某三缸发动机性能分析与优化

Three Cylinder Engine Performance Analysis and Optimization

某三缸发动机原设计为增程器用发动机,现将该款发动机改为传统汽车用发动机,主要是通过对发动机燃烧室、气道、进排气歧管进行重新设计,提高发动机的功率和扭矩,样机试验后,发动机的油耗比较理想,但是最大功率和扭矩没有达到设定目标。通过GT power软件搭建发动机模型,并联合modefrontier优化软件对进气歧管结构、进气凸轮型线、配气相位进行优化,最终获得两个方案:功率最大化和扭矩最大化方案。功率最大化方案的最大功率为55.25kW/5250rpm,扭矩106N·m/4250rpm;扭矩最大化方案的最大功率为50kW/5250rpm,108.1N·m/3500rpm,优化结果达到预期目标。

A three cylinder engine was originally designed for Extended range device,now the change of design is implemented for traditional automobile engine.Main change is structure of engine combustion chamber,intake port and intake manifold,exhaust port and exhaust manifold.The power and torque of Engine can be increased by this change.After the test of prototype,the BSFC is ideal,but the goal of maximum power and torque is not arrived.In the paper,engine GT power model is built,and unites with mode frontier to optimize the structure of intake manifold,intake cam profile,valve timing,at last two solutions is gained：maximization of power and maximization of torque.The result of first solution is that max power 55.25kW/5250 rpm,max torque 106N·m/4250rpm;the result of second solution is that max power 50kW/5250 rpm,max torque 108.1N·m/3500 rpm.The result of Optimization has reached the expected aim.