Date of Graduation


Document Type


Degree Type



Statler College of Engineering and Mineral Resources


Mechanical and Aerospace Engineering

Committee Chair

Mridul Gautam


Portable emission measurement systems (PEMS) are taking center stage as in-use testing programs are getting underway. EPA-mandated manufacturer-run in-use testing programs require a PEMS, and currently there is one commercially available and widely used, the SEMTECH-D built by Sensors, Inc. The SEMTECH-D was first unveiled in 2002, and numerous software and hardware upgrades have given way to the SEMTECHDS. The manufacturer claims this system is fully compatible with all new Code of Federal Regulations (CFR) including part 1065 subpart J (which addresses field testing and PEMS). Yet, while West Virginia University (WVU) was using the SEMTECH-D during the summer of 2005, problems were encountered that prompted further insight into its performance. A ten month study ensued to study SEMTECH-D's behavior compared to an EPA certified engine test cell on the campus of WVU at Morgantown, WV. After multiple test days, exhaust configurations, and comparisons to both the heavy-duty engine dynamometer laboratory (compliant with CFR40 Part 86 Subpart N) at WVU, and another PEMS, the SEMTECH-D was found to consistently exhibit high discrepancies. Over a twenty minute Federal Test Procedure (FTP) transient test the total NOX mass emitted error was as high as 25%, while the CO2 total mass emitted error was as high as 15% compared to the engine dynamometer laboratory.