name on a study exploring the effects of E15 (15 percent ethanol, 85 percent gasoline) on vehicles from the 1994 to 2000 model years.
One of the biggest call outs on the implementation efforts of concentrated ethanol-blend fuels is the side effects. The increased alcohol content affects the chemical properties of gasoline and is corrosive to rubbers, metals, and plastics in varying degrees. In smaller amounts, the ethyl alcohol reacts and combusts with little problem -- in fact, E5 and E10 availability continues to grow in the United States. Now, a push for another five parts of ethanol to E15 has some parties concerned about the effects on engines, fuel delivery, and emissions-control systems.
Looking to help rid furrowed brows, the Renewable Fuels Association had Ricardo study observed changes from E10 to E15 blends with special emphasis on what the report dubbed "older vehicles." The report found "older vehicles," or those from the 1994 to 2000 model years, comprise 25 percent of the U.S. light-duty vehicle fleet. The model years from 2001 to 2010 are expected to make up another 63 percent, indicating 88 percent of the vehicles on the road today are from the years of 1994 to 2010 (around 200 million units). Ricardo's testing focused on the top-selling "older vehicles" and discovered the additional ethanol content made little to no change to tailpipe and evaporative emissions, assuming vehicles have working O2 sensors.
While the report didn't explicate testing time periods and conditions, the overall consensus was the effects of E15 would be barely different from the effects of E10. Ricardo extracted common fuel system components for evaluation and found three noteworthy changes to the two grades of nylon used in fuel lines and the aluminum in the fuel injectors compared to E10. However, the changes were small enough that Ricardo doesn't consider them hazardous. Consequently, Ricardo's final analysis determined using E15 wouldn't negatively impact the majority of vehicles on the road today.
"Older vehicles represent a significant yet previously comparatively under-researched element of the US national vehicle fleet," said Kent Niederhofer, Ricardo president. "In considering the potential risks and benefits of increasing the current ethanol blend ceiling in regular gasoline from 10 to 15 percent it is crucial that the interests of the potentially very large stakeholder group represented by the owners of these vehicles are investigated. While many previous studies by Ricardo and others have evaluated the impact of higher ethanol blends on newer vehicles, this study demonstrates for the first time that raising the blend ceiling to E15 is likely to have a negligible impact on vehicles manufactured between 1994 and 2000."
Take a look at the summary of Ricardo's E15 study HERE.