Abstract: Gas fuel was induced to the helical intake port and the tangential intake port of a large-bore port fuel injection engine separately by elbow connected to the outlet of gas fuel injection device(GID). The transient computational fluid dynamics(CFD) engine model incorporating the GID’s motions was established to analyze the effects of injection location on the in-cylinder mixing processes. The results indicate that the intake flow of two adjacent intake ports, the helical intake port and the tangential intake port will interfere with each other near the cylinder head during the intake stroke. For the helical port injection case, the gas fuel approaches to the cylinder center and concentrate on the cylinder head near the end of the compression stroke; while for the tangential port injection case, the gas fuel flows to the piston top and concentrate on the piston top near the end of the compression stroke. At ignition time, the helical port injection case shows best in-cylinder mixing performance, while the tangential port injection case is the worst.

Key words: large-bore gas-fuelled engine, combined intake port, elbow, mixing performance

摘要： 在喷射装置出口加装导管，将燃气分别导向大缸径多点电喷气体燃料发动机的螺旋进气道和切向进气道，建立了联合喷射装置内部流动区域的发动机瞬态CFD计算模型，分析了导管位置对缸内掺混过程的影响。研究结果表明：对于该切向气道、螺旋气道的组合进气道，进气冲程在缸内靠近缸盖截面上产生了干涉涡流，对于螺旋气道喷射方案，燃气向气缸中心靠近，压缩末了时刻燃气集中在缸盖附近；而对于切向气道喷射方案，燃气冲向活塞顶，压缩末了时刻燃气集中在活塞顶附近。点火时刻的混合效果从优到劣依次为螺旋气道喷射方案、无导管喷射方案、切向气道喷射方案。

关键词: 大缸径气体燃料发动机, 组合进气道, 导管, 混合效果