Monitoring of Lubricating Condition between Piston Ring and Cylinder Liner by Electro-Conductivity Method

In the case of large-size marine diesel engines, it is advantageous to measure lubricating condition between piston rings and cylinder liner to prevent scuffing and abnormal wear. The authors have developed the oil film condition monitoring system using electro-conductivity sensor on cylinder liner running surface. This sensor could recognize the condition of oil film formation easily. It was found that when the sensors were attached in 10% stroke area from top dead center, where the lubricating condition is severe, the difference of lubricating condition could be evaluated well. The lubricating condition between piston rings and cylinder liner was strongly influenced by the change of running surface roughness, bot by the change of oil feed ratio in the range of 0.8∼1.5g/PS·hr.