Diesel Engine Performance and Exhaust Emissions Using Cottonseed Oil Biodiesel

Non-road diesel engines are significant contributors to air pollution in the United States (USEPA, 2004). These engines emit particulate matter (PM), nitrogen oxides (NOx), sulfur dioxide (SO2), and other pollutants. The Clean Air Non-road Diesel Rule was put in place to reduce emission levels from agricultural, construction, and industrial diesel powered equipment. This rule calls for a reduction in sulfur concentrations in diesel fuel. While this reduction will decrease SO2 emissions, it will also affect fuel lubricity since sulfur in the fuel acts as a lubricant. Biodiesel is a clean burning alternative fuel produced from plant oils or animal fats (NBB, 2006a). Biodiesel is easily blended with petroleum diesel to create biodiesel blends, and is essentially free of sulfur. Biodiesel blends, which contain less sulfur than petroleum diesel, decrease the concentration of sulfur in the fuel, while providing engine lubrication that would otherwise be provided by the sulfur in the fuel. Biodiesel has a lower energy content than petroleum diesel. Therefore, biodiesel blends have a lower energy content. This difference in energy content will likely result in lower fuel efficiency for biodiesel blends. In the experiment planned for this research, brake specific fuel consumption will be determined for a 19 horsepower engine using several cottonseed oil-biodiesel blends. Engine performance curves will also be developed.