Maximizing engine oil fuel efficiency in the same SAE grade without compromising oil consumption - An investigation into the relationship between Noack evaporation and oil consumption in state-of-the-art turbocharged gasoline engines

Improving fuel efficiency is a major goal of the automotive industry. One approach is to lower an engine oils viscosity grade raising durability concerns and requiring engine re-design. Study [6] demonstrates that higher fuel efficiency is also achieved in the same SAE grade by increasing the Noack evaporation loss and using advanced viscosity index improvers like comb polymers.

Increased Noack volatility might raise concerns of oil consumption. Evonik investigated this in a state-of-the- art engine using a test matrix including multiple Noack volatilities, SAE grades and base stocks. Additionally base oil viscosities and VII treat rate were investigated. All parameters showed no correlation with engine oil consumption. This allows to maximize fuel efficiency within the same SAE grade through optimized viscometric performance.