Examination of the Sources of Variability in Particle Emission Measurements by the Transient Test Method for Heavy-Duty Diesel Engines. Phase 1. Final Report

摘要

A series of Round Robin tests of emissions from heavy-duty diesel engines were conducted under the guidance of the Engine Manufacturers Association Calibration Task Force and the Coordinating Research Council Smoke and Particulate Panel during the mid to late 1980's. These tests showed significant intra- and inter-lab variability in particulate measurements using the Heavy Duty Transient Test (40 CFR Subpart N). The most recent Round Robin showed an inter-lab variability of 0.09 gm/bhp-hr. These results are disturbing because this is nearly equal to the 1994 particulate emission standard of 0.10 gm/bhp-hr. The report describes the results of a study of the sources of this variability. The study consisted of several phases: an examination of the test procedure with emphasis on aspects of it that might especially influence particle measurements, an examination of procedures used in the Round Robin tests, visits to representative industrial and government test facilities to compare and contrast facility designs and test procedures, development of a simplified model of the exhaust dilution and sampling systems used for the Heavy-Duty Transient Test, and application of the model to an actual test facility. The model focused on the influence of the dilution and cooling process upon particle deposition on the walls of the sampling system and upon the solvent extractable fraction. A sub-model was also developed to examine propagation of measurement error.