Evaluation of Emissions and Performance of Diesel Locomotives With B20 Biodiesel Blends: Static Test Results

This paper describes the results to date of a study to quantify the exhaust emissions and performance characteristics of 20% soy methyl ester biodiesel blends (B20) in diesel locomotives representative of a typical commuter transit fleet. Testing is performed with #2 diesel summer blend, #2 diesel winter blend, ultra low sulfur diesel (ULSD) summer blend, ULSD winter blend and B20 blends with each of these fuels. Tests are performed on two different diesel locomotive types to determine the differences in performance and emissions between older and newer locomotive engines when operating on biodiesel blends. Specifically, tests are performed on a GP40FH-2 locomotive equipped with an EMD 16-645 engine manufactured from a 1960’s design and a recently manufactured ALSTOM PL42AC locomotive equipped with an EMD 16-710 engine. The tests are being performed in two phases. The first phase of the project is performed by operating the diesel engines statically (using a load bank) over the full test matrix of 8 fuels. During the static testing phase, brake specific exhaust emissions and fuel consumption are computed for each fuel blend using the line-haul and switcher duty cycles as outlined in the CFR Part 40 Title 92 Federal Test Procedure. Each fuel/locomotive test combination is performed 3 times to ensure repeatability. The second phase of the project consists of mobile in-use emissions testing using a simulated, mobile duty cycle based on actual commuter rail routes. To accurately quantify the exhaust emissions, measurements are made using a Sensors SEMTECH-D mobile emissions analyzer to measure CO, CO₂, NO₂, NO, O₂, and total unburned hydrocarbons (HCs), along with a Wager 6500RR Railroad Opacity Meter. Instantaneous fuel consumption is monitored using two AW Company JV-KG positive displacement flow meters, which measure the supply and return fuel flow rate, respectively.