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The properties sought in a multi-layer steel cylinder head gasket include cylinder pressure sealing and fatigue strength in order for there to be no damage while the engine is in operation. Diesel engines, in particular, have high cylinder pressure and a high axial tension by the cylinder head bolt demanding severe environment to the gaskets. As engine performance is enhanced, there are cases when cracks develop in the gasket plate, necessitating countermeasures. The cause of cracking in a flat center plate, in particular, has not yet been explained, and no method for evaluation had previously existed. Three-dimensional non-linear finite element calculation was therefore performed to verify the cause. First, a static pressurization rig test was used and the amount of strain was measured to confirm the validity of the calculations. Then the same method of calculation was used to verify the distribution of strain, with a focus on the plate position.

The independent bearing cap is a cylinder block bearing structure that has high mass reduction effects. In general, this structure has low fastening stiffness compared to the rudder block structure. Furthermore, when using combination of different materials small sliding occurs at the mating surface, and fretting fatigue sometimes occurs at lower area than the material strength limit. Fretting fatigue was previously predicted using CAE, but there were issues with establishing a correlation with the actual engine under complex conditions, and the judgment criteria were not clear, so accurate prediction was a challenge. This paper reports on a new CAE-based prediction method to predict the fretting damage occurring on the bearing cap mating surface in an aluminum material cylinder block. First of all, condition a fretting fatigue test was performed with test pieces, and identification of CAE was performed for the strain and sliding amount.