Intake System Design And Flow Field Characteristics Optimization Analysis Of FSCC Racing Engine

According to the rules of the FSCC racing,a flow-limiting valve does not exceed 20mm in diameter should installed between throttle and air inlet for every present university engine.As suction device for engine,intake system parameters directly affect the charging efficiency of the engine,air intake resistance and intake uniformity,which affect the dynamic,economic and emission characteristics of engine.Therefore,the intake system plays a key role in the development of the engine.This paper analyzes and optimizes the flow field characteristics of the intake system of FSCC CBR600 engine,for the following problems,low air flow rate,large intake flow loss,low torque and power of the engine under the condition of medium and high speed.Firstly,the research and development status of numerical simulation for engine aspirating system is briefly introduced,and the dynamic effect and energy loss of the gas flow in the intake system are analyzed.GT-Power is used to set up the model of engine and intake-exhaust system,and the correctness of the experimental data is verified.The influence of change of Inlet manifold length and diffuser outlet diameter on engine power and torque was analyzed through simulation,and the inlet manifold length and diffuser outlet diameter are determined to be 130mm and 50mm respectively.The influence of the volume change of the pressure stabilizing cavity on the power and torque of engine is analyzed and compared.The volume of the pressure stabilizing cavity is selected as 3.0L.Secondly,the basic knowledge of fluid mechanics is analyzed.CATIA is used to establish a 3D model of the intake system.The flow limiting valve of the intake system is analyzed by using Fluent,a 3D fluid simulation software.The optimal angles of inlet cone Angle and outlet diffusion cone Angle are determined to be 16~0?6~0.Finally,the intake system is analyzed as a whole,determine the form of intake according to the analysis results.Lastly,Using a one-dimensional GT-Power software to cycle simulate the working process of the internal combustion engine to determine the basic parameters of three-dimensional Fluent simulation required.Accuracy of parameters from one dimensional simulation is verified by three dimensional simulation.The optimization and the design goal of the intake system is realized.In the presence of limiting valve,the dynamic performance of engine is largely improved.This research has provides a theoretical basis for FSCC racing intake system design.