Effect of Diethylene Glycol Dimethyl Ether–Diesel Blends on Tribological Characteristics of Base Oils

In this study, tribological characteristics of diethylene glycol dimethyl ether (DGM)/diethylene glycol dimethyl ether–diesel blend A (10 vol% DGM + 90 vol% diesel)/diesel were compared after being subjected to quill roller-ball friction and four-ball friction tests. The lubricity and antiwear property of blend A were worse than those of diesel, albeit considerably better than those of DGM. In addition, effects of diesel and blend A on the tribological characteristics of synthetic base oils were examined by using a four-ball friction machine and the fuzzy analytic hierarchy process: trimellitate TM128/TM320A, alkyl naphthalene AN5, and polyalphaolefin PAO6/mPAO65 exhibited good tribological characteristics, and 5 wt% blend A mixed with base oil maintained good tribological characteristics stability. Analysis results revealed that the excellent tribological characteristics of trimellitate, alkyl naphthalene, and polyalphaolefin are related to the rigid molecules of benzene rings and l