Investigation of techniques to improve measurement accuracy of nitric oxide, nitrogen dioxide and nitrogen oxide emissions from heavy-duty diesel engines

Nitric oxide (NO) and nitrogen dioxide (NO₂), commonly referred to as NO_x, are known to be harmful to human health. Oxides of nitrogen also rate among the principal agents of photochemical smog.; In an effort to improve the accuracy of the NO and NO₂ measurement process, this study has explored the NO to NO₂ exhaust gas chemistry in the sampling train, external converter performance at high NO₂ concentrations, solubility of NO and NO₂ in water, and analyzer operational parameters.; The effect of variations in sample line temperatures and sample residence time, the use of an external NO_x converter, a sample dryer and two different types of analyzers, (FT-IR) and a chemiluminescent analyzer, on NO_x measurements was evaluated. A 12.7-liter, Detroit Diesel Series 60, 6 cylinder, turbocharged diesel engine was used to generate the exhaust. All measurements were made by operating the engine over customized 5-mode, and 4-mode steady state tests, as well as a transient test. (Abstract shortened by UMI.)...