缸内直喷天然气发动机燃烧室选型及其混合气形成机理  

Combustion chamber selection and its mixture formation mechanism in CNG-DI engine

作　　者：杨淼[1] 林学东[1] 许涛[1] 李德刚[1] 江涛[1] 郭亮[1] YANG Miao;LIN Xue-dong;XU Tao;LI De-gang;JIANG Tao;GUO Liang(State Key Laboratory of Automotive Simulation and Control,Jilin University,Changchun 130022,China)

机构地区：[1]吉林大学汽车仿真与控制国家重点实验室,长春130022

出　　处：《吉林大学学报（工学版）》2019年第2期426-433,共8页Journal of Jilin University:Engineering and Technology Edition

基　　金：国家自然科学基金项目(51676084);吉林省发改委产业技术研究与开发项目(2016C038);吉林省科技发展计划项目(20150101032JC)

摘　　要：利用FIRE软件建立了2.0L型直喷CNG发动机的燃烧模型,在光学样机上对CNG燃料缸内直喷的燃烧模型进行验证的基础上,仿真研究了不同燃烧室形状对缸内微观物理场的影响,探索燃烧室形状对混合气形成机理和燃烧特性以及NO生成规律的影响。结果表明:CNG燃料缸内直喷时燃烧室形状对缸内湍流特性及浓度场分布特性,特别是对火花塞附近的浓度场和湍流特性的影响很大;NO生成量不仅取决于NO的反应速率,还与反应区域的面积和反应持续时间密切相关;当燃烧室采用直口且底部适当凸起的形状时,不仅有效抑制了NO的生成,而且可以有效控制火焰传播速度,有利于稀薄燃烧。TThe combustion model of 2.0 LCNG-DI engine was built with software FIRE,and the model was verified on an optical prototype of CNG-DI engine.The effect of the combustion chamber shape on the micro-physical fields was studied to explore the influence of chamber shape on mixture formation mechanism,combustion characteristics and NO formation mechanism.Results show that the combustion chamber shape has significant influence on the turbulence characteristic of the cylinder and on the distribution of the concentration fields especially around the spark plug.The amount of NO is closely related not only to the NO reaction rate but also to the size of the reaction area and reaction duration when the CNG fuel is injected into the cylinder directly and ion burned thin,which can be controlled by rational design of the structure of the combustion chamber.

关 键 词：动力机械工程 缸内直喷天然气发动机 燃烧室结构 混合气形成机理 燃烧特性 氮氧化物生成规律 

分 类 号：TK411[动力工程及工程热物理—动力机械及工程]