【摘要】 针对增压柴油机废气再循环(EGR)性能评估问题,特别是"小样本"下的最优决策,提出了一种基于不等权优化的评估及决策方法。首先,在TBD234V12型相继增压柴油机上搭建高压废气再循环系统,采集柴油机缸内爆压、燃油消耗率、NO_x、CO及烟度等主要参数试验数据,建立最优关联分析模型,用来不同EGR方案的初步评价。其次,根据柴油机不同负荷工况,通过客观优化方法建立综合评价模型。最后,基于MATLAB GUIDE设计和建立了增压柴油机EGR性能综合评估及最优决策仿真平台。仿真结果表明:低负荷时小EGR率对应的综合评估值更高,因此宜采用较小EGR率;高负荷时,较低EGR率对应的综合评估值较低,较高EGR率获得了更高的评估值,但是过高的EGR率的综合评估值反而下降,因此不宜采用过高EGR率。仿真优化平台可以快捷、方便地解决增压柴油机EGR性能评估及最优决策问题。更多还原

【Abstract】 In view of EGR performance evaluation of turbocharged diesel engine, especially the optimal EGR rate under‘small sample’, an optimization evaluation and decision-making method is proposed.First, the major test parameters including in-cylinder burst pressure, fuel consumption rate, NO_x, CO and smoke are selected based on TBD234V12 type turbocharged diesel engine with a high-pressure exhaust gas recirculation system to establish the optimal correlation analysis model for the preliminary evaluation of different EGR schemes. Second, according to different speed conditions of diesel engine, a comprehensive evaluation model is established using optimized objective evaluation method. Finally, a simulation optimization platform for comprehensive performance evaluation and optimal decision-making of EGR is designed and established using MATLAB GUIDE. The results show that When diesel engine is in low-speed conditions, low EGR rate corresponds to a higher comprehensive assessment value, so a smaller EGR rate should be adopted. When diesel engine is in high-speed conditions, the comprehensive assessment value corresponding to the lower EGR rate is lower, and the higher EGR rate obtains a higher assessment value. However, the evaluation value of overly high EGR rate decreases. This result is basically consistent with the current control principle of EGR; The simulation optimization platform can quickly and easily solve the EGR performance evaluation and optimal decision-making of turbocharged diesel engine.更多还原