Date Approved


Embargo Period


Document Type


Degree Name

M.S. in Engineering


Chemical Engineering


Henry M. Rowan College of Engineering


Hesketh, Robert


Diesel motor exhaust gas--New Jersey; School buses--Standards--New Jersey


Chemical Engineering


Since January 2002, the New Jersey Department of Transportation (NJDOT) has sponsored a research study at Rowan University to develop strategies for reducing diesel emissions from mobile sources such as school buses and class 8 trucks. This thesis presents research conducted on reducing emissions from school buses during mobile operating conditions. Four fuel blends and three aftertreatment devices were tested on three school bus engines.

For all of the tests, exhaust gas emission measurements were made using a Sensors Semtech-D to measure CO, CO2, NO2, NO, O2, and HC, along with a Sensors PM-300 to measure Particulate Matter (PM). In addition to the exhaust emissions measurements, instantaneous vehicle speed, engine speed, percent load and fuel flowrate were acquired from the engine electronic control module (ECM) during testing.

Prior work has suggested that alternative fuels reduce CO, HC, and PM emissions. In the work presented in this thesis, tests were conducted using a 20% biodiesel mixture with standard diesel fuel, ULSD, and a 20% biodiesel mixture with ULSD. Two diesel particulate filters and one diesel oxidation catalyst were also tested.

In order to evaluate the reductions, all tests were performed using a drive cycle developed by Rowan University. This drive cycle is a composite cycle developed from 11 actual school bus routes. The results reported herein were obtained by performing the drive cycle on a test track in Aberdeen, MD within the Aberdeen Test Center (ATC).

It has been well documented that NOx emissions are a strong function of ambient temperature and humidity. In order to evaluate NOx emission reduction potentials, a NOx correction factor was developed to correct for temperatures and humidity observed during the course of the mobile testing. This thesis also presents the development of the new NOx correction factor from idle school bus data.