Use of amines and/or Mannich adducts in fuel and lubricant compositions for direct-injection spark ignition engines

A process for reducing deposits in a direct-injection gasoline engine, comprising:

• directly injecting a fuel into a combustion chamber of the direct injection gasoline engine through a nozzle disposed in the combustion chamber;
• wherein the fuel comprises a Mannich reaction mixture of (i) an reaction product of a phenol of formula HOC6(H4.m)(R9)m and a polyisobutene of formula HR8, (ii) an aldehyde of formula CHR10O and (iii) a secondary amine of formula HNR1R2,
• wherein R9 is a C1-C6-alkyl group and m is a number from 0 to (4-n),
• R8 is a polyisobutene radical which is derived from a reactive polyisobutene polymer having at least 50 mol % of terminal double bonds based on the total number of polyisobutene macromolecules, and
• R10 is H or C1-C6-alkyl,
• R1 and R2 are each independently H, C1-C20-alkyl or C3-C2-cycloalkyl, and two alkyl radicals together with the nitrogen atom to which they are bonded may form a ring and the alkyl and the cycloalkyl radicals may be interrupted by one or more groups selected from O and NR4 and/or may be substituted by one or more OR5 or NR6R7 groups, where R4, R5, R6 and R7 are each independently H, C1-C20-alkyl or C3-C20-cycloalkyl,
• R4, R5, R6 and R7 are each independently H, C1-C20-alkyl or C3-C20-cycloalkyl, wherein the Mannich reaction mixture comprises at least one Mannich adduct of the formula I
• wherein n is a number from 1 to 3, with the proviso that the sum of the molecular weights of the radicals R1 and R2 is from 120 to 1,000 g/mol.