Numerical Simulation And Optimized Research On Intake And Exhaust System Of 490 Diesel Engine Based On GT-Power

The diesel engine has been through a development of about one hundred years since 1892, and now it is widely used in vehicles, engineering mechanics and ships. Due to the working process of a diesel engine which is firstly inhaling the fresh air, then leting the diesel and the air mix and burn adequately to create energy, finally exhausting the high temperature waste gas, the design of the intake and exhaust system is directly essential to the performance of the engine. Along with the higher update rate and requirements of the diesel engine products, conventional design method can hardly meet the needs of the development of modern diesel engine. Applying the new design method based on computational simulation technology can not only evaluate the design object rapidly, but also decrease large amount of repeated testing work, lower the cost and shorten the development period. Hence, the method of using computers to do numerical simulation and optimization design has been a new mainstream design method of developing a diesel engine.This article aiming at the Quan Chai 490 diesel engine, has built up an engine test bench platform for experiments under different operating conditions and the related performance parameters are measured. According to the theory of one-dimensonal unsteady flow, a numerical simulation model is established in the GT-Power software. Through the comparison between the simulation data and the test data under same steady operating conditions, the validity of the simulation model is proved.Based on this model, the 3D models of the intake and exhaust system are discretized to modify several structure parameters including the length of the intake pipe, volume of the resonant cavity, length and diameter of the intake manifold, length and diameter of the exhaust manifold and the different layout for the intake and exhaust system, then the influence to engine performance as power, torque, fuel consumption, intake air flow rate, exhaust pressure and exhaust temperature is studied and analyzed.Taking each structure parameters as the factors and the engine performance as the responses, a DOE(Design of Experiment) method is applied and a quadratic response surface was fit. Targeting maximum power and torque, minimum fuel consumption as the optimization object, the genetic algorithm was applied for multi-objective optimization. The contrast of the performance between original and optimized parameters shows that the power and the torque are improved, the fuel consumption is decreased.With the optimized structure parameters, the new 3D models of the intake and exhaust system are built. According to the fluid simulation analysis in the Fluent software, some optimization opinions of the 3D structure are proposed and the final shape and 3D model of the intake and exhaust system is obtained.