Sealing characteristics analysis of composition of combustion chamber system considering nonlinear factors

Based on a V type highly intensified diesel engine, the combustion chamber cylinder gasket sealing characteristics finite element model was established, considering the elastic-plastic deformation characteristics of cylinder gasket, the sealing rubber super elastic characteristics and the nonlinear contact factors between the components of the combustion chambers. With the help of the nonlinear finite element solution method, the contact pressures of the cylinder gasket sealing embossed surface and rubber sealing ring were calculated to evaluate the sealing effect of the combustion chamber for the intensified engine. Mean while, the correlation between the cylinder head bolt preload force and the combustion chamber sealing characteristics was studied to define the preload preferred range of cylinder head bolts for the intensified engine. The results demonstrate that the minimum contact pressure of the cylinder gasket sealing embossed surface is decreased by 13% under thermal-mechanical coupling conditions after intensification and the combustion chamber sealing effect is reduced than that before intensification. In order to improve the combustion chamber sealing performance, the cylinder head bolt preload force should be controlled within the range of 88~92 kN, so that the combustion chamber sealing performance can reach the level before intensification.