In recent years, in association with the increase of the development of higher turbocharged diesel engines for commercial vehicles, the requirements for the gas sealing ability of cylinder head gaskets have been getting more severe.
This paper introduces the requirements of the optimum design of a cylinder head gasket having the structure that minimizes: 1)the amplitude of motion between a cylinder head and a block and 2)the contact pressure fluctuation of the cylinder head gasket. Both of these are caused by the internal pressure change in the bore of the running engine.
In order to examine the relationship of the structure of the various sealing areas with the amplitude of motion and the contact pressure change in cylinder head gaskets, the amplitude between the head and block and the contact pressure changes were empirically observed at three different locations. These were in the vicinity of: 1)the periphery of gas sealing areas, 2)the head bolt openings and 3)the periphery of the gasket bodies.
It was found that for the optimum design which minimizes the effects of the internal pressure changes in the bore, it was necessary not only to put sufficient sealing pressure on the gas sealing armors but also to provide adequate contact pressure in the vicinity of their peripheries.