Analysis of Cylinder Head Bolt Cross Pattern Tightening and Its Effect on Gasket Sealing Performance and Bore Deformation

Abstract

Cylinder head gasketed joint is one of the most important sealing joints in an I.C Engine. It directly affects the engine performance. Gaskets are very crucial components in providing sealing of combustion chamber to prevent escape of combustion gases and leakage of coolant and oil. Also they prevent the cross flow of the fluids between the various passages in the engine. But to ensure this, it is necessary to have adequate pressure distribution in the various sealing regions of the gasket i.e., at the various cavities or openings in the head and block deck interface of the engine. Apart from providing sealing action, it also affects engine piston ring conformability in cylinder bore, engine blow-by and lubricant oil consumption. Thus careful design of the gasket is very crucial, in order to provide just the optimum loading at the various sealing regions. During assembly of gasketed joint, there is a relaxation of the gasket when the bolts are tightened successively, this leads to reduction of gasket pressure which causes leakages. In order to assess the variation in gasket sealing pressure, non-linear 3-D FEM technique is employed to model a contact problem to find the contact pressure distribution at the various sealing regions of the gasket. Then the results obtained will be validated against the Fuji-Film experimental Analysis.