Investigation of exhaust valve seat insert damages of diesel locomotive heavy duty engine

The exhaust valve seat insert is an engine component located in the cylinder head of an internal combustion engine. It fulfils sealing through operating in contact with the exhaust valve. The exhaust seat insert operates at high temparature, in the presence of gases as a result of combustion and under the influence of repetitive loads coming from the valve. Damage on the exhaust seat insert causes negative effects on engine efficiency and exhaust emissions. In this study, exhaust valve seat inserts in TLM16V185 were examined. The extent of the damage was determined and wear mechanisms causing the damage were investigated. The effect of the designed angle between the valve and the seat insert was determined by finite element analysis on the seat insert. As a result of this investigation, high stress was detected in a small area on the seat insert due to the angle between valve and seat insert. Material loss and geometry change were observed. Oxidation, impact wear, abrasive wear, adhesive wear and corrosion were detected. It was concluded that the damage occured as a result of these wear mechanisms.