予混合圧縮着火機関の着火に関する分光学的研究

抄録

In this study, spectroscopic techniques were used to investigate the effects of the residual gas state and fuel octane number on ignition characteristics of a Homogeneous Charge Compression Ignition (HCCI) engine. Spectroscopic measurements were made of light emission spectra and of light absorption spectra. The results revealed that varying the fuel octane number and the residual gas state changed the cool flame magnitude and the duration of the low-temperature reaction period, which substantially altered the ignition characteristics of HCCI combustion. Specifically, when a low-octane fuel was used, the heat release rate waveform for HCCI combustion showed cool flame, which was clearly observed in the light emission spectra and light absorption spectra. The level of absorbance at a wavelength corresponding to the cool flame reaction decreased when the fuel octane number was increased. Additionally, the level of absorbance also decreased when residual gas was applied to HCCI combustion of a low-octane fuel and approached that seen for HCCI combustion of a high-octane fuel. With the application of residual gas, the low-temperature reactions showed less reactivity when low-octane fuels were used, and the reactions were less sensitive to changes in the octane number of the fuel. As a result, the ignition timing tended not to change in relation to variation of the fuel octane number.