双燃料发动机天然气逃逸的仿真研究

以Z6170型柴油机改造后的进气总管喷射进气柴油/LNG双燃料发动机为研究对象,在Fluent软件环境中,运用动网格技术模拟气门重叠期天然气逃逸过程,定量分析转速、进气提前角和排气迟闭角对双燃料发动机气门重叠期天然气逃逸的影响。仿真结果表明:进气总管喷射进气双燃料发动机气门重叠期存在天然气逃逸现象;在其他条件相同的情况下,发动机转速升高,一个工作循环内气门重叠期CH_4逃逸量减少;气门重叠角大小对气门重叠期CH_4逃逸的影响最大,特别是进气提前角影响尤为突出。

Simulation Study of Natural Gas Escape of Dual Fuel Engine

Aiming at the inlet manifold injection diesel/LNG dual fuel engine retrofitted from diesel engine Z6170, with the use of Fluent software, dynamic mesh technology was employed to simulate the process of natural gas escape during valve overlap,and the effect of speed, intake advance angle and exhaust lag angle on natural gas escape during valve overlap were analyzed. The simulation results show that natural gas escape is subsistent in inlet manifold injection diesel/LNG dual fuel engine during valve overlap; in the situation with the same other conditions, as the engine speed increases, the escape of CH₄ within one work cycle period decreases during valve overlap; the effect of valve overlap on the escape of CH₄ during valve overlap is the biggest, especially the intake advance angle.