火花点火天然气掺氢发动机结合EGR时的循环变动规律  

Cycle-by-Cycle Variations of a Spark Ignition Engine Fueled with Natural Gas-Hydrogen Blends Combined with EGR

作　　者：黄彬[1] 胡二江[1] 黄佐华[1] 郑建军[1] 刘兵[1] 蒋德明[1] 

机构地区：[1]西安交通大学动力工程多相流国家重点实验室,陕西西安710049

出　　处：《内燃机学报》2011年第1期16-22,共7页Transactions of Csice

基　　金：国家自然科学基金资助项目(50636040;50821604);国家重点基础研究发展计划资助项目(2007CB210006)

摘　　要：在火花点火式天然气掺氢发动机上,开展天然气掺氢结合EGR时发动机循环变动的试验研究,分析了不同EGR率和掺氢比时发动机燃烧循环变动规律.结果表明,对于给定的燃料,随EGR率的增加,缸内最高压力和最大压力升高率下降,循环变动增加,缸内最高压力和最大压力升高率与其对应的曲轴转角之间的相关性减弱.平均指示压力下降且分布趋于分散,平均指示压力与其对应的缸内最高压力对应的曲轴转角之间的相关性减弱.对于给定的EGR率,随着掺氢比的增加,燃烧稳定性增强,循环变动下降.EGR率对平均指示压力的循环变动系数的影响呈非线性关系,小EGR率时对循环变动系数的影响较小,大EGR率时循环变动系数随EGR率的增加而大幅度增加.高转速下由于缸内气体运动增强,发动机可在较大的EGR率下保持较低的循环变动系数.增加掺氢比可使发动机运行在较高的EGR率下而保持较低的循环变动系数.Cycle-by-cycle variations of a spark ignition engine fueled with natural gas-hydrogen blends combined with EGR were investigated.The effects of EGR ratio and hydrogen fraction on cycle-by-cycle variations of the engine were analyzed.The results show that,with the increase of EGR ratio,the maxi-mum pressure rise,the maximum rate of pressure rise and the indicated mean effective pressure are de-creased and cycle-by-cycle variations are increased.Weak interdependency is presented between the above parameters and their corresponding crank angles with the increase of EGR ratio.For a given EGR ratio,combustion stability is promoted and cycle-by-cycle variations are decreased with the increase of hydrogen fraction in the fuel blends.Non-linear relationship is presented between indicated mean effective pressure and EGR ratio.Slight influence of EGR ratio on indicated mean effective pressure is observed at small EGR ratio while large influence of EGR ratio on indicated mean effective pressure is demonstrated at high EGR ratio.Increasing engine speed decreases cycle-by-cycle variations due to the enhancement of air flow in cylinder.Increasing hydrogen fraction can maintain low cycle-by-cycle variations at high EGR ratios.

关 键 词：循环变动 天然气 氢气 发动机 

分 类 号：TK431.2[动力工程及工程热物理—动力机械及工程]