A method for identifying a lubricant composition that reduces the propensity for knock in an engine. The lubricant composition is mixed with a solvent to reduce the viscosity of the lubricant composition, thereby forming a lubricant-solvent mixture having a viscosity similar to or less than that of engine fuel. A sample of a lubricant-solvent mixture is then subjected to a constant volume combustion test to determine the reactivity associated with the lubricant-solvent mixture. The test is repeated for a range of lubricant-solvent ratios, and statistical methods are used to calculate the reactivity of the lubricant composition without solvent.
Manfred Amann; Terrence F. Alger II