Evaluation of the biodiesel fuels lubricity using vibration signals and multiresolution analysis

The vibration is an important feature associated with metallic contact during operation of the injection system of diesel engines, also its analysis constitutes a tool to evaluate the lubricity indirectly. In this sense, this work uses multiresolution analysis to characterize vibration signals, improving lubricity evaluation. The experimental setup consisted of the lubricity analysis of different fuels using HFRR equipment where friction coefficient was monitored during the test as well as vibration signals. After that, Discrete Wavelet Transform generated time-scale representation of the vibration signals. This analysis provides complementary information about lubrication, in real time, and it can be associated with wear scar diameter (WSD). The results demonstrated the feasibility of this approach to evaluate fuels lubricity in a dynamic way.