LUBRICANT COMPOSITIONS FOR DIRECT INJECTION ENGINES

摘要

The present invention relates to a method for reducing low speed pre-ignition events of a spark ignited direct injection internal combustion engine by supplying a lubricant composition containing an oil of lubricating viscosity and a metal overbased detergent to a sump. Metal overbased detergents can be selected from sulfonate detergents, phenate detergents and salicylate detergents, and are in particular sulfonate detergents with a metal ratio of 5 or more.