Abstract: Compounds with general formula ##STR1## where R.sup.1 represents a hydrogen atom or a hydrocarbon group containing 1 to 40 carbon atoms. R.sup.2 represents a hydrogen atom or a hydrocarbon group containing 1 to 12 carbon atoms, A, B, and C, which may be identical or different, each represent a divalent hydrocarbon group containing 2 to 6 carbon atoms, n is a whole number from 5 to 50, m and p are each zero or a whole number from 1 to 25, and the sum n+m+p is a whole number from 5 to 50.These compounds are used in multifunctional additive compositions for fuels used in internal combustion engines, in particular spark ignition engines, in admixture with at least one compound selected from the group formed by detergent-dispersant compounds, and at least one compound selected from the group formed by mineral or synthetic lubricating oils and polyglycols which are soluble in said fuels.

Abstract: Additive formulation for engine fuels incorporating at least one constituent (A) and at least one constituent (B), constituent(A) consisting of at least one composition incorporating products resulting from the reaction of at least one dicarboxylic compound(D), whose carboxylic functions are separated by at the most eight carbon atoms, with at least one polyoxyalkylene glycol or glycol mono-ether (E) of general formula (I):R.sup.1 --O--(R.sup.2 --O).sub.n --H,in which R.sup.1 represents a hydrocarbon group having 1 to 30 carbon atoms, R.sup.2 represents a divalent hydrocarbon group having 2 to 6 carbon atoms and n is a number from 1 to 60; and constituent (B) consisting of at least one detergent-dispersant product. This formulation preferably also comprises a constituent (C) chosen from within the group formed by mineral or synthetic lubricating oils and polyglycols soluble in the fuel.

Abstract: An additive composition for fuels comprising at least one constituent (A) and at least one constituent (B), the said constituent (A) comprising at least one multinitrogen-containing compound of general formula (I): ##STR1## where R.sup.1 and R.sup.2, which are the same or different each represent a hydrocarbon group or a group of formula R.sup.5 --(--O--R.sup.6 --).sub.a --(--O--R.sup.7 --).sub.b --, R.sup.3 is a hydrocarbon group or a group of formula R.sup.8 --(--X--R.sup.9 --).sub.c --(--X--R.sup.1 O--).sub.d --(--X--R.sup.1 1--).sub.e -- in which X is selected from the groups --O-- and --NR.sup.1 2--, R.sup.5, R.sup.6, R.sup.7, R.sup.8, R.sup.9, R.sup.1 0 and R.sup.1 1 each represent a hydrocarbon group, a, d and e are each zero or a whole number, b and c are each a whole number, R.sup.4 and R.sup.1 2 each represent a hydrogen atom or a hydrocarbon group and n is a number from 0 to 20 and the said constituent (B) comprises at least one polyglycol which is soluble in the fuel in question.

Abstract: Polynitrogen compound having two terminal cycles of the imide type, its preparation by conventional organic chemistry methods and its use as an additive for engine fuel. This compound complies with the general formula (I): ##STR1## in which R.sup.1, R.sup.2, R.sup.3, and R.sup.4 are as set forth in the specification.

Abstract: The cetane numbers of directly distilled diesel fuels are significantly improved by intimately contacting same with an effective amount of hydrogen peroxide in the presence of a carboxylic acid, or with an effective amount of a percarboxylic acid either in the presence or absence of hydrogen peroxide.

Abstract: The cetane numbers of viscoreduced diesel fuels are significantly improved by intimately contacting same with an effective amount of hydrogen peroxide in the presence of a carboxylic acid, or with an effective amount of a percarboxylic acid either in the presence or absence of hydrogen peroxide; the final product diesel fuels are also effectively deodorized and decolorized.

Abstract: Formulations of additives for engine fuels comprising at least one constituent (A) and one constituent (B) resulting from the reaction of at least one alkenyl or polyalkenyl-succinic derivative with at least one polyamine to form constituent (A) and with at least one 1-(2-hydroethyl) imidazoline substituted in the 2-position by a linear or branched alkyl or alkenyl radical with 1 to 25 atoms of carbon to form constituent (B). The preferred formulations also contain a constituent (C) consisting of at least one polyglycol soluble in said fuel, with an average molecular mass ranging from 480 to 2,100. The (A)/(B) and (A)+(B)/(C) molar ratios preferably are respectively 0.2/1 to 5/1 and 0.05/1 and 20/1.