【作者】

Emmanuella Sotiropoulou

【摘要】

该论文已在赫尔辛基举行的第28届CIMAC世界大会上发表，论文的版权归CIMAC所有。 The cyclic combustion variation is an inherent characteristic of premixed combustion engines affecting not only the reliability of engine components but also the engine efficiency and power stability. The homogeneity of the mixture lambda and the distribution of the residual gas are generally recognized to be the main causes of combustion cycle variation. However, recent studies conducted by the authors and discussed in this paper, have revealed the effect of two additional factors contributing to the cyclic combustion variation. One factor is the autoignition of lubricating oil occurring prior to the ignition timing and resulting in combustion cycles with very high firing pressures. This phenomenon is the common issue nowadays for the majority of the premixed combustion engines with high mean effective pressure. Furthermore, the autoignition of the lubricating oil, when occurring after the start of combustion, has been found to enhance the rate of combustion causing a stochastic increase in the maximum firing pressure, hence, contributing to a worsening of the combustion cyclic variation. A second factor is the variation in the location where ignition occurs within the electrodes of a spark ignited engine. It has been observed that small variations in the location of ignition can cause different rates of flame kernel growth, resulting in large variations of the maximum firing pressure. While the development of the flame kernel is strongly influenced by the flow field at the location where the spark breakdown occurs, the parameters determining the location of the breakdown are also analyzed and discussed in this paper. The effects of lubricating oil autoignition and location of ignition on the combustion cyclic variation are described with advanced CFD technology combined to experimental data. Moreover, a demonstration of some potential countermeasures, aiming at reducing combustion cyclic variation in premixed engines, is provided with the help of CFD.

【会议名称】

第28届CIMAC会议

【会议地点】

芬兰 赫尔辛基

【下载次数】

2

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