Semester

Spring

Date of Graduation

2002

Document Type

Dissertation

Degree Type

PhD

College

Statler College of Engineering and Mineral Resources

Department

Mechanical and Aerospace Engineering

Committee Chair

Mridul Gautam.

Abstract

Further growth of diesel engines in the light-duty and heavy-duty vehicular markets is closely linked to the potential health risks of diesel exhaust. Cleaner burning fuels, such as those derived from natural gas via the Fischer-Tropsch (FT) process, offer a potentially economically viable alternative to standard diesel fuel. As part of this study, a two-liter, single-cylinder, four-stroke direct-injected engine was instrumented for in-cylinder pressure measurements. The emissions and performance data from engine operation with Federal low sulfur No. 2 diesel fuel (DF) and natural gas derived FT fuel were compared. Also as part of the study, an investigation was carried out on the mutagenic characteristics of particulate matter (PM) derived from FT and DF fuel combustion by relating the in-vitro mutagenic activity of the particulate matter to engine operating conditions and particle size via the Ames Salmonella typhimurium bioassay (Maron and Ames, 1983). Particulate matter from two engine conditions were gathered using a Micro-Orifice Uniform Deposition Impactor (MOUDI) for size selective mutagenic analysis.;Results of the mutagenicity study indicate differences in the mutagenic response of the PM soluble organic fraction (SOF) of both Federal diesel No. 2 and FT fuel as functions of engine operating conditions, fuel type and particle size. The extracted solubles from particles of aerodynamic diameters greater than 100 nm were found to exhibit significantly greater mutagenic effect than their smaller counterparts (<100 nm) for both fuels. Results of the combustion and emission study revealed a general trend for lower emissions for FT fuel compared to DF fuel. NOx emissions correlated well with ignition delay and the amount of heat released in the premixed combustion phase. With the exception of two high load engine conditions, lower CO and total hydrocarbon (THC) emissions were the general trend for FT fuel.;Engine test facilities were located at the U.S. DOE's National Energy Technology Laboratory (NETL) in Morgantown, WV. Particulate matter samples were collected in the NETL engine test cell. Measurement and extractions were also performed at NETL. The extracted PM was analyzed at the National Institute of Occupational Safety and Health (NIOSH), also in Morgantown, WV, to determine particulate matter in-vitro mutagenicity via the AMES bioassay method.

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