Search Results

A recently completed program was developed to evaluate ultra-low sulfur diesel fuels and passive diesel particle filters (DPF) in several different truck and bus fleets operating in Southern California. The primary test fuels, ECD and ECD-1, are produced by ARCO, a BP company, and have less than 15 ppm sulfur content. A test fleet comprised of heavy-duty trucks and buses were retrofitted with one of two types of catalyzed diesel particle filters, and operated for one year. As part of this program, a chemical characterization study was performed in the spring of 2001 to compare the exhaust emissions using the test fuels with and without aftertreatment. A detailed speciation of volatile organic hydrocarbons (VOC), polycyclic aromatic hydrocarbons (PAH), nitro-PAH, carbonyls, polychlorodibenzo-p-dioxins (PCDD) and polychlorodibenzo-p-furans (PCDF), inorganic ions, elements, PM10, and PM2.5 in diesel exhaust was performed for a select set of vehicles.

A study was performed in the spring of 2001 to chemically characterize exhaust emissions from trucks and buses fueled by various test fuels and operated with and without diesel particle filters. This study was part of a multi-year technology validation program designed to evaluate the emissions impact of ultra-low sulfur diesel fuels and passive diesel particle filters (DPF) in several different heavy-duty vehicle fleets operating in Southern California. The overall study of exhaust chemical composition included organic compounds, inorganic ions, individual elements, and particulate matter in various size-cuts. Detailed descriptions of the overall technology validation program and chemical speciation methodology have been provided in previous SAE publications (2002-01-0432 and 2002-01-0433).

Transit agencies across the United States operate bus fleets primarily powered by diesel, natural gas, and hybrid drive systems. Passenger loading affects the power demanded from the engine, which in turn affects distance-specific emissions and fuel consumption. Analysis shows that the nature of bus activity, taking into account the idle time, tire rolling resistance, wind drag, and acceleration energy, influences the way in which passenger load impacts emissions. Emissions performance and fuel consumption from diesel and natural gas powered buses were characterized by the West Virginia University (WVU) Transportable Emissions Testing Laboratory. A comparison matrix for all three bus technologies included three common driving cycles (the Braunschweig Cycle, the OCTA Cycle, and the ADEME-RATP Paris Cycle). Each bus was tested at three different passenger loading conditions (empty weight, half weight, and full weight).