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: A diesel fuel composition containing metallic additives that are stabilized against phase separation. The diesel fuel contains a colloidally dispersed or solubilized metal catalyst compound, which can be used for diesel particulate trap regeneration and, as a stabilizer, 5-1,000 ppm (weight) of an oil-soluble or oil-dispersible organic compound having a lipophilic hydrocarbyl chain having attached directly thereto at least two contiguous polar head functional groups, i.e., the functional groups are separated by no more than three carbon atoms. The diesel fuel composition is particularly suitable for use with diesel engines fitted with a particulate trap for emissions control.

Abstract: A fuel oil composition is disclosed. The fuel oil includes a major proportion of a fuel oil and minor amounts of: (a) at least one polar nitrogen compound effective as a wax anti-settling additive; and (b) at least one reaction product between a hydrocarbyl-substituted succinic acid or anhydride and hydrazine.

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: A method of substantially removing, or reducing the occurrence of, injector deposits in a diesel engine operated using a diesel fuel containing a minor amount of a metal-containing species is disclosed. The method includes adding to a diesel fuel the reaction product between a hydrocarbyl-substituted succinic acid or anhydride and hydrazine. The diesel engine is equipped with fuel injectors having a plurality of spray-holes, each spray-hole having an inlet and an outlet, and the fuel injectors have one or more of the following characteristics: (i) spray-holes which are tapered such that the inlet diameter of the spray-holes is greater than the outlet diameter; (ii) spray-holes having an outlet diameter of 0.10 mm or less; (iii) spray-holes where an inner edge of the inlet is rounded; (iv) 6 or more spray-holes; (v) an operating tip temperature in excess of 250° C.

Abstract: A fuel additive composition comprising a solution or dispersion of an oil soluble metal carboxylate or metal complex derived from a compound of the formula: where R1, R2, R3 and R4 represent hydrogen or a hydrocarbyl having 1-30 carbon atoms (C1-C30), but at least two of R1, R2, R3 or R4 are C1-C30 hydrocarbyl; R5 is a hydrocarbyl having 1 to 120 carbon atoms and m and n may each be zero or an integer such that the total number of carbon atoms in the carboxylate is not more than 125.

Abstract: A method of improving the low temperature properties of a fuel oil and minor amounts of (a) at least one polar nitrogen compound effective and (b) at least one polyamine detergent is disclosed. The method involves adding to the composition (c) at least one acidic organic species.

Abstract: A fuel oil composition is disclosed. The fuel oil includes a major proportion of a fuel oil and minor amounts of: (a) at least one polar nitrogen compound effective as a max anti-settling additive; and (b) at least one reaction product between a hydrocarbayl-substituted succinic acid or anhydride and hydrazine.

Abstract: A method of substantially removing, or reducing the occurrence of, injector deposits in a diesel engine operated using a diesel fuel containing a minor amount of a metal-containing species is disclosed. The method comprises adding to the diesel fuel a salt formed by the reaction of a carboxylic acid with di-n-butylamine or tri-n-butylamine, wherein the diesel engine is equipped with fuel injectors having a plurality of spray-holes, each spray-hole having an inlet and an outlet, and wherein the fuel injectors have one or more of the following characteristics: (i) spray-holes which are tapered such that the inlet diameter of the spray-holes is eater than the outlet diameter; (ii) spray-holes having an outlet diameter of 0.10 mm or less; (iii) spray-holes where an inner edge of the inlet is rounded; (iv) 6 or more spray-holes; (v) an operating tip temperature in excess of 250° C.

Abstract: A method of substantially removing, or reducing the occurrence of, injector deposits in a diesel engine operated using a diesel fuel containing a minor amount of a metal-containing species is disclosed. The method includes adding to a diesel fuel the reaction product between a hydrocarbyl-substituted succinic acid or anhydride and hydrazine. The diesel engine is equipped with fuel injectors having a plurality of spray-holes, each spray-hole having an inlet and an outlet, and the fuel injectors have one or more of the following characteristics; (i) spray-holes which are tapered such that the inlet diameter of the spray-holes is greater than the outlet diameter; (ii) spray-holes having an outlet diameter of 0.10 mm or less; (iii) spray-holes where an inner edge of the inlet is rounded; (iv) 6 or more spray-holes; (v) an operating tip temperature in excess of 250° C.

Abstract: A diesel fuel composition made up of a major amount of a diesel fuel, a minor amount of at least one metallic species and a minor amount of a detergent additive is disclosed.

Abstract: A fuel additive iron salt composition effective in improving the operation of diesel engine particulate traps when added to a diesel fuel so as to provide 1-25 ppm iron in the fuel which comprises an oil soluble or oil dispersible neutral or overbased iron salt of an acidic organic compound, 50-99 mole % of the total iron present in the composition being in the ferric form, the balance being the ferrous form.

Abstract: An additive concentrate comprises a lubricity enhancer dissolved in a solvent. The lubricity enhancer comprises from 10 to 90% by weight of the concentrate and is a salt formed by the reaction of a carboxylic acid with di-n-butylamine or tri-n-butylamine. The concentrates have excellent low temperature stability.

Abstract: A method of reducing piston deposits, smoke or wear in a diesel engine. The method involves the step of running the engine on fuel comprising an oil soluble iron carboxylate or iron complex that includes Fe3+.

Abstract: A salt formed by the reaction of a carboxylic acid with a hydrocarbyl derivative of pyridine. The salts are effective lubricity enhancers when added to low sulphur content fuels and are soluble at low temperatures.

Abstract: A fuels additive metallic salt composition effective in improving the operation of diesel engine particulate traps when added to a diesel fuel so as to provide 1-25 ppm metal in the fuel which comprises an oil soluble or oil dispersible overbased metal salt of an acidic organic compound, said salt composition containing 5-85 wt. % of a stoichiometric excess of metal over that required to neutralize the anionic portion of the salt, the metal being selected from the group consisting of Ca, Fe, Mg, Sr, Na, Ti, Zr, Mn, Zn and Ce.

Abstract: A diesel fuel composition which improves the performance of diesel engine particulate exhaust traps comprising a diesel fuel containing a combination of 1-25 ppm of metal in the form of a metal salt additive and 100 to 500 ppm of an oil soluble nitrogen containing ashless detergent additive.

Abstract: An additive composition comprises at least one colloidal metal compound or metallic species and a stabilising component, wherein the stabilising component comprises the product obtainable by the condensation reaction between: (i) at least one aldehyde or ketone or reactive equivalent thereof, and (ii) at least one compound comprising one or more aromatic moieties bearing at least one hydroxyl group and at least one further substituent chosen from a hydrocarbyl group, —COOR1 or COR1, wherein R1 represents hydrogen or a hydrocarbyl group. The composition may further include at least one lubricity enhancer. Compositions of the invention tend to resist haziness, cloudiness and phase separation at relatively low and relatively high temperatures, and in the presence of lubricity enhancers and fatty acid methyl esters (FAME).

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, characterised 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: A diesel fuel composition containing metallic additives that are stabilised against phase separation. The diesel fuel contains a colloidally dispersed or solubilised metal catalyst compound, which can be used for diesel particulate trap regeneration and, as a stabiliser, 5-1,000 ppm (weight) of an oil-soluble or oil-dispersible organic compound having a lipophilic hydrocarbyl chain having attached directly thereto at least two contiguous polar head functional groups, i.e., the functional groups are separated by no more than three carbon atoms. The diesel fuel composition is particularly suitable for use with diesel engines fitted with a particulate trap for emissions control.