Gasoline additives such as butyrolactam for reducing the amount of internal combustion engine intake valve deposits and combustion chamber deposits

An unleaded gasoline for reducing at least one of combustion chamber deposits and intake valve deposits, comprising:

• a major amount of an unleaded gasoline base fuel;
• and
• an effective amount of an additive having a formula selected from the group consisting of:
• 4 5
• and mixtures thereof;
• wherein n is an integer from 9 to 35 inclusive;
• e, f, and g independently are an integer from 0 to 50 inclusive, wherein at least one of e, f, and g is not 0;
• R5 and R5′ are independently selected from the group consisting of H, CH3, and CH2CH3;
• R6 is H or C1-C20 alkyl;
• and
• wherein R1, R2, R3, and R4 are independently selected from the group consisting of H, and C1-C100 alkyl, or taken together with the two carbons between R1 and R2 , or R3 and
• R4 form an aliphatic ring of 5-8 carbon atoms,
• y is an integer from 1-50 inclusive (preferably 1-35, more preferably 20-35),
• m is an integer from 2-6 inclusive, and
• R7 is C1-C25 alkyl or cycloalkyl, preferably C1-C4 linear or branched alkyl.