Date of Graduation
2002
Document Type
Thesis
Degree Type
MS
Committee Chair
Mridul Gautam
Abstract
Nitric oxide (NO) and nitrogen dioxide (NO2), commonly referred to as NOx, are known to be harmful to human health. Oxides of nitrogen also rate among the principal agents of photochemical smog. Consequently, the Federal standards for NOx emissions have become increasingly stringent and have been lowered from 6.0 g/bhp-hr in 1990 to 0.2 g/bhphr in 2007. Engine out NOx emissions from diesel engines are typically composed of about 95% of NO and 5% NO2. However, under low load and speed conditions, as in present urban day driving, the NO2 component of NOx can be as high as 30%. Considering the ever decreasing limits and the higher concentrations of NO2 being measured, it is imperative that more accurate NOx measurement techniques be developed. 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. As a first step, bench tests were conducted with bottled gases and a preliminary evaluation of the sampling system components and sampling parameters was performed. Using these parameters as inputs, different sampling train configurations were developed and their effect on measurements of NOx emissions in raw exhaust streams from heavy duty diesel engines was investigated. The effect of variations in sample line temperatures and sample residence time, the use of an external NOx converter, a sample dryer and two different types of analyzers, namely, the Fourier Transform Infrared analyzer (FT-IR) and a chemiluminescent analyzer, on NOx 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.
Recommended Citation
Narasimhamurthy, Praveen Rampatna, "Investigation of techniques to improve measurement accuracy of nitric oxide, nitrogen dioxide and nitrogen oxide emissions from heavy-duty diesel engines." (2002). Graduate Theses, Dissertations, and Problem Reports (ETD). 10662.
https://researchrepository.wvu.edu/etd/10662