Numerical Simulation Of Intake And Exhaust Pipe System For4D24Diesel Based On1D/3D Model And Coupling

As intake and exhaust system of diesel directly determine the volume efficiency, the quality of gas exchange process and the use of exhaust pressure wave,they have an important influence on the power performance,fuel economy and emission performance,So there is very important significance to study on them.In view of experimental research on them have difficulties and we need complex devices with big cost to do it for long time, the modern technology of CFD simulation will be a good choice.With CFD,we can not only research on them in a short time and low cost,but also can get results which can not be measured or difficult to measure by experiments,especially it have great advantages in the work of optimal choice of dedign schemes.Therefore, in the paper,we use of modern technology of CFD simulations to have a relatively deep and painstaking research on the valve timing,intake and exhaust system of certain type turbocharged diesel.First of all, using the software of BOOST, computational simulation model of one-dimension for the work process of the diesel engine was created,and for the accuracy of the simulation,the model was verified by using the base experiment datas.With the validated model, we study the effects on the performances of the diesel with varies of parameters of intake and exhaust systems, the results of calculation show:the parameters of intake and exhaust pipe structure is reasonable.Secondly,we do researchs on the three dimension flow in the intake and exhaust manifold, which are the most complex and most critical parts in the intake and exhaust system.For the intake maniflod, we not only study on the characteristics of internal flow resistance and evenness of fluid homogenization at outlet in steady mode by using the software of FIRE.but also the air intake unevenness of each cylinder in t transient mode by using the cosimualtion of FIRE and BOOST,theses quantitative evaluation index from calculation show,the intake manifold can meet the needs of engineering.but there are some places needs to be modified. With the similiar CFD methods, we study on the characteristics of internal flow resistance and interferer of exhaust from different cylinder for exhaust manifold of different structure based on different scheme of layout,and compare the performances of the diesel when it match up with different exhaust manifold,the results of calculation shows that the performances of exhaust manifold1is better than exhaust manifold2.