Investigation On Cylinder Liner Bore Distortion Of Diesel Engine Based On FEM

With the modern engines designed to operate at higher engine speeds with lowerweight and higher power density, the cylinder liner, one of the pivotal parts of engine,works with higher thermal effects, combustion pressure and mechanical loads, withthe cylinder liner distortion which cannot be avoided. In the proceeding of engineoperating, the clearance between cylinder liner and piston rings, and the sealedbetween cylinder liner and cylinder head will be affected by the cylinder linerdistortion directly, which will cause the oil consumption, the blow-by, the wearbehavior and the fuel consumption. In order to achieve future requirements regardingexhaust emissions and fuel consumptions, the research of cylinder liner distortionproblem is essential, and plays a significant role.It is limited to studycylinder liner distortion bytheory analysis or experiment dueto the complicacy of this problem. By the development of CAE technology, thethree-dimensional simulation become more mature, and using Finite Element Methodto calculate cylinder liner distortion become feasible. Taking the advantage of CAEtechnology, this paper will study cylinder liner distortion under the function ofclamping loads and coupled thermal-stress.To discuss reasonable loading method of clamping loads, the article builds thethin wall barrel (TWB) model, and the bolt-block model, by the reference of 4100QBmodel. The result shows that it is logical to simulate preloads by establishing contactpairs, and the calculating accuracyis acceptable.By setting up different preloads, material property, length of bolts and location ofthe first whorl, this paper study cylinder liner distortion of TWB model, focuses onthe rule of distortion, and analyze influence factor. The consequence indicates that thecylinder liner under the clamping loads performs fourth-order distortion with higherdistortion on upper part and lower distortion on underside; clamping loads which willcause larger distortion with higher loads value are the major reason of forth-orderdistortion; the stiffness of cylinder liner and gasket have influence on the distortion,which means the lower stiffness generates lager distortion; owing to the long boltdistributing loads average, it can effect distortion and the lower location of the first whorl will reduce the distortion.Using the consequence above, this paper analyses the temperature distributionafter building 4100QB solid model and finite element model, to study cylinder linerdistortion under the function of clamping loads and coupled thermal-stress. The resultshows that the distortion under coupled is far larger than it under clamping loads, andthe cylinder liner performs second-order distortion.