The failure of valve affects the engine performance and as a result importance is given to the failure analysis of internal combustion engine valves. The valve may fail by valve face recession, wear failure, fatigue failure, thermal fatigue, erosion / corrosion of valves, overheating of valves and carbon deposits on valves. Mostly valves fail due to high pressure and temperature. This paper presents a failure analysis of diesel engine exhaust valve used in a passenger car. The analyzed exhaust valve failed after a very short period of usage of the car. To determine the cause of failure stress analysis is carried out by finite element method which shows the highly stressed region on the valve. A proper CAD model is developed by using CATIA software and saved in 'iges' format. It is then imported into ANSYS 14 software which gives the von mises stress, strain and deformation. The stress analysis shows that maximum stress is developed near the head of valve when piston crashed to the valve and material analysis shows that the strength of valve decreases due to decarburization of material and as a result the valve was bent.
A WEAR MODEL FOR DIESEL ENGINE EXHAUST VALVES
