Date of Graduation


Document Type


Degree Type



Statler College of Engineering and Mineral Resources


Mechanical and Aerospace Engineering

Committee Chair

Mridul Gautam.


Increasing urban pollution levels have driven the Federal and the local air control boards to impose stricter emissions regulations on heavy-duty engines earmarked for transit buses. This has made natural gas a promising fuel for reducing the emissions of oxides of nitrogen and predominantly particulate matter from heavy-duty transit buses. Recent research studies performed at WVU and elsewhere have showed that natural gas engines emit an order of magnitude lower PM emissions, on a mass basis, when compared to diesel engines without any exhaust aftertreatment devices. However, on a number basis the emissions from natural gas fueled buses were an order of magnitude higher than their diesel counterparts.;This project was initiated by Southern California Air Quality Management District to design and develop an exhaust aftertreatment device for retrofitting urban transit buses powered by heavy-duty natural gas engines. The exhaust aftertreatment device was developed for a Cummins Westport C8.3G+ natural gas engine. Exhaust samples were collected by operating the vehicle on the Central Business District cycle on a chassis dynamometer. Regulated emissions were continuously measured while non-regulated emissions samples were collected on different media from a full flow dilution tunnel. In addition, PM concentrations and size distributions were also measured. (Abstract shortened by UMI.).