Development of a test method for a realistic, single parameter-dependent analysis of piston ring versus cylinder liner contacts with a rotational tribometer

A rotational tribometer as well as a corresponding test method for measuring friction and wear under pure sliding conditions were developed for the purpose of single parameter analysis of piston ring to cylinder liner contacts. Using this rotational tribometer and applying the developed test method, such analyses were carried out at a high level of precision and under close-to-engine conditions within a wide range of relevant operation parameters of internal combustion engines. In order to validate the test method, the friction and wear of a compression piston ring running against a honed cylinder liner were studied. In this paper, the influence of the test parameters ring temperature, ring load, test duration and sliding speed on the friction and wear behavior of a hard chrome-plated piston ring against a thermally sprayed, iron-based cylinder liner coating (NANOSLIDE®) was analyzed. The friction and wear study at low, medium and high combustion chamber pressures, low to high sliding speeds as well as at moderate to high ring temperatures are discussed exemplarily. The obtained wear results show very good correlation with engine durability tests.