Locomotive emissions measurements for various blends of biodiesel fuel.

The objective of this project was to assess the effects of various blends of biodiesel on locomotive engine exhaust emissions. The emission tests were conducted on two locomotive models, a Tier 2 EMD SD70ACe and a Tier 1 Plus GE Dash9-44CW, using two baseline fuels: (1) conventional Environmental Protection Agency (EPA) ASTM No. 2-D S15 certification diesel fuel and (2) commercially available California Air Resource Board (CARB) Ultra Low Sulfur Diesel (ULSD) fuel. A single batch of soy-based B100 was mixed in with the EPA and CARB diesel to yield a 5 percent and 20 percent blend of fuel. A randomized test matrix was used to perform triplicate tests on each of the six test fuels (EPA0, CARB0, EPA5, CARB5, EPA20, and CARB20). General emissions and fuel economy trends seen in other studies and applications for biodiesel use were also observed in this study. Higher blend levels of biodiesel were associated with lower carbon monoxide and particulate matter, as well as with higher levels of nitrogen oxides and fuel consumption. Use of diesel fuel with 20 percent biodiesel often resulted in statistically significant differences from the fuel with 0 percent or 5 percent biodiesel, while the difference between 0 percent and 5 percent biodiesel was generally not statistically significant.