|| U.S. Environmental Protection Agency, Office of Air, Noise and Radiation, Office of Mobile Source Air Pollution Control, Emission Control Technology Division, Standards Development and Support Branch,
The Engine Manufacturers Association/Environmental Protection Agency (EMA/EPA) cooperative test program was initiated in May 1981 to analyze lab-to-lab variability in particulate emission measurements and to assess whether or not the large amount of transient emissions data generated at the Southwest Research Institute (SwRI) was repeatable at other laboratories. The program also was designed to determine ways to improve repeatability. Six engines which are newer models of engines tested under the SwRI baseline program, were chosen to be tested by seven labs: Cummins, Detroit Diesel Allison (DDA), International Harvester (IHC), Caterpillar (CAT), Mack, SwRI, and EPA. A total of 30 sets of tests were scheduled to be conducted on these six engines. Currently 77 percent of these tests have been completed. By June 1, 90 percent of the testing should be complete, and the program will be completed by July 1, 1982. This report will analyze all of the data currently available. First, interlab variability will be discussed, followed by a discussion of intra-lab variability. The correlation between 13-mode and transient particulate emissions will not be presented in this report due to the limited amount of data available, but will be reviewed in the final report.