With increasingly stringent emissions regulations for NOx and the known tradeoff of fuel consumption with NOx, ensuring the use of appropriate correction factors becomes increasingly significant to the OEM and customer. The Environmental Protection Agency (EPA) has specified in 40CFR Part92 that locomotive engines shall use a NOx correction factor, KNOx = f(KH), where KH is the humidity correction factor. This paper will present an alternative NOx humidity correction factor for GE Rail 4-stroke medium speed diesel engines. GE Rail’s NOx humidity correction factor will be compared with five other correction factors in a numerical exercise to assess the sensitivity to variations in ambient temperature, ambient pressure, relative humidity and A:F ratio. GE Rail’s alternative correction factor provides a 25% reduction in Line Haul Duty Cycle BSNOx variation and a mean BSNOx reduction of 3% as compared with KNOx correction factor from Part92.

The Environmental Protection Agency (EPA) has regulated that locomotives must comply with emissions regulations from sea level up to 2133 meters (7000 feet) altitude. GE Rail has assembled a mobile emissions test laboratory that can be taken by rail to desired testing locations of varying altitude anywhere in North America. This paper gives an overview of the mobile test laboratory’s make up and locomotive preparation for test. Testing was conducted as part of GE Rail’s development of 21st Century Locomotive. The paper presents test results of altitude effects on GE’s Evolution Series Locomotive including regulated emissions and engine performance. The Evolution Series Locomotive meets EPA Tier 2 locomotive emissions regulations applicable to new locomotives manufactured after January 1, 2005.

As with most internal combustion engines, the locomotive diesel is subjected to increasingly stringent regulatory emissions standards. Currently, diesel electric freight locomotives are regulated by the Tier 1 emission standards that went into effect January 1, 2002 as ruled by the United States Environmental Protection Agency (EPA). Beginning January 1, 2005 the US EPA Tier 2 diesel locomotive emissions standards will become effective. To achieve the new emissions standards an extensive engine development program was initiated. This paper will present a portion of the development conducted on a single cylinder engine (SCE) investigating the effects of injection pressure on emissions. The experimental results are presented with a discussion of the possible mechanisms leading to the results with supporting evidence from existing literature and analysis. This paper will focus on the effect of injection pressure as generated by pump capacity and nozzle cup hydraulic flow.