1D/3D Coupling Simulation Of Intake And Exhaust System For Multiple Cylinder Diesel

The intake and exhaust system is an important components of diesel engine,whose structure affect the volume efficiency,quality of gas exchange process and waste gas from cylinders.The pressure waves in the exhaust manifold of turbocharged engine also have an important influence on exhaust energy using and the effect of the supercharger,and affect the power performance,fuel economy and emission performance of the whole engine.Compared to experimental methods,the CFD simulation has many advantages on the difficulty,cost and experimental time.In this paper,an one-dimensional and three-dimensional coupling calculating method by GT-Power and Fluent software is used to study the intake and exhaust system in real conditions.The one-dimensional computational simulation model of standard propeller characteristics diesel of TBD620V12 engine in speed range is built by GT-Power software.The model is verified with experimental data.The structural parameters of intake and exhaust system are optimized by using the model.By changing a parameter at a time,we studied the influence of the structure parameters,such as length and diameter,of the intake and exhaust system on power,effective fuel consumption rate and the maximum explosion pressure.But just the performance of engine in low speed is improved by optimizing the structure.Then we optimized the opening time and angle of intake and exhaust valves of engine in high speed by changing a parameter at a time.After that,to optimize timing phase,we select the cam timing angle of intake and exhaust valves as experimental factors,apply multi-objective optimization DOE to improve the power and reduce fuel consumption rate.As the result,performance of engine in middle and high speed are improved.We established the three-dimensional structure of exhaust manifold by Pro/Engineer,divided the grid using Hypermesh software,GT-Power provide inlet mass flow of exhaust manifold in one-dimensional and three-dimensional coupling calculating model at 1800r/min when simulated.The results are more reality and provided a basis for the exhaust manifold design and optimization,and laid a foundation for further study.