A Study on NO2/NOX Ratio and NOX Emission Characteristics of Heavy-Duty Diesel Vehicles

Abstract

NOX emitted from heavy-duty diesel vehicles has a high percentage of domestic emissions in Korea. It is known that the NO2 emission was polluted the atmospheric environments and was harmful to humans. Therefore, investigation on NO2//NOX Ratio and NOX Emission Characteristics of Heavy-Duty Diesel Vehicles were carried out. In this study, NOX emissions from heavy-duty trucks and buses were measured by chassis dynamometer for heavy-duty vehicle in real time. Also, NO2/NOX ratio and NOX emission characteristics were analyzed by emission analyzer according to various conditions. It is revealed that NO and NO2 concentrations were increased in the acceleration section from results of NOX concentration in real time. The NOX emissions of heavy-duty trucks in test mode was confirmed a high level in order the average speed, but NOX emissions of heavy-duty buses were increased as the average speed increased. The NO2/NOX ratio of heavy duty trucks and buses was 0.7~1.0% and 7.7~7.8% at hot start engine condition. The results of this study will contribute to be used as basic data for the estimation of NO2 concentration in the roadside air monitoring network. Key words: Nitrogen oxide, Nitrogen dioxide, NO2/NOX Ratio, Heavy-duty diesel vehicles