Simulation On The Optimization Of Performance And Turbocharged Match For An Aviation Piston Engine

Since the first half of the last century since the advent of the important role of UAV system has attracted increasing attention around the world.Based on the needs of the implementation of the task,unmanned aerial vehicles require its power system should have long life,low fuel consumption,and high thrust-weight ratio characteristics.Co MPared with other power plant,the two-stroke engine has the advantages of a co MPact structure,low fuel consumption,low failure rate,and light weight,therefore,two-stroke engine has become the main power source.of low-altitude UAV.Because the scavenging process of two-stroke engine will have a significant i MPact on engine performance,the need for its ventilation process for in-depth study and reasonable optimization.At the same time,in order to adapt to the UAV needs a long time in the high altitude environment of the actual flight conditions,the need to use the two-stroke engine corresponding boost matching to ensure stable engine power output.In this paper,an aviation piston engine with a variable exhaust strategy was chosen as the research object,and the engine performance test platform was built up.The engine speed characteristic curve and the cylinder pressure curve of cruise engine were obtained.The effect of variable exhaust on engine performance was analyzed.And the combustion process and the cycle variation of the cruise engine are analyzed.The results show that the change of the state of the exhaust valve will affect the performance of the engine obviously.The variable exhaust strategy of the original engine has the optimized space.In the prototype model for the study established direct injection aviation piston engine performance simulation model by GT-Power software;.The effect of the state of the exhaust valve on the performance of the engine was simulated and analyzed by using the established model.The reason of the engine exhaust pressure fluctuation is clarified.Based on the research of the ventilating process of different exhaust valves,the reasons of the variable exhaust strategy affecting the engine performance are clarified,and the optimization direction of control strategy of the external characteristics and the exhaust valve in the cruise control condition are given.Based on the simulation model of the original engine performance,the performance simulation model of the two-stroke turbocharged engine was established based on the requirement of the full recovery of the critical altitude.The effect of exhaust gas turbine arrangement on the process of engine exhaust was analyzed by using simulation model,and the law of outgassing of turbocharged engine at different altitudes was studied.Through the study of the geometric parameters of the exhaust system,the length of the exhaust pipe is determined as the main factor affecting the performance of the two-stroke supercharged engine,and the performance of the two-stroke turbocharged engine was optimized through the design of the exhaust system geometry.