关键词: 甲醇发动机, 响应面模型, 多目标优化, ＮＳＧＡⅡ算法

Abstract: In this paper, air-fuel ratio, EGR rate, intake early opening angle and exhaust early opening angle of the engine are considered as optimization variables, and their influence on torque, effective fuel consumption rate and NOx emission at different full load speeds is studied. Firstly, a one-dimensional numerical model of the methanol engine is constructed using GT-power software. Secondly, the response surface model of the engine is constructed using D-Optimal Latin Hypercube experimental design method. Then, the influence of each optimization variable on the engine performance is analyzed. Finally, taking the maximum engine torque, effective fuel consumption and NOx emission as optimization objectives, NSGA-Ⅱ genetic algorithm is used to obtain the Pareto frontier optimal solution set. The optimized results show that the average torque of the methanol engine increases by 2.09% and the average NOx decreases by 18.77% at the three rotational speeds. At the same time, the effective fuel consumption of the methanol engine is also improved.