Development of a Comprehensive Modal Emissions Model

In August 1995, the College of Engineering-Center for Environmental Research and Technology (CE-CERT) at the University of California-Riverside along with researchers from the University of Michigan and Lawrence Berkeley National Laboratory, began a four-year research project to develop a Comprehensive Modal Emissions Model (CMEM), sponsored by the National Cooperative Highway Research Program (NCHRP, Project 25-11). The overall objective of the research project was to develop and verify a modal emissions model that accurately reflects Light-Duty Vehicle (LDV, i.e., cars and small trucks) emissions produced as a function of the vehicle's operating mode. The model is comprehensive in the sense that it is able to predict emissions for a wide variety of LDVs in various states of condition (e.g., properly functioning, deteriorated, malfunctioning). The model is now complete and capable of predicting second-by-second tailpipe emissions and fuel consumption for a wide range of vehicle/technology categories. In creating CMEM, over 350 vehicles were extensively tested on a chassis dynamometer, where second-by-second measurements were made of both engine-out and tailpipe emissions of carbon monoxide, hydrocarbons, oxides of nitrogen, and carbon dioxide. CMEM itself runs on a personal computer or on a UNIX workstation. The model and the emissions database are both available on a CD.