Piston and Ring Assembly Friction Studies in Cummins 903 Engine.

摘要

Piston and ring assembly friction has been measured in a single cylinder Cummins 903 diesel. The engine was motored and fired, cooled and uncooled. For uncooled operation, plasma sprayed chromium oxide ring and liner coatings were employed with a synthetic lubricant. The Instantaneous IMEP and Fixed Sleeve methods were used for the friction measurement on a crank angle by a crank angle basis, with a cycle average of about 1.5 to 4 psi fmep. Considerable effort was expended in developing the measurement techniques, with a major effort on the Instantaneous IMEP method. In a parallel effort a bench type, heated, piston ring and liner wear simulator was developed. This permitted rapid screening of promising candidate materials for uncooled engine tests. The plasma sprayed chromium oxide coatings were found to be best.