Finite Element Reliability Analysis of a Ceramic Exhaust Port Liner Subjected to Thermomechanical Interactions During Casting

Recent advanced heat engine development has led to the use of a ceramic port liner casted into the aluminum cylinder head as a thermal insulation between aluminum and exhaust gas to reduce the weight of the engine and improve its performance. This study evaluates the high transient tensile stresses generated in the port liner due to thermal shock during casting and the compressive shrinkage stresses during cool-down by finite element simulation. The survivability of the liner under thermal shock was assessed by a statistical failure criterion and the results showed that both cordierite and aluminum titanate survive. Shrinkage stress analyses indicated that the shrinkage stresses in the aluminum titanate were less than its compressive strength except at the sharp edge around the valve guide hole while the shrinkage stresses in the cordierite were greater than its compressive strength in most of the region.