四气阀大功率双燃料发动机进排气口优化设计

Optimization design of intake/exhaust port for a 4-valve heavy duty dual fuel engine

为保证船用大功率双燃料发动机气道与气缸的匹配优化,采取建模仿真方法研究了进排气道流量、涡流特性随气道流通截面面积的变化规律。利用气道实物模型的试验结果,验证并分析了气道匹配优化效果。试验表明:涡流系数随进气流通截面积的增加而减少,流量系数随气道流通截面积的增加而增加至一定值后减小。最终得到具备最佳气阀升程适应性的气道,其进气道口径88.60 mm,排气道口径80.00 mm。

To achieve an optimum match between the cylinder and the intake/exhaust port in a marine heavy-duty dual fuel engine,an air dynamics modeling and simulation approach is used to research the change rule relating to the flow coefficient and the swirl number for different intake/exhaust port circulation areas. Optimized match results are verified by experimental results of physical intake and exhaust port models. Experiments show a decrease in the swirl number with an increase in the intake flow section area. In addition,the flow coefficient increases to a maximum and then decreases with an increase in the intake flow section area. Final results show that an optimized airway port circulation area that has an inlet diameter of 88. 60 mm and exhaust duct diameter of 80. 00 mm provides excellent valve lift adaptability.