Effect of Fuel and Lubricant on Engine Vibration

Vibration problems in internal combustion engines produce premature wear on the internal components of the engine, which contributes both to reduce the lifespan of the engine itself as well as cause discomfort to the occupants of the vehicle. Thus, since it is impossible to totally eliminate vibrations from engines, it is important to understand the sources of vibration production and control them to acceptable levels. The general objective of this paper is to measure the vibration in the areas that undergo greater efforts due to the processes of combustion and mechanical forces. These areas are the fixed bearings located to the extremes of the crankshaft. The specified objective of this study is to correlate these levels of crankshaft engine vibration relative to the fuel used, ethanol and gasoline, and assess the influence of lubricant oils on the vibration levels as a function of the viscosity of the lubricant. The results demonstrated that the vibration intensity of the engine increases with increasing engine speed and load. In all operating conditions, the ethanol-run engine has higher vibration intensities than the gasoline-run engine. For the same type of fuel, an oil of higher viscosity attenuates the level of vibration of the engine. Measurements show an average increase of 18% of transverse vibration and 12% of longitudinal vibration in the crankshaft of the engine running on ethanol in relation to gasoline with low viscosity lubricant and 14% and 10% with higher viscosity lubricant.