Additives for minimizing intake valve deposits, and their use

摘要

Mannich product composition is formed from: (i) one mole part of at least one hydroxyaromatic compound having on the ring an aliphatic hydrocarbyl substituent derived from a polyolefin with number average molecular wt. of 500-3000; (ii) 0.8-1.5 mole pts. of at least aliphatic polyamine with one prim. or sec. amino group; and (iii) 0.8-1.3 mole pts. of at least one aldehyde, the mole ratio of aldehyde:amine being 1.2 or less. A fuel additive composition comprises : (a) the above Mannich product composition as dispersant/detergent; and (b) at least one liquid carrier for (a) to give 0.3-2 pts. wt. liquid carrier per 1 pt. (a). A fuel composition for use in spark ignited internal combustion engines contains the above fuel additive composition in an amount sufficient to reduce or minimise the wt. of intake valve deposits in the engine.