Evaluation of the tribological behavior and application of several running-in lubricants for cylinder liner-piston ring pair of internal combustion engine

Two running-in lubricants were prepared in an attempt to prevent the cylinder liner-piston ring pair of internal combustion engine from scuffing and seizure. The antiwear and extreme pressure properties of the two lubricants were compared with that of a reference commercial counterpart on a four-ball machine, while the thermal stability of the lubricants was examined by thermogravimetric analysis and differential scanning calorimetry. The surface morphology of the cylinder liner after running-in tests was observed with scanning electron microscopy. As a result, the two lubricants show better antiwear and extreme pressure properties than the reference counterpart. They also have good thermal stability. The cylinder liner-piston ring pair made of GCr15 steel has good surface quality after running-in tests with the two lubricants.