Cylinder Head Bolt Tightening Strategies in Case of Multi-Cylinder Engines and Its Effect on Gasket Sealing Performance, Bore Deformation and Piston Ring Conformability

Abstract

ABSTRACT The cylinder head gasket (CHG) joint is the most critical sealing joint for IC engine performance. Cylinder head bolt preload application should be stoichiometric. Excess cylinder head bolt pre-tension develops more stress and further leads to bore deformation. Insufficient cylinder head bolt pre-tension leads to gasket leakage. It is challenging to achieve uniform pressure distribution because of variation in stiffness of block and head. But the minimum pressure must be ensured for leak-proof joint. In this article, gasket pressure distribution around the cylinder bore is estimated by non-linear Finite Element Analysis (FEA) and compared with Fuji Film results. Bore deformations, due to spiral and cross patterns, are determined and compared. Piston ring conformability is estimated in terms of percentage sealing of the ring to the liner. Effects of bolt tightening strategies are investigated for engine gasket sealing parameter, bore deformation and piston ring conformability.