对置活塞二冲程汽油机缸内滚流的组织与利用  

In-cylinder Tumble Organization and Utilization of an Opposed-piston Two-stroke Gasoline Engine

作　　者：马富康[1,2] 赵长禄[1] 赵振峰[1] 王豪[1] 

机构地区：[1]北京理工大学机械与车辆学院,北京100081 [2]中北大学机械与动力工程学院,山西太原030051

出　　处：《兵工学报》2015年第9期1601-1609,共9页Acta Armamentarii

基　　金：国家部委科研基金项目(B2220110005)

摘　　要：通过三维计算流体力学软件AVL-Fire模拟了对置活塞二冲程(OP2S)缸内直喷汽油机的扫气、混合气形成和燃烧过程,对比分析了3种不同的缸内流动组织方案,包括:平顶活塞加均匀扫气、平顶活塞加非均匀扫气和凹坑活塞加非均匀扫气对气流运动和扫气过程的影响。同时,针对采用非均匀进气腔的平顶活塞和凹坑活塞方案,分析混合气形成和燃烧过程。结果表明:均匀进气方式可组织较强的涡流,有利于扫气效率的提高;非均匀进气方式可组织滚流,有利于提高压缩过程缸内的湍动能。"凹坑活塞加非均匀扫气"的扫气系统更有利于组织滚流和维持缸内湍流强度,并在点火时刻火花塞附近形成可供稳定着火的可燃混合气。凹坑活塞燃烧室相比平顶活塞燃烧室,其缸内湍动能提高了1.5倍,燃油蒸发量提高了10%,有利于形成均匀混合气和加速燃烧过程。The processes of intake, mixture formation and combustion of opposed-piston two-stroke （OP2S） gasoline direct injection engine are simulated by AVL-Fire code. The effects of three scavenging system configurations, viz. , flat piston-uniform scavenging chamber, flat piston-non-uniform scavenging chamber and pit piston non-uniform scavenging chamber, on the in-cylinder fluid flow and scavenging process are comparatively analyzed. Test verification is also carried out. The effects of flat piston- non-uniform scavenging chamber and pit piston-non-uniform scavenging chamber on the mixture formation and combustion process are comparatively analyzed. Results show that the uniform scavenging chamber can organize swirl and increase scavenging efficiency, and the non-uniform scavenging chamber can organize tumble and increase turbulent kinetic energy. Pit top surface of piston with non-uniform scavenging chamber is favorable to organize tumble and maintain the in-cylinder turbulence intensity. It helps to form the combustible mixture around spark plug at ignition. Compared with flat piston- non-uniform scavenging chamber, the turbulent kinetic energy of pit piston-non-uniform scavenging chamber is increased by 150 percent and its fuel evaporation is increased by 10 percent at ignition, which is favorable to form more uniform mixture and accelerate combustion process.

关 键 词：动力机械工程 对置活塞 二冲程 缸内流动 滚流 混合 

分 类 号：TK412[动力工程及工程热物理—动力机械及工程]