Abstract
Recently, deposit formation has been observed due to deterioration of the FAME (Fatty Acid Methyl Ester). FT-IR, EPMA, GPC, NMR and TEM results of the injector deposit clarified the components, structure, and mechanism of deposit formation. Radical oxidation of FAME generates carboxylic acid and polymerized FAME. Due to friction on the surface of the injector valve, carboxylic acid salts adhere to the surface of the valve, where polymerized FAME deposits adhere to form a two-layer structure. In addition, the result of bench test using B20 fuel showed that DLC coating was effective to prevent deposit adhesion to the injector.
