Abstract: The use as a valve deposit controlling additive in a fuel composition for a direct injection spark-ignition internal combustion engine of a combination of: a) at least one hydrocarbyl-substituted aromatic compound; and b) at least one polyalkylene amine.

Abstract: The use as a sludge controlling additive in a fuel composition for a spark-ignition internal combustion engine or a compression-ignition gasoline internal combustion engine of a combination of: a. a hydrocarbyl-substituted aromatic compound; and b. a polyalkylene amine. The fuel composition may also be used for maintaining oil pathways and/or lubrication in an engine.

Abstract: The use as a piston varnish controlling additive in a fuel composition for a spark-ignition internal combustion engine or a compression-ignition gasoline internal combustion engine of a combination of: a. a hydrocarbyl-substituted aromatic compound; and b. a polyalkylene amine. The fuel composition may also be used for controlling power output, fuel economy, engine wear, piston ring sticking and blow-by.

Abstract: The use as an intake valve deposit clean-up additive in a fuel composition for a port fuel injection spark-ignition internal combustion engine or a fuel injector deposit clean-up additive in a fuel composition for a direct injection spark-ignition internal combustion engine of a combination of: a. at least one hydrocarbyl-substituted aromatic compound; and b. at least one polyalkylene amine.

Abstract: The use as a valve deposit controlling additive in a fuel composition for a direct injection spark-ignition internal combustion engine of a combination of: a) at least one hydrocarbyl-substituted aromatic compound; and b) at least one polyalkylene amine.

Abstract: The invention provides a fuel oil composition comprising a major proportion of liquid hydrocarbon middle distillate fuel oil having a sulphur concentration of at most 0.05% by weight, and a minor proportion of a dispersant additive obtained by reacting, in a molar ratio A:B in the range 4:3 to 1:10, (A) a polyalkenyl derivative of monoethylenically unsaturated C4-C10 dicarboxylic acid material in which the number average molecular weight (Mn) of the polyalkenyl chain is in the range from 850 to 1150 with (B) a polyamine of general formula H2N(CH2)m—[NH(CH2)m]n—NH2  (1) where m is in the range from 2 to 4 and n is in the range from 1 to 6; a process for the preparation of such a fuel composition, and a method of operation a compression-ignition engine with enhance injector cleanliness using such a fuel oil composition.

Abstract: The use of a detergent-containing fuel additive in a diesel fuel composition, for the purpose of reducing engine power loss and/or reversing a previously incurred power loss, and optionally also for reducing smoke and/or particulate emissions. Also provided is a method for assessing the performance of a candidate diesel fuel composition based on its ability to reduce or reverse power loss, and a diesel fuel composition containing a detergent at an active matter concentration of between 100 and 500 ppmw.

Abstract: The invention discloses a fuel oil composition comprising a major proportion of a liquid hydrocarbon middle distillate fuel oil, from 1 to 100 ppmw based on the composition of a polyoxyalkylene glycol dehazer and from 1 to 100 ppmw based on the composition of an organosilicone antifoam additive, wherein before mixing of the organosilicone antifoam with any other component of the fuel oil composition, the organosilicone antifoam additive is heated at a temperature of at least 40° C. for a sufficient period of time to achieve improved antifoam properties of the fuel oil composition; a process for the preparation of such a fuel oil composition; and a method of fuelling a road vehicle with such a composition.

Abstract: This invention provides alkoxy acetic acid derivatives of general formula I: ##STR1## wherein R is the residue of an amine, an aminoalcohol or a polyol linked to the or each --CHR'--CO-- moiety via an amide or ester linkage;R' is hydrogen or a C.sub.1-4 alkyl group;R.sup.1 is an optionally substituted hydrocarbyl group of 1 to 300 carbon atoms;one of R.sup.2 and R.sup.3 is independently selected from hydrogen and optionally substituted hydrocarbyl of 1 to 10 carbon atoms, the other of R.sup.2 and R.sup.3 being independently selected from optionally substituted hydrocarbyl of 1 to 10 carbon atoms;m is from 3 to 200;n is from 0 to 20, provided that m/n is at least 1; andp is from 1 to 5; a process for their preparation; and their incorporation in additive concentrates and fuel compositions for internal combustion engines.