Assessing Efficiency Benefits of Low Viscosity Gasoline Engine Oils 2021-28-0014

In line with Global targets of reducing CO₂ Emissions, transportation industry is witnessing a significant shift in focus — from emissions to fuel economy — by regulators, researchers, OEMs, fuels and lubricant manufactures. Improvements in fuel economy can have a significant bottom-line impact for fleets and owner operators alike. There are many paths to take when looking at a program to reduce fuel consumption. These include new engine and transmission designs, new metallurgies, surface finish, coatings, new injection technologies, turbochargers and of course through engine and transmission lubricants. Passenger car engine lubricants are being upgraded time to time and customized for fuel economy and emission compliance benefits as the vehicle technology evolved to meet the emerging regulations. New vehicle technology has shifted surface tribology more towards boundary regime as new designs are compact, offer high operating temperatures and pressures. Fuel Economy (FE) Regulations also require lower viscosity for reducing hydrodynamic friction. Thus, engine oil at reduced viscosity has to face tough challenges of hardware durability by maintaining the right film thickness and better anti wear protection through it’s ingredients, which are base oils and performance additives. Friction Modifiers are key additives in automotive lubricants to take care of boundary friction through adsorption at tribo surface under mild load conditions and plays extremely important role now a days to achieve the required FE targets of original engine manufacturers.

Engine oils can play a major role in improving the FE. Nowadays, Frictional torque test is widely used for assessing the frictional performance of engine oils and thereby for optimizing the composition of engine oils for its better fuel economy.

There is also a requirement of compatible engine oils for after treatment devices used in new generation engines and this again requires new Low SAPS additive chemistry. Therefore, new generation engine oils for mobility sector has to strike the right balance of base oils and additive components to ensure not only sufficient engine protection, but also to maintain the overall performance & fuel economy requirements besides taking care of latest after treatment systems. Key challenge is to deliver fuel economy along with hardware durability, which requires balanced approach at tribo level by selecting the right screening methodology, high quality base oils, and superior additives chemistries. Friction Torque Test and MIDC Test on Chassis Dyno were carried out on selected candidate oils. Up to 3% efficiency improvement was achieved in SAE 0W-16 grade meeting API SN credentials under MIDC Test Cycle run on Bharat Stage VI passenger car with gasoline engine. This paper presents an effort made by IndianOil R&D in the direction of achieving fuel economy through low viscosity engine lubricants.