Exploring advanced additive chemistry for achieving fuel economy in passenger car motor oils

Original Equipment Manufacturers (OEM’s) are focusing towards fuel economy of passenger cars to meet the next generation emission norms. Few techniques such as downsizing of engines, raising lubricant temperature, reducing combustion time and regulating the start-stop system of engines are various efforts being considered by Automobile OEMs to attain fuel efficiency along with next generation emission norms. On the other hand, lubricants used for such engines are also to be modified accordingly to meet more fuel efficiency. Lowering viscosity along with addition of friction modifiers for normalizing frictional losses is widely practiced as the most economical techniques. To achieve this lubricant formulator and additive manufacturers have moved towards modern base oils and advanced additive technologies. This study is done to understand key parameters which reduce friction and increase fuel economy using same viscosity grade oils. In the current study, we have formulated different low viscosity engine oils of SAE grade 0W-16 using advanced base oils and novel additive systems. We have evaluated the formulations on various parameters including physico-chemical and performance techniques such as High Temperature High Shear Viscosity (HTHS), High Frequency Reciprocating Rig test (HFRR), SRV, Friction Torque Test (FTT) to understand synergism among these properties. We observed a strong correlation between kinematic viscosity at 40 0C, HTHS data especially at 80 0C and friction reduction from this study. Key words: Fuel economy; Low viscosity engine oils; High Temperature High Shear Viscosity; Friction behavior