Theses and Dissertations

Issuing Body

Mississippi State University


Toghiani, Hossein

Committee Member

George, E. Clifford

Committee Member

Molen, Marshall G.

Committee Member

Toghiani, K. Rebecca

Date of Degree


Document Type

Graduate Thesis - Open Access


Chemical Engineering

Degree Name

Master of Science


James Worth Bagley College of Engineering


Dave C. Swalm School of Chemical Engineering


The addition of Tier 2 standards by United States Environmental Protection Agency (EPA) has increased focus on light-duty vehicle emissions. In this study, a diesel-electric hybrid vehicle was used for testing under the Challenge X program. The diesel engine was powered by a 20% soy-based biodiesel - 80% diesel blend, and the electric motor received its energy from a 330 volt Nickle Metal Hydride battery pack. The diesel engine, notorious for high emissions of nitrogen oxides (NOx) and particulate matter (PM), requires aftertreatment of these emissions to achieve Tier 2 EPA compliance. The primary focus of this thesis is use of a urea injection selective catalytic reduction (SCR) system to reduce NOx emissions. Also, a diesel particulate filter (DPF) was employed for PM reduction purposes. Significant decreases in both NOx and PM emissions were achieved.