Use of additives with detergent action for further increasing the cetane number of fuel oils

A fuel additive concentrate consisting of:

• (C1) 5 to 45% by weight of at least one additive with detergent action selected from the group consisting of:
• (i) a compound with moieties derived from succinic anhydride and comprising at least one selected from the group consisting of a hydroxy group, an amino group, an amide group, and an imido group;
• (ii) a nitrogen compound quaternized in an acid-free manner, wherein the nitrogen compound is obtained by a process comprising:
• adding a compound comprising an oxygen or a nitrogen-comprising group reactive with an anhydride and additionally a quaternizable amino group into a polycarboxylic anhydride compound, and
• subsequently quaternizing the compound,
• thereby obtaining the nitrogen compound;
• (iii) polytetrahydrobenzoxazine and bistetrahydrobenzoxazine;
• (C2) 20 to 90% by weight of at least one cetane number improver;
• (C3) 5 to 35% by weight of at least one organic diluent or solvent selected from the group consisting of an aromatic hydrocarbon, an aliphatic hydrocarbon and an alcohol;
• (C4) 0 to 10% by weight of one or more customary co-additives selected from the group consisting of:
• (iv) a corrosion inhibitor, wherein the corrosion inhibitor is not a mixture of (A) aliphatic saturated or unsaturated monocarboxylic acids comprising 12 to 24 carbon atoms or dimerization or trimerization products thereof, which optionally are free carboxylic acids, ammonium salts, amides, esters, or nitriles, and (B) polycyclic hydrocarbon compounds, which are obtained by a process comprising:
• distilling residues of natural oils extracted from tree resins;
• (v) a demulifier;
• (vi) a dehazer;
• (vii) an antifoam;
• (viii) an antioxidant and a stabilizer
• (ix) a metal deactivator;
• (x) an antistat;
• (xi) a lubricity improver;
• and
• (xii) a dye and a marker.