Patent ID: 8129320

Claim:
A process for providing a reduced reactivity lubricant for reducing engine knock in an internal combustion engine cylinder comprising: providing a base stock oil having an IQT[Cetane Number] (−100%)(Base Stock oil) ; said base stock oil formulated for use as a lubricant for an internal combustion engine utilizing a selected fuel having a fuel cetane number wherein IQT[Cetane Number] (−100%)(Basestock Oil) ≦Fuel Cetane Number; and wherein said fuel cetane number is an extrapolated fuel cetane number and is provided by an ignition quality tester (IQT) where the fuel is injected into a constant volume combustion chamber along with a solvent having a viscosity of less than or equal to 1.0 cP at 25° C. and the ignition delay is determined as the time difference between the start of injection and the start of combustion for different concentrations of solvent to provide cetane numbers, wherein said fuel cetane number is determined by linear curve fitting of a plot of said cetane numbers versus concentration of said low viscosity solvent excluding the 100% solvent condition.