The lubricant industry is emphasizing the use of low-viscosity lubricants to increase fuel economy. Fuel mileage increases as high as 8% are claimed when conventional engine and driveline lubricants are replaced with new-generation products. Low viscosity lubricants, however, must contain more robust anti-wear and extreme pressure additives to counteract their reduced λ ratio. Consequently, switching to lower viscosity lubricants in order to gain fuel economy entails risk. Should the additive package fail to perform, engine, transmission, and drivetrain components will be seriously damaged. It seems appropriate then, to attempt to increase the λ ratio for low viscosity lubricants. This, of course, can be done by reducing surface roughness. Superfinishing the surface using chemically accelerated vibratory finishing is a practical and well proven approach for accomplishing this. This paper will present data from both laboratory and field testing demonstrating that superfinished components exhibit lower friction, operating temperature, wear and/or higher horsepower, all of which translate directly into increased fuel economy.
ORNL-GM: Development of Ionic Liquid-Additized, GF-5/6 Compatible Low-Viscosity Oils for Automotive Engine and Rear Axle Lubrication for 4% Improved Fuel Economy