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采用工作过程联合燃烧分析的方法,分析了EGR对TBD234共轨柴油机排放性能的影响。利用工作过程分析软件对配有EGR系统的TBD234柴油机进行建模及仿真分析,将计算结果作为初始条件对柴油机缸内燃烧过程进行燃烧计算分析,研究了不同EGR率下共轨柴油机排放特性。结果表明,随着EGR率的增加,NOx的排放显著降低,但soot生成量明显提高,燃烧过程的最高压力和最高温度降低,放热速率减小,燃烧进行变缓。当EGR率达到0.4时NO的生成量降低到原机的2.25%,但是soot的生成量几乎是EGR率为0.3时的两倍,所以在较高负荷情况下应该采用小EGR率。
The effect of EGR on the emission performance of TBD234 common rail diesel engine was analyzed by the method of combined combustion analysis in working process. The working process analysis software is used to model and simulate the TBD234 diesel engine equipped with EGR system. The calculation results are taken as the initial conditions to calculate the combustion process of diesel engine cylinder. The emission characteristics of common rail diesel engine with different EGR rates are studied. The results show that with the increase of EGR rate, the emission of NOx decreases significantly, but the generation of soot obviously increases. The maximum pressure and maximum temperature of combustion decrease, the rate of heat release decreases and the combustion slows down. When the EGR rate reaches 0.4, the amount of NO generated is reduced to 2.25% of the original machine. However, the generation of soot is almost doubled when the EGR rate is 0.3. Therefore, the EGR rate should be used at higher load.