Optimization of Air Intake Uniformity of Diesel-methanol Dual-fuel Engine
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摘要: 针对某四缸柴油甲醇双燃料发动机进气均匀性较差的问题, 采用GT-power软件构建了柴油甲醇双燃料发动机仿真模型, 分析进气总管、进气歧管的结构参数以及进气正时对进气均匀性的影响程度。以进气总管直径、进气歧管长度、2、3缸的进气歧管直径以及进气正时为优化变量, 以降低进气不均匀度为设计目标建立响应面模型, 并结合多岛遗传算法进行优化。优化结果表明: 减小进气总管直径和进气歧管长度以及进气正时, 增加2、3缸的进气歧管直径几何参数, 改善了进气歧管内空气和甲醇的流动质量, 使发动机的进气不均匀度由原机的10.35%降低到2.19%。
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关键词:
- 柴油甲醇双燃料发动机 /
- 进气均匀性 /
- 响应面模型 /
- 多岛遗传算法
Abstract: Aiming at the poor intake uniformity in a four-cylinder diesel methanol dual-fuel engine, a simulation model for diesel methanol dual-fuel engine was constructed with GT-Power software in order to analyze the structural parameters of the intake manifold and intake manifold and the influence of the intake timing on the intake uniformity. Taking the diameter and length of the intake manifold, the diameter of the intake manifold of the 2nd and 3rd cylinders, and the intake timing as the optimization variables, the response surface model is established with the design goal of reducing the unevenness of the intake air, and combined with multiple islands Genetic algorithm for optimization. The optimization results show that by reducing the diameter of the intake manifold, the length of the intake manifold and the intake timing, and increasing the geometric parameters of the intake manifold diameter of the 2nd and 3rd cylinders, the flow quality of air and methanol in the intake manifold is improved, and the intake uniformity in the engine is reduced from 10.35% to 2.19% of the original engine. -
表 1 发动机主要技术参数
参数名称 数值 缸径x行程 108 mm×115 mm 压缩比 17∶1 排量 4.214 L 进气门开启时刻 -16.5℃A ATDC 排气门开启时刻 112.2℃A ATDC 最大扭矩 420 Nm 点火顺序 1-3-2-4 最大输出功率 103 kW 额定转速 2 800 r/min 表 2 进气系统主要技术参数
参数名称 数值 进气总管直径 80 mm 进气总管长度 90 mm 进气歧管直径 40 mm 进气歧管长度 120 mm 谐振腔容积 3.6 L 表 3 发动机各歧管进气质量流量
歧管序号 进气质量流量/(g·s-1) 1 167.0 2 152.5 3 150.6 4 163.9 表 4 各参数水平的设置
参数 最小值 最大值 水平数 D1(A) 60 mm 100 mm 3 L(B) 100 mm 200 mm 3 D2(C) 40 mm 56 mm 3 K(D) -16 ℃A -6 ℃A 3 表 5 响应面模型的方差分析
方差来源 平方和 自由度 均方 F值 P值 显著性 模型 570.27 14 40.73 32.44 < 0.0001 显著 A 3.83 1 3.83 3.05 0.1025 B 40.75 1 40.75 32.46 < 0.0001 C 22.39 1 22.39 17.83 0.0009 D 35.33 1 35.33 28.14 0.0001 残差 17.58 14 1.26 失拟误差 17.58 10 1.76 纯误差 0.000 4 0.000 表 6 随机生成的样本点
序号 D1/mm L/mm D2/mm K/(℃A) 1 80.82 162.79 46.50 -18.74 2 87.63 121.36 49.00 -9.57 3 72.25 124.05 53.23 -22.52 4 66.82 152.88 40.64 -21.83 5 76.87 174.11 51.68 -10.18 6 80.14 144.47 47.22 -21.29 7 69.55 166.89 48.76 -17.19 8 74.08 179.05 50.82 -13.37 9 86.55 108.70 42.10 -9.35 10 68.16 145.24 52.88 -18.67 11 61.27 121.31 45.22 -8.32 12 81.09 144.62 50.78 -9.94 表 7 优化后的参数及目标与优化前的对比
参数及目标 数值 变化率 原机值 优化值 D1 80 mm 63.9 mm 20.1% L 120 mm 110.3 mm 8.1% D2 40 mm 53.8 mm 34.5% K -16.5 ℃A -6.8 ℃A 58.7% T 10.35% 2.17% 79% -
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