Gas exchange process of two-stroke engine based on multi-objective optimization

The gas exchange process of two-stroke aviation piston engine directly affects the combustion effect and the performance of the engine.Taking a two-stroke aviation piston engine as an example，a simulation model was established，and multi-objective optimization based on dynamic performance，economic performance，and scavenging performance was conducted.The optimization analysis of structure parameters of scavenging ducts and exhaust ducts was also performed.In addition，the parameters of the ducts structure under different altitude operating conditions （speed of 5 600 r/min，100% throttle opening） were optimized.The conclusion showed that the optimization of the engine ducts structure using the NSGA-Ⅱ algorithm can effectively improve the engine scavenging efficiency and power （speed of 5 600 r/min），by 0.841 kW and 2.712 kW respectively，and reduce the fuel consumption by 22.08 $\mathrm{g}/(\mathrm{k}\mathrm{W}?\mathrm{h})$；in addition，under different altitude operating conditions，as the altitude increased，the length of the scavenging duct showed a trend of decrease，while the length of the exhaust duct gradually increased，and the trend changed more obviously when the altitude was greater than 1 800 m.