An investigation of in-cylinder tumbling motion in a four-valve spark ignition engine
An investigation of in-cylinder tumbling motion in a four-valve spark ignition engine
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DOI：
10.1243/0954407011525511
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发表时间：
2001-02
期刊：
影响因子：
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通讯作者：
Y. Li;S. Liu;S. Shi;M. Feng;X. Sui
中科院分区：
文献类型：
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作者：
Y. Li;S. Liu;S. Shi;M. Feng;X. Sui
摘要 使用激光多普勒风速仪 (LDA) 测量和多维数值模拟研究了单缸四气门火花点火发动机中气缸内滚流的形成和破坏。还使用循环解析 LDA 数据处理方法分析了翻滚破碎产生的流动结构。这些结果表明，在进气冲程期间，进气流沿气缸两侧在气缸内产生两个反向旋转涡流。然后它们在压缩冲程的初始阶段逐渐演变为翻滚涡流。可以通过增加沿排气门表面流动的进气流量和/或减少直接沿进气门侧面的气缸壁下降的进气流量来加强翻滚运动。尽管在压缩结束时燃烧室的中心部分仍然存在部分衰减的翻滚涡流，但在燃烧室的其他部分，翻滚扭曲并破碎成小涡流和涡流，使得均方根速度脉动增大。翻滚破碎产生的流动结构具有频率较低、涡尺度较大的特点。
Abstract The formation and break-up of the tumble in the cylinder were studied in a single-cylinder four-valve spark ignition engine using laser Doppler anemometry (LDA) measurements and multidimensional numerical simulations. The flow structure generated by the tumble break-up was also analysed using the cycle-resolved LDA data processing method. These results show that, during the intake stroke, two counter-rotating vortices are generated in the cylinder by the intake flow along the two sides of the cylinder. They then gradually evolve into the tumble vortex at the initial stage of the compression stroke. Tumble motion can be strengthened by increasing the intake flow going along the surface of the exhaust valves and/or decreasing the intake flow descending directly along the cylinder wall on the side of intake valves. Although a partially decayed tumble vortex still exists in the central part of the combustion chamber near the end of compression, in other parts of the combustion chamber the tumble distorts and breaks up into small vortices and eddies so that the root mean square velocity fluctuation increases. The flow structure generated by the tumble break-up has a characteristic of lower frequency and larger eddy scale.