Development of a new composite school bus test cycle and the effect of fuel type on mobile emissions from three school buses

The New Jersey Department of Transportation sponsored a research study at Rowan University to develop strategies for reducing diesel emissions from mobile sources such as school buses and class 8 trucks. The results of mobile school bus testing performed to quantify the emission reduction capabilities of various alternative fuels, e.g., B20/#2 diesel, ultra low sulfur diesel (ULSD), and B20/ULSD, when applied to school buses that are representative of those currently in use in the state of New Jersey were presented. Exhaust gas emission measurements were carried out to measure CO, CO₂, NO₂, NO, O₂, and unburned hydrocarbons, and particulate matter (PM). For all three buses, HC emissions were significantly reduced for each of the three alternative fuels tested. Emission reductions of NO_x, PM, and CO varied for each bus tested. For example, both the ULSD and the B20/#2 diesel blend reduced CO and PM emissions by over 30% for the T444E and Cummins engines. The ULSD/B20 blend reduced CO and PM emissions by 20-50% for the T444E and DT466E engines. Generally, the B20 blends resulted in slight increases in NO_x emissions, with the exception of the DT466E engine with B20/ULSD blend, which resulted in decreased NO_x emissions. This is an abstract of a paper presented at the AIChE Annual Meeting and Fall Showcase (Cincinnati, OH 1/04/2005).