| The impact of the financial crisis which is decreased gradually on China’s automarket and a series of policies adopted by the government to encourage thedevelopment of the automobile industry from2009made Chinese automobile andengine industry develop quickly. And along with increasingly stringent emissionsregulations, the research and development of the engine becomes critical. So thispaper is written on base of the positive development process of automobile dieselengine, and CAE finite element analysis tools are used to predict the deformation ofthe engine block and its impact on emissions.First, establish a CAD model which is similar to the actual work environmentthrough retain important engine structure the engine body, cylinder head, water jacket,oil core, however, peripheral attachments of the body cylinder head will be deleted,and the cylinder head bolt and the gasket will be simplified appropriately. But itsbasic characteristics will be still maintained, especially the gasket. Because sealing ofthe engine is mainly affected by the gasket.Secondly, a finite element model was established. The model was discrete andthe boundary conditions were imposed to the model in this process.Thirdly, finite element analysis, and evaluation of results, which is the coresection of this article, accurate simulation process of the actual engine operatingconditions during the analysis can generate accurate simulation results closest to theactual engine situation, which will provide strong evidence for the preliminary designof the engine. So the method of this article is the thermosetting coupling joint finiteelement analysis. Not only bolt preload, the outbreak of the pressure and othermechanical loads is loaded, but also the water jacket cooling field and the cylindercombustion thermal stress field are taken into account, so we can get comprehensiveand accurate analysis results. The main work of this paper is: cylinder bore distortionanalysis in the cylinder head bolt preload, cylinder bore deformation analysis basedon coupling field, heat transfer analysis, body strength and fatigue analysis, gasketsealing analysis, the results show that the analysis indicators meet the designrequirements. Analysis results are the minimum principal stress is556Mpa, minimumsafety factor of the body is1.13, minimum safety factor of the water jacket is1.18, crock mouth wave minimum surface pressure is71.58Mpa, oil、water bar minimumline load is123.2N/mm, crock mouth wave maximum swing is13.6μ m, which arenormal. On the other hand, the article discussed the influence of gasket compressioncharacteristics to the body cylinder bore deformation; analysis results showed that thegasket affects the body deformation greatly, in particular, the deformation of thecylinder bore and tightness.In addition to, in order to predict the cylinder bore deformation of vehicle dieselengine in the positive development process and engine optimization process moreaccurately, step-by-step coupled numerical analysis based on three-dimensionalnonlinear finite element contact model was made, and the cylinder deformationevaluation parameter named the influence coefficient of channeling gas andnamed cylinder safety coefficient were put forward in the method named the fastFourier transform (FFT) based on the coupling analysis results. The application ofthese parameters can predict cylinder bore deformation、oil consumption rate andcylinder safety more accurately, which will guide the positive development workmore accurately.Finally, workbench test results show that torque、power、fuel consumption isnormal, channeling gas and cylinder score is not happened in the test, which show theprediction of the thermal-solid indirect coupling FEA is right. |
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