A method of reducing the incidence of deposits on the pistons of a 4-stroke marine diesel engine during operation of the engine when it is fuelled with a marine residual fuel meeting the ISO 8217 2017 fuel standard for marine residual fuels and having a sulphur content of more than 0.1% and less than 0.5% by mass. The method includes the step of lubricating the engine using a lubricating oil composition comprising: a) at least 50% by mass, based on the mass of the composition, of an oil of lubricating viscosity; (b) 5 to 25% by mass, based on the mass of the composition, of an oil-soluble or oil-dispersible alkali metal or alkaline earth metal salicylate detergent, or a mixture of two or more oil-soluble or oil-dispersible alkali metal or alkaline earth metal salicylate detergents; (c) 0.1 to 10% by mass, based on the mass of the composition of one or more oil-soluble or oil-dispersible ashless dispersants; and optionally, (d) 0.1 to 10% by mass, based on the mass of the composition of a polyalkylene-substituted succinic anhydride.

The present disclosure relates to a method of reducing regeneration frequency of a diesel particulate filter in a vehicle combusting diesel fuel. The method includes combusting a diesel fuel in a vehicle engine having a diesel particulate filter and wherein the diesel particulate filter requires regeneration thereof. The diesel fuel has less than about 50 ppmw of sulfur and one or more select additives to reduce a measured frequency of regeneration of the diesel particulate filter.

The use of tetrahydrobenzoxazines I ##STR00001##
where R.sup.1 is a hydrocarbyl radical and R.sup.2, R.sup.3, R.sup.4 and R.sup.5 are each independently hydrogen atoms, hydroxyl groups or hydrocarbyl radicals, and where R.sup.2 to R.sup.5 may also form a second and a third tetrahydrooxazine ring, with the proviso that at least one of the substituents has from 4 to 3000 carbon atoms and the remaining substituents, when they are hydrocarbyl radicals, each have from 1 to 20 carbon atoms, as stabilizers for stabilizing inanimate organic material, especially turbine fuels, against the action of light, oxygen and heat.

A diesel fuel lubricant as a replacement for sulfur lubrication in Ultra-Low and Low Sulfur Diesel fuels, the process for producing said lubricant, and the method of using said lubricant. This lubricant comprises alpha-olefins; low odor aromatic solvents; and at least one a base oil selected from the base oil group consisting of hydroisomerized high base oils and HT Severe Hydro-cracked Base Oils; as well as other ingredients. Also disclosed is a method for producing this lubricant.

A composition for scavenging hydrogen sulphide and/or mercaptans in hydrocarbon streams includes a H2S scavenger selected from oxazolidine compounds, triazine and metal-based carboxylate compounds, and a synergistic additive allowing boosting the effect of the H2S scavenger compound.

The present technology is related to imide containing quaternary ammonium salts having a hydrocarbyl substituent of number average molecular weight less 300, and additive packages having such quaternary ammonium salts and improved stability.

New, highly effective substantially pure Mannich detergents for use in hydrocarbon fuels reduce engine deposits in spark and compression ignition internal combustion engines. The Mannich condensation reaction products are obtainable by reacting: (i) a polyamine having primary amino groups, (ii) a hydrocarbyl-substituted hydroxyaromatic compound, and (iii) an aldehyde, wherein the reaction is conducted at in a molar ratio of (i):(ii):(iii) of approximately 1:2:3. The Mannich detergent compounds may be dispersed in a liquid carrier to provide a fuel additive concentrate for hydrocarbon engine fuels which effectively control engine deposit formation in intake valves, port fuel injectors and combustion chambers.

A composition of fuel additives includes at least a first additive having a partial ester derivative of polyols and a second additive having a quaternary ammonium salt. The first additive includes at least 50% by mass of a compound A selected from the partial esters of polyols and saturated or unsaturated, linear or branched, cyclic or acyclic C.sub.4 to C.sub.36 monocarboxylic aliphatic hydrocarbarbons, the partial esters being able to be used alone or in a mixture. The disclosure also relates to a diesel fuel including such a composition and the use of the fuel for limiting the deposits in a diesel engine. In particular, the disclosure relates to the use of the fuel containing the composition of additives of the present disclosure in direct-injection diesel engines.

Haze may be removed from a biofuel or biofuel intermediate by using a clarifier. The clarifier includes copolymer prepared using a formulation comprising an alpha olefin and maleic anhydride. The clarifier may also be used with admixtures of biofuels, biofuel intermediates, or biofuel feedstocks with conventional hydrocarbons.

A quaternary ammonium salt of formula wherein each of R.sup.1, R.sup.2, R.sup.3 and R.sup.4 is independently selected from an optionally substituted alkyl, alkenyl or aryl group having less than 8 carbon atoms and R.sup.5 is hydrogen or an optionally substituted hydrocarbyl group.

##STR00001##