Abstract
Knocking is one phenomenon that can be cited as a factor impeding efforts to improve the efficiency of spark-ignition engines. With the aim of understanding knocking better, light emission spectroscopy was applied in this study to examine preflame reactions that can be observed prior to auto-ignition. Light emission intensity was measured at wavelengths of 306.4nm (characteristic spectrum of OH), 395.2nm (HCHO). In this research, preflame reaction when the ignition timing and the fuel were changed was measured for the generation phenomenon of the reaction.
