Exhaust gas recirculation (EGR) is an effective technique to reduce exhaust emission of nitrogen oxides (NOx) from diesel engines because it lowers the flame temperature in the combustion chamber. However, as NO x is reduced, the emission of particulate matter (PM) is increased, resulting from the lowered oxygen (O2) concentration. In this study, carbon dioxide (CO2) was used as a diluent to simulate the EGR process at ratios of 4:3, 9:5, and 14:3 per cent, thus making O2 concentrations 20, 19, and 18 per cent respectively. A single-cylinder rapid compression machine (RCM) was used to simulate diesel-type combustion. The ignition and the combustion processes of diesel fuel spray were observed by high-speed direct photography. Flame temperature (indication of NO formation) and the KL factor (an indication of soot concentration inside the fuel spray) were analysed by the two-colour method. The tests have demonstrated that maximum flame temperatures and soot generation were reduced with an increase in CO 2 in the inlet charge, while at same time soot extinction times were increased.
|ジャーナル||Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering|
|出版物ステータス||Published - 2007 12 1|
ASJC Scopus subject areas
- Aerospace Engineering
- Mechanical Engineering