LUBRICATING OIL COMPOSITIONS

摘要

The present invention generally relates to a method for reducing intake valve deposits in a Direct Injection Spark Ignition engine, the method comprising operating the engine with a lubricating oil composition comprising: (a) a major amount of an oil of lubricating viscosity; and (b) at least one foam inhibitor selected from the group consisting of silicon oils, polysiloxanes, polyacrylates, and polymethacrylates; wherein the foam inhibitor is not poly (phenyl-methyl) siloxane; and further wherein the amount of said foam inhibitor in said lubricating oil composition is at an effective concentration to achieve at least 10% reduction in intake valve deposits in said Direct Injection Spark Ignition engine compared to operating the engine with said lubricating oil composition without any foam inhibitor.