Modelling the impact of reducing lubricant viscosity on a conventional passenger car fuel economy and wear protection
Javier Blanco-Rodríguez, Xavier Simón-Montero, Martí Cortada-García, Santiago Maroto, Jacobo Porteiro
Abstract
This study explores how reducing lubricant viscosity affects fuel economy in passenger cars through experimental characterization and semi-predictive modelling. Thus, three engine oils (0W-20, 5W-30, and 5W-40) were tested for their rheological and tribological properties. Data were introduced into a detailed GT-Suite model of a turbocharged gasoline SUV. Simulations over six different driving cycles, including European homologation and real-driving conditions, used a fast-running model (FRM) to assess engine friction and wear protection. Results showed that lower viscosity oils, especially 0W-20, significantly reduced frictional losses, enhancing fuel economy. However, lower viscosity also increased contact friction under high power demand, raising durability concerns. A comprehensive evaluation of lubricants performance, offering insights into the trade-offs between fuel economy improvements and potential durability risks. • Simulation offers advantages for lubricants assessment in real driving scenarios. • The study focuses on fuel economy and wear protection. • A multiphysics simulation model is developed to account full vehicle. • Commercial passenger car lubricants are detailed characterize. • Evaluation results guide lubricant selection for more efficient performance.