A method of removing deposits from a diesel engine, the method comprising combusting in the engine a diesel fuel composition comprising an engine cleaning additive, wherein the engine cleaning additive is the product of a Mannich reaction between: (a) an aldehyde; (b) ammonia, hydrazine or an amine; and (c) an optionally substituted phenol; wherein the or each substituent of the phenol component (c) has an average molecular weight of less than 400.
一种清除柴油发动机沉积物的方法,该方法包括在发动机中燃烧含有发动机清洁添加剂的柴油燃料组合物,其中发动机清洁添加剂是以下物质曼尼希反应的产物:(a) 醛;(b)
氨、
肼或胺;和 (c) 任选取代的
苯酚;其中
苯酚组分 (c) 或每个取代基的平均分子量小于 400。