One of the California Air Resources Board’s highest priorities is to reduce NOx and PM emissions from diesel engines. To support this goal, this project evaluated two different brands of experimental diesel particulate filters (DPF’s) on a 1,500 kW GenSet Switcher locomotives to determine their efficiency at reducing PM for this application. The locomotive used for these tests was UPY2737, an NREC Model 3GS-21B Ultra Low Emissions Locomotive (ULEL) originally manufactured in 2007. This is one of 70 of this type of locomotive operating in California. These locomotives are powered by three EPA Tier 3 nonroad, 522 kW, diesel engine driven generator sets.
Upon receipt, the locomotive was baseline emission tested and the results were provided to two DPF system suppliers. Experimental DPF’s provided by these suppliers were then installed and tested using only one of the three engine-gen sets.
The experimental DPF provided by Supplier “A” reduced PM emissions by 92 percent from baseline switch cycle levels, or 77 percent below the US EPA Tier 4 locomotive PM emission limit. Additionally this system essentially did not change the NOX emissions and cycle weighted fuel consumption from the engine. The experimental DPF provided by Supplier “B” also showed no significant change in the switch cycle weighted fuel consumption and NOX emission and reduced the PM emissions by 88 percent, which is 63 percent below the Tier 4 locomotive PM emissions limit.
Based on these successful screening test results, projects are underway to equip all three engines with production intent retrofit DPF systems on two revenue service locomotives, one for each of the two DPF suppliers.