Abstract
In this study, a Homogeneous Charge Compression Ignition (HCCI) engine was operated on blended test fuels of dimethyl ether (DME) and methane, which have different ignition characteristics. The simultaneous measurement of light emission and absorption of HCCI combustion were used to examine the combustion characteristics of the HCCI combustion. This is to investigate the effects of the mixing ratios and quantities of two types of fuel on the combustion characteristics. Also, we analyzed cool flame reaction behavior in detail on the basis of in-cylinder spectroscopic measurements. As a result, it was found that the light emission intensity at wavelength corresponding to HCHO had the peak for the period when the absorbance at wavelength corresponding to HCHO increased rapidly. The behavior of the light absorption (timing, absorbance) depends on the quantities of DME. Additionally, the behavior of the absorbance at wavelength corresponding to HCHO and calculated result of HCHO mole fraction were qualitatively corresponding.
