The Effect on Friction of Engine Oil Seal Using Low Viscosity Engine Oil for Fuel Economy Improvement

Low viscosity engine oil can improve the fuel economy by lessening the friction between the engine components that relatively moves in action. Frictional torque variation values with the velocity change on different viscosity characteristic of SAE grade as 5W20, 5W30 and 5W40 were measured in order to get an outline for the effect of low viscosity engine oil seal frictional characteristic to improve fuel economy. Engine oil seal frictional torque has increased in proportional to the shaft rotational speed for all three engine oil grades. Engine oil seal frictional torque decrease due to the usage of low viscosity engine oil was confirmed. Also, the leak free performance of the engine oil with the seal was satisfying the criteria for the life limit durability test. Thus, low viscosity engine oil usage to improve the fuel economy not only decrease the frictional loss of the engine oil seal, but also have no defect in the performance of the leak free function.