16. Gaskets

This chapter describes the importance of application and designing of gaskets with the main focus on cylinder head gasket which plays a very important role in engine performance. The gaskets are classified as cylinder head gasket, exhaust line gasket, intake line gaskets, and sump gaskets and cover gaskets in the order of decreasing complexity. The design philosophy of cylinder head gasket with stopper or non-stopper type for combustion gas sealing is an important decision made with the experience of the designer of the gasket and the engine. The highly non-linear load deflection characteristics is challenging. The cylinder head lift during the combustion stroke is carefully studied to avoid the potential failure by gas leakage, and coolant and oil leakage. The load balance must be arrived at by both finite element analysis as well as a number of experiments both at the bench as well as at the engine dynamometer. The oil and coolant holes have to be sealed with appropriate gasket pressures with single seal bead or by elastomeric element. The cylinder head gasket surface is treated for reducing friction. The design of exhaust flange and turbocharger gaskets are confounding because of large relative thermal expansion, mechanical vibration and loss of bolt tension. Design principle of rocker cover gasket and oil sump gaskets to seal oil from leakage is discussed. The formed-in-place gasket is cost effective and avoids severe loss of elasticity of the joints.