基于CONVERGE的车用柴油机缸内燃烧及排放的仿真研究

Simulation Research on In-cylinder Combustion and Emission of Vehicle Diesel Engine Based on CONVERGE

针对某型车用高强化柴油机,研究了进气加湿对NO_(x)、碳烟生成的作用机理及油耗的影响,提出采用进气道喷水的方式对进气加湿,运用仿真软件CONVERGE研究了不同油水比对柴油机缸内燃烧及排放的影响,获得了在特定时刻下NO;和当量比在缸内的分布情况,分析比较了不同油水比对缸内温度及压力的影响情况。结果表明:随着油水比的不断下降,缸内温度以及压力均下降,峰值最大降幅分别为6.26%、4.05%,燃烧重心CA50相位后移,NO_(x)生成质量及油耗下降,但碳烟排放情况有所恶化。

For a certain type of high-enhanced diesel engine, the mechanism of air intake humidification on the formation of NO_(x) and soot and the effect of fuel consumption are studied. The method to humidify the intake air by spraying water into the intake port is propsed The simulation software CONVERGE is used to study the influence of different oil-water ratios on the combustion and emissions of the diesel engine cylinder, and the distribution of NO;and equivalent ratio in the cylinder at a specific time is obtained. The influence of different oil-water ratios on the temperature and pressure in the cylinder is analyzed and compared. The results show that as the oil-to-water ratio keeps decreasing, the temperature and pressure in the cylinder decrease. The maximum peak drops are 6.26% and 4.05%, respectively. The CA50 phase of the combustion center of gravity shifts backward, and the quality of NO_(x) production and fuel consumption decrease, but soot emissions deteriorate.