燃焼光によるエンジン筒内の空気過剰率計測

抄録

The fluctuations of excess air factor in a combustion chamber of a spark ignition engine have been measured with an optical diagnostic technique. The excess air factor was estimated by the ratio of light emission intensities of two different wavelengths, 431nm (CH radical) and 517nm (C₂ radical). The experimental data showed that, in one combustion cycle, the excess air factor at the beginning of combustion was higher and gradually decreased, and that the fluctuation of an excess air factor obtained by stoichiometric flame was smaller than under other combustion conditions. Furthermore, two types of fuel injectors were evaluated from the viewpoint of fluctuation of the excess air factor. The Probability density function (PDF) showed that the injector, whose mean droplet size was 50μm, provided smaller variance of the excess air factor than another injector, which had a larger mean droplet diameter of 200μm.