特种车辆柴油机在不同海拔高度的性能预测与分析

Prediction and Analysis of Performance of Special Vehicle Diesel Engines at Different Altitudes

以Hiroyasu喷雾和燃烧模型为基础,建立了适应不同海拔环境的特种车辆增压柴油机模型,并利用平原台架试验和海拔3 700 m实车试验对计算结果进行了验证。计算了该柴油机在0～5 000 m海拔实际运行时的动力性、经济性和排放性,预测了不同环境下柴油机热负荷、机械负荷主要参数的变化规律。结果表明,当海拔高度为5 000 m时,柴油机动力性、经济性比平原恶化10%以上;柴油机缸内燃烧温度峰值上升235℃以上,涡前排气温度最多增加150℃左右;最大压升率比平原升高15%以上,NOx排放减少,碳烟排放剧增。

A simulation model of a turbocharged diesel engine which adapts to different altitudes is established based on Hiroyasu spray and combustion model. The calculation results are validated by engine bench test in plain and road test data at 3 700 m altitude. The power performance, fuel economy, emission of this diesel engine which operates at altitude of 0-5 000 m are calculated, and variation of thermal and mechanical load of this diesel engine at different operating environments are predicted. The simulation results show that when altitude is elevated to 5 000 m, the power and economy is 10% lower than that in plain; peak value of in-cylinder combustion temperature increases over 235 ℃, and the exhaust temperature before turbocharging increases to 150 ℃ at the maximum; the maximum pressure rise rate is 15% higher than plain, and NOx emission lowers whereas soot emission increases dramatically.