2012年第4期
文章编号：10094687(2012)04003305
车辆与动力技术 Vehicle & Power Technology
二冲程汽油机扫气过程瞬态模拟研究
李昌远，汤东，陈欢（江苏大学汽车与交通工程学院，镇江212013）
总第128期
摘要：利用CFD软件Fire对二冲程汽油机扫排进气道-曲轴箱-气缸系统流场进行了三维瞬态模拟，动态再现了扫气过程缸内气流运动和废气分布情况。模拟计算发现，气缸上部流场以两个对称环流和滚流为主，靠近扫气口的下部则以4个径向涡流以及短路损失为主随着扫气的进行，气缸内的新鲜充量区域和混合区域不断增大，废气区城不断减少，活塞到达下止点时，废气区域基本消失，计算结果表明，曲轴箱和扫气道的压力变化
并不相同，曲轴箱压力波动对扫气道和缸内的流场有一定影响。关键词：二冲程汽油机；扫气过程；瞬态；数值模拟
中图分类号：U464.171
文献标识码：A
TransientSimulationofScavengingProcessin
Two-Stroke Gasoline Engine LIChang-yuan，TANGDong，
CHENHuan
(School of Automobile and Traffic Engineering, Jiangsu University,Zhen Jiang 212013, China) Abstract: By using the Fire module of CFD software, a three-dimension transient numerical simulation aeeeoosesaasse system of a two-stroke gasoline engine, dynamically showing the situation of airflow movement and exhaust gas distribution in the scavenging process. The simulation calculations showed that the flow structure on the upper cylinder mainly consisted of a pair of toroidal vortex and tumble vortex, but four radial swirls and " short-circuiting" fuel losses gave first place in the flow structure on the lower cylinder. With the development of scavenging process, both the fresh charge area and mixture area increased while the exhaust gas area decreased accordingly. When the piston reached to its bottom dead center (BDC), the exhaust area almost disappeared. The analytic results further indicated that the pressure changes in the crankcase were not the same as them in the transfer ducts, and that the pressure fluctuation in the crankcase had a certain effect on the flow field of both the cylinder and the transfer ducts.
Key words: Two-stroke engine; Scavenging process; Transient; Numerical simulation
二冲程汽油机具有升功率高、质量轻、结构紧收稿日期：2012-04-23.
凑、价格低廉等优点，在小型动力机械领域得到广
基金项目：国家自然科学基金资助项目（51176068）；江苏高校优势学科建设工程资助项目（PAPD)；江苏大学研究生创新计划立项
项目。
作者简介：李昌远（1987-），硕士生，研究方向：内燃机燃烧和排放控制万方数据