Abstract: In order to achieve the condition-based maintenance and improve the reliability and maintainability of the heavy vehicles,makes long-term spectrometric oil monitoring of a heavy-duty vehicle drive lubricants,according to spectrum monitoring data,builds the concentration gradient and concentration degree of relative difference two-dimensional model.A comprehensive evaluation method was used to define wear conditions using fuzzy sets theory.Results show that the model has higher accuracy and stability,provides a new theoretical basis for heavy vehicles spectrometric oil analysis and data processing.

Key words: the oil monitoring, gradient, relative degree of difference, fuzzy theory