This paper describes the development, testing, and application of a low emissions upgrade kit for 1.5 MW EMD GP20D locomotives. Low emissions development focused on changes to fuel injection timing combined with the application of crank case ventilation system (CCV) and catalyzed diesel particulate filters (DPF). Composed of a porous cordierite ceramic material, the diesel particulate filters are specifically designed for entrapment of diesel particulates while allowing exhaust gases to flow through. Furthermore, the filters are coated with a proprietary catalyzed washcoat that promotes the oxidation of soot within the exhaust gas temperature range observed under normal engine operation. In addition to the low temperature oxidation of soot, the catalyzed filter also reduces carbon monoxide and unburned hydrocarbons.
The test locomotive used for this development, which is owned by CIT Rail, was powered by a recently rebuilt Caterpillar 3516B engine with a rated power of 1.5 MW (2,000 HP). Baseline exhaust emission testing was performed, followed by low emissions retrofit development. In combination with the CCV and new fuel injection calibrations, the DPF system netted significant emissions reductions. The result of the final low emissions upgrade kit was an EPA Tier 1+ certification, with emissions levels that were below EPA Tier 3 locomotive switch cycle standards for oxides of nitrogen (NOx) and below EPA Tier 4 switch cycle standards for hydrocarbons (HC), carbon monoxide (CO), particulate matter (PM), and smoke.