Abstract: A fuel oil composition comprises a fuel oil in a major amount, which fuel oil has a mass % against n-alkane carbon number distribution curve characterised by: (i) a maximum negative gradient from carbon number 18 to carbon number 26 that is less than ?0.30; and (ii) a ratio of the mass of n-alkanes of carbon number greater than 22 to the mass of n-alkanes from carbon number 18 to carbon number 21 that does not exceed 0.

Abstract: This invention relates to fuel oil, especially middle distillate fuel oil, compositions comprising middle distillate fuel oil and incorporated therein an incorporated therein an additive composition comprising (a) at least one fuel-soluble or fuel-dispersible neutral alkaline earth metal compound and/or at least one fuel-soluble or fuel-dispersible neutral alkali metal compound, and (b) at least one fuel-soluble or fuel-dispersible transition metal compound, characterized in that the fuel oil composition contains at most 0.05 mass % of sulfur, the total metal content derived from (a) and (b) in the fuel oil composition is at most 50 ppm by mass, and the mass proportion of (a) to (b), based on metal content, is in the range of from 1:99 to 99:1.

Abstract: An additive composition for a fuel oil composition and that is free of polycyclic carboxylic acids and of acid derivatives thereof comprises an additive that comprises one or more monocarboxylic acids, each having from 10 to 24 carbon atoms, or acid derivatives thereof, optionally in combination with one or both of an anti-oxidant additive and an anti-static additive.

Abstract: An additive composition for a fuel oil composition and that is free of polycyclic carboxylic acids and of acid derivatives thereof comprises an additive that comprises one or more monocarboxylic acids, each having from 10 to 24 carbon atoms, or acid derivatives thereof, optionally in combination with one or both of an anti-oxidant additive and an anti-static additive.

Abstract: Oils having improved lubricity and low temperature properties and additives for use therein.

Abstract: The lubricity of low sulfur content middle distillate fuel oil boiling over a temperature range of 100°C. to 500°C. is enhanced by incorporation of a heavy fuel component having hydrocarbon components resulting from distillation of a crude oil, whereby the incorporation of the heavy fuel component increases at least one of (a) the 50% distillation temperature, and (b) the polynuclear aromatic content of the composition, and wherein the composition gives a wear scar diameter, as measured by the HFRR test at 60°C., of at most 500 &mgr;m.