Archive | 2019
Evolution of wear rate, friction and roughness depending on lubrication regime
Abstract
New engine strategies, such as frequent start-stop operation and increasingly severe loading conditions due to efforts to optimize engine performance and efficiency, lengthen the time the bearings spend in mixed or even boundary lubrication regimes. To investigate how the lubrication regime affects bearing bush wear, a series of tests were performed at distinct positions on the Stribeck curve, representing, as closely as possible, the boundary, mixed and hydrodynamic lubrication regimes. Both friction and wear were measured throughout the test, while the evolution of surface roughness was determined for the boundary condition in a series of shorter tests. The absolute amount of wear, as well as the running-in time needed to reach steady-state behaviour, depends strongly on the preset lubrication regimes with the running-in time showing a similar trend for friction and wear. The running-in time for the surface roughness is considerably shorter than for either friction or wear.