Abstract
It is commonly known that NOx emissions of diesel spray flame increases when the fuel injection pressure is increased. On the contrary, higher fuel injection speed in a steady diffusion flame results in decreased NOx emissions. The authors have been investigated on this contradiction, and found that significant amount of NO is formed mainly in the region vicinity of the spray tip, causing the difference in NOx emission characteristics between steady and unsteady jet flames. The paper presents a brief results of experiment and simulation, and discusses concepts of NOx reduction in diesel engine based on the result.
