Fuel Economy Lubricants in Manual and Dual-Clutch Transmissions

摘要

The viscosity temperature characteristic of the lubricant has a great impact on the gearbox drag torque, especially at low temperatures and in the partial load range. Fuel Economy (FE) lubricants consist of a very low-viscosity base oil component and a viscosity index (VI) improver. The VI improver helps to reduce the viscosity decrease with increasing oil temperature. Due to the reduced base oil viscosity shear and splash losses in a gearbox are reduced especially in the range of low operating temperatures which occur especially at start-up and under partial load conditions. These no-load losses are a significant portion of the overall losses of a passenger car transmission. Theoretical and experimental investigations on lubricants for use in manual transmission (MT) systems and dual-clutch transmission (DCT) systems for passenger car applications are carried out. The focus of the investigations is on the effect of FE lubricants on both gear box efficiency and gear load carrying capacity.