Variable Air Intake System Research Of FSC Racing Engine

The engine has different requirements on the gas motion in different conditions. When the engine runs at a low speed, air and fuel is fully mixed, while in high speed operation, fresh refrigerants need to enter the cylinder quickly. Air intake system of single type of structure cannot meet the requirements of the engine air intake. The variable intake system by changing the inlet structure to achieve the intake in different ways. Enter the cylinder charge size and form of exercise varies with engine operating conditions and that can improve the engine power. The study has the theory significance and the practical significance. This paper takes the Honda CBR600 engine as the research object. Combined with the simulation and test, the intake manifold two-step variable intake system is designed. The main research contents are as follows:According to the original structure parameters of the engine, through using the GT-Power software to establish the one dimensional simulation model of the engine. Take the intake manifold length as a variable, in order to improve the engine power as the goal to calculate and analysis. Then under different variable manifold length to obtain the engine volumetric efficiency, power and torque curve with different speed. Through comparing the curve to determine the two-step variable manifold length optimal parameters and the speed switching point.Based on the one-dimensional simulation of the structural parameters and the arrangement of the whole car demand, design the variable intake system by using CATIA three-dimensional model and through using FLUENT 3D flow calculation software to analysis the flow field characteristic of the intake model and the limiting valve model. Study on the change of current limiting valve entrance angle and outlet cone angle of the influence of gas flow rate and the gas velocity, turbulence intensity, pressure distribution of the inlet system models. Through the analysis of the flow field, to determine the flow limiting valve import and export cone angle parameters and verify the rationality of the design of two-step variable intake system.Build engine test bench and complete the fuel injection pulse width and ignition advance angle calibration. To obtain fuel injection MAP map and ignition MAP map. Process the test data and then draw the engine output power and output torque curve before and after switching to a different length of intake manifold. The correctness of the simulation results is verified through the experiment.