优化凸轮轴及进气歧管设计改善发动机性能

Design Optimization of the Camshaft and Intake Manifold for the Engine Performance Improvement

为改善某小型汽油发动机的中低速性能,通过优化凸轮轴凸轮工作段及缓冲段的型线设计,提高进气凸轮轴的运动学和动力学性能;优化进气歧管的形状,增加进气歧管的长度,改善了进气歧管的气流特性。优化后的进气歧管的稳态流量均优于原机,最大增加7.5%。经过台架试验验证,优化后的发动机扭矩在中低转速范围内均优于原机,最大扭矩提升12.4%;优化后的发动机燃油消耗率在全转速范围内均优于原机,最大燃油消耗率下降16.4%。

To improve one engine＇s performance in low and medium speed, the cain＇s profiles were opti- mized including operation area and cushion area. A better performance in kinematics and dynamics was gained, and the shape of the intake manifold was optimized, the length of the intake manifold increased, thus the airflow character was improved. The steady-state flow performance of intake manifold was im- proved, the max rise rate is 7.5%. Via the dyno test, the optimized engine has a better torque in low and medium speed compared to the original engine, the max torque rises by 12.4%; the specific fuel consump- tion of engine is superior to the original engine, and the max specific fuel consumption decreased by16.4%.