Stress Analysis and Fatigue Life Determination of Engine Valves

In this work, an FEM based methodology was adopted to determine the stresses developed in engine valves and determining their fatigue life. The design specifications to improve the valve performance to meet endurance, reliability and emission norms requirement are very vital. The Fatigue failure of valves is one of the most severe problems which are of real concern due to the above changes in engine design. In the current analysis, FEM was used to calculate the thermal and mechanical stresses that act on the valve during its operation.

A stress based approach was adopted to estimate the fatigue life of the valves using FE-Fatigue. The material properties considered were based on peak engine firing pressure, temperatures and loads. Both theoretical and software results correlated very well with each other at the end of the analysis. It was also found out that the life of the engine valves is quite stable till temperatures of about 650∼680°C for this selected material and application. Once these temperatures are exceeded, the fatigue life drops drastically.