Date of Graduation


Document Type


Degree Type



Statler College of Engineering and Mineral Resources


Mechanical and Aerospace Engineering

Committee Chair

Gregory J Thompson


Heavy-duty diesel engines exhaust emissions contribute to the ambient air quality; therefore, the United States Environmental Protection Agency (EPA) and California Air Resources Board (CARB) have created stringent emissions standards. Since the implementation of these standards in the early 1970s, overall engine and fuel technology improvement have created a significant reduction in emissions. Many different factors, such as fuel composition, properties, additives, and engine technology, influence regulated emissions constituents.;This study was completed in order to evaluate engine emissions from several different diesel fuels with and without cetane improving additives on recent and early production electronically controlled heavy duty diesel engines (HDDE). Both petroleum-based diesel and biodiesel were tested to compare the advantages and disadvantages of each fuel type. Five engines --- 1991 Detroit Diesel Corporation S60, 1992 Detroit Diesel Corporation S60, 1992 rebuilt Detroit Diesel S60, 1999 Cummins ISM 370, and 2004 Cummins ISM 370 were used to represent a wide spectrum of engine technologies. The chosen engines were tested using the Federal Test Procedure (FTP) and Supplemental Emissions Test (SET) dynamometer cycles. In order to determine the effectiveness of each fuel additive, it was necessary to investigate the NOx production as a function of the brake specific power for each engine since NOx emissions are the primary concern from HDDE. It was found that the additives had the most impact on reducing emissions in the early production Detroit Diesel Corporation engines, and there was a negative effect on the recent production Cummins engines.;It was also found that the additives reduced NOx up to about 250 brake horsepower, but increased NOx production above this point. The older technology DDC S60 engines showed an average reduction of 6.5% for NOx and NO2 during low power operation, but showed an average increase of 2% while in high power operation. The other emissions constituents of THC, TPM, and CO have an average reduction of 10%, 3% and 15%, respectively. The Cummins engines showed an average NOx and NO2 reduction of 5% for low power operation, but quickly increased NOx production up to 6% during high power operation. The emissions constituents of THC, TPM and CO show an average reduction of 20%, 25% and 20%, respectively for the newer technology engines.