柴油引燃直线氢内燃机稀薄燃烧特性研究
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摘要
直线氢内燃机特殊的自由活塞运动导致了较低的燃烧反应速率和放热等容程度。为减少燃烧时间损失,提高能量利用效率,在一台直线氢内燃机中尝试应用了引燃稀薄燃烧技术。首先通过原理试验验证了引燃稀薄燃烧技术的可行性,然后采用一种耦合活塞运动的迭代计算方法对柴油引燃直线氢燃料内燃机燃烧性能和运行特点进行了模拟研究。结果表明:采用引燃燃烧技术,有助于提高直线氢内燃机的燃烧速度,减小放热时间损失,增加指示效率。相对于传统点燃燃烧,引燃技术能够提高直线氢内燃机活塞往复运动频率和压缩比,增加直线氢内燃机输出功率,但是引燃燃烧会轻微加重直线氢内燃机的NOx污染物排放。
The special free piston motion of linear hydrogen engines results in slow combustion rate and low heat release around the top dead center.To improve the combustion rate and linear engine efficiency,the diesel pilot-ignition technology was introduced in a linear hydrogen engine to accelerate the heat release rate.A principle experiment was performed to validate the feasibility of the diesel pilot-ignition technology for linear hydrogen engines with variable compression ratio,and iterative computation was conducted to describe the main combustion characteristics and operation performances of the linear hydrogen engine.The results show that the diesel pilot-ignition technology is helpful to improve the combustion rate and engine efficiency and reduce the combustion loss.Compared with the traditional spark-ignition technology,the diesel pilot-ignition technology can enhance the linear hydrogen engine's speed,compression ratio and piston motion stroke,leading to increased output power of the linear engine.However,a slightly increased pollutant product NOxis also found with this technology.
The special free piston motion of linear hydrogen engines results in slow combustion rate and low heat release around the top dead center.To improve the combustion rate and linear engine efficiency,the diesel pilot-ignition technology was introduced in a linear hydrogen engine to accelerate the heat release rate.A principle experiment was performed to validate the feasibility of the diesel pilot-ignition technology for linear hydrogen engines with variable compression ratio,and iterative computation was conducted to describe the main combustion characteristics and operation performances of the linear hydrogen engine.The results show that the diesel pilot-ignition technology is helpful to improve the combustion rate and engine efficiency and reduce the combustion loss.Compared with the traditional spark-ignition technology,the diesel pilot-ignition technology can enhance the linear hydrogen engine's speed,compression ratio and piston motion stroke,leading to increased output power of the linear engine.However,a slightly increased pollutant product NOxis also found with this technology.
引文
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[2]XIAO J,LI Q,HUANG Z.Motion characteristic of a free piston linear engine[J].Applied Energy,2010,87(4):1288-1294.
[3]秦朝举,杨振中,高玉国,等.基于耦合动力学的直线氢内燃机工作特性研究[J].华中科技大学学报(自然科学版),2014,42(10):93-97.QIN Zhaoju,YANG Zhenzhong,GAO Yuguo,et al.Coupled dynamic modeling of performance characteristics in linear hydrogen engine[J].Journal of Huazhong University of Science and Technology(Natural Science Edition),2014,42(10):93-97.
[4]YUAN C,XU J,HE Y.Performance characteristics analysis of a hydrogen fueled free-piston engine generator[J].International Journal of Hydrogen Energy,2016,41(4):3259-3271.
[5]FENG H,GUO C,YUAN C,et al.Research on combustion process of a free piston diesel linear generator[J].Applied Energy,2016,161:395-403.
[6]刘杰,张欣,杨福源,等.引燃油量对柴油引燃天然气发动机燃烧特性的影响[J].汽车工程,2015,37(4):375-379.LIU Jie,ZHANG Xin,YANG Fuyuan,et al.Effects of pilot fuel quantity on the combustion characteristics of a diesel pilot ignition CNG engine[J].Automotive Engineering,2015,37(4):375-379.
[7]李伟峰,刘忠长,王忠恕,等.引燃柴油量和当量比对双燃料发动机低负荷燃烧的影响[J].内燃机学报,2015,33(6):481-489.LI Weifeng,LIU Zhongchang,WANG Zhongshu,et al.Effects of pilot diesel amount and equivalence ratio on the combustion of a dual fuel engine under lower loads[J].Transactions of CSICE,2015,33(6):481-489.
[8]袁晨恒,冯慧华,王梦秋,等.自由活塞汽油直线发电机燃烧过程特性[J].吉林大学学报(工学版),2015,45(1):127-132.YUAN Chenheng,FENG Huihua,WANG Mengqiu,et al.Combustion characteristics of free-piston gasoline engine for linear alternator[J].Journal of Jilin University(Engineering and Technology Edition),2015,45(1):127-132.
[9]李云清,成传松,刘宾.等.改善495汽油机燃烧性能的分析研究[J].内燃机工程,2010,31(3):52-56.LIU Yunqing,CHENG Chuansong,LIU Bin,et al.Investigation of improving combustion performance of model 495gasoline engine[J].Chinese Internal Combustion Engine Engineering,2010,31(3):52-56.
[10]YANG Zhenzhong,WANG Lijun,ZHANG Qingbo,et al.Research on optimum method to eliminate backfire of hydrogen internal combustion engines based on combining postponing ignition timing with water injection of intake manifold[J].International Journal of Hydrogen Energy,2012,37(17),12868-12878.