船用柴油机废气再循环性能评估及应用

Exhaust gas recirculation performance evaluation of marine diesel engine and its application

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。

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.