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在一台改进的单缸机实验系统上采用自行设计的快速热管理系统进行乙醇燃料HCCI燃烧的实验研究,获得了乙醇燃料HCCI燃烧的运行工作范围.与SI燃烧方式相比,在HCCI运行区域内,发动机的热效率高,NOx排放大幅度降低.在SI和HCCI的工作区域边界进行了不同工况乙醇燃料SI/HCCI燃烧模式转换的实验研究.结果表明,在当前实验条件下,采用进气热管理系统能实现乙醇HCCI和SI两种燃烧方式的转换,但不能在一个工作循环内完成,在转换过程中转速和平均有效压力出现波动.考察了火花辅助点燃对乙醇HCCI临界温度工况燃烧稳定性的作用,结果显示采用火花辅助点燃,基本上能避免失火循环的产生,改善了燃烧稳定性.在此基础上,研究了火花辅助点火对SI/HCCI混合燃烧模式发动机燃烧模式切换平顺性的影响.研究发现,单纯通过火花辅助点火并不能完全消除过渡过程中的波动,需要进一步的优化模式转换的控制策略.
An improved single-cylinder experimental system using a self-designed rapid thermal management system for ethanol fuel HCCI combustion experimental study obtained ethanol fuel HCCI combustion operating range.Compared with the SI combustion mode in the HCCI operating area , The engine has high thermal efficiency and greatly reduced NOx emission.Experimental research on SI / HCCI combustion mode conversion at different working conditions of SI and HCCI is carried out.The results show that under the current experimental conditions, The thermal management system can realize the conversion of HCCI and SI ethanol but it can not be completed in one working cycle and the rotational speed and average effective pressure fluctuate during the conversion process.It is investigated that the combustion of HCCI at the critical temperature of ethanol The results show that spark assisted ignition can basically avoid the occurrence of misfiring cycle and improve the combustion stability.Based on this, the effects of spark assisted ignition on the combustion smoothness of SI / HCCI hybrid combustion mode The study found that simply spark-assisted ignition and can not completely eliminate the fluctuations in the transition process, need to enter One-step control strategy for optimization mode conversion.