Patent ID: 8048834

Claim:
A lubricated surface of a device containing an exhaust catalyst for an engine, the surface comprising a lubricant composition including a base oil of lubricating viscosity, at least one ash-free phosphorus compound, at least one zinc dialkyl dithiophosphate (ZDDP) compound derived from methyl-isobutyl carbinol (MIBC), and an amount of at least one hydrocarbon soluble titanium compound that is effective to provide an aged catalyst temperature that converts at least fifty percent of exhaust gas hydrocarbons, carbon monoxide, and NOx that is lower than an aged catalyst temperature that converts at least fifty percent of exhaust gas hydrocarbons, carbon monoxide, and NOx of the lubricant composition devoid of the hydrocarbon soluble titanium compound, wherein a weight ratio on a phosphorus basis of the ZDDP compound to the ash-free phosphorus compound ranges from about 3:1 to about 1:3.