Research On Parametric Design Method Of Intake Manifold Based On Flow Uniformity

The intake manifold is one of the important components of the engine intake system.The structure of the intake manifold has an important influence on the intake uniformity and resistance,which affects the power,economy and emissions of the engine.Therefore,the good structure of the intake manifold is indispensable for a good engine.The design process of the traditional intake manifold mainly relies on the steady flow experiments and personnel experience,but the cost of this method is relatively high,and it takes a lot of time.With the development of computer technology,more and more CAE software has been applied in the development of automobiles.This paper uses one-dimensional and threedimensional simulation software to design and analyze the intake manifold for 2.0L four-cylinder in-line four-stroke naturally-aspirated gasoline engine.Firstly,use the GT-Power one-dimensional simulation software to establish the target engine model.The establishment of the one-dimensional model is mainly divided into three major parts,namely the intake system,the cylinder and crankcase,the exhaust system.After verifying the simulation results of the one-dimensional model,the influence of branch pipe length,diameter,resonator volume,and external pipe length,diameter on engine performance were investigated by using the inflation efficiency,torque,and power as evaluation indicators at each engine speed and determine the values on the basis of the requirements of engine.Secondly,a three-dimensional model of the intake manifold is built based on the main structural parameters determined by one-dimensional simulation.Fluent software was used to simulate the distribution of pressure and velocity vectors in the intake manifold,and the outlet flow rates and uniformity is observed and discussed.It is found that there is a large local resistance in the internal flow field,which exists at the intersection of the branch pipe and the resonator,and the minimum curvature radius of the branch pipe.And the non-uniformity of intake air is high.Therefore,it is decided to improve the structure at the intersection of the external pipe and the resonator,the resonator,the junction of the branch pipe and the resonator,and the minimum curvature radius of the branch pipe.Based on the original model,the connecting mode of the external pipe and the resonator,the structure of the resonator,and the round radius at the connection between the branch pipe and the resonator is increased,and the minimum curvature radius of the branch pipe is also increased.The improved intake manifold is analyzed through CFD simulation and it is found that the local resistance has been significantly reduced,and the non-uniformity of the intake air has been reduced to reach the design criteria.Take this as the final design plan.In this thesis,the general parametric design method of the intake manifold is explored in the process of designing for target engine,which provide reference for the design.