TECHNOLOGY FOCUS - COMPUTING AND CONTROL - Preferred Method: The method (M1) involves extracting the unsaturated ester molecules of the first fuel by solvent dewaxing and/or fractional crystallization. The step of reacting epoxy-ester species involves reacting substep of epoxide ring opening by acid-catalyzed hydrolysis or direct esterification of at least some of the epoxy-ester species to form a dihydroxy ester. The method (M1) involves reacting substep of esterifying the dihydroxy ester species with an esterification species selected from carboxylic acid, acyl halide, and/or acyl anhydride.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The first and second biodiesel fuels are the same, and are selected from biodiesel 100 (B100) and at least one mixture of biodiesel and conventional petroleum diesel. The oxidizing species is selected from hydrogen peroxide, organic peroxide, and/or peroxy acid. The epoxy-ester-containing intermediate comprises a heterogeneous mixture of epoxy-ester species formed by the oxidation of a heterogeneous mixture of unsaturated ester molecules. The epoxy-ester species present in the enhanced biodiesel fuel are residual constituents in the functionalized ester composition, and are supplied as additives. The unsaturated ester molecules are selected from monounsaturated ester species and/or polyunsaturated ester species or a compound of formula (R3-CH=CH-R2-C(=O)-O-R1) (I). The functionalized ester species comprise a compound of formula (R3-CH(R5)-CH(-O-C(=O)-R4)-R2-C(=O)-O-R1) (II). The enhanced biodiesel fuel comprises (wt.%): functionalized ester species (0.1) that function as pour point depressants, and epoxy-ester species (0.1, preferably 10) that function as combustion improvers in the enhanced biodiesel fuel.R1=1-3C alkyl moieties;R2 and R3=1-10C alkyl moieties or 1-10C alkenyl moieties;R4=2-20C alkyl moieties or 2-20C alkenyl moieties;andR5=-H, hydroxyl or 2-20C ester-forming carboxylate functional moieties. EXAMPLE - No suitable example given.