Abstract
For reduction of NOx emission from diesel engines, it is important to capture temporal and spatial changes of NOx produced in a cylinder. However, it is difficult to observe presence of the NOx itself visually in a cylinder. Therefore, the authors quantitatively evaluated a correlation between the NOx emission and flame temperature, focusing on a relation between the NOx formation process and temperature. Consequently, the evaluation confirmed that there is a high correlation between NOx production index derived from the flame temperature measured by the two-color method using the extended Zeldovich mechanism and the NOx emission from an optical engines.
