TRIBOLOGICAL PROFILE OF ENⅥRONMENTALLY ACCEPTABLE LUBRICANTS FOR PASSENGER CAR SHOCK ABSORBERS

摘要

Due to restrictions, such as European regulation EC/1907/2006 (REACH), substances for environmentally friendly and biodegradable lubricants getting more in focus of passenger car OEM's and suppliers R&D activities. Ecotox-properties are now mandatory in the U.S. Vessel General Permit. Goal of the present investigation is to characterize the tribological performance of different shock absorber fluids, including those as environmentally acceptable lubricants (EAL) declared. Therefore, six lubricants differing in their base oil were tested under laboratory conditions, in bench tests and finally in vehicle tests. The oils tested are composed of Group Ⅰ- and Group Ⅲ-mineral base fluids and two synthetic Group Ⅴ base stocks (one classified as readily biodegradable EAL), formulated with standard additives for shock absorbers. Friction properties under oscillating sliding conditions and Stribeck-curves were determined besides damping force in real applications. Subjective car evaluation on public roads gave good conclusions how the oil and its tribological properties can influence the driving characteristics.